IP network management
Liisa Uosukainen - Tuomas Lilja - Lasse Metso -
Stiina Ylänen - Seppo
Ihalainen - Jouni Karvo - Ossi Taipale
ACL |
Access Control List |
ADSL |
Asymmetric Digital Subscriber Line |
AH |
Authentication Header |
API |
Application Programming Interface |
ASN.1 |
Abstract Syntax Notation One |
B-ISDN |
Broadband ISDN |
BN |
Bayesian Networks |
BOOTP |
Bootstrap Protocol |
CAC |
Connection Admission Control |
CATV |
Cable television |
CBR |
Case-Based Reasoning |
CCB |
Customer Care and Billing |
CIM |
Common Information Model |
CMIP |
Common Management Information Protocol |
CNM |
Customer Network Management |
CORBA |
Common Object Request Broker Architecture |
CoS |
Class of Service |
CPN |
Customer Premises Network |
DDR |
Dynamic Document Review |
DEN |
Directory Enabled Network |
DHCP |
Dynamic Host Configuration Protocol |
DiffServ |
Differentiated Services |
DMTF |
Distributed Management Task Force Inc |
DNS |
Domain Name Service |
ESP |
Encapsulating Security Payload |
FCAPS |
Fault, Configuration, Accounting, Performance and Security Management |
FTP |
File Transfer Protocol |
GoS |
Grade of Service |
HDSL |
High bit-rate Digital Subscriber Line |
HFC |
Hybrid Fiber-Coax |
HTML |
HyperText Markup Language |
HTTP |
Hypertext Transfer Protocol |
IAP |
Internet Access Provider |
ICMP |
Internet Control Message Protocol |
IETF |
Internet Engineering Task Force |
IKE |
Internet Key Exchange |
IN |
Intelligent Network |
IntServ |
Integrated Services |
IP |
Internet Protocol |
IPSec |
IP Security Architecture |
IS-IS |
Intra-Domain Intermediate System to Intermediate System Routing |
ISAKMP |
Internet Security Association & Key Management Protocol |
ISDN |
Integrated Services Digital Network |
ITU-T |
International Telecommunication Union -- Telecommunication standards |
ISP |
Internet Service Provider |
JMAPI |
Java Management API |
JMX |
Java Management Extensions |
MANET |
Mobile Ad-hoc Networking |
MBR |
Model-Based Reasoning |
MIB |
Management Information Base |
MPLS |
Multi-Protocol Label Switching |
MTBF |
Mean Time Between Failure |
MTTR |
Mean Time To Repair |
NAT |
Network Address Translation |
NFS |
Network File System |
NMS |
Network Management Station |
NN |
Neural Networks |
OMAP |
Operations, Maintenance and Administration Part |
OMG |
Object Management Group |
ORB |
Object Request Broker |
OSI |
Open Systems Interconnection |
OSPF |
Open Shortest Path First |
PAT |
Port Address Translation |
PBN |
Policy-Based Networking |
PCT |
Private Communication Technology |
PN |
Public Network |
POTS |
Plain Old Telephone Service |
PSTN |
Public Switched Telephone Network |
QoS |
Quality of Service |
QR |
Qualitative Reasoning |
RADIUS |
Remote Authentication Dial-In User Service |
RBR |
Rule-Based Reasoning |
RIP |
Routing Information Protocol |
RM-ODP |
Basic Reference Model for Open Distributed Processing |
RPC |
Remote Procedure Call |
RSVP |
Resource ReSerVation Protocol |
RTFM |
Real-time Traffic Flow Measurement |
S-HTTP |
Secure HTTP |
S/MIME |
Secure Multipurpose Internet Mail Extension |
SA |
Security Association |
SGML |
Standardized Generalized Markup Language |
SLA |
Service-Level Agreements |
SMFs |
Systems Management Functions |
SMI |
Structure of Management Information |
SNMP |
Simple Network Management Protocol |
SRM |
Scalable Reliable Multicast |
SS#7 |
Signalling System #7 |
SSH |
Secure Shell |
SSL |
Secure Socket Layer |
TCP |
Transport Control Protocol |
TINA |
Telecommunications Information Networking Architecture |
TMN |
Telecommunications Management Network |
TMN-MS |
TMN Management Service |
TMN-SM |
TMN Systems Management |
TOM |
Telecommunications Operations Map |
UDP |
User Datagram Protocol |
URL |
Uniform Resource Locator |
USM |
User-based Security Model |
VACM |
View-based Access Control Model |
VoD |
Video on Demand |
VPN |
Virtual Private Network |
WAP |
Wireless Application Protocol |
WWW |
World Wide Web |
XML |
eXtensible Markup Language |
XMP |
X/Open Management Protocols API |
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Networks and distributed processing systems have become critical factors in the business world. Companies and organizations develop large and complex networks with an increasing number of applications and users. The need for high capacity IP networks is growing because of the new WWW and multimedia applications, faster data transmission in mobile networks, and IP telephony. Today's routed IP networks suffer from serious problems related to scalability, manageability, reliability and cost.
Helsinki University of Technology has started IPMAN project in 1999. The target of the IPMAN project is to research and develop a network management paradigm for massive IP-networks.
Introduction of new equipment and new technologies means introduction of new information systems, which also increases the number of data repositories and fault management systems. As networks become larger and more complex, tools and applications to ease network management are critical. Automated network management is needed [92].
Time is a critical factor in network management (see figure 1.1). Managers strive for shorter cycles and customers demand faster response. Shorter cycles lead into lower costs and greater productivity [29]. Effective use of network facilities can improve a competitive position, create new market opportunities and afford efficient communications between business units and customers.
Figure:
Network management, modified [29]
 |
Network management views the computing environment as a collection of co-operating systems connected by various communication mechanisms. Sun Microsystems expresses that the network is the computer. This means that effective system management is thinking the network as a single, multilayer entity, one that requires its own care [82]. An important aspect is that management is useless to a company if it does not solve business problems and ease the work of operators [104].
A recent Gartner Group study "Strategies to Control Distributed Computing's Exploding Costs" reports that while the strategic value of systems and networks continues to increase, the escalating cost of managing that technology is undermining the organization's expected return on its investment [29].
Network management that is effective and adapts to business strategy requires:
- the right abstraction level of information,
- information at the right time, and
- information in an easy-to-use format [29].
Effective network management that adapts to business strategy contains functions, such as technology selection, network automation, capacity planning, predictive problem avoidance and sophisticated trouble-shooting. These functions all require information that goes beyond the data available to most of network management staff.
Experts forecast the changes that will happen in the next years. According to James Herman in the Sixth IFIP/IEEE International Symposium on Integrated Network Management (May 1999): "The main affect of the Internet is to enable the rise of virtual business and services. There will also be large data volumes (more customers x more interactions with customers x more data per interaction = an explosion). PC will no longer be the dominant access device, the network is the center of everything. There will be more need for mobile and wireless infrastructure. Data will find you wherever you are. When there are no connectors, it means lighter, cheaper and simpler devices."
Figure 1.2 expresses the vision of Internet development. Almost every telephone company has become involved in delivering non-telephone services to end users. Plain Old Telephone Service (POTS) is the basic telephone call service. Internet Access Provider's (IAP's) role is to ensure that the end user has a reliable connection to the Internet.
Figure:
The Internet picture [28]
 |
Most cable television (CATV) providers are interested in offering telephone and Internet services as well as video-on-demand services. The Hybrid Fiber-Coax (HFC) network is an emerging cable architecture for providing residential video, voice telephony, data, and other interactive services to end users over fiber optic and coaxial cables. The HFC network can provide the bandwidth that some multimedia applications require, using the spectrum from 5 MHz to 450 MHz for conventional downstream analog information, and the spectrum from 450 MHz to 750 MHz for digital broadcast services such as voice and video telephony, video-on-demand, and interactive television.
An alternative to a coaxial or fiber/coaxial network is offered by a
technology that can transmit relatively high-speed data over untwisted
or twisted pair cables for distances up to 4000 m. The technology can
use existing digital telephone subscriber lines. The High bit-rate
Digital Subscriber Line (HDSL) offers bi-directional transmission at
1.5 Mbps with a transmission bandwidth of 200 kHz
. Asymmetric Digital Subscriber Line (ADSL) can transmit
four one-way 1.5 Mbps video signals, in addition to a full-duplex 384
Kbps data signal, a 16 Kbps control signal, and analog telephone service. ADSL has a transmission bandwidth of 1.1 MHz.
Many end users want to access services not only in their homes, but also outside the homes. Wireless transmission enables the desired mobility among users. Because the bandwidth is shared, users are grouped into small cells. The users in each cell communicate with a single base station, and base stations are linked together by a wired network.
Mobile Ad hoc Networking (MANET) is an autonomous system of mobile nodes, where a node is both a host and a router. Mobile nodes communicate via wireless technology, and they are free to move randomly and organize themselves arbitrarily. MANET supports robust and efficient operation in mobile wireless networks by incorporating routing functionality into mobile nodes.
Satellite transmission also facilitates mobility. Because the transmission area covered by a satellite is very large, it is well suited for video and audio broadcasting [125, pages 16-20].
Chapter 2 studies models developed to classify and order network management problems. Chapter 3 describes some protocols used for network management, and chapter 4 covers some possible future trends in network management.
Professor Olli Martikainen suggested use of a reference model, where network management is divided into four levels (see figure 1.3).
Figure 1.3:
Reference model by Professor Olli Martikainen
 |
IPMAN project has developed further the reference model, and has modified its structure (see figure 1.4).
Figure 1.4:
Modified reference model
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Chapters 5 to 8 study each layer of the
modified reference model. Finally, chapter 9 gives a short
summary of commercial network management tools.
The IPMAN project is funded by TEKES, Nokia, and OES. We thank them
for their support. The help of Juha Liukko and Jaakko Akkanen in
proofreading this report is also highly appreciated.
2. Network Management Models
This chapter describes models that are used to structure the problems and ideas in network management. Section 2.1 studies the OSI network management models, and section 2.2 describes the TMN network management model. Management of customer networks is briefly addressed in section 2.3. SMART TMN, described in section 2.4, has a broader scope on network management. Finally, network management for the TINA architecture is studied in section 2.5.
1. OSI Management
The Open Systems
Interconnection (OSI) Management is documented in ITU-T
and CCITT X.700-series Recommendations [40]. It is based on four
components: Management Model, Information Model, Communication
Protocol for Transferring Management Information, and Systems
Management Functions. OSI Management functionality is divided into
five Management Functional Areas according to the OSI
FCAPS model [33].
The transfer of management information in OSI networks is provided by
Common Management Information Protocol (CMIP, see
page
) [22].
1. Management Model
The Management Model describes a manager-agent concept (figure 2.1). The manager system manages Managed Objects in distributed manner by issuing remote management requests to agent processes. The agents manage the Managed Objects and are responsible for implementing the functionality needed to execute the requests. They may also return values and send notifications (events or traps generated by Managed Objects) back to the manager [118,22,114,126].
Figure:
The manager-agent concept [23]
 |
A network to be managed can be divided into management domains. A domain is an administrative partition of a managed network or Internet. Domains may be useful for reasons of scale, security, or administrative autonomy. Domains allow the construction of both strict hierarchical and fully cooperative and distributed network management systems [126,23].
2. Information Model
The information model deals with Managed Objects that are abstractions of the real resources on the network [33]. All information relevant to network management and definitions of the objects to be managed resides in a Management Information Base (MIB). MIB is a "conceptual repository of management information", an abstract view of all the resources to be managed. All information within a system that can be referenced by management protocol is considered to be part of MIB [126].
The logical structure of MIB and the conventions for describing and uniquely identifying MIB information are defined in the Structure of Management Information (SMI). SMI is defined in terms of Abstract Syntax Notation One (ASN.1), that provides a machine-independent representation for the information [126].
Systems Management Functions (SMFs) define common facilities that can be applied to particular Managed Objects corresponding to different resources. The SMFs include mechanisms for controlling access to Managed Objects and the distribution of events, common formats for reporting alarms and status, and mechanisms for invoking and controlling remote test execution [114].
4. Management Functional Areas -- OSI FCAPS model
OSI Management functionality is divided into five management functional areas [22]:
- Fault Management encompasses fault detection, isolation and the correction of abnormal operation. It includes functions to maintain and examine error logs, accept and act upon error notifications, trace and identify faults, carry out diagnostic tests and correct faults.
- Configuration Management identifies and exercises
control over open systems. It also collects data from and provides
data to open systems. The purpose of Configuration management is to
prepare for, initialize, start, provide the continuous operation of,
and terminate interconnection services.
- Accounting Management enables charges to be established for the use of resources in OSI environment, and for costs to be identified for the use of those resources. It includes functions to inform users of costs incurred or resources consumed, to enable accounting limits to be set and tariff schedules to be associated with the use of resources and enable costs to be combined where multiple resources are used.
- Performance Management offers functions to report and evaluate the operation of network and it's elements. Statistical data is collected for the analysis and development of the network.
- Security Management includes functions to create,
delete and control security services and mechanisms, distribute
security-relevant information, and report security-relevant
events.
2. Telecommunications Management Network
A Telecommunications Management Network (TMN) provides management functions for telecommunications network and services. It also offers communications between itself and the network and it's services. It is an architecture that provides interconnection between various types of Operations Systems (OSs) and/or telecommunications equipment for the exchange of management information [39].
The top-level standards and recommendations for OSI systems management
form the basis for TMN standards [40]. The TMN standards are
defined in ITU-T M.3000-series documents [116, page 48].
Figure 2.2 shows a general relationship between a TMN and the telecommunications network it manages. TMN is conceptually a separate network that interfaces a telecommunications network at several different points to send/receive information to/from it and to control it's operations. A TMN may use parts of the telecommunications network to provide it's communications [39].
Figure:
General relationship of a TMN to a telecommunications network [116, page 25]
 |
The scope of network management is broader in telecommunications than
in data communications. Thus a TMN must provide more than just the
functionality defined in the OSI FCAPS model. TMN Management Services
(TMN-MSs) include
- customer administration,
- network provisioning management,
- workforce management,
- tariff, charging and accounting administration,
- quality of service and network performance administration,
- traffic measurement and analysis administration,
- traffic management,
- routing and digit analysis administration,
- maintenance management,
- security administration, and
- logistics management.
An overview on TMN-MSs is provided in ITU-T Recommendation
M.3200. A more detailed description can be found in ITU-T
Recommendation M.3400.
A TMN Management Service is made up of TMN Management Function Set
Groups. They are further subdivided into Management Function Sets and
eventually into Management Functions. A TMN application of any
complexity can be created by combining these elementary building
blocks. The management functions are then mapped to TMN Systems
Management (SM) services. The TMN SM services are provided by
OSI Systems Management Functions. These principles are
illustrated in
figure 2.3. Figure 2.4 shows
the mapping of OSI Management Functional Areas (MFAs) and TMN
Management Function Set Groups. The Management Function Sets and
individual Functions are defined in ITU-T Recommendation
M.3400 [116, page 48-53].
Figure:
TMN Management Services, Management Functions and Systems Management Services [116, page 50].
 |
Figure:
Mapping of OSI MFAs and TMN Management Function Set Groups [116, page 53].
 |
2. TMN Management Layers
The needed management functionality is achieved by using five layers of management, described in [116, pages 19-21]. Each layer has it's own functions and interfaces to layers above and below. The lower layers perform more specific functions and upper layers are concerned with functions more general. Each layer must interact with the layer below in order to execute it's task.
- Business management layer is responsible for management at the enterprise level. The layer is concerned with the network planning, agreement with operators, and executive-level activities such as strategic planning.
- Service management layer provides the customer interface. It's functions include service provisioning, opening and closing accounts, resolving customer complaints, fault reporting, and maintaining data on Quality of Service.
- Network management layer manages the whole network. It receives data from network element management layer and provides total-network-level views.
- Network element management layer is responsible for managing a subnetwork of the whole managed network. The interaction with network elements is provided by network element layer.
- Network element layer provides for the agent functions of the managed network elements.
TMN architecture is divided into three aspects, which can be
considered separately when designing a TMN: functional,
information and physical architecture.
- Functional
architecture describes the appropriate division and distribution of
functionality within the TMN to allow the creation of building blocks,
from which a TMN of any complexity can be implemented [39].
