
\chapter{Network Management Models}
\label{ch:nmm}

This chapter describes models that are used to structure the problems and ideas in network management. Section~\ref{sec:osi} studies the OSI network management models, and section~\ref{sec:tmn} describes the TMN network management model. Management of customer networks is briefly addressed in section~\ref{sec:cnm}. SMART TMN, described in section~\ref{sec:stmn}, has a broader scope on network management. Finally, network management for the TINA architecture is studied in section~\ref{sec:tina}.


\section{OSI Management}
\label{sec:osi}

\index{open systems interconnection (OSI) management} The Open Systems
Interconnection (OSI\index{OSI}) Management is documented in ITU-T\index{ITU-T}
and CCITT X.700-series Recommendations~\cite{a11}. It is based on four
components: \textit{Management Model, Information Model, Communication
Protocol for Transferring Management Information}, and \textit{Systems
Management Functions}. OSI Management functionality is divided into
five \textit{Management Functional Areas} according to the \textit{OSI
FCAPS model}~\cite{a2}. 
%\begin{itemize}
%\item Management Model,
%\item Information Model,
%\item Communication Protocols for Transferring Management Information, and
%\item Systems Management Functions.
%\end{itemize}

The transfer of management information in OSI networks is provided by
Common Management Information Protocol (CMIP, see
page~\pageref{sec:cmip})~\cite{a12}.
% The management operations and notifications are transferred using Common Management Information Protocol (CMIP)~\cite{a12}.


\subsection{Management Model}
\label{manageragent}

The Management Model describes a manager-agent concept (figure~\ref{fig:manageragent}). 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~\cite{a5, a12, a18, rfc1095}.

\begin{figure}[htb]
\begin{center}
\epsfxsize1.0\textwidth
\epsfbox{kuvat/manager-agent}
\caption{The manager-agent concept~\cite{a27}}
\label{fig:manageragent}
\end{center}
\end{figure}

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~\cite{rfc1095, a27}.


\subsection{Information Model}
\label{mib}
\label{managedobjects}

The information model deals with Managed Objects that are abstractions of the real resources on the network~\cite{a2}. All information relevant to network management and definitions of the objects to be managed resides in a Management Information Base (MIB)\index{MIB|textbf}. 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~\cite{rfc1095}.

\index{SMI} 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)\index{ASN.1}, that provides a machine-independent representation for the information~\cite{rfc1095}.






\subsection{Systems Management Functions}

\index{SMFs} 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~\cite{a18}.


\subsection{Management Functional Areas --- OSI FCAPS model}
\label{fcaps}

OSI\index{OSI}\index{OSI!FCAPS} Management functionality is divided into five management functional areas~\cite{a12}:\index{FCAPS}
\begin{itemize}
\item \textbf{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\index{fault management}.

\item \textbf{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\index{configuration
management}. 

\item \textbf{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\index{accounting management}.

\item \textbf{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\index{performance management}.

\item \textbf{Security Management} includes functions to create,
delete and control security services and mechanisms, distribute
security-relevant information, and report security-relevant
events\index{security management}.

\end{itemize}


\section{Telecommunications Management Network}
\label{sec:tmn}
\label{tmn}

\index{TMN} 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~\cite{a17}.

The top-level standards and recommendations for OSI\index{OSI} systems management
form the basis for TMN standards~\cite{a11}. The TMN standards are
defined in ITU-T\index{ITU-T} M.3000-series documents~\cite[page~48]{a30}.

Figure~\ref{fig:tmn} 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~\cite{a17}.


\begin{figure}[htb]
\begin{center}
\epsfxsize1.0\textwidth
\epsfbox{kuvat/tmn}
\caption{General relationship of a TMN to a telecommunications network~\cite[page~25]{a30}}
\label{fig:tmn}
\end{center}
\end{figure}


\subsection{TMN Management Services}

% TMN Management Services (TMN-MSs) provide operations, administration, maintenance, and provisioning (OAM\&P) support for a telecommunications network.
% A TMN supports management areas which cover the planning, installation, operation, administration, maintenance and provision of telecommunications networks and services~\cite{a30, a17}.

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\index{OSI!FCAPS}\index{FCAPS} model.  TMN Management Services
(TMN-MSs)\index{TMN-MS} include
\begin{itemize}
\item customer administration,
\item  network provisioning management,
\item  workforce management,
\item  tariff, charging and accounting administration, 
\item quality of service and network performance administration, 
\item traffic measurement and analysis administration,
\item traffic management,
\item  routing and digit analysis administration,
\item maintenance management,
\item  security administration, and
\item  logistics management.
\end{itemize}
 An overview on TMN-MSs is provided in ITU-T\index{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)\index{TMN-SM} services. The TMN SM services are provided by
OSI\index{OSI} Systems Management Functions. These principles are
illustrated in
figure~\ref{fig:tmnservices}. Figure~\ref{fig:tmnfunctionsets} 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\index{ITU-T} Recommendation
M.3400~\cite[page~48--53]{a30}. 


\begin{figure}[htb]
\begin{center}
\epsfxsize1.0\textwidth
\epsfbox{kuvat/tmn_services}
\caption{TMN Management Services, Management Functions and Systems Management Services~\cite[page~50]{a30}.}
\label{fig:tmnservices}
\end{center}
\end{figure}


\begin{figure}[htb]
\begin{center}
\epsfxsize1.0\textwidth
\epsfbox{kuvat/tmn_function_sets}
\caption{Mapping of OSI MFAs and TMN Management Function Set Groups~\cite[page~53]{a30}.}
\label{fig:tmnfunctionsets}
\end{center}
\end{figure}


\subsection{TMN Management Layers}
\label{tmnlayers}

The needed management functionality is achieved by using five layers of management, described in~\cite[pages~19--21]{a30}. 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.
\index{fault management}\index{configuration management}\index{accounting management}\index{performance management}\index{security management}
\begin{itemize}

\item \textbf{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.

