2001: Homework assignment 9

• General instructions
• Material
• Assignment
• Returning

• Deadline: Tuesday 13.11.2001 at 4pm

Material

If you use other sources than the material mentioned below, add a reference list to your homework assignment!

• Course handouts
• The coursebook
• Simulating the Wander Accumulation in a SDH Synchronisation Network

Important information for all: Copyright basics for Web authors and users by Jukka Korpela

Assignment: Transmission in Telecom networks

1. SDH (8 points total)

1. The synchronisation information for SDH is distributed in SSM (Synchronisation Status Messaging) messages, which also carry information on the level of the synchronisation reference. The levels of synchronisation are PRC, T-SSU, L-SSU, SEC and DNU (Do Not Use). The synchronised node takes its synchronisation reference from the highest level incoming SSM-messages. SSM messages have priorities within each level.

   In the synchronisation network shown in figure, PRC-level SSM-messages flow in the primary synchronisation chain. The secondary synchronisation chain has PRC-level SSM-messages with a lower priority. In normal operation all nodes synchronise using the primary synchronisation chain. What happens in the following events? (4 p)

   1. All synchronisation messages on link 1 are lost.
   2. All synchronisation messages on link 2 are lost.
   3. All synchronisation messages on link 3 are lost.
   4. Why is the primary synchronisation reference chain not transmitted on link 4?

2. Connect those terms to the correct SDH physical layer sublayers. Write out the acronyms. (4 p)

   photonic section line path

   PTE DCS optical fiber ADM STE regenerator LTE POH repeater

2. ISDN (6 points total)

1. Briefly tell about ISDN channels and explain the use of each. (3 p)
2. Explain the differences between ISDN BRI and PRI interfaces. (2 p)
3. In which cases an ISDN connection would be more suitable than a DSL connection? Why? (1 p)

3. xDSL in theory and practise (4 + 3 points total)

1. Compare different xDSL technologies (at least HDSL, ADSL, VDSL and SDSL). For each, list it's speed, the maximum wiring distance, advantages and disadvantages and the target users. (4 p)
2. OPTIONAL: Now investigate the current situation in Finland. (+ 3 p)
   1. Is a technology available in Finland and where?
   2. How much does it really cost? (please mention the provider)
   3. For what kind of users is it offered?
   Search the information for this assignment yourself. Don't forget to tell your references!

4. Get connected (6 points total)

3 companies want to get an Internet connection in Tlarktown. What kind of connection would be more suitable for each one? Please state your reasons.
Tlarktown Interactive (A) is a content providing company having 30 employees at the moment. Expecting huge growth.
Tlarktown Shoeshop (B) is a small family company, mostly runned by Ms. Tlarkins and her teenage son.
Tlarktown Soap Factory (C) is an old and respectable company with 100 employees.

5. Feedback (1 point)

1. How many hours did you spend doing this assignment?
2. Was the assignment too hard or too easy? Why?
3. What topics should this assignment cover next year?

Returning your answer