- Information architecture describes the nature of the information that needs to be exchanged between the building blocks, and also describes the understandings that each building block must have about the information held in other building blocks [39].
- Physical architecture describes the implementation of function blocks on physical systems and the interfaces between them [116, page 31].
3. Customer Network Management
The purpose of Customer Network Management (CNM) is to provide external users of a telecommunications network with a limited control and view of the managed network. It enables customers to manage a portion of the whole network and subscribe it's services. Figure 2.5 illustrates the CNM functional architecture [116, pages 38-42].
Figure:
CNM functional architecture [116, page 39].
 |
Customers are provided with a subset of the TMN management services, limited management information, and CNM supporting services. CNM supporting services enable customer's management system to request service provisioning and service usage from a service provider [116, pages 38-44].
4. SMART TMN
Smart TMN [113] is a program of Telemanagement Forum, a non-profit organization of dozens of product vendors and operators. The goal of SMART TMN is to present a larger scale, business process-driven model of telecommunications networks management.
The SMART TMN consists of four elements:
- Telecommunications Operations Map (TOM) which describes key business processes,
- Technology Integration Map, which contains recommendations of technologies to adopt for different management applications [112],
- Central Information Facility for information store for technical specifications, object models etc., and
- Catalyst Projects, which are projects to validate technology concepts.
5. Telecommunications Information Networking Architecture
Telecommunications Information Networking Architecture (TINA) is designed to meet the needs of telecommunications services ranging from traditional voice-based services to interactive multimedia, multi-party services, information services, as well as management services. All these services are considered to be software-based applications that operate on a distributed computing platform [73, page 137]. TINA addresses a wide range of issues and provides a complex set of concepts and principles. In this respect, it is much more a framework, a compilation of concepts and principles for developing future distributed telecommunications and management services, than a specific architecture [73, page 148].
TINA architecture is based on four principles: Object-oriented analysis and design, distribution, decoupling of software components and separation of concern. The purpose of these principles is to ensure interoperability, portability and re-usability of software components, independence from technologies, and to help to create and manage complex systems [115]. The two major separations of concern are the separation between applications and the environment, and the separation of applications into the service specific part and the generic management and control part [115].
Due to the complexity of TINA, it's architecture is divided into four sectors: computing architecture, service architecture, network architecture and management architecture [121, page 24].
- The computing architecture defines a set of concepts
and principles for designing and building distributed
software [121]. It is based on the Basic Reference Model for Open
Distributed Processing (RM-ODP, ITU Recommendation
X.900) [73, page 148].
- The service architecture defines a set of concepts and principles for the design, specification, implementation and management of telecommunication services [121, pages 25-26].
- The network architecture provides generic concepts that describe transport network in general, technology-independent way. The TINA network is a transport network that is capable of transporting information that is heterogeneous in terms of data formats, bandwidth and other quality of service related aspects. The network is capable of handling streams and their point-to-point or multi-point connections [121, page 26].
- The management architecture is based on the OSI management and TMN standards. In particular, the management architecture adopts the TMN functional layers. All the other TINA architectures are influenced by the management architecture principles [73, page 163]. The TINA management architecture is still under study [121, pages 27-28].
TINA network management model extends the OSI
FCAPS model (see
page
) [73,25]. Configuration management is
divided into connection management and resource
configuration management.
- Connection management is considered a fundamental activity in telecommunications network [121]. TINA represents a new approach to the traditional way of connection control [73, page 163]:
Connection control includes the establishment, modification and release of connections. Traditionally these are considered as control operations, which are viewed as being different from management. In TINA, these operations are seen as dynamic management operations. Connection management is used by service architecture components whenever a service requires connections.
- Resource configuration management contains installation support, provisioning of network resources to make them available for use, monitoring and control of resource status. It also includes management of the relationships among the resources.
3. Network Management Protocols
This chapter describes different existing standard protocols that are
used in network management. SNMP (section 3.1) is widely
used in IP networks, and is also basis for some other protocols.
CMIP, described in section 3.2 is an OSI based protocol.
Network management protocols used in SS#7 are described in
section 3.3, and network management for the ATM in
section 3.4.
1. Simple Network Management Protocol
Simple Network Management Protocol (SNMP) is the most widely used management protocol in TCP/IP networks. This is due to it's simplicity, expandability, easy implementation and the fact that it poses only little stress on the managed network and the managed nodes [118,21].
SNMP is based on a agent-manager concept, similar to the one illustrated in figure 2.1: A manager sends requests to agents in network elements. The agents control Managed Objects (see page
) accordingly, send responses and issue trap messages to the manager. The objects to be managed are defined in a MIB (see page
). The requests and responses are exchanged using the User Datagram Protocol (UDP), which is a connectionless protocol. Trap-directed polling is used to decrease the management traffic on the network [64].
The management functionality is centralized in a Network Management Station (NMS), which acts the manager role. Agents are kept simple, and thus SNMP is particularly conservative in the memory and computational requirements placed on devices connected to the network [116].
The first version of SNMP, SNMPv1, became both an IETF (the Internet Engineering Task Force) and a de facto standard. This was due to it's widespread market acceptance. However, due to the lack of adequate security features, a new version of SNMP had to be developed. Various proposals on SNMPv2 were made, but none were adopted as a new standard. SNMPv2 failed because it had lost the simplicity of SNMPv1 [118,26].
Third version of SNMP, SNMPv3, is now in it's final stages of standardization. It builds on the first and the second versions of SNMP, and is intended to offer new capabilities for open, interoperable, and secure network management. It includes methods for security (authentication, encryption, privacy, authorization, and access control), and a new administrative framework (naming of entities, user names and key management, notification destinations, and proxy relationships, remotely configurable via SNMP operations) [26, pages 501-503].
The SNMP architecture makes a distinction between message security services (integrity, authentication and encryption) and access control services. Both message security and access control services can be provided by multiple security or access control models. The architecture allows coexistence of multiple models in order to allow future updates, in case the security requirements change or cryptographic protocols need to be replaced [95, pages 690-692].
The User-based Security
Model (USM) provides integrity, authentication and privacy, and is the
standard security model currently used with SNMP version 3
(SNMPv3). The View-based Access Control Model (VACM)
provides checking
whether the users have proper access rights to access one or more
objects in a Management Information Base (MIB) and perform
operations on these objects. USM is discussed in [17] and
VACM in [128].
2. Common Management Information Protocol
Common Management Information Protocol (CMIP) is a much
more complicated and extensive network management protocol than
SNMP. It improves on many of SNMP's weaknesses, the security issues
for instance, thus providing a more efficient network management
environment. CMIP can also be used to perform tasks that would be
impossible under SNMP [118].
In CMIP, requests and responses between managers and agents (see
figure 2.1) are exchanged using the OSI
connection-oriented transport protocol that provides in-order,
guaranteed delivery [64].
CMIP also has some disadvantages: Due to it's complicity CMIP poses a lot of stress on the network and it's implementation is very difficult [118].
3. Signalling System #7
Signalling System #7 (SS#7) Operations,
Maintenance and Administration Part (OMAP) offers a framework for
operation and maintenance in SS#7 networks. OMAP uses principles of
management defined in TMN Recommendations (ITU-T M.3010 or ETSI ETR
037, see reference [39]) and in OSI Management
Recommendations of the ITU-T X.700-Series. Overview of OMAP and
Signalling System #7 management is provided in ITU-T Recommendation
Q.750 [56].
The definition of TMN is concerned with five layers in management (see page
), namely business management, service management, network management, network element management, and elements in the network that are managed. Of these, OMAP provides the three lowest layers. It is not concerned with business management, and interacts with other TMN parts to provide service management [56].
Management functions and resources provided by OMAP allow management within the SS#7 signalling points. Three categories of management functionality (fault, configuration and performance management) of the five in OSI FCAPS model (see page
) are provided [56].
4. ATM Network Management
ATM Forum has standardised Broadband ISDN (B-ISDN), and
defined also an ATM network management model. This model is based on
TMN, and uses the lower three layers of the reference architecture of
ITU-T M.3010 (Network Management, Element Management, and Element
Layer) [78]. The interfaces between layers are specified as
function points, and leave physical implementation unspecified. ITU-T
has also used TMN as a basis in its ATM network management
standardisation [96].
ATM Forum specifications define five managment intefaces: M1
between private network manager and end user,
M2 between private network manager and
private network, M3 between private network
manager and public network manager, M4 between
public network manager and public network, and
M5 between two public network managers.
In addition to M1-M5 network management, ATM-Forum provides a protocol called Interim Local Managment Interface (ILMI), which is a SNMP-based protocol [7].
4. Future network management
New technologies, management models, and visions of future network management, that are currently under development, are described in this chapter. Section 4.1 presents Open Group's X/Open Systems Management Reference Model. Web-based network management is discussed in section 4.2, and Java Management Extensions in section 4.3. Section 4.4 presents CORBA-based management, and section 4.6 SPIN's vision on network management. Finally, section 4.7 discusses Policy-based network management.
1. X/Open Systems Management Reference Model
Open Group, a vendor-neutral international consortium for buyers and suppliers, has presented an X/Open Systems Management Reference Model. It's goals are [114]:
- to identify the crucial aspects of the distributed systems management problem space, especially those that are unique to this topic,
- to establish common terminology, and
- to establish a problem-oriented approach to the realization of distributed systems management solutions.
The reference model describes concepts necessary to build a comprehensive distributed systems management environment. It identifies the mapping between the abstract concepts and some technologies that provide suitable implementation bases for the realization of the model. The model is intended to enable a network of heterogeneous systems to be managed as a single system [114].
The X/Open Systems Management Reference Model uses object-oriented
techniques in the specification of systems management. These
techniques are derived from those used in the OSI
Management Model, as well as the Object Management Group Common Object
Request Broker Architecture (CORBA).
The Reference Model consists of three basic components:
- Managers, which implement Management Tasks and other composite management functions,
- Managed Objects, which encapsulate the resources, and
- Services, which provide the X/Open Systems Management Support Environment.
It is anticipated that the primary vehicle for implementation of the Reference Model will be the Object Management Group's Object Request Broker (ORB) technology.
Another significant implementation technology is that embodied by the
ISO/CCITT and Internet management protocols, CMIP and SNMP. The X/Open
Management Protocols API (XMP) provides a
uniform access method to these technologies [114].
In addition to the above, which represent the anticipated future development of distributed systems management, the Reference Model can also be implemented using currently available technologies. These include those based on existing Remote Procedure Call (RPC) technologies, such as ONC NIS and DCE RPC [114].
2. Web-based Network Management
Doing network management
operations using Internet/intranet technologies is called Web-based
network management. Web-based network management comprises controlling
network systems and/or data gathering, delivery of network
management tasks and data analysis.
Basic applications of web-based network management are web-based
configuration and management of individual devices, advanced network
wide management capabilities and web reporting of network status
information.
For network element configuration with a web browser, a management
agent with a web (HTML) interface must be used. The management agent may
configure the element using web forms and give reports as web pages.
Advanced network wide management capabilities seem to offer a web interface for traditional network management tools. Web reporting of network status means reporting statistics and query information of network elements on Intranet pages.
A pro for web-based network management is the ability to use cheap
hardware and software for user interfaces; the personnel may move
physically and use the web interface for network management. However,
it seems that web-based network management mainly is a user interface
improvement and does not add significantly to the actual network
management.
3. Java Management Extensions
Java Management API (JMAPI) [107] was intended to
provide a standard interface between different computers and network
devices. The system can be used by Java programmers, and was created
in alliance with Sun Microsystems, Bullsoft, Computer Associates,
Exide Electronics, Jyra, Lumos Technologies, TIBCO, and Tivoli.
Specification version 2.0 was intended for publication in March 1999.
Instead of version 2.0 of JMAPI, the product was named Java Management
Extensions [108], and released in August, 1999.
4. CORBA-based Telecommunication Network Management System
The Object Management Group (OMG) is a non-profit
international trade association. OMG has presented an outline of an
architecture for a CORBA-based Telecommunications Network Management
System. One of the objectives of this architecture is to ensure a
complete compatibility with proprietary, ITU-T/ISO, SNMP and
CORBA -based network elements [87].
CORBA (Common Object Request Broker Architecture)
is an architecture that supports the distribution of management
functionality and managed objects [114].
In the context of TMN, CORBA is seen to offer potential in two
significant areas: in the description and implementation of management
interfaces supported by network devices, and in the description and
implementation of interfaces within and between management operations
systems [87].
Common Information Model (CIM) is a common data model
developed by Distributed Management Task Force, Inc. It is
implementation-neutral and can be used to describe management
information in a network/enterprise environment. The model is intended
to enable interchange of management information between management
systems and applications, thus providing for distributed network
management [35,34]. See section 8.2 for a more
detailed discussion about CIM.
CIM is currently supported by at least Microsoft (Windows NT/98), Hewlett-Packard (HP OpenView), and IBM (Tivoli)
.
6. SPIN's Intelligent Network Management
SPIN is a research project in the Institute for Information Technology at Canada's National Research Council [1]. The SPIN Intelligent Network Management project studies and develops new agent-based technologies for controlling, planning and problem definition of heterogeneous networks. The application development of SPIN networks uses integration of the off-the-self NM components, and testing and usage of popular tools, such as HP Openview.
7. Policy-Based Networking
A policy is a combination of rules and services where
rules define the criteria of resource access and usage. Policies can
contain other policies, they allow to build complex policies from a
set of simpler policies, so they are easier to manage. They also
enable to reuse previously built policy blocks [106].
Policy groups and rules can be classified by their purpose to [80]:
- service policies,
- usage policies,
- security policies,
- motivational policies,
- configuration policies,
- installation policies, and
- error and event policies.
Service policies describe services available in the network. These
services will be available for usage policies. For example, QoS
service classes (Voice-Transport, Video-Transport, ...) are made by
using service policies.
Usage policies describe how to allocate the services defined by
service policies. Usage policies control the selection and
configuration of entities based on specific usage data. For example,
usage policies can modify or re-apply Configuration Policies.
Security policies identify clients, permit or deny access to
resources, select and apply appropriate authentication mechanisms, and
perform accounting and audit of resources.
Motivational policies describe how a policy's goal is
accomplished. For example the scheduling of file backup based on
activity of writing onto disk is a kind of motivational policies.
Configuration policies define the default setup of a managed entity,
for example the setup of the network forwarding service or the
network-hosted print queue.
Installation policies define what can be put on the system, as well as
the configuration of the mechanisms that perform the
installation. Typical installation policies are administrative
permissions, and they can also describe dependencies between different
components.
Error and event policies, for example, ask the user to call the system
administrator, if a device fails between 8am and 5pm. Otherwise, error
and event policies ask the user to call the Help-Desk [80].
Policy-Based Networking (PBN) is gaining a wider
acceptance in the IP management, because it makes more unified control
and management possible in complex IP networks [15].
5. Network Element Management
This chapter discusses network element management. Section 5.1 describes network configuration management. Section 5.2 describes security management, including protocols and programs developed to provide security over the Internet, and network elements used to secure risky areas of networks. Section 5.3 studies fault management, including troubleshooting, fault localization, and testing methods.
1. Configuration Management
Configuration management means
initializing and shutting down parts of a network (for example
routers, hubs, and repeaters) and reporting the changes. It is also
concerned with maintaining, adding and updating the relationships
among elements and the status of elements during network
operation. Network traffic patterns and identified bottlenecks that
reduce performance must be understood. Nowadays modern elements and
subsystems can be configured to support many different
applications. The same device can be configured to act either as a
router or as an end system node or both. Depending on the
configuration, the appropriate software and a set of attributes and
values are chosen for the device [101, page 481]. Reconfiguration
may be necessary in case of fault isolation or when the network is
expanded.
As the network scales up in physical size (capability and complexity),
also the management capabilities must be enlarged. The aim is that
these actions could be automated. It should also be possible to make
on-line changes without affecting the entire element or
network [92]. Large-scale network management systems must be
constructed to support diverse network elements. They must also be
extensible and flexible enough to support new elements and the rapid
deployment of new highly customized services.
Activities in network management can be divided into three groups [47]:
- activities that do not affect the functioning of an element,
- activities that affect the functioning of an element (for example switching off an element in a subnetwork), and
- activities that make an element to do a desired function (for example restarting an element).
