This presentation provides an overview of SDH (Synchronous Digital Hierarchy) networks for BSNL employees at the E2-E3 level. It covers SDH fundamentals including frame structure and synchronization, advantages over PDH networks, protection schemes like linear protection and rings, and CPE (Customer Premises Equipment). The document aims to help attendees upgrading from E2 to E3 understand SDH concepts.

1. For BSNL internal circulation only.
E2-E3
E&WS
SDH Overview ,
Protection Schemes & CPE

2. For BSNL internal circulation only.
WELCOME
• This is a presentation for the E2-E3 EW&S
Module for the Topic: SDH Overview ,
Protection Schemes & CPE
• Eligibility: Those who have got the
Upgradation to from E2 to E3.
• This presentation is last updated on 15-3-
2011.
• You can also visit the Digital library of
BSNL to see this topic.

3. For BSNL internal circulation only.
SDH Overview
Understand PDH & SDH Hierarchy
SDH protection Schemes
CPE

4. For BSNL internal circulation only.
Synchronization of Digital Signals
Synchronous,
Plesiochronous, and
Asynchronous
In a synchronous network, all the clocks are traceable
to one Primary Reference Clock (PRC).

5. For BSNL internal circulation only.
Limitations of PDH Network
Inability to identify individual channels in a higher
order bit stream.
Insufficient capacity for network management;
Most PDH network management is proprietary.
There’s no standardized definition of PDH bit rates
greater than 140 Mbit/s.
There are different hierarchies in use around the
world. Specialized interface
equipment is required to interwork the two
hierarchies.

6. For BSNL internal circulation only.
SDH Advantages
An optical mid-span meet between operators.
it’s synchronous.
it allows single- stage multiplexing and
demultiplexing.

7. For BSNL internal circulation only.
Basic SDH Signal
Carry many different services in its Virtual container
(VC)
It is bandwidth-flexible. Can carry high-speed packet-
switched services like ATM.
SDH still permits transport and networking at the 2
Mbit/s, 34 Mbit/s, and 140 Mbit/s levels,
accommodating the existing digital hierarchy signals.

8. For BSNL internal circulation only.
SDH Frame Structure

9. For BSNL internal circulation only.
Logic composition of SDH equipment

10. For BSNL internal circulation only.
Physical topology of an SDH transmission network

11. For BSNL internal circulation only.
Physical topology of an SDH transmission network

12. For BSNL internal circulation only.
SDH Network
Survivability
(Protection Schemes)

13. For BSNL internal circulation only.
Linear Protection
1+1
1:1
N:1,N+1,1:N, 1+N

14. For BSNL internal circulation only.
Protection in SDH Ring
SHR
USHR BSHR
2F 4F
2F 4F
Path Prot.
(SNCP)
Path Prot.
(SNCP)
Path Prot.
(SNCP)
Line Switched Prot.
(MSSPRING)

15. For BSNL internal circulation only.
FEATURES OF USHR
This scheme offers less information regarding
operating system.
In normal condition the traffic flows in clockwise
directions in one fiber.
In failure condition the traffic in counter clockwise
directions path is used.
The USHR mechanism itself does not remain aware
that which fiber is carrying traffic.

16. For BSNL internal circulation only.
FEATURE OF BSHR:
The scheme requires an APS protocol to make it
operative.
The traffic flows from node 1 to node 3 in clockwise
direction along links 1p and 2p.
But in return path the traffic flows from node 3 to
node 1 in counter clockwise direction along links 7p
and 8p
No tie up of any primary channel bandwidth in the
other half of the ring

17. For BSNL internal circulation only.
Concept of Speech in SDH Ring
A – in Bio Directional Self Healing Ring
RX TX
TX RX
TX RX
RX TX
Node 1
Node 2
Node 3
Node 4
RX TX
TX RX
TX RX
RX TX
1p
2p
3p
4p
5p
6p
7p
8p

18. For BSNL internal circulation only.
Node A
Circuit Q
Node B Node C
Node F Node E Node D
Working
Protection
Circuit Transporting Service
Normal Traffic In MS-Spring
Node a
Node b Node c
Node d
Node e
Node f
working
protection
Ckt transporting service
Normal state

19. For BSNL internal circulation only.
`
Node A
Circuit Q
Node B Node C
Node F Node E Node D
Working
Protection
Circuit Transporting Service
Protected Traffic In MS-Spring
working
protection
Ckt transporting service
Node a Node b Node c
Node d
Node e
Node f
Failed state

20. For BSNL internal circulation only.
MS shared protection rings
MS shared protection rings scheme is supported
by only BSHR
.The ring protocol is essential for both two fiber
ring or four Fiber ring.
In BSNL only two fiber rings are deployed.

21. For BSNL internal circulation only.
CPE( Customer Premises Equipment)
Demand for optical connectivity at various SDH bit
rates like 2Mbps, 34 Mbps/ DS3 and STM1 level.
Demand for Ethernet connectivity at 10/ 100 Base T
Ethernet Trib. & 100 Base FX Ethernet trib with
facilities of inbuilt aggregation.
There will be an option of Ethernet Adapter to
convert Ethernet in desired bit rates.

22. For BSNL internal circulation only.
CPE( Customer Premises Equipment)
For CPE, Remote monitoring through EMS on DCC
channel through VC12 in STM-1.
CPE terminals are having capabilities of Next
Generation SDH. (UPS for long duration required)
The VCG capabilities on VC12 and VC3 level can be
carried out in these equipments on VCAT principles

23. For BSNL internal circulation only.