42.6.2 Deployment strategies

There are three main strategies for the deployment of SDH equip­ment:

1. Synchronous islands.

2. 'Thin' overlay networks.

3. Ad hoc deployment dictated by traffic growth, etc.

Many PTOs are currently using the ad hoc approach and deplo­ying the latest STM-16 (2.5 Gbit/s) transmission systems, not so much because they conform to the SDH standards, but because they offer higher transmission capacities than any available PDH sys­tems. Even so, most PTOs which are doing this, are intending to eventually fill in the gaps between these ad hoc deployments so as to create an SDH overlay network.

The idea behind the 'thin overlay' strategy is to rapidly deploy a limited SDH capability across the whole of a PTO network so that a small nucleus of key business customers can be offered the benefits of SDH as soon as possible. This type of deployment is most appropriate to networks where the important communities of interest are geographically widely dispersed.

The synchronous 'island' deployment strategy assumes that the most important communities of interest are geographically concen­trated, and that each one can start to benefit from SDH without necessarily having full SDH connectivity with similar communities of interest. The classic example here is that of the financial com­munity in the City of London. With the passage of time, a syn­chronous island would normally increase in geographical size, so as to eventually coalesce with other islands. Long before this, they would probably be interconnected by an emerging SDH trunk network.

1. Learn the following technical words and word-combinations:

42.6.1

1.	ring topology	кольцевая топология; топология типа «кольцо»
2.	ring structure	кольцевая структура
3.	a duct	тракт, канал
4.	switching center	коммутационный узел; центр коммутации; телефонная станция
5.	microwave radio	СВЧ-связь
6.	transmission core	передающий сердечник
7.	digital distribution frame	1.цифровая распределительная стойка; 2. коммутационный щит (в телефонии)
8.	database integrity	целостность базы данных
9.	meshed cross connects	многоконтурные поперечные соединения
10.	spare bandwidth	запасная (резервная) полоса пропускания
11.	off-line management	управление автономного режима
12.	mesh topology	многоконтурная топология
13.	standby capacity	резервная (автономная) пропускная способность
14.	point-to-point-transmission	прямая передача; передача по 2-х точечной линии
15.	coalesce	сливаться, срастаться, коалесцировать
16.	deployment	развертывание, ввод в действие, применение, использование
17.	ad hoc deployment	(специальное, устроенное для данной цепи), использование, ввод в действие

Exercise 2 Read the text 42.6.1- 42.6.2

Exercise 3 Find the Russian equivalents for the following English technical word- combinations:

1.	traffic routing flexibility
2.	the drop and insert ring topologies
3.	a simple clockwise/counter-clockwise routing decision
4.	an SDH line system
5.	the old analogue local exchanges
6.	a partial physical ring
7.	a mesh of cross connects
8.	point to point transmission systems
9.	the relevant transmission links and cross connects
10.	the network’s transmission capacity
11.	the completely free mash topology
12.	a traffic re-route
13.	an SDH overlay network
14.	the synchronous “island” deployment strategy
15.	an emerging SDH trunk network

Exercise 4

Find the English equivalents for the following Russian technical word-combinations:

1.	наиболее очевидное представление
2.	разрыв кабеля
3.	районный коммутационный узел
4.	звездная схема (компановка)
5.	целостность баз данных систем управления
6.	резервный (запасной, аварийный)
7.	сбой передачи
8.	развертывание, ввод в действие
9.	специальный
10.	соответствовать(подчиняться) стандартам синхронной цифровой иерархии

Exercise 5

Answer the following questions:

1.What are the most important influences on the topologies proposed for the deployment of SDH equipment?

2.What is one of the biggest advantages of the ring topology?

3.Does the versatility of drop and insert rings extend to drop and insert chains?

4.What is the main problem with implementing the ring made from a chain of drop and insert multiplexers?

5.In what way is it sometimes possible to produce a physical ring?

6.How can cross connects providing complete traffic routing flexibility be viewed?

7.What happens to a network of meshed cross connects when a transmission link fails?

8.Are there several potential solutions to the problem of database integrity? What are they?

9.How many strategies are there for the deployment of SDH equipment? What are they?

10.Why are many PTOs currently using the ad hoc approach and deploying the latest STM-16 transmission systems?

Exercise 6

a) Translate into Russian in writing part 42.6.1 paragraphs 4,5(from “The main problem…” up to …”Finally… “.

b) Translate into Russian in writing part 42.6.2.

Exercise 7

Make a short report on deployment strategies of SDH equipment.

Part 7 (42.7-42.9)

2. Impact of broadband standards

3. Frame relay

4. Switched Multimegabit Data Service (SMDS)

5. Fibre Distributed Data Interface (FDDI)

6. Future technologies

7. Integrated circuits

8. Optical interfaces

9. Optical amplifiers

10. Optical switching

11. Memory and processing power

12. Conclusion