Dynamic updating of configuration needs to be done periodically to ensure that the existing configuration is known. This is essential for fault management as well.
Configuration management tools have reporting components. When network configuration changes, users must be informed about new network elements and resources. Configuration management is well organized when all the gathered information and operations are in statistical form.
There is a risk of spending money on hardware and services that remain underutilized. On the other hand the underprovisioning usually lowers productivity, which reflects to the service level [16]. When the network is designed, it is essential to predict the growth of the network. The network should also be prepared to varying volumes of users.
By continuously addressing the cost of maintenance (MTBF
and MTTR
statistics, costs associated with maintaining) the network as a system can be tuned [104].
TCP/IP networks cause more work for system administrators than other networking systems. Administrators have to manually configure each computer for network use when it is added to the network, or when it is moved from one subnet to another. Each computer must manually be assigned a unique IP address and various configuration parameters must be set.
There is a need for tools that automatically assign addresses and set
configuration parameters. Some client/server solutions are already
available. Client hosts find the details of other hosts on the
network using the Domain Name Service (DNS) protocols, and can be
told their network configuration using Bootstrap (BOOTP)
protocol. Dynamic allocation of IP addresses to particular hosts
can be chosen over static allocation using the Dynamic Host
Configuration Protocol (DHCP) [37].
2. Security Management
Security management covers such areas as detecting, tracking and reporting security violations, and creating, deleting and maintaining security-related services such as encryption, key management, and access control. Distributing passwords and secret keys to bring up systems are also functions of security management [116, page 12].
As computer-based communications and networks that link open systems continue to expand, security management becomes critical. Nevertheless, standardization of security properties has developed slowly. Network management must provide proactive management of security and integrate it with protocols, such as IPSec and services, like VPNs. Security of devices and networks must be compared to possible threats and risks. If the risks are high, the devices and the networks must be provided with more reliable secure properties.
Table 5.1 describes protocols and programs,
that are developed to provide security over the Internet. Secure-HTTP
(S-HTTP) is an application-level protocol that provides security
services across the Internet. It provides confidentiality,
authenticity, integrity, and non-repudiability. S-HTTP is limited to
the specific software that is implementing it, and it encrypts each
message individually [5].
Table 5.1:
Protocols and programs developed to provide security over the Internet
Level |
Protection Used |
Application-level |
S-HTTP, SSH, stelnet, S/MIME |
Transport-level (TCP, UDP) |
SSL, PCT |
Network-level (IP) |
IPSec |
|
Secure Shell (SSH) and Secure telnet (stelnet) are programs that allow you to log in to remote systems and using an encrypted connection. SSH uses public-key cryptography to encrypt communications between two hosts, as well as for user authentication.
Secure Multipurpose Internet Mail Extension (S/MIME) is an encryption standard used to encrypt electronic mail, or other types of messages on the Internet. It is an open standard developed by RSA Data Security Inc.
Secure Socket Layer (SSL) is an encryption method developed by Netscape to provide security over the Internet. SSL is a protocol layer that is located between the network layer and applications, so that, in theory, it can be used with any application. However, it is vulnerable to poor application design. It provides data encryption, server authentication, message integrity, and optional client authentication for a TCP/IP connection [5].
The Private Communication Technology (PCT) protocol is developed by the Microsoft Company to be used mainly in their Internet Explorer browser.
IP Security Architecture (IPSec) provides a standard
security mechanism and services to the currently used IP version 4
(IPv4) and to the new IP version 6 (IPv6). IPSec is less dependent of
individual applications than SSL. It provides IP-level encryption by
specifying two standard headers: IP Authentication Header (AH)
and IP Encapsulating
Security Payload (ESP). IP Authentication Header provides strong integrity and
authentication. It computes a cryptographic authentication function
over the IP datagram and uses a secret authentication key in the
computation. IP Encapsulating Security Payload provides integrity and
confidentiality for IP datagrams. It encrypts the data to be protected
and places it in the data portion of the IP Encapsulating Security
Payload. However, these mechanisms do not provide security against
traffic analysis. Any specific protocol for key management is not
provided by the architecture, only requirements for such systems to be
used in conjunction are described [91].
IPSec requires a key management
protocol. IETF has standardized Internet Security Association & Key
Management Protocol (ISAKMP) and Internet Key Exchange (IKE) for this
purpose. ISAKMP defines the procedures for authenticating a
communicating peer, creation and management of Security Associations,
key generation techniques and threat mitigation (e.g. denial of
service and replay attacks). These are necessary to establish and
maintain secure communications in an Internet environment. Security
Association (SA) is a security-protocol-specifistic set of parameters
that defines the services and mechanisms necessary to protect traffic
at that security protocol location.
ISAKMP separates the details of security association management and
key management from the details of key exchange. It provides a
framework for Internet key management, but it does not define session
keys by itself. IKE is a protocol that defines key exchange functions
for ISAKMP.
Protocols and programs discussed in this subsection are further studied in [5]. IPSec is defined in [61], ISAKMP in [76] and IKE in [45].
2. Access Control Tools
Hubs, routers and firewalls can be used to
limit access to networks or to parts of the networks. These security
level operations can be restricted to a date or to a time period.
- Hubs used in LANs are provided with simple security properties. Hubs protect sensitive data on the network by checking destination addresses on each packet and sending readable packets only to authorized nodes. Hubs automatically detect and/or disable unauthorized log-on attempts and record the events at the management station. Hubs also track changes involving users and devices on the network, giving the manager a complete record. These security level operations can be restricted to a date or a time period.
- Routers are provided with security properties as well. A router handles packets up through the IP layer. The router forwards each packet based on the packet's destination address, and the route to that destination is indicated in the routing table [49]. Routers can improve network security, but also introduce new problems: Routing protocols are susceptible to security attacks, and routing mistakes may allow the entrance of unauthorized personnel into the network. Unlicensed remote and local operations of routers must be prevented by using usernames.
Traffic can be controlled with packet filtration based on the access
control lists. On the access control lists it is defined what
addresses and protocols to each interface can be routed. Properties
such as NAT
,
PAT
,
and logging of events and alarms can be attached to the
router. However, it has not been possible to expand the capacity of
traditional routers as cost-effectively as the capacity of PC
workstations or the network traffic volume [51].
- Firewall systems control connections between closed networks and outside world. There are two major approaches used to build firewalls: packet filtering and proxy services. Packet filtering systems route packets between internal and external hosts, but they do it selectively. They allow or block certain types of packets in a way that reflects a site's own security policy. The type of router used in a packet filtering firewall is known as a screening router.
Proxy services are specialized application or server programs that run on a firewall host: either a dual-homed host with an interface on the internal network and one on the external network, or some other bastion host that has access to the Internet and is accessible from the internal machines. These programs take users' requests for Internet services (such as FTP and Telnet) and forward them, as appropriate according to the site's security policy, to the actual services. The proxies provide replacement connections and act as gateways to the services. For this reason, proxies are sometimes known as application-level gateways [24].
There are three ways to put various firewall components together:
A dual-homed host architecture is built around the dual-homed host computer, a computer that has at least two network interfaces. Such a host could act as a router between the networks these interfaces are attached to; it is capable of routing IP packets from one network to another. Systems inside the firewall can communicate with the dual-homed host, and systems outside the firewall (on the Internet) can communicate with the dual-homed host, but these systems can not communicate directly with each other. IP traffic between them is completely blocked.
Figure 5.1 shows the network architecture for a dual-homed host firewall. The dual homed host sits between, and is connected to, the Internet and the internal network [24].
Figure 5.1:
Dual-homed host architecture
 |
- Whereas a dual-homed host
architecture provides services from a host that is attached to
multiple networks (but has routing turned off), a screened host
architecture provides services from a host that is attached only to
the internal network, using a separate router. In this architecture,
the primary security is provided by packet filtering. For example,
packet filtering is what prevents people from going around proxy
servers to make direct connections. Figure 5.2 shows the
network architecture for the screened host architecture [24].
Figure 5.2:
Screened host architecture
 |
The screened subnet
architecture adds an extra layer of security to the screened host
architecture by adding a perimeter network that further isolates the
internal network from the Internet. There are two screening routers,
each connected to the perimeter net. The perimeter network is another
layer of security, an additional network between the external network
and the protected internal network. The perimeter net offers an
additional layer of protection between attackers and the internal
system. One screening router sits between the perimeter net and the
internal network, and the other sits between the perimeter net and the
external network (usually the Internet). To break into the internal
network with this type of architecture, an attacker would have to get
past both routers. Figure 5.3 shows the network architecture
for the screened subnet architecture [24].
Figure 5.3:
Screened subnet architecture
 |
3. Fault Management
Physical network problems account more than half of all network
problems. Locating the origins of such problems as a fiber cut, an
incorrect earthing, broken or incorrectly connected adapters, costs
network providers time and money. Network management systems have also
traditionally focused on the logical connection between the end user
and the network destination, since many network problems have been a
result of errors created by software applications [92]. Finding
and repairing failures of software applications is usually difficult,
for example in such a case that the workstation sends but does not
receive packets, too many collisions occur or frames are too short or
too long.
Fault management means troubleshooting, fault localization, isolation and correction. Today, the process of fault management needs to be automated. Rapid and accurate correction of network problems has to be created by the network or by the end user. Even if the entire network was violated, the network management application should work.
Expert systems provide an efficient and cost effective way of automating network fault management. By automating fault management, problems and possible diagnosis can be done faster and more efficiently. However, real-time performance represents a problem for expert systems [41]. Bounds on response times are difficult to establish. There are also risks pushing the limits of automation through the introduction of new or only partially proven technologies.
There are two mechanisms of transferring network management information from a managed entity to a manager: polling and sending alarms (messages are initiated by managed network elements). Advantages and disadvantages exist within both methods. Most network management systems use an optimal combination of alarms and polling in order to maintain advantages of each and eliminate disadvantages of pure polling [103].
Most systems poll the managed objects, search for error conditions and
illustrate the problem in graphical format or as a textual
message. Disadvantages of polling are the response time of problem
detection and the increased volume of network management
traffic. Having to poll many management information base (MIB)
variables per element on a large number of elements is
itself a problem. The ability to monitor such a system is
limited. Polling many objects on many elements increases the amount of
network management traffic flowing across the network. It is possible
to minimize this through the use of hierarchies (polling an element
for a general status of all the elements it polls). Anyway, the
response time will be a problem [103].
If a system fails shortly after being polled, there may be a significant delay before it is polled again. During this time, the manager must assume that a failing system is acceptable. While improving the mean time to detect failures, it might not greatly improve the time to correct the failure. The problem will generally not be repaired until it is detected.
There are problems attached also to the second method, sending alarms: There is a possibility to lose of critical information and to over-inform the manager. An ideal management system would generate alarms to notify its management station of error conditions. However, alarms cannot usually be delivered when the managed entity fails or the network experiences problems. It is important to remember that failing elements and networks can not be trusted to inform a manager that they are failing. The manager should periodically poll to ensure connectivity to remote stations, and to get copies of alarms that were not delivered by the network [103].
Alarms in a failing system can be generated so rapidly that they impact functioning resources. An "open loop" system in which the flow of alarms to a manager is fully asynchronous can result in an excess of alarms being delivered. There may be a situation where all available network bandwidth into the manager is saturated with incoming alarms, thus preventing the manager from disabling the mechanism generating the alarms. Methods are needed to limit the volume of alarm transmission and to assist in delivering a minimum amount of information to a manager. Alarm correlation is done by filtering secondary alarms, e.g. using expert systems
.
Many management tools also log events with different formats and different sources. These events should later be correlated using time stamp to identify the source of the problem. Also topology information is needed to identify the precise location of the problem.
Many devices have buffers reserved for logs. When a buffer becomes full, new logs are written over the oldest ones. If the buffer becomes full quickly, some important logs may disappear before they are noticed. Buffers also consume disk space that could be used for other purposes.
Several diagnostic tools are used for troubleshooting and fault localization purposes. These include ifconfig, arp, netstat, ping, nslookup, dig, ripquery, traceroute, and etherfind [49, pages 260-262].
The ping
(Packet InterNet Groper) program is used with TCP/IP internets to test
reachability of destination hosts by sending an ICMP (Internet Control
Message Protocol) echo request and waiting for a reply. Ping can only be
used to determine whether the target IP address is available or not. Since
echo request and response to the request may use different routes, the
violated route cannot be determined. Another usage of ping is to measure
the response times of different packet sizes [16, page 33].
Unlike ping, traceroute forces every
router to send back an ICMP-control message. Most traceroute
applications send a sequence of User Datagram Protocol (UDP)-packets
to a randomly selected UDP-port [9, page 202]. Sometimes the
firewalls filter these packets from the main traffic, in which case
the tracing ends.
After detecting a fault, operators should as soon as possible find the
root cause of the problem. Clearly defining the problem helps to
isolate the root cause from symptoms [84]. Operators must also
determine what troubles it causes and to whom.
At first it is useful to find the parts of the network, where the
fault can not be, by eliminating processes. These parts can be
neglected. If the problem is very serious and difficult, the network
can be divided into smaller parts to be inspected one by
one. Connectivity tests are also used to find the violated devices. At
the same time it can be detected whether the fault is local or
widespread. It can be found out by testing data integrity if some of
the packets are lost in transmission. Delays are also to be tested,
because some faults result from excessive delays [9, page 198].
Measuring the accessibility of devices helps us to collect information about the status of the network. A few devices are chosen usually from the network, and the functionality of the connections is measured from them to other devices. Measurements are done by a control device. After measurements, the results are interpreted.
Measuring the accessibility is not a perfect method, for example, in the case where only routers are controlled. If the router has been set up so that it gives preference to packet switching, it will send packets normally even if it is heavily loaded and perhaps can not answer to messages of the controlling device. Another example is that two devices that can be reached might not have a connection with each other.
Another method of testing is to control routing tables. Routing should change only when the topology of the network changes. If there are changes at other times, there is probably
something wrong with the network [9, pages 183-189].
Routing tables express the topology of the network. Finding out the network topology from routing tables is more difficult than controlling accessibility. In order to get information from routing tables of routers, routers must be Simple Network Management Protocol (SNMP) compatible, dynamic routing tables must support sending request or routing information must be tapped from a routing protocol. These requirements are not necessarily realized although SNMP is a commonly used protocol. Analysis of the routing tables can concentrate on the parts of the network which are most susceptible to failures.
6. Traffic Management
This chapter discusses data communications in IP networks at OSI network layer and link layer levels. Section 6.1 describes different types of IP network traffic, introducing terms Quality of Service and Grade of Service. In section 6.2, the development of a new service model for IP networks is discussed. Section 6.3 discusses performance management and performance related issues.
1. Communications in IP Networks
Data communications in IP networks can be divided into
connectionless and connection-oriented
communications. Communications based on the Internet Protocol (IP) is
connectionless by nature. This means that no end-to-end connection is
established before data is transmitted by the protocol [49, page
13]. In IP networks, Quality of Service (QoS) is defined
in terms of parameters such as bandwidth, delay, delay variation
(jitter), and packet loss
probability [14].
Connection-oriented communications in IP networks is enabled by
protocols built upon the connectionless IP. This means that a logical
connection between communicating network nodes is established before
transmission [49, page 20]. Grade of Service
(GoS)
is defined
in terms of connection blocking probability (i.e. the probability of
failing to establish a connection). Connection blocking can be
controlled using Connection Admission Control (see
page
).
Traffic in IP networks is composed of individual transactions and flows. A flow is a sequence of packets belonging to an instance of application running between hosts. Flows can be divided into two categories: stream flows and elastic flows.
- Stream flows are generated by real-time audio and video applications such as Internet phone and video conferencing. These applications may require a minimum level of QoS in order to function properly, and thus would benefit from guaranteed QoS.
- Elastic flows are generated by non-real-time applications (e.g. e-mail and FTP). They don't state critical demands on QoS, but adjust their rates to make full use of QoS available [89].
2. New Service Model for IP Networks
The current IP architecture does not support any QoS guarantees because routing is traditionally based on a best-effort principle. This means that each packet of information is treated independently and processed in the order of arrival [14].
