1. Formation/basics of E1
Basics of PDH
Basics of SDH
Formation of STM

2. PDH (Plisynchronous Digital Hierarchy )
PDH is almost synchronous.
It is simply Multiplexing of E1`s.
Sampling, Quantizing & Encoding (i.e. PCM) of Analog voice channels produces 64Kbps channel.
32 such channels multiplexed to produce E1 (the basic unit of PDH)
Clock
8000 Hz
Voice
Coded in 8 bits/sample
E1 (TS0 to TS31)
A/D
Primary unit of PDH
i.e. E1
(8000 samples)X(8bit/sample)
=64,000bps
32 Channels each
64 Kbps

3. PDH (Plisynchronous Digital Hierarchy ) Contd…
Formation of E2, E3…
As basic unit of PDH is E1
E1=32X64Kbps = 2.048Mbps
E2=4E1=8.44Mbps
E3=4E2=16E1=34.368Mbps
E4=4E3=140Mbps
Disadvantages of PDH System:
Not fully synchronous.
Complex hardware
Back to back multiplexing
Less bandwidth
More hardware cost
If we want to get E1 from E4 ,we have to demultiplex it by going back
step by step. i.e.1st E4 is broken into E3, then E3 to E2 & so on, thus form a complex hardware.

4. Basics of E1 E1 Concentrated E1: 2.5 TS for 1 TRx
TS0: Frame synchronization & Alarms
TS16: Signaling & Alarms
TS1 to TS15 & TS17 to TS31 : For Data
TS0
TS1
TS2
TS16 TS 29 30 31 E1
Concentrated E1: 2.5 TS for 1 TRx
Un-concentrated E1: 3TS for 1 TRx
Hybrid E1: 2TS for 1 TRx

5. (TUG3)X (3)+(High order POH)+( Stuffing)
Journey from E1 to STM 1 E1
2.048 Mbps
Justification bit
Low path overhead
Pointer
X 3=
TUG 2
6.972Mbps (i.e. 3 E1)
(TUG2)X( 7) + (Pointer)
C12
2.224Mbps
TUG 3
49.536Mbps (i.e. 21 E1)
VC12
2.240Mbps
(TUG3)X (3)+(High order POH)+( Stuffing)
TU12
2.304Mbps
SOH + Pointer
VC 4
Mbps (i.e. 63 E1)
STM 1, 155.5Mbps

6. (TUG3)X (3)+(High order POH)+( Stuffing)
Journey from E1 to STM 1 E1
2.048 Mbps
TU12(Tributary Unit)
Justification bit
Low path overhead
Pointer
X 3=
TUG 2
6.972Mbps (i.e. 3 E1)
(TUG2)X( 7) + (Pointer)
C12
2.224Mbps
TUG 3
49.536Mbps (i.e. 21 E1)
VC12
2.240Mbps
(TUG3)X (3)+(High order POH)+( Stuffing)
TU12
2.304Mbps
SOH + Pointer
VC 4
Mbps (i.e. 63 E1)
STM 1, 155.5Mbps

7. SDH (Synchronous Digital Hierarchy )
Key features
It is fully synchronous.
It can carry circuit switched or Packet Switched both.
All network element use same clock.
Tributary can mapped or extracted directly from pointers.
Different transmission rates in STM
STM1: 155Mbps
STM4: 622Mbps
STM16: 2.48Gbps
STM64: 10Gbps

8. KLM in SDH & PDH PDH: All 17 E1 SDH: All 63 E1 1.1.1 1.2.1 1.3.1 1.4.1
1.1.2
1.2.2
1.3.2
1.4.2
1.1.3
1.2.3
1.3.3
1.4.3
1.1.4
1.2.4
1.3.4
1.4.4
1.1.1
1.1.2
1.1.3
1.2.1
1.2.2
1.2.3
1.3.1
1.3.2
1.3.3
1.4.1
1.4.2
1.4.3
1.5.1
1.5.2
1.5.3
1.6.1
1.6.2
1.6.3
1.7.1
1.7.2
1.7.3
2.1.1
2.1.2
2.1.3
2.2.1
2.2.2
2.2.3
2.3.1
2.3.2
2.3.3
2.4.1
2.4.2
2.4.3
2.5.1
2.5.2
2.5.3
2.6.1
2.6.2
2.6.3
2.7.1
2.7.2
2.7.3
3.1.1
3.1.2
3.1.3
3.2.1
3.2.2
3.2.3
3.3.1
3.3.2
3.3.3
3.4.1
3.4.2
3.4.3
3.5.1
3.5.2
3.5.3
3.6.1
3.6.2
3.6.3
3.7.1
3.7.2
3.7.3

9. Krishna Mohan Prepared by: Fill free to contact