\item \textbf{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.

\item \textbf{Network management layer} manages the whole network. It receives data from network element management layer and provides total-network-level views.

\item \textbf{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.

\item \textbf{Network element layer} provides for the agent functions of the managed network elements.
\end{itemize}


\subsection{TMN Architecture}

TMN architecture is divided into three aspects, which can be
considered separately when designing a TMN: \textit{functional,
information} and \textit{physical architecture}. 

\begin{itemize}

\item \textbf{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~\cite{a17}.

\item \textbf{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~\cite{a17}.

\item \textbf{Physical architecture} describes the implementation of function blocks on physical systems and the interfaces between them~\cite[page~31]{a30}.
\end{itemize}


\section{Customer Network Management}
\label{sec:cnm}

\index{CNM} 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~\ref{fig:cnm_architecture} illustrates the CNM functional architecture~\cite[pages~38--42]{a30}.

\begin{figure}[htb]
\begin{center}
\epsfxsize.9\textwidth
\epsfbox{kuvat/cnm_architecture}
\caption{CNM functional architecture~\cite[page~39]{a30}.}
\label{fig:cnm_architecture}
\end{center}
\end{figure}


Customers are provided with a subset of the TMN management services, limited management information, and \textit{CNM supporting services}. CNM supporting services enable customer's management system to request service provisioning and service usage from a service provider~\cite[pages~38--44]{a30}.
% Figure~\ref{fig:cnm_services} presents the CNM services and mapping to the OSI Management Functional Areas~\cite[pages~38--44]{a30}.

%\begin{figure}[htb]
%\begin{center}
%\epsfxsize1.0\textwidth
%\epsfbox{kuvat/cnm_services}
%\caption{CNM services and mapping to the OSI Management Functional Areas~\cite[pages~38--44]{a30}.}
%\label{fig:cnm_services}
%\end{center}
%\end{figure}


\section{SMART TMN}
\label{sec:stmn}

Smart TMN~\cite{a6} 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:
\begin{itemize}
\item \textbf{Telecommunications Operations Map (TOM)}\index{TOM} which describes key business processes,

\item \textbf{Technology Integration Map}, which contains recommendations of technologies to adopt for different management applications~\cite{a7},

\item \textbf{Central Information Facility} for information store for technical specifications, object models etc., and 

\item \textbf{Catalyst Projects}, which are projects to validate technology concepts. 

\end{itemize}


\section{Telecommunications Information Networking Architecture}
\label{sec:tina}

\index{TINA} 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~\cite[page~137]{a13}. 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~\cite[page~148]{a13}.


\subsection{TINA Architecture}

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~\cite{a15}. 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~\cite{a15}.

Due to the complexity of TINA, it's architecture is divided into four sectors: \textit{computing architecture, service architecture, network architecture} and \textit{management architecture}~\cite[page~24]{a14}.

\begin{itemize}

\item The \textbf{computing architecture} defines a set of concepts
and principles for designing and building distributed
software~\cite{a14}. It is based on the Basic Reference Model for Open
Distributed Processing (RM-ODP\index{RM-ODP}, ITU Recommendation
X.900\index{X.900|see{RM-ODP}})~\cite[page~148]{a13}.

\item The \textbf{service architecture} defines a set of concepts and principles for the design, specification, implementation and management of telecommunication services~\cite[pages~25--26]{a14}.

\item The \textbf{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~\cite[page~26]{a14}.

\item The \textbf{management architecture} is based on the OSI\index{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~\cite[page~163]{a13}. The TINA management architecture is still under study~\cite[pages~27--28]{a14}.
\end{itemize}


\subsection{TINA Network Management Model}

TINA network management model extends the OSI
FCAPS\index{OSI!FCAPS}\index{FCAPS} model (see
page~\pageref{fcaps})~\cite{a13,a16}. Configuration management is
divided into \textit{connection management} and \textit{resource
configuration management}. 

\begin{itemize}

\item \textbf{Connection management} is considered a fundamental activity in telecommunications network~\cite{a14}. TINA represents a new approach to the traditional way of connection control~\cite[page~163]{a13}:

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.

\item\index{resource management}\index{configuration management} \textbf{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.

%\index{fault management} \textbf{Fault management} includes alarm surveillance, fault localization, fault correction, testing functions and trouble administration information.

%\index{accounting management} \textbf{Accounting management} is responsible for measuring and establishing charges for the use of resources.
\end{itemize}