The diversity of applications and their requirements raises a need to
develop a new service model for IP networks. The purpose is to
satisfy the requirements of rigid real-time applications while
avoiding costs of over-provisioning
. This
could be done by introducing a service model with several classes of
QoS instead of a single class of best-effort service.
The Internet Engineering Task Force (IETF) has three working groups
developing the new service model or network architecture. These
working groups are described and compared in following
subsections. Also, Traffic Engineering/Constraint-based Routing
approach is discussed. The relationship between OSI layers and
concepts described in this section are illustrated in
figure 6.1.
Figure:
The relationship between OSI layers and concepts described in section 6.2 [131].
 |
IETF Integrated Services (IntServ) working
group
is currently defining an enhanced service model which involves
creating two service classes in addition to best-effort service:
Guaranteed service for applications requiring fixed delay
bound, and controlled-load service for applications that
require reliable and enhanced best-effort service. The model is based
on resource reservation initiated by applications. This could be done
e.g. using Resource Reservation
Protocol
[54,131].
Resource Reservation Protocol (RSVP) is used to signal routers in the network to reserve resources and set up a path for a flow [48,131]. If RSVP is used in the network, there should be a mechanism to manage resource reservation policies of applications that initiate the reservation. RSVP and resource reservation are further discussed in [48, ch. 13] and in [133]. Standardization of RSVP can be found in [19].
To provide QoS allocated by a reservation protocol,
Connection Admission Control (CAC) should be used in
routers. CAC functions by blocking incoming stream flows
if the
increase in traffic would drop QoS below an acceptable level for that
or any previously accepted flow. On the other hand, CAC affects also
on GoS, as the level of GoS is decreased when connections are
refused [75, page 33].
Besides the benefits, CAC bears one disadvantage: Implementation of
CAC would increase the complexity of networks, already complex
enough. Discussion on the benefits and disadvantages of CAC can be
found in [97].
According to Xiao and Ni [131], the Integrated Services
architecture has several problems: It doesn't scale well, states high
requirements on routers, and requires ubiquitous deployment for
guaranteed service. According to Baumgartner et
al. [11], the architecture is suitable only for small networks
(e.g. corporate networks or Virtual Private Networks (VPNs)), not for
Internet backbone networks.
The approach of IETF Differentiated Services (DiffServ) working group
involves creating distinct Classes of Service (CoS), each with reserved resources. The basic difference between IntServ and DiffServ architectures is that while IntServ provides an absolute level of QoS, DiffServ is a relative-priority scheme
. Secondly, in DiffServ the QoS in each CoS is defined by an agreement between customer and service provider. This eliminates the need of each application to signal their QoS needs at run time. It also provides better scalability as there is no need to maintain per flow state information in routers [53,131,4].
In Differentiated Services, each packet of information is classified by marking the DS field
in IP datagram. Packets receive their forwarding treatment, or per-hop behavior, according to the classification. The use of the DS field is standardized in [86] and in [13]. A small number of per-hop behaviors will also be defined by the working group [53,131].
According to Xiao and Ni [131], DiffServ is more scalable,
requires less from routers, and is easier to deploy than IntServ
architecture. Baumgartner et al. [11] discuss more
widely the DiffServ architecture, it's possible drawbacks, and related
issues.
3. Multi-protocol Label Switching Architecture
Multi-protocol Label Switching (MPLS) architecture is being standardized by IETF MPLS working group
. MPLS is a forwarding scheme that is based on a label-swapping forwarding (label switching) paradigm instead of standard destination-based hop-by-hop forwarding paradigm [55,120].
Each packet arriving to an ingress router of an MPLS
domain
is routed, classified, and
given a label
. Inside the MPLS domain forwarding decisions are
made by using the label instead of processing the packet header and running a routing algorithm. The label is used as an index to a forwarding table
where the next hop and a new label can be found. The old label is replaced with the new one and the packet is forwarded. The label is removed as the packet leaves the MPLS domain [68].
MPLS labels can be used to provide forwarding along an explicit route, and to identify packets to receive certain QoS. An efficient tunneling mechanism is also provided. These features make MPLS useful for traffic engineering [131,55].
A disadvantage of MPLS is that it should be extensively deployed, i.e. the MPLS domain of the network should be relatively big. Otherwise MPLS offers no benefit.
Dynamic routing
protocols such as RIP
, OSPF
, and IS-IS
can
cause uneven traffic distribution. ``Traffic Engineering is
the process of arranging how traffic flows through the network so that
congestion caused by uneven network utilization can be
avoided'' [131].
Constraint-based Routing can be used to make the traffic engineering process automatic. It enables computing routes that are subject to multiple constraints such as resource availability, QoS requirements, and other policies [131].
Constraint-based Routing increases the size of routing tables, and may introduce instability as routing tables change frequently [131]. Thus it should be considered whether it offers any benefit or just consumes more resources.
The nature of the Internet is decentralized and heterogenous. This causes several problems that need to be solved before new technologies can be deployed:
- Inter-domain QoS guarantees, CoS classifications, and the involved interaction between Internet Service Providers (ISPs) may represent problems due to different policies and diverse architectures of underlying networks.
- Usage of new services should be charged, otherwise they offer no benefit
. Charging for network usage in the Internet with a large number of ISPs might be difficult.
- Some proposed technologies demand ubiquitous deployment in order
to offer any benefit. However, big changes to the best-effort architecture currently in use are difficult, perhaps impossible to deploy.
Some of these problems and other aspects related to the development of
a new service model are addressed in [97] and it's references 4,
8, 30, and 37.
3. Performance Management
Performance management is used to evaluate the behavior of managed objects and the efficiency of communications activities. It is collecting statistical data, analyzing it, and where appropriate, predicting trends of communications between open systems [60].
A network performance management system must be able to provide reports on the efficiency of the system and its current and previous performance. Reports on a daily, monthly and annual basis are needed.
Network performance analysis becomes important when the network increases in size and complexity. Analyzers are used for traffic monitoring, protocol analysis and statistics collection and interpretation of performance-related data. Analyzers are understood as troubleshooting tools, but they should be used as proactive indicators as well.
The analyzers available typically gather and display large volumes of detailed data rather than interpret and highlight the meaning of the data. Many of these tools also look at a single element rather than the network as a whole. Data becomes information when it is organized, correlated and presented in a way that clarifies it's meaning, helping the network manager make the best decisions [29]. Managers must also predict future trends based on historical network trends and business information.
Until the introduction of expert
systems, alarms and events were checked manually by the operators. Now
expert systems are tested in the automation of this process. There are
several artificial techniques that can be used, such as Rule-Based
Reasoning (RBR), Bayesian Networks (BN), Neural Networks (NN),
Case-Based Reasoning (CBR), Qualitative Reasoning (QR) and Model-Based
Reasoning
(MBR) [8].
Generally, network
performance metrics are classified into two areas: network-centric
metrics and end-to-end measurements [93]. Network-centric
metrics are router and switch metrics, link metrics, and metrics for
the routing subsystem.
- Router and switch metrics deal with the operations of
routers and switches; queuing packets, processing them, and placing
them on the appropriate outbound link queue. The metrics include
Offered load, Dropped traffic, and Average queue lengths (to assess
queuing delays and potential dropped packets at a router).
- Link metrics describe the network capacity. They
include e.g. Bandwidth Utilization.
- Metrics for the routing sub-system describe the impact
of the routing traffic and fluctuations on the network
performance. The rate of route changes characterizes the stability of
the network system.
End-to-end metrics are
- end-to-end latency and jitter,
- effective throughput, usually measured as a function of the packet size and the window size, and
- packet loss probability.
The tools and techniques required to measure performance characteristics in these two categories are different. In the Internet performance analysis, it has been difficult to define metrics that reflect both perspectives.
Performance management control is responsible for controlling the performance of a network. It includes such areas as network traffic management policies, traffic control, traffic administration, performance administration, execution of traffic control, and audit reporting [116, page 56].
Traffic control needs resources. Usually a separate control station is needed to collect and analyze traffic statistics. There should be a method to link a control station so that the traffic information is collected from the network. Controlling the traffic is, however, a reliable and cost effective method for finding out problems before they exist. Traffic controlling can be limited to the most important parts of the network [9].
Performance management is also related to the configuration management. It is easier for the operator to plan modifications of the network, when the use of the network is known. Operator finds out which connections and services are used and which are needed.
7. Service Management
This chapter discusses service management. There are many definitions
of service:
- ``A service is anything that a service
provider determines that customers will wish to purchase and that the
service provider is willing to supply.'' (Kong, Chen and Hussain [63])
- ``A service is a set of functions offered to a user by an
organisation.'' [90, page 889]
- ``A service is an application with a well-defined interface and functionality.'' [12]
- ``An abstract concept
that includes the behaviour of a service provider as seen by a service
user. Alternatively, the service definition includes a set of
capabilities provided to a service user by a service provider. Service
definition does not include the internal behaviour of a service
provider.'' (International Telecommunication Union --
Telecommunication standards (ITU-T) and
ISO systems management documents [117, pages 82-83])
The rest of the chapter is organized as follows:
Section 7.1 presents some motivation for service
management. Section 7.2 describes the expected
convergence trend, and who uses and who offers services.
Section 7.3 describes some basic security management
concepts. Section 7.4 studies customer care and billing
processes, while section 7.5 discusses
accounting at enterprice level.
Section 7.6 studies service platforms, and
section 7.7 some future architectures. Finally,
section 7.8 presents some unresolved problems in
service management.
1. Motivation
The number of services deployed over an infrastructure that spans
multiple control domains, such as e-commerce, web hosting etc., and
their users is increasing. These end-to-end services require co-operation in internetworking
between multiple organizations, systems and entities. Service providers need to deploy interoperability,
distributed scaleable architectures, integration and automation of
network management systems. The management system must make management
easy and flexible to service providers. The management system must
also make service providers' operations and end goals
easier [12].
Service providers need to find new and effective ways to [27]:
- deploy services more quickly,
- deliver guaranteed services through Service-Level
Agreements (SLA),
- evolve from reactive network management to proactive service
management, and
- reduce costs by automating network and service management.
Currently, there are no standard mechanisms to share selective
management information between the various service providers or
between service providers and their customers. Such mechanisms are
necessary for end-to-end service management and diagnosis as well as
for ensuring the service level obligations between a service provider
and its customers or partners [12].
2. Demand and Supply of Services
IP networks get more customers, because more services will
be available for customers. This has raised the importance of service
management. In the past, technology orientation has placed products
and equipment ahead of the services. Today, customers want reliable
and easy-to-use services.
1. IP Networks and Convergence in Telecommunications
Internet is popular as the basic infrastructure in providing world-wide distributed services to end-users. Internet is an open and distributed environment which allows different types of service providers to provide different types of services on the network [63, page 22].
Massive IP networks of the future might include the
Internet, but also Cable television
(CATV), telecommunication networks, such as Public Switched
Telephone Network (PSTN), Integrated Services Digital Network
(ISDN), Intelligent
Network (IN), and mobile systems. However, there are two
other important network technologies which make new services
available: wireless transmission on radio frequencies, and microwave
satellite transmission.
Telephone companies are interested in delivering non-telephone services to end-users. CATV providers are interested in telephone and Internet services as well as in Video on demand (VoD) services. These companies believe that cost savings are possible through value-added services. Also, the number of end users is increasing. These users have unique interests, and because of their interests, they require different services from the service providers. [81, page 129]
The CATV industry is migrating to a digital transmission technology, in order to increase the number of TV channels and services available to the end users. To provide new services, such as VoD and interactive TV, the CATV industry is designing bi-directional networks. End-users are connected to video servers, and they can select the video program, and the video program is sent over the network to the user [125, pages 16-19].
The differences between telephone, computer, and CATV networks are still great. However, each type of network is now able to provide services that were originally created for other networks. This tendency is convergence [125, page 20].
Media industry, telecommunications industry and computer industry are converging. Media industry produces the content, for example entertainment and publishing. Computer industry produces equipment and applications, which can make this content available for everyone. Telecommunications industry, both fixed and mobile, produces the connections to networks. See Figure 7.1 [110]
Figure:
Convergence [110]
 |
2. Service Providers
By service providers we mean companies that provide services as a business on the network. Service providers operate on the network, or they integrate the services of other provides in order to deliver services to their customers.
Service providers are increasingly using Service Level Agreements (SLAs) to define agreements for sharing resources with partners, as well as for offering service quality guarantees to customers. These SLAs contain details of information that are shared, and service level guarantees that are offered by the service provider [12].
Service providers offering reliable services in a cost-efficient way
will succeed. Service users do not use services that are not operating
properly.
3. Service Users
Service users are often called end-users or customers. Service providers
have to fulfil the end-user needs before the end-user uses any
services. The service users want that the user interfaces of the services are
logical and easy to use. They do not want to use services that are not
operating properly.
They also expect that the connection and the billing are reliable,
installations are easy and software products are good.
3. Security Management
Basic security services that are defined in ITU-T
Recommendation X.800 are access control, authentication,
confidentiality, integrity and non-repudiation.
- Access control
is the property of controlling network and
computer resources in such way that only legitimate users can access
them within their limits. One approach is to attach to an object a
list which explicitly contains the identity of all permitted users (an
Access Control List (ACL)) [98].
- Authentication
is the property of knowing that the data
received is the same as the data that was sent and that the claimed
sender is in fact the actual sender [6]. For
authentication techniques, see [94].
- Confidentiality
is the property of communicating so that the
intended recipients know what was being sent but unintended parties
cannot determine what was sent. Encryption is commonly used to provide
confidentiality [6].
- Integrity
is the property of ensuring that data is transmitted
from source to destination without undetected alteration. Integrity
is often achieved as a by-product of providing confidentiality by
encryption.
- Non-repudiation
is the property of a receiver being able to
prove that the sender of some data did in fact send the data even
though the sender might later desire to deny ever having sent that
data [6]. This is problematic, since it includes the
assumption that no-one can falsely identify himself to the system.
Consider a case where a cracker gains unauthorized access to a
computer and then uses the computer owner's identity for a business
transaction. If non-repudiation is assumed to hold, the other end may
then claim that the owner of the computer did the transaction, which
is incorrect [38].
Effective security management must be involved in all the steps of data storage and transfer process. Logs are important security tools and therefore security management is involved with the collection, storage and examination of the audit records and security logs. Increasing the level of network security will affect the openness of the system and the cost of maintaining the network.
Almost all applications utilize user information and presume an authentication of users. Authorization is determining whether an identity is permitted to perform some actions, such as accessing a resource [72]. Passwords, smart cards and certificates are used to authenticate a user. A user may have the right to use more than one name and identities established by multiple organizations (such as universities and scholarly societies). There might be an advantage if all the user information is available in same directory. All the applications could then use the same information. Users have to log in only once to be able to use all the services and resources [77].
There are some basic requirements for
authentication [72]:
- The access management solution needs to work at a practical level,
- the solution needs to be secure,
- it should make access easier, minimizing redundant authentication interactions and providing user-friendly information resources,
- it needs to scale,
- it needs to be robust, for example, a forgotten password should not be an intractable problem,
- it must be able to recognize the need for a user to access a resource independent of his or her physical location (for example, a user must be able to connect to the Internet via a commercial Internet Service Provider (ISP), a mobile IP link, or a cable television Internet connection from home), and
- there should be a simple and well-defined (standard) interface between the resource operator and the licensing institution.
The basic access management problem is licensing agreements for networked information resources. The situations where institutions agree to share limited access are difficult. There is a need for fine-grained access control where institutions want to limit resource access to only individuals registered for a specific class, for example, when a class may be offered to students at multiple institutions. At present, most access to network information resources is not controlled on a fine-grained basis. There is a danger that by accommodating all the needs for fine-grained access management into the basic access management mechanisms will produce a too complex and costly system [72].
Management data represents a problem in the current access framework. The problem is the conflict between the private and public data. Most of the data has to be sorted out at the institutional policy level and it may involve making sacrifices in order to ensure privacy. Some institutions may be legally limited in their ability to collect certain management data.
Proxies and credential-based authentication (the user presents a credential to the operator as an evidence that he or she is a member of the user community) schemes seem to be viable. Proxy servers will become a focal point for policy debates about privacy, accountability and the collection of management information. Successful operation of a proxy server means that the user trusts the licensee institution to behave responsibly and to respect privacy.
A cross-organizational authentication system based on a credential approach has the advantage of greater transparency. Resource operators can have a higher level of confidence in the access to management mechanisms and a greater ability to monitor irregular access patterns. Privacy, accountability and collection of management statistics must be taken up for discussion among a larger group of parties.
An institution might choose to manage access by IP source address. IP source filtering means that packets are filtered on the basis of their source address. It does not seem to be a viable solution for access management. However, it may be very useful for some niche applications, such as supporting public workstations. It could be used more widely, although it cannot flexibly support remote users in its basic form. Most real-world access management systems are going to have to employ multiple approaches and IP source address filtering is likely to be one of them [72].
The list below describes the security problems in the current Internet.
- Weak authentication
Passwords on the Internet can be cracked by a number of different ways. The two most common methods are cracking the encrypted form of the password, and monitoring communications channels for password packets.
Another problem with authentication results from some TCP
or UDP services being able to authenticate only the
granularity of host addresses and not to specific users. For example,
an NFS (Network File System, on UDP) server cannot grant
access to a specific user on a host, it must grant access to the
entire host. The administrator of a server may trust a specific user
on a host and wish to grant access to that user, but the administrator
has no control over other users on that host and is thus forced to
grant access to all users (or grant no access at all).
- Ease of spying and monitoring
When a user connects to his or her account on a remote host using TELNET or FTP, the user's password travels across the Internet unencrypted. A method to break into systems is to monitor connections of IP packets bearing a username and password, and then use them to login normally. If an administrator-level password is captured, the job of obtaining privileged access is made much easier.
Electronic mail, as well as the contents of TELNET and FTP sessions, can be monitored and used to learn information about a site and its business transactions. Most users do not encrypt e-mail, yet many assume that e-mail is secure and thus safe for transmitting sensitive information.
The increasingly popular X Window System is also vulnerable to spying and monitoring. The system permits multiple windows to be opened at a workstation.
- Host-based security does not scale
Host-based security does not scale well: as the number of hosts at a site increases, the ability to ensure that security is at a high level for each host decreases. Secure management of just one system can be demanding, managing many such systems could easily result in mistakes and omissions. A contributing factor is that the role of system management is often short-changed and performed in haste. As a result, some systems will be less secure than other systems, and these systems could be the weak links that will break the overall security chain [124].
4. Customer Care and Billing
Customer care and billing(CCB) processes have been traditionally kept as a background process. CCB processes have not been the key functions in the business. Today, customer care and billing are an important part of making profit.
Good customer care and billing enables getting more profit, better customer relationships, and competition advantage. Today, succeeding in the market depend more on the quality of products and services than just on the prices.
1980's was product oriented time in the telecommunication and data
transfer market, whilst customer orientation is leading now. Marketing
to the customers as well as the ability to sell more and the ability
to high quality customer care are one of the key components to
success. Also, it is important to get the products quickly to the
market, and to be able to support existing and new services. A good
customer care and billing system has to be flexible enough to fulfil
these criteria [2].
Even electronic commerce depends on customer relationships, says
Lester Wanninger, professor at the University of Minnesota. It is
important to teach how to make good customer relations for people
going to start electronic commerce. Also, in electronic commerce a
company and a customer should handle all the communication
channels. Electronic commerce has to implement functional processes of
the company, information systems, databases, and other channels. It is
important that a customer gets the same service from any service
channel of the company. Ease of use brings more value to the
customer. Also, in electronic commerce, the customer buys again only
if the customer gets what was promised. WWW-pages can have
an effect on attitudes, intends, and shopping habits. High quality
information, easy use, and new experiences, bind customers to
services. Traditional media, such as TV, radio, and printed media are
good in getting new customers, whereas the Internet is good in keeping
old customers [59].
1. Customer Care
Customer care means maintaining customer services and customer relationships and answering routines, for example Help desk functions. Customer care links to the level of the offered service and the connection with the service level and the price of the service [111].
Customer care deals with processes needed to deliver services to customers, such as order handling, problem solving, performance reporting, and billing.
A good customer care system enables providing current and accurate
information to the customers. It helps in delivering services when
promised, resolving problems quickly, and keeping customers informed
of the status of their orders. It also enables to meet stated service
level agreements (SLAs) for performance and availability,
and providing accurate billing in a format that customer wants. This
all ensures that the customer gets good service from the
service provider.
Automation of customer care enables better services and cost savings. The service provider's Help desk can see all the information needed quickly, and then he or she can answer to the customer. Also, new services can be implemented and delivered to the customers easily when customer care processes are automated. Service providers can use the same methods to all services, when customer care processes are automated.
2. Billing
Internet is becoming able to support heterogeneous applications and services to a diverse user community. Delivered services must be billed. In the future network operators and service providers want to know who is using the network, what the network is being used for and when the network is being used [69]. Pricing mechanism will be necessary in order to manage the quality of services (QoS). Accounting and billing systems must be reliable, scaleable and have high performance, and offer flow-through operation from the other systems.
According to Sun Microsystems [109], some of the requirements of
the billing systems of the future include
- real-time reactions to market activities,
- flexible billing formats and media to meet customer demands,
- flexible rating engine that allows discounting,
- integrated billing, which includes charges from third-party
providers, and
- well-defined interfaces to allow easy integration and data sharing between business systems and the billing system.
Internet payment mechanisms can be grouped into three classes: electronic currency systems, credit-debit systems and systems based on secure presentation of credit card numbers [85].
Collecting and rating usage, tracking services, managing inventories and reconciling invoices are key features of accounting systems [69].
The safety issues are under discussion. Some payment mechanisms are
totally anonymous and payers can not be tracked (such as E-cash --
electrical purse, where you load money and pay with it). The principal
advantage of electronic currency is its potential for anonymity. The
disadvantage is the need to maintain a large database of past
transactions to prevent double spending.
In the credit-debit model (like NetCheque system), customers are
registered with accounts on payment servers. Customers authorize
charges against those accounts. The credit-debit model is
audible. Once a payment instrument has been deposited, the owner of
the debited account can determine who authorized the payment, and that
the instrument was accepted by the payee and deposited [85].
Some payment mechanisms are based on credit cards (such as CyberCash). Information is often shared with the owner of the credit card, payment service provider and the credit card company. The owner of the credit card does not need to give his credit card number to the merchant without encrypting it. A customer's credit card number is encrypted by using public key cryptography. The merchant has a message that it cannot read completely but which authorizes the purchase. The merchant adds his identification information and sends it to the CyberCash server. The entire message is digitally signed by the merchant to prevent tampering in transit. The CyberCash server unwraps the message and creates a standard credit card authorization request. The CyberCash server then forwards the request to the appropriate bank or processing house for authorization and returns the result to the merchant. The advantage is that the customer does not need to be registered with a network payment service; all that is needed is the credit card number [30].
Internet payment system should be secure, reliable, scalable,
anonymous, acceptable, flexible, convertible, effective, easy to
integrate with applications and ease to use. Anonymity is more
important in some communities or for certain kinds of transactions,
than they are in other communities [85].
- Security
The infrastructure must be usable and resistant to attacks in an environment where modification of messages is easy.
- Reliability
The infrastructure must be available and should avoid failures.
- Scalability
The payment infrastructure must be able to handle the addition of users without suffering loss of performance.
- Anonymity
For some transactions, the identity of the parties to the transaction should be protected. Where anonymity is important, the cost of tracking a transaction should outweigh the value of the information that can be obtained by doing so.
- Acceptability
A payment instrument must be accepted widely.
- Customer base
The acceptability of the payment mechanism affects the size of the customer base.
- Flexibility
Alternative forms of payment are needed. The payment infrastructure should support several payment methods including credit cards, personal checks, cashier's checks and anonymous electronic cash.
- Convertibility
There will be several forms of payment, providing different trades.
- Efficiency
Royalties for access to information may generate frequent payments for small amounts. Applications must be able to make these ``micropayments'' without noticeable performance deterioration.
- Ease of integration
Applications must be modified to use the payment infrastructure in order to make a payment service available to users.
- Ease of use
Users should not be constantly interrupted to provide payment information; most payments should occur automatically. Users should be able to limit their losses and monitor their spending.
Threats of misusing electronic currency can lead for example to dept
(unpaid bills), forgeries, unauthorized payments on behalf of another
person, double purchases (order twice -- pay once), refusal of
payments and unsuccessful deliveries.
Another threat could be pre-paid services. Customers' loyalty to
service provider will become more difficult
to check when he or she is using pre-paid services. Customers can
easily change the service provider, because they can easily buy new
pre-paid services from any other service providers. Also, cheating and
lost income remains a problem. CCB systems can help to get over and to
prevent cheating; as well as new technologies such as certificate
based authentication will open more accurate and faster charging for
the services [62].
5. Accounting Management
Accounting management deals with information that concerns individual users, including following issues:
- Usage measurement
Usage measurement is collecting data for charging, and processing the data. It has to be reliable, and sometimes it has to be done in real time.
- Tariffing and pricing
A tariff is a set of data used to determine the charges for services used. It depends on the service, origination and destination, tariff period, and day.
- Collections and finance
This includes administration of customer accounts, informing customers, payment dates, payment amount, and collection of payments.
- Enterprise control
Enterprise control is responsible for proper financial management of
an enterprise. It includes identifying and ensuring financial
accountability of officers. Also, checks and balances needed for
financial operation of the enterprise are included [117, pages
64-66].
A system that generates data for accounting purposes is called an accounting management agent. Accounting managers are systems, which interrogate accounting management data or obtain it in other ways. If accounting management is distributed across various systems, all systems may be required to control their own area themselves. Furthermore, a system may request information from other systems in order to square its accounts [60, pages 188-189].
Accounting data is sensitive information. The collector must provide confidentiality at the point of collection, through transmission and up to the point where the data is delivered. The delivery function may also require authentication of the origin and the destination and provision for connection integrity (if connections are utilized). Security services can be provided for example by SNMPv3
.
According to Busse [20], an accounting system should fulfil some
basic requirements. It should be
- cost effective, performant, transparent,
- able to provide up-to-date information,
- customer configurable, and
- secure.
To be cost effective, the accounting system should be highly automated, based on standards, and easy to interact with. It should provide a reasonable response time. The whole accounting process should be transparent to the customer.
The accounting system should provide up-to-date information, i.e. it has to minimize the time needed to process the usage information from the network elements or other service providers. This is important especially when real-time information should be provided to the customer order status.
The accounting system should be configurable according to customer preferences for example with respect to tariff, billing cycle, details of the bill, local currency and taxes, the format in which the bill is expected, and the method of payment.
The accounting system should fulfil strong security requirements: identification, authentication, access control, confidentiality, integrity, and auditing.
Internet pricing contains four basic elements (see
figure 7.2). An access fee is usually a monthly charge
for using an access link of the network. The price depends on the
capacity of the link. Setting up connections or making reservations
can be charged separately. Usage fee can be used to charge services on
time-, volume-, or QoS-basis. This fee determines the
actual resource usage of a customer. Content fee depends on the
application content. It may be omitted (e.g., telephony, fax, e-mail
services where the content is provided by the user), billed separately
(e.g., Helsingin Sanomat on-line edition), or integrated into the
telecommunications charging system (e.g., commercial 0900 numbers in
Finland) [105].
Figure:
Components of Internet pricing [105]
 |
The current pricing model is based on an assumption of a single best-effort service model that provides similar service to all customers. Service provider and customer do not have a direct control over the actual service in terms of parameters determining volume, connection time
, and QoS.
Accounting is usually based on mechanisms offered by commercially available routers and switches. The most commonly used approach employs packet filtering and statistical sampling. However, it is difficult to charge for usage-based traffic since the granularity of these methods is too coarse and the measurement overhead significant [105].
Another problem concerning accounting data collection in routers is whether packets should be counted on entry to or on exit from a router
[79].
For volume measurements the IETFReal-time Traffic Flow Measurement (RTFM) working group has proposed standards to meter flows and to distribute this accounting information via SNMP [105].
The Remote Authentication Dial-In User Service
(RADIUS) is a protocol specified by the IETF radius
working
group
.
It helps managing the Internet access links. Since
these links are sensitive to security and accounting, a protocol is
provided to authenticate dial-in users and negotiate configuration
data. RADIUS services are implemented by most router
manufactures. Accounting data can be collected on a time-, packet-, or
octet-basis for a particular service [105].
6. Service Provisioning
Competition is increasing in service provision. Customer satisfaction
is becoming important for service providers. One of the most critical
problems faced by service providers today is managing changes. The
ability to focus deployment of new services and network technologies
requires a new level of management flexibility to support a new level
of customer care. Competitive advantage for service providers will
depend on the ability to rapidly deliver end-to-end service
solutions. A key management question is to meet these
challenges. Service providers have to optimize their service
management to meet business and customer needs [46, page 701].
1. Managing New Services
Managing new services means development of new services and taking care of the economic use of the network. For example implementing a cost-effective service quickly, and guaranteeing the specified service level to all end-users. End-to-end service process automation improves the accuracy and speed of a task while also freeing personnel from routine jobs. The advantages of automating end-to-end service process are in cost reduction and in improved customer service.
Today all service providers have to create their own services in the Internet. Same services are created in many different ways, because there does not exist any one method to create new services in a way these services can be reused and modified.
Services are usually implemented when needed in IP
networks. Service providers do not have reusable service platform
models, so they must always implement services from scratch. Service
providers have their own service processes, which can be incompatible
with other service providers' systems and might be made with
incompatible software, for example Java applets can cause problems.
2. WWW Service Platforms
The World Wide Web (WWW) is an architecture for sharing information. The WWW provides a hypertext system linking people, computers, and information around the world. The WWW consists of information servers and client browser programs, linked together by a set of standards and agreements. The user runs the browser to access WWW servers, which deliver information to the requesting browser [102, pages 87-88].
The key components of the WWW architecture are the Uniform Resource
Locator (URL), the Hypertext Transfer Protocol
(HTTP), and the Hypertext Markup Language
(HTML) [102, page 88].
URLs provide standardized specifications for objects or resources located on a network, detailing both the network address of the object and the protocol to be used to interact with that object. See table 7.1.
Table 7.1:
The URLs for various types of resources
Service |
Uniform Resource Locator (URL) |
Anonymous File Transfer |
ftp://ftp.frack.com |
Hypertext Transfer |
http://www.frack.com |
Remote Login |
telnet://frack.com |
Gopher Retrieval |
gopher://gopher.frack.com |
Wide-Area Info Service |
wais://wais.frack.com |
Usenet News |
nntp://news.frack.com |
|
The URL is an enhanced Internet address. WWW clients use the URL to find an object on the network and select the proper protocol for interacting with that object [102, pages 88-89].
The HTTP is a connection-oriented protocol designed for the rapid
transport of files consisting of a mixture of text and graphics. HTTP
is a protocol consisting of simple commands that support negotiation
between a client and a server. This negotiation allows WWW
browsers and servers to develop independently emerging technologies
because the negotiation process established a common basis of
communication between the client and the server [102, page 89].
A universally understood language is needed when publishing
information for global distribution. The publishing language used by
the World Wide Web (WWW) is HyperText Markup Language (HTML) [123]. HTML is a standardized document tagging
language, based on the Standardized Generalized Markup Language
(SGML) [102, pages 89-90].
According to W3 [123], HTML gives authors the means to:
- publish online documents with headings, text, tables, lists, photos, etc.,
- retrieve online information via hypertext links, at the click of a button,
- design forms for conducting transactions with remote services,
for use in searching for information, making reservations, ordering
products, etc., and
- include spread-sheets, video clips, sound clips, and other applications directly in their documents.
HTML has been developed with the vision that all manner of devices should be able to use information on the Web: PCs with graphics displays of varying resolution and colour depths, cellular telephones, hand held devices, devices for speech for output and input, computers with high or low bandwidth. HTML now offers a standard mechanism for embedding generic media objects and applications in HTML documents. The object element provides a mechanism for including images, video, sound, mathematics, specialized applications, and other objects in a document. It also allows authors to specify a hierarchy of alternate renderings for user agents that don't support a specific rendering [123].
3. Problems
HTML based pages embedded with images, sounds and video
clips are easy to create, but they can be uninteresting and do not
allow true interactivity [99, page 5].
Communication between client programs (browsers) and servers is done
using non-ideal paradigms (HTML). Instead of that, it should be done
in an object-oriented manner, in order to reduce development time and
increase ease of maintenance. Internet service developers find it
difficult that support systems have to be hand-built for each service
and each system must often be managed separately [99, page 6].
The use of services is often based on registration at the providers site. A user of several services has a multitude of login names and passwords. Also, payments for these services go directly to each provider, normally using credit cards. It is risky to send credit card numbers over the web and the user may not have any knowledge of how trustworthy the service provider is [99, page 6].
Today incompatible pages, usually made by Java script, have become a problem. These pages do not work perfectly with different browsers.
Directories are logical data repositories to save and to search for information. Directory services are important in helping users to find information on the network. Directory services must be reliable and secure in performance. Directories are used for example in saving personal data with telephone numbers and e-mail addresses. Data is often saved in a logical tree form.
Special programs on the Internet have basic directory functions
(mapping names to addresses and visa versa). The Domain Name System
(DNS) provides these directory services on the Internet by
mapping domain names to IP addresses, thus providing routing
information for domain names.
A directory is a logical place for usernames and passwords as well as for public-key data such as certificates and keys. Another use of directories is yellow-pages functions, where searches find all entries in the directory where attributes satisfy some search criteria. Policy-based networks (PBNs) and guaranteed Quality of Service (QoS) applications are also driving the demand for directories [67].
There is a need to consolidate directory data. When intranet systems are expanded to extranet systems, there is a problem of combining different types of directories and databases. A standardized model of directories will help this integration. Decreasing the number of directories means cost savings, higher data quality and lower security hazards [67]. Development of an application is also easier if all the information is available in directories using standardized protocols [77].
7. Future Service Platforms
Current architectures in service management are based on management protocols like Simple Network Management Protocol (SNMP) and Common Management Information Protocol (CMIP) or trouble ticketing interface [20, page 167].
In the Web-based architecture the
customer downloads an applet that communicates with a proxy server in
the service providers domain. The proxy
server interacts with the actual inter-domain management system. It is
possible to use standard gateways like IBM Webbin or build a service
specific solutions in order to simplify the funtionality at the
customer site. This makes download times shorter and there is less
need for code [20, page 167].
The inter-domain management system implements the interactions with co-operating service providers. Requests to the local domain are processed by the intra-domain management system and then forwarded down the hierarchy to the network managers and finally to the network element managers [20, page 167].
Security restrictions in browsers do not allow applets to interact with local resources, i.e. with the file system or local network nodes. In Netscape Communicator, the security restrictions can be configured based on the right to trust relationships with the applet provider. Signed applets can be given the right to access the local network. This provides also a network management solution for customer premises network [20, page 167].
Figure 7.3 shows a web-based service management architecture. CPN is Customer Premises Network and PN is Public Network.
Figure:
Web-based service management architecture [20, page 167]
 |
This prototype has been developed providing a web based interface covering subscription management, configuration management, alarm surveillance, trouble ticketing as well as accounting management. The usage of the web and Java (applets) simplifies the service interaction between the customer and the service provider. It will reduce the cost on both sides. For service provider it is important to automate the customer care process in order to cut the costs to survive in the emerging competitive market [20, page 168].
2. Hybrid Services
Future services will span many communication infrastructures. Users
will be able, for example, to generate telephone calls from their Web
browsers. These services are called hybrid services. Hybrid services span different network technologies, for
example the Public Switched Telephone Network (PSTN) and
the Internet. Data networks do not offer much support in enabling such
hybrid services other than transport and delivery. Most of the support
for switching, billing, and access control of the calls is done in the
switched network [119, page 167].
The demand for hybrid services is becoming more
important, because cellular networks are already well integrated with
the PSTN. These networks have wide penetration. This makes
purely Internet-based solutions impractical. The PSTN provides a
reliable, available and ubiquitous system, with guaranteed Quality of
Service (QoS). Gbaguidi et al. claim that the PSTN and Internet are
far from being an ideal ground for developing future hybrid services
when taken separately. However, if coupled together they can
complement each other effectively [43, page 9].
The PSTN includes a powerful service creation and provision platform
called Intelligent Network (IN). The design of IN follows a
simple principle: separation of service-specific software from basic
call processing. Before IN services were incorporated in the network
switches in a manner that was specific to each
manufacturer. Introducing new services required software modification
in every switch in the network. It took years to complete such a
process, and it made network operators dependent on their equipment
suppliers. The IN reduced a great deal of this dependency by using
service-specific software [42, page 9].
The Internet has no global service creation and provision framework. New services can be created by any user that can afford a server. Creating new services implies developing a distributed application that must be installed and executed in the terminals and servers. Internet applications take advantage of intelligent terminals and powerful user interfaces [42, page 9].
Gbaguidi et al. [43, pages 9-10] claim that
hybrid services are expected to play a very
important role in the years to come. This is due to both the desire of
users to integrate the ways they communicate and the willingness of
service providers to differentiate their offers from their
competitors. Also, smart cellular phones are expected to fuel the
integration of services.
There has been an extensive work toward validation of services in the
IN or TINA services, bur there has not been much work on
the application of formal methods of Internet to the development of
Internet services or hybrid services [71, page 134]. There are
two main questions:
- Are Internet services and hybrid services any different from other telecommunication services?
- What do the differences mean for the application of formal techniques?
Hybrid services have characteristics that change the way formal
methods should be applied to the design of services. In the following
list there are four important characteristics of hybrid
services [71, page 134-135].
- Interworking of Connection-Oriented and Connectionless Services
Hybrid services combine connection-oriented and
connectionless techniques. There is no commonly accepted call model
for hybrid services. Telecommunications industry uses formal methods
based on specific call models, such as those used in the IN. As long
as formal methods were applied to standardized architectures such as
the IN, in which all services were structured in a similar way by
using service-independent building blocks, the application and reuse
of formal approaches was significantly easier.
The lack of a common call model for hybrid services implies that most
of the work of applying formal techniques to telecommunication systems
has to be revised and checked to see whether and how it can be reused
and adapted for hybrid services.
- Integration of Network-Centric and Terminal-Centric Service Control Mechanisms
In the Internet, services are implemented in end users systems, while the telecommunications community normally has a network-centric vision where services are implemented in the network. These two different views of service control may converge to a service-centric vision for the deployment of hybrid services.
For the use of formal methods in development of hybrid services, it is necessary to consider software running at the user's site and in the network.
- Decreased Service Lifetime and Time to Market
Introducing new services in a telephone or cellular network was a slow process, and the deployed of services were offered for a rather long period. Compared to typical telecommunication services, the time to market of Internet and hybrid services is significantly reduced. As market pressure increases and time to market decreases, increased development time using formal techniques on the development of hybrid services is hardly acceptable. It seems to be more promising to formally express single properties with which a service should comply, rather than developing large abstract service specifications.
- Significantly Increased Heterogeneity
An example of the impact of heterogeneity is the problem of service interactions. A service interaction occurs when the addition of a new feature to a system disrupts the existing services. In most cases it is wanted that the behaviour of a service does not change other services.
Whereas in homogeneous environments the assumptions are relatively easily defined and checked, this is rarely true for telecommunications systems, and definitely not true for hybrid services. As heterogeneity increases in the environment which hybrid services run, more time has to be spent to check whether the implemented service behaves correctly in its environment.
Svanbäck [110] claims that mobile, fixed and Internet networks
converge and create needs among consumers and business to access any
service from any network. The same functionality and service
provision is expected of all terminal devices; telephones, computers,
cable televisions and other equipment. The telecommunications
industry, the computer industry and the media industry are melting
together in the market convergence. Martikainen [74] claims
that convergence creates new rules for service provisioning, branding
and pricing, and opens new business opportunities for agile players,
one being the provision of solutions that tie different networks or
protocols together.
There are some demands that are expected for the future service
platforms. The service platforms should
- provide extensive network services for converging networks [110],
- enable fast time to market for new services,
- provide ease of deployment, configuration, and management,
- use the open, modular, distributed and standardised architecture,
- make use of commercially available hardware and software components,
- ensure application-independent high quality of service and fault tolerance,
- ensure high usability and appropriate diagnostics [74], and
- enable the use of advanced charging mechanisms [65].
8. Problems in Service Management
There are unresolved questions in service management:
- How can management information be shared across administrative domain boundaries in a secure way? This capability is important when a service is composed of components from several service providers.
- How to get measurable aspects from Service Level Agreements (SLAs)? It is unclear how a legal service level agreement document is translated into a measurable specification that can be automatically monitored for compliance.
- How to define metrics and their bounds for service compliance? There are no recommendations and policies to define what the metrics are and how their values are computed.
8. Content management
IP traffic on the Internet and private enterprise networks has been
growing exponentially for some time. Today, the convergence of
computing, telecommunication and digital media is enabled by the
technology, but it is actually driven by the content. For example, in
the case of electronic publishing, lack of established
advertising and billing models and insufficient results have hindered
online advertising [100].
Markus Kajanto states in his doctoral dissertation the notion of
virtualization of content. Kajanto calls the initial content
``primary content'', which is divided into two parts: a virtual part and
a physical part. The virtual part of the content is distributable
through the information network, but the physical part is distributed
outside the information network. What the primary content is, depends
on the industry and application in question. From the Internet service
provider's point of view it is essential that more and more products
are already virtual of their basic nature or can be virtualized by
exploiting information networks. The same applies
also to many business processes, such as commerce, marketing, and
customer service [100].
This chapter describes content management on the
Internet. Section 8.1 gives an overview why content
should be managed. Section 8.2 gives an overview of management
information modeling technologies, such as markup languages, CIM, and
DEN. Finally, section 8.3 gives
examples of content management.
1. Demands for Content Management
In this project we mean content management as determining what kind of
data is transmitted in the network, and managing that data according
to the needs of content suppliers, information intermediaries and
customers. The purpose of the content management is to control the
flow of content during the creation and delivery of any service.
Content supplier usually creates and formulates the original content,
both the physical and the virtual part. Information intermediary
(service provider) is an organization, which matches the content
suppliers to the relevant end customers. It will also have the
knowledge of the content preferences, consumption habits of the end
customers, and what may be the optimal choice for
them [100]. Customers then use the content through the Internet
and may also pay for it. It should be noticed that the content
supplier, information intermediary, and customer usually have
different kinds of demands of content management. The needs for
content management are, for example:
- Security, proprietary rights and licenses
Security and copyright issues must be guaranteed at the satisfying
level. For example, electronic commerce and communications
applications require the security features the most. There is also a
demand for content protection, to provide content owner a mechanism
that can robustly protect copyright and identify rightful ownership in
the court of law and to prevent illegal distribution and easy tracking
of fraud. Techniques used to content protection are for example,
cryptography, authentication, watermarking, and access control in
different services. Users should also be able to check the originality
of the content of a digital product. Content verification can be
performed by attaching digital signatures to the transmitted
data [122].
In the broader sense, content could also mean communications content,
such as desktop videoconference, e-mail, discussion forums, etc. The
difference between the copyright content and the communications
content is that communications content is produced and consumed at the
same time, and it is not stored for the further commercial
use [100].
- Billing
Internet services that provide QoS (e.g. TV and radio over IP) cannot
cover costs using billing models available today [105]. In the
Internet environment, billing has been based on flat rates and
monthly billing and only seldom on the traffic itself. Full deployment
of services with built-in cost sharing functionality could be the
final reason to converge services, such as broadcast media, into the
Internet and make them globally available.
- Location and delivery
Today the information contained on the Internet is unstructured,
unsorted, and difficult to find. For example, current search engines
are limited to textual keywords. There is the desire for Internet
multimedia search engines capable of searching and locating the
relevant sources containing the desired media types given a
description of the specific content. This will be beyond the bounds of
text currently used to formulate queries. Such capabilities could be
achieved with pre-defined, hierarchical categories and use of natural
language [57].
The content must be managed throughout its entire lifetime, from
initial conception and creation, to integration in an application, and
delivery to the user, as well as the eventual archival or
destruction. Information service providers also have multiple
distribution options using a wide variety of client and network
technologies. The key to commercial success is managing information in
such a way that it can be easily located and distributed in a format
that matches the requirements of the requesting client [32]. The
issues of secure access, and secure content and payment transaction
are also essential to the distribution of content.
- Different customer needs
Different customer needs must be provided for by traffic
prioritization and traffic guarantees. For example, policy-based
networking enables the allocation of network resources to
applications, users, and groups based on a set of defined rules. This
approach provides the control over traffic prioritization based on the
business importance of applications.
2. Management Information Modeling Technologies
This section gives a brief summary of markup languages and
object-oriented models (CIM and DEN) that were developed to model
management information.
Markup languages (such as SGML -- Standardized Generalized Markup
Language, HTML -- HyperText Markup Language, and XML -- eXtensible
Markup Language) are designed to add structure and convey information
about documents and data. In markup languages, the main mechanism for
supplying structural and semantic information is by adding to the
document elements comprising a start tag, optionally some content, and
an end tag.
SGML does not enforce any particular set of element types. SGML
provides a means for defining new element types. Because of this, SGML
is thought of as a language for defining markup languages. XML is
similar in concept to HTML (see page
). Whereas HTML is
used to convey graphical information about a document, XML is used to
represent structured data in a document. HTML is an SGML application
targeted at display markup for documents, XML is a subset of SGML
targeted at data representation. It is possible therefore to imagine
the Web as consisting of HTML for display purposes, and XML for data
representation and description purposes [36].
2. Object-Oriented Models
Distributed Management Task Force Inc (DMTF) has developed the
Common Information Model (CIM). CIM is used to model
management information for desktop and server systems. It is also
used to describe management information between different management
applications, such as HP Open View, Microsoft SMS, and Tivoli
Management Software, in order to provide common understanding of
management information.
CIM is an object-oriented conceptual model. It provides a framework, including representation of products, systems, applications, and components that can be managed. It unifies the information coming from many numbers of sources. CIM is not bounded to any particular implementation. It can be implemented as a relational database, as an object database, or as an object/relational database. This allows for the interchange of management information between management systems and applications.
At the present time, there are no CIM based implementations
available. No programming interfaces or protocols are defined by the
CIM document, and hence it does not provide an exchange mechanism. CIM
does not define a common set of APIs (Application Programming Interface)
that software developers can use to make Web management applications
work together. Nor does it specify how the database of gathered
information should be structured. CIM makes also no mention of the
communications protocol that should be used for moving all that
information around. So it is difficult for vendors to develop software
that can integrate data gathered by third-party
applications [66].
Version 1.0 of the DMTF's CIM XML encoding specification was announced
in 1998.
The Directory Enabled Network (DEN) specification provides a schema and informational model for representing network elements and services in a directory. The primary purpose of DEN is to separate the specification and representation of network elements, and services from implementation details.
In a directory enabled network user profiles, applications, and network services are integrated through a common information model that stores network state and exposes network information. This information enables bandwidth utilization to be optimized, it enables policy-based management, and it provides a single point of administration of all network resources.
The philosophy of network management is shown in figure 8.1. Network management protocols (SNMP, CMIP, RMON) are used to talk to the network elements. The network schema extensions for the directory service are used to talk about network elements.
Figure:
Directory service and network management [58]
 |
The integration of the network infrastructure with the directory
service allows the applications and users to discover the existence of
devices and relationships by querying the directory service. This is
more scalable and manageable than contacting the individual devices
and aggregating the results. Exposing network elements in the
directory enhances their manageability and usability while reducing
the load on the network. The end user and administrator experiences are
enhanced because there is a single authoritative place to obtain the
information of interest. One example of how the network wide data might
be used is to set up and tear down a certain level of QoS at a given
time for a specified user across many network resources.
3. Examples of Content Management
In the relation of information provider and end-user the core benefit
of content management can be described: ``information is managed so the
right people receive the right information at the right
time'' [52]. With today's information glut, the value of
information increases, when the content is managed in such a way to
apply the stored information to the right people in an efficient
way. The benefit can be ensured in many ways. The next examples will
describe some of these different ways and they also reflect how widely
content management is understood by different people. First, this
section will deal with the examples where the end-user is the right
person, and secondly the benefits of content management for the
information provider.
1. Multimedia Content Management
The purpose of a multimedia content management system is to control
the flow of content during the creation and delivery of any multimedia
service offering. The content must be managed throughout its entire
lifetime, from initial conception and creation, to integration in an
application, and delivery to the user, as well as the eventual
archival or destruction. This entails managing content across a number
of different organizations and over an extended time period. Practical
experience of the benefits of providing extensive content management
systems has come for example in the areas of interactive television,
web services, multimedia kiosks and video streaming to the corporate
desktop [32].
2. Content Management and the End-user
End-users will not continue to use a service, let alone pay for it, just because it has the best technology. They are usually more concerned with the content of the service [32].
- Content personalization service
A multimedia service can be significantly enhanced if it is able to
pre-empt the need of each user, automatically supplying the information
the user wants without prompting, tailored to the user's current
environment. This kind of service can be called personalization
service. Personalization and adaptation of information systems to
personal needs and personal interests become more and more
important. The trend to offer a user the most suitable and narrowed
down multimedia information can be seen in research prototypes from
different research areas, e.g. an adaptive tutorial agent, adaptive
textbooks on the WWW, personalized newspaper, personalized news
delivery etc. [18].
The different requirements of each user create a problem for authors
and distributors of information. Typically, the author must either
limit the types of user and client technology that can access the
information, or else create significantly different versions of the
information, each targeted to a particular user group. For instance
the authors of a simple Web page need to remember that the page should
be viewable by a wide variety of clients, including web-tvs, personal
organizers and advanced mobile phones. The wireless application
protocol (WAP) provides a service for wireless mobile terminals by
automatically adjusting Web pages for presentation [32]. Also,
the end-user has the possibility to view the same content via
different delivery channels. For instance, it is possible to view a
film via terrestrial analogue, satellite analogue, cable analogue and
pre-recorded VCR tapes and DVD, soon via digital terrestrial, digital
satellite and digital cable. This range of distribution channels can
actually confuse the viewer (the user of the content). Therefore one
objective is simplifying the situation for the user [31].
- Content validation service
Content validation service is the task of ensuring that the media
content of the service is correct. Content validation can be broken
into four task categories. Syntactic validation is the process of
ensuring that the media content is technically correct without
reference to its actual value. Syntactic validation will ensure that
the media is in the correct format and playable by the system expected
to receive it. Semantic validation is the process of determining if
the content matter is correct in its current use context and whether
it can safely be passed to the next stage of the media production
process. Semantic validation is the core of any useful validation
system. Once a piece of content has been validated, the details of the
validation check and its result should be added to the metadata
information associated with the content. The information can then be
used by future validation services to increase the speed and accuracy
of the service. Finally, in order for a validation service to be
effective, the information on which a validation result is based must
be completely trustworthy. Therefore, it is vital that automatic
services for the encryption and digital signing of all content
packages is provided as part of any validation service. The inclusion
of digital watermarking can also be included under this
task [32].
- Filtering programs
Filtering programs are a part of the semantic validation process. There
is a lot of inconvenient content in the web. What is
inconvenient depends on the end-user, are they children surfing in the
web or company's employees working at the business hours. There are
two types of filtering software -- client based software filtering and
server based software filtering.
The client filtering software programs are individual programs. At the
moment there are programs that go by names like Surf Watch, Cyber
Patrol, Net Nanny and Cyber Sitter in the market. These are mainly
meant to filter the unsuitable content to young audience. In general,
these programs come with a pre-determined list of inappropriate sites
with the option to subscribe to the updated list of sites. Some of
these programs also have controls that can be set to be tighter or
looser at filtering based on certain words and phrases. However,
without updating and continued monitoring, this type of software
becomes less effective over time as additional inappropriate sites are
placed online. The software works by blocking the unsuitable content
from the user [127].
There are not so many server based filtering software solutions
available. One of the more popular server filtering program is I-Gear
by URLabs. The server approach involves a main computer, usually
designated for Internet only applications. The server is the main
gateway between the local network and the Internet. As the gateway,
the server is able to function as a web host, an e-mail host and a
filtering interface to all of the computers on the local network. By
having a server controlling all Internet features of a connection,
there are many more options available for management of the content
available on the Internet. Server software has the capability to
control what computers on the network can access from the Internet and
at what times, as well as the ability to cache Web pages
requested. Server filtering software has the capability to regulate
access by requiring the user to have a log-in account. An example of
how I-Gear works: when a Web page from the Internet is requested, the
List Agent compares the URL with a list stored in the I-Gear subject
categories, then the URL is either denied or allowed. Next, the DDR
(Dynamic Document Review) Agent reviews each page of web traffic
looking for unconditionally vulgar words and replaces them with
``- - - -''. The Local DDR Agent also reviews the documents for any
words that have been added to the category list based on local
community standards or determined inappropriate for the
setting. Finally, the Post Agent views words posted to the Internet
and searches for items that have been rated unconditionally
vulgar. Based on the criteria set, the agent either allows the
requested Web page to be displayed in the browser or the user views a
message indicating the reason that the requested page will not be
displayed [127]. This kind of software works well for the
protection of children at homes and at schools. URLabs I-Gear for
FireWall-1 is a content management solution for organizations
concerned about providing Internet access for their employees. It
enables organizations to ensure that the Internet usage is focused on
business during core hours and permits the option of open, unmonitored
access after hours [88].
The Internet population is already big and growing fast. The question
is how can the potential value of the Internet be well employed? What
is the potential value of e-distribution? First of all, techniques
that facilitate easy and quick browsing, retrieval, manipulation and
secure access, transaction and purchasing of multimedia content
through Internet are needed [132].
``EMusicOnline'' is a music purchasing scenario illustrating the
potential capability and advantages of on-line information
representation, retrieval, browsing, transaction and purchasing. A
corresponding scenario for video renting is ``EVideoOnline''. Instead
of going to the store, music can be purchased by logging into
EmusicOnline. It is possible to search for new songs and listen to a
sample of each song before the decision of buying it. It is also
possible to buy just certain songs instead of an entire CD. No one has
to worry about the songs being sold out. The distribution takes place
by downloading the file. With EvideoOnline the renting starts by
logging into EVideoOnline and specifying the preferred movies. As
search results the service presents a list of movie titles alone with
a short description. It is possible to see the story board, a list of
key frames and a short presentation video on the chosen video. Renting
is charged with credit card, the rent-per-view fee. Distribution takes
place again by downloading the file. For these kind of services, there
are still technical challenges to be solved [132].
4. Benefits of Content Management to the Content Provider
The Banta Corp. and Glyphica [10,44] claim that managing
the content creates lower costs in production and in distribution of
the content. It also enables the use of new channels of distribution
like the Internet, laser disc, DVD and VoD. Accessing the content is
also easier. Content management also enables better protection of
content by automatically managing intellectual property
rights. Personalizing the content for target audiences and individual
end-user gives the possibility for the company to gain greater
profits. As the company has better control over the information
provided, they also have better control over the company image on the
global market.
Content providers have also realized that they can generate significant profits by reusing, re-expressing, or re-purposing old content. For example, newspapers can be published also on the Internet and TV and motion pictures can be published in a digital TV with digital special effects added. For this reason, media and entertainment companies are seeing that effective management of their old and new content will allow them to maximize their profits [3].
- Web Site Administration
While creating HTML pages is getting more and more simple, the
administration of a web site is still a time consuming and a demanding
task. Available tools for web content management only cover some of
the relevant aspects of the whole task -- an integrated, fully
functional solution is still missing. Web administrators still have to
cope with many problems, such as ensuring validity of documents for
instance management of document availability and expiration, or
avoiding invalid links. Other current problems concern the maintenance
of document validity -- as soon as the document gets outdated, it
should be removed in order to avoid waste of resources and to
guarantee topicality. Besides a topic index many Web sites maintain a
search engine helping to find local documents. Nevertheless, documents
of interest may not be found because index data is gathered and
updated only periodically and documents can exclusively be reached via
hyperlinks. Keeping index data topical is a general problem to be
solved. On corporate Web sites, a homogeneous page layout is wanted to
establish corporate identity. Therefore, templates or style files have
been used to create new documents. Nevertheless, due to the
multiplicity of information providers and daily changing Web site
content, it is rather difficult to observe compliance with internal
style guides. It is obvious that Web site administration is a very
demanding task [70]. The present content management systems
available can though ensure that the site can handle the explosive
growth of information, it also allows people to make simple changes
without being concerned that a major modification could negatively
affect the whole site accidentally [83]. For example iWebDB --
Web Site Administration based on Object-Relational Database Technology
-- is an integrated database for Web content management, designed to
meet the requirements of Web site administrators [70].
Companies also feel the need to personalize their Web sites. When
asked what are the biggest obstacles they face with Web site
personalization, almost a half of the companies felt that it was
understanding what content to deliver according to a
survey by Wilde [129]. Between 10 to 20 percent of the companies felt that
not enough resources, getting the technology to work, analyzing the
data, keeping content fresh or internal organizational challenge was
the biggest problem. Also, making personalization easy for users,
integrating legacy systems and showing personalizations's value to
users caused some problems [129].
IBM Research has studied HDTV broadcast technology. Within this
project, a content management system for a TV studio has been
developed. The rest of this section is a quote from [50].
Managing content in a studio involves a number of critical issues
including copyright protection and content re-purposing. The system
must be scalable, provide high availability, ensure the un-compromised
integrity of content, limit access to only authorized users and enable
the quick retrieval of archived material.
Figure:
Content management in a studio [50]
 |
The architecture of such a content management system is illustrated in
figure 8.2. The heart of the system is a library server (or
content manager), which maintains the directories and metadata for the
content stored on the media servers. The media servers store and
stream the content to clients in a real-time fashion. In addition they
are responsible for storing and maintaining the time-invariant
metadata of their own content. This includes playout information such
as shot and frame indexing. An annotation station is provided for
logging (ingesting) new content into the system. As new content is
ingested, the annotation station will create metadata that can later
be used to perform searches on the content. It stores the metadata on
the library server and, simultaneously, the content itself is stored
on one of the media servers. Once ingested, the browse station is able
to search, browse and retrieve content stored anywhere in the
studio. This content includes video, audio, text, data, graphics,
animation, and images.
The library server is the single centralized store of metadata for all
content in the studio. Although it is a single logical entity, it can
be instantiated as a cluster of machines to achieve high availability
and support large amounts of content. Alternatively, in smaller
studios, the library server, media servers and even the SRM (Scalable
Reliable Multicast) can be implemented on a single machine. The
metadata in the library server includes time-invariant and
time-variant metadata, among which are shot length and visual
motion. Content in the studio will be identified by a single key which
will be unique within the studio and, in some cases, industry-wide
(such as an extended-ISCI or a SMPTE 298M Universal Media
Identifier).
The annotation station permits manual annotation and performs
automatic annotation for incoming content. As video is ingested, it
will perform an automatic annotation that includes shot-boundary
detection, face detection, and keyframes selection. The logger may
also manually enter bibliographic data, a description of the program,
and other metadata. This may include copyright and access information
for each clip.
9. Commercial Network Management Products
HP OpenView
Hewlett-Packard
In addition to traditional network management features, HP OpenView includes systems management and service management features. Users are provided with Web/Java-based and traditional user interfaces.
http://www.openview.hp.com
SUN Solstice
Sun Microsystems
Solstice is a traditional network management application. Different versions are provided for SOLARIS, Windows and Web/Java-based environments, and for TMN and SNMP network management.
http://www.sun.com/solstice
Java Dynamic Management Kit
Sun Microsystems
Java Dynamic Management Kit (JDMK) is the first application using JMAPI technology (for more information on JMAPI, see section 4.3). JDMK helps to develop Web-based management services using Java agents or JavaBeans for Management -technology.
http://sun.com/software
TIVOLI
IBM
TIVOLI is a network management system that contains features that meet the requirements of especially demanding network environments. The product is aimed at both enterprises and network operators.
http://www.tivoli.com
CYBERMANAGE
Wipro Limited
CYBERMANAGE is a Web-based network manager. Development tools are included.
http://cybermanage.wipro.com/index1.html
SPECTRUM
CABLETRON Systems
http://www.cabletron.com/spectrum
INTEL LANDesk
Intel
http://www.intel.com/network/products/LANDesk_srvr_mgr.htm
ASANTEVIEW
Asante Technologies, Inc.
http://www.asante.com/products/p_soft_int.html
UNICENTER TNG
Computer Associates
http://www.cai.com
CONCORD
Concord Communications
http://www.concord.com/products.htm
CLEARSTATS
RedPoint Network Systems
http://www.redpt.com/ClearStats/
NETSCOUT WEBCAST
Netscout
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IBM.
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3COM.
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ATM FORUM.
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Digital content management.
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In Proc. High Performance Networking, HPN'98 (Vienna,
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BLAKE, S., BLACK, D., CARLSON, M., DAVIES, E., WANG, Z., AND WEISS, W.
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RFC 2475 (Dec. 1998), 36.
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BLIGHT, D. C., AND HAMADA, T.
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BLUMENTHAL, U., AND WIJNEN, B.
User-based Security Model (USM) for version 3 of the Simple
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RFC 2274 (Jan. 1998), 76.
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BOLL, S., KLAS, W., AND WESTERMAN, U.
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BUSSE, I.
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DISTRIBUTED MANAGEMENT TASK FORCE, INC.
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DROMS, R.
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GLYPHICA.
Content management.
Nov 15, 1999
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HARKINS, D., AND CARREL, D.
The internet key exchange (IKE).
RFC 2409 (Nov. 1998), 41.
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HARRIS, S. J.
Proactive service management: Leveraging telecom information assets
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IBM RESEARCH.
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ICL.
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INTERNATIONAL LEARNINGS SYSTEMS, INC.
Content management.
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INTERNET ENGINEERING TASK FORCE.
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KENT, S., AND ATKINSON, R.
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RFC 2401 (Nov. 1998), 66.
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KERTTULA, E.
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NICHOLSA, K., BLAKE, S., BAKER, F., AND BLACK, D.
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OBJECT MANAGEMENT GROUP.
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WARRIER, U., AND BESAW, L.
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WIJNEN, B., PRESUHN, R., AND MCCLOGHRIE, K.
View-based Access Control Model (VACM) for the Simple
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WILDE, C.
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ZHANG, L., DEERING, S., ESTRIN, D., SHENKER, S., AND ZAPPALA, D.
RSVP: A new resource ReSerVation Protocol.
IEEE Network 7, 5 (Sept. 1993), 8-18.
- Abstract Syntax Notation One
- see ASN.1
- access control
- 3. Security Management
- Access Control List
- see ACL
- accounting management
- 4. Management Functional Areas
| 2. TMN Management Layers
- ACL
- 3. Security Management
- ADSL
- 2. Future trends
- alarms
- 1. Transferring information
- API
- CIM
- 2. Object-Oriented Models
- JMAPI
- 3. Java Management Extensions
| 9. Commercial Network Management
- XMP
- 1. Anticipated Implementation Technologies
- Application Programming Interface
- see API
- ASN.1
- 2. Information Model
- Asymmetric Digital Subscriber Line
- see ADSL
- authentication
- 3. Security Management
| 1. Authentication and Authorization
| 1. Authentication and Authorization
- authorization
- 1. Authentication and Authorization
- B-ISDN
- 4. ATM Network Management
- Basic Reference Model for Open Distributed Processing
- see RM-ODP
- Bayesian Networks
- see BN
- BN
- 1. Performance analysis
- BOOTP
- 1. TCP/IP Networks
- Bootstrap Protocol
- see BOOTP
- Broadband ISDN
- see B-ISDN
- Cable television
- see CATV
| 1. IP Networks and
- CAC
- 1. Communications in IP
| 1. IETF Integrated Services
- Case-Based Reasoning
- see CBR
- CATV
- 2. Future trends
| 1. IP Networks and
| 1. IP Networks and
| 1. IP Networks and
- CBR
- 1. Performance analysis
- CCB
- 4. Customer Care and
- CIM
- 5. Common Information Model
| 2. Object-Oriented Models
- Class of Service
- see CoS
- CMIP
- 2. Common Management Information
| 7. Future Service Platforms
- CNM
- 3. Customer Network Management
- Common Information Model
- see CIM
- Common Management Information Protocol
- see CMIP
- Common Object Request Broker Architecture
- see CORBA
- confidentiality
- 3. Security Management
- configuration management
- 4. Management Functional Areas
| 2. TMN Management Layers
| 2. TINA Network Management
| 1. Configuration Management
- Connection Admission Control
- see CAC
- constraint-based routing
- 4. Traffic Engineering and
- CORBA
- 1. X/Open Systems Management
| 4. CORBA-based Telecommunication Network
- CoS
- 2. Differentiated Services Architecture
| 5. Difficulties in Development
- CPN
- 1. Web-based Architecture
- Customer Care and Billing
- see CCB
- Customer Network Management
- see CNM
- Customer Premises Network
- see CPN
- DDR
- 2. Content Management and
- delay
- 1. Communications in IP
- DEN
- 2. Object-Oriented Models
- DHCP
- 1. TCP/IP Networks
- Differentiated Services
- see DiffServ
- DiffServ
- 2. Differentiated Services Architecture
- DS field
- 2. Differentiated Services Architecture
- Directory Enabled Network
- see DEN
- Distributed Management Task Force Inc
- see DMTF
- DMTF
- 2. Object-Oriented Models
- DNS
- 1. TCP/IP Networks
| 4. Directories
- Domain Name Service
- see DNS
- Dynamic Document Review
- see DDR
- Dynamic Host Configuration Protocol
- see DHCP
- dynamic routing protocols
- IS-IS
- 4. Traffic Engineering and
- OSPF
- 4. Traffic Engineering and
- RIP
- 4. Traffic Engineering and
- end-to-end@ services
- 1. Motivation
- expert systems
- 3. Fault Management
| 1. Performance analysis
- eXtensible Markup Language
- see XML
- fault management
- 4. Management Functional Areas
| 2. TMN Management Layers
| 3. Fault Management
- Fault, Configuration, Accounting, Performance and Security Management
- see FCAPS
- FCAPS
- 4. Management Functional Areas
| 1. TMN Management Services
| 2. TINA Network Management
| 2. Management Functionality
- File Transfer Protocol
- see FTP
- firewalls
- dual-homed host architecture
- 2. Access Control Tools
- packet filtering
- 2. Access Control Tools
- proxy services
- 2. Access Control Tools
- screened host architecture
- 2. Access Control Tools
- screened subnet architecture
- 2. Access Control Tools
- flows
- elastic flows
- 1. Different Types of
- stream flows
- 1. Different Types of
- FTP
- 2. Access Control Tools
| 1. Different Types of
| 2. Security Problems of
- GoS
- 1. Communications in IP
- Grade of Service
- see GoS
- HDSL
- 2. Future trends
- HFC
- 2. Future trends
- High bit-rate Digital Subscriber Line
- see HDSL
- HTML
- 2. Web-based Network Management
| 2. WWW Service Platforms
| 2. WWW Service Platforms to 2. WWW Service Platforms
| 3. Problems
| 1. Markup languages
- HTTP
- 2. WWW Service Platforms to 2. WWW Service Platforms
- hubs
- 2. Access Control Tools
- Hybrid Fiber-Coax
- see HFC
- hybrid services
- 2. Hybrid Services
| 2. Hybrid Services
| 2. Hybrid Services
| 2. Hybrid Services
| 2. Hybrid Services
| 2. Hybrid Services
| 2. Hybrid Services
- hybrid@ services
- 2. Hybrid Services
- HyperText Markup Language
- see HTML
- Hypertext Transfer Protocol
- see HTTP
- IAP
- 2. Future trends
- ICMP
- 2. Troubleshooting and Fault
- IETF
- 1. Protocols and Programs
| 2. New Service Model
| 1. IETF Integrated Services
| 2. Differentiated Services Architecture
| 3. Multi-protocol Label Switching
| 2. Internet Pricing
- IKE
- 1. Protocols and Programs
- IN
- 1. IP Networks and
| 2. Hybrid Services
| 2. Hybrid Services
| 2. Hybrid Services
- Integrated Services
- see IntServ
- Integrated Services Digital Network
- see ISDN
- integrity
- 3. Security Management
- Intelligent Network
- see IN
- International Telecommunication Union -- Telecommunication standards
- see ITU-T
- Internet Access Provider
- see IAP
- Internet Control Message Protocol
- see ICMP
- Internet Engineering Task Force
- see IETF
- Internet Key Exchange
- see IKE
- Internet Security Association & Key Management Protocol
- see ISAKMP
- Internet Service Provider
- see ISP
- IntServ
- 1. IETF Integrated Services
- IP
- 2. Demand and Supply
| 1. IP Networks and
| 1. Authentication and Authorization
| 1. Authentication and Authorization
| 2. Security Problems of
| 2. Internet Pricing
| 1. Managing New Services
| 4. Directories
- IP Security Architecture
- see IPSec
- IPSec
- 1. Protocols and Programs
- IP authentication header (AH)
- 1. Protocols and Programs
- IP encapsulating security payload (ESP)
- 1. Protocols and Programs
- ISAKMP
- 1. Protocols and Programs
- ISDN
- 1. IP Networks and
- ISO
- 7. Service Management
- ISP
- 5. Difficulties in Development
| 1. Authentication and Authorization
- ISTU-T
- 3. Signalling System #7
- ITU-T
- 1. OSI Management
| 2. Telecommunications Management Network
| 1. TMN Management Services
| 1. TMN Management Services
| 4. CORBA-based Telecommunication Network
| 7. Service Management
| 3. Security Management
- Java Management API
- see JMAPI
- Java Management Extensions
- see JMX
- jitter
- 1. Communications in IP
| 2. Performance metrics
- JMAPI
- 3. Java Management Extensions
| 9. Commercial Network Management
- JMX
- 3. Java Management Extensions
- logs
- 1. Transferring information
- Management Information Base
- see MIB
- MANET
- 2. Future trends
- MBR
- 1. Performance analysis
- Mean Time Between Failure
- see MTBF
- Mean Time To Repair
- see MTTR
- MIB
- 2. Information Model
| 1. Simple Network Management
| 2. SNMP Security
| 1. Transferring information
- Mobile Ad-hoc Networking
- see MANET
- Model-Based Reasoning
- see MBR
- MPLS
- 3. Multi-protocol Label Switching
- MTBF
- 1. Configuration Management
- MTTR
- 1. Configuration Management
- Multi-Protocol Label Switching
- see MPLS
- NAT
- 2. Access Control Tools
- Network Address Translation
- see NAT
- Network File System
- see NFS
- Neural Networks
- see NN
- NFS
- 2. Security Problems of
- NN
- 1. Performance analysis
- non-repudiation
- 3. Security Management
- Object Management Group
- see OMG
- Object Request Broker
- see ORB
- OMAP
- 3. Signalling System #7
- OMG
- 4. CORBA-based Telecommunication Network
- Open Systems Interconnection
- see OSI
- open systems interconnection (OSI) management
- 1. OSI Management
- Operations, Maintenance and Administration Part
- see OMAP
- ORB
- 1. Anticipated Implementation Technologies
- OSI
- 1. OSI Management
| 4. Management Functional Areas
| 2. Telecommunications Management Network
| 1. TMN Management Services
| 1. TINA Architecture
| 3. Network Management Protocols
| 2. Common Management Information
| 3. Signalling System #7
| 1. X/Open Systems Management
- FCAPS
- 4. Management Functional Areas
| 1. TMN Management Services
| 2. TINA Network Management
| 2. Management Functionality
- layers
- 2. New Service Model
- packet inter net groper
- see ping
- PAT
- 2. Access Control Tools
- PBN
- 7. Policy-Based Networking
| 4. Directories
- PCT
- 1. Protocols and Programs
- performance management
- 4. Management Functional Areas
| 2. TMN Management Layers
| 3. Performance Management
- performance analysis
- 1. Performance analysis
- performance management control
- 3. Performance management control
- performance metrics
- 2. Performance metrics
- ping
- 2. Troubleshooting and Fault
- Plain Old Telephone Service
- see POTS
- PN
- 1. Web-based Architecture
- policy
- 7. Policy-Based Networking
- Policy-Based Networking
- see PBN
- polling
- 1. Transferring information
- Port Address Translation
- see PAT
- POTS
- 2. Future trends
- Private Communication Technology
- see PCT
- PSTN
- 1. IP Networks and
| 2. Hybrid Services
| 2. Hybrid Services
- Public Network
- see PN
- Public Switched Telephone Network
- see PSTN
- QoS
- 7. Policy-Based Networking
| 1. Communications in IP
| 1. Different Types of
| 1. Different Types of
| 2. New Service Model
| 5. Difficulties in Development
| 2. Billing
| 2. Internet Pricing
| 2. Internet Pricing
| 4. Directories
- QR
- 1. Performance analysis
- Qualitative Reasoning
- see QR
- Quality of Service
- see QoS
- RADIUS
- 2. Internet Pricing
- RBR
- 1. Performance analysis
- Real-time Traffic Flow Measurement
- see RTFM
- Remote Authentication Dial-In User Service
- see RADIUS
- Remote Procedure Call
- see RPC
- resource management
- 2. TINA Network Management
- Resource ReSerVation Protocol
- see RSVP
- RM-ODP
- 1. TINA Architecture
- RMON
- 2. Object-Oriented Models
- routers
- 2. Access Control Tools
- routing tables
- 3. Testing
- RPC
- 1. Anticipated Implementation Technologies
- RSVP
- 1. IETF Integrated Services
- RTFM
- 2. Internet Pricing
- Rule-Based Reasoning
- see RBR
- S-HTTP
- 1. Protocols and Programs
- S/MIME
- 1. Protocols and Programs
- SA
- 1. Protocols and Programs
- Scalable Reliable Multicast
- see SRM
- Secure HTTP
- see S-HTTP
- Secure Multipurpose Internet Mail Extension
- see S/MIME
- Secure Shell
- see SSH
- Secure Socket Layer
- see SSL
- secure telnet
- see stelnet
- Security Association
- see SA
- security management
- 4. Management Functional Areas
| 2. TMN Management Layers
| 2. Security Management
- service providers
- 7. Service Management
| 1. Motivation
| 2. Service Providers
| 3. Service Users
| 1. Customer Care
| 4. Demands for Electronic
| 2. Internet Pricing
| 1. Managing New Services
| 3. Problems
| 1. Web-based Architecture
| 1. Web-based Architecture
- Service-Level Agreements
- see SLA
- service@ providers
- 1. Motivation
- SGML
- 2. WWW Service Platforms
| 1. Markup languages
- Signalling System #7
- see SS#7
- Simple Network Management Protocol
- see SNMP
- SLA
- 1. Motivation
| 2. Service Providers
| 1. Customer Care
| 8. Problems in Service
- SMFs
- 3. Systems Management Functions
- SMI
- 2. Information Model
- SNMP
- 1. Simple Network Management
| 3. Testing
| 5. Accounting Management
| 5. Accounting Management
| 2. Internet Pricing
| 7. Future Service Platforms
- agent-manager concept
- 1. Simple Network Management
- network management station (NMS)
- 1. Simple Network Management
- user-based security model (USM)
- 2. SNMP Security
- view-based access control model (VACM)
- 2. SNMP Security
- SRM
- 5. Case: Content Management
- SS#7
- 3. Signalling System #7
- SSH
- 1. Protocols and Programs
- SSL
- 1. Protocols and Programs
- Standardized Generalized Markup Language
- see SGML
- stelnet
- 1. Protocols and Programs
- Structure of Management Information
- see SMI
- Systems Management Functions
- see SMFs
- TCP
- 2. Security Problems of
- Telecommunications Information Networking Architecture
- see TINA
- Telecommunications Management Network
- see TMN
- Telecommunications Operations Map
- see TOM
- TELNET
- 2. Security Problems of
- TINA
- 5. Telecommunications Information Networking
| 2. Hybrid Services
- TMN
- 2. Telecommunications Management Network
- TMN Management Service
- see TMN-MS
- TMN Systems Management
- see TMN-SM
- TMN-MS
- 1. TMN Management Services
- TMN-SM
- 1. TMN Management Services
- TOM
- 4. SMART TMN
- traceroute
- 2. Troubleshooting and Fault
- UDP
- 2. Security Problems of
- Uniform Resource Locator
- see URL
- URL
- 2. WWW Service Platforms to 2. WWW Service Platforms
- Video on Demand
- see VoD
- Virtual Private Network
- see VPN
- VoD
- 1. IP Networks and
| 1. IP Networks and
- VPN
- 1. IETF Integrated Services
- WAP
- 2. Content Management and
- web-based
- service management architecture
- 1. Web-based Architecture
- architecture
- 1. Web-based Architecture
- network management
- 2. Web-based Network Management
- Wireless Application Protocol
- see WAP
- World Wide Web
- see WWW
- WWW
- 4. Customer Care and
| 2. WWW Service Platforms
| 2. WWW Service Platforms
| 2. WWW Service Platforms
- X.800
- 3. Security Management
- X.900
- see RM-ODP
- X/Open Management Protocols API
- see XMP
- XML
- 1. Markup languages
| 2. Object-Oriented Models
- XMP
- 1. Anticipated Implementation Technologies
IP network management
This document was generated using the
LaTeX2HTML translator Version 98.2 beta6 (August 14th, 1998)
Copyright © 1993, 1994, 1995, 1996,
Nikos Drakos,
Computer Based Learning Unit, University of Leeds.
Copyright © 1997, 1998,
Ross Moore,
Mathematics Department, Macquarie University, Sydney.
The command line arguments were:
latex2html -split 0 -show_section_numbers -local_icons doku.tex
The translation was initiated by Jouni Karvo on 2000-02-11
Footnotes
- ... (Tivoli)
- See ch. 9 for commercial network management products.
- ... (MTBF
- Mean Time Between Failure
- ... MTTR
- Mean Time To Repair
- ...NAT
- Network Address Translation is a method of
connecting multiple computers to the Internet using one IP address.
- ...PAT
- Port Address Translation is a method of translating all
local private addresses to a single globally registered IP address.
- ... systems
- Expert systems are discussed briefly on page
- ...GoS
- Grade of Service (GoS) is traditionally
related to connection-oriented telecommunications. In this
document, GoS is also used in the context of IP networks.
- ... over-provisioning
- According to S. Shenker
in [97], over-provisioning is not cost-effective in networks
with real-time applications because of high variance in traffic.
- ...
group
- http://www.ietf.org/html.charters/intserv-charter.html
- ...
Protocol
- See [130] for the use of Resource
Reservation Protocol with Integrated Services
architecture.
- ... flows
-
According to L. Massouliè and J. Roberts in [75], CAC should
also be used for elastic flows. They argue that there is a minimum
acceptable level of throughput for elastic flows, below which users
gain no utility. Besides preserving QoS, CAC would also prevent
instability and congestion collapses caused by uncontrolled
retransmission of lost packets [75, pages 33-34].
- ... group
- http://www.ietf.org/html.charters/diffserv-charter.html
- ... scheme
- Admission Control is not used in DiffServ architecture. Thus only priorities between different classes are guaranteed. Within each class, packets receive best-effort service.
- ... field
- The DS field stands for Type of Service (TOS) byte in IPv4 and for Traffic Class byte in IPv6.
- ... group
- http://www.ietf.org/html.charters/mpls-charter.html
- ...
domain
- An MPLS domain consists of MPLS-capable routers,
called Label Switching Routers (LSRs).
- ... label
- Labels are distributed to set up Label Switched
Paths (LSPs) using Label Distribution Protocol
(LDP) [131].
- ... table
- Forwarding table is constructed as the result of label distribution [131].
- ... RIP
- Routing Information Protocol,
see [48, ch. 4].
- ... OSPF
- Open Shortest Path First,
see [48, ch. 5].
- ... IS-IS
- Intra-Domain Intermediate
System to Intermediate System Routing, see [48, ch. 6].
- ... benefit
- Charging would ensure only the most performance-sensitive applications would request higher service.
- ...SNMPSNMPv3
- See section 3.1 for Simple Network Management Protocol (SNMP).
- ... time
- Connection time for connectionless communications would be difficult to measure (except for dialup access).
- ... router
- The nature of IP is that not every packet received by a router is actually passed to an output port, but can be discarded for example at times of congestion.
- ...
group
- http://www.ietf.org/html.charters/radius-charter.html
Jouni Karvo
2000-02-11