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7.1 STM-1 Frame structure is defined by 9x270 Matrix, each point of the Matrix is a byte (8 bits).
Show that STM-1 will carry 155.52 Mbps.

Data rate = [(9*270)*8]/125*10-6
  = 155.52Mbits/s

7.2 The following shows the STM-1 frame. Explain the importance of each area shown.

1 – RSOH: carries overhead information for the management of regenerator section
2 – AU Pointer: Used as the VC-4 pointer
3 - MSOH: carries overhead information for the management of multiplexer section
4 - Payload: Contains actual user information

7.3 SDH will use the following 3 processes.
v. Mapping
vi. Aligning
vii. Multiplexing
Briefly explain the applications of above when a PDH 2.048 Mbps, 34.368 Mbps, 139.264
Mbps is converted to STM-1. Draw the relevant diagram.

Mapping – process where a container is converted to a virtual container by adding a POH
Aligning – Process of assembling a VC into a tributary unit where a pointer is added to point
to the position of the first byte of the VC
Multiplexing – Process where a TUG/AU is formed by TUs by byte interleaving

7.4 Draw the SDH multiplexing hierarchy from STM-1 to STM-256 and show the basic information of 1 bit is shrink from 6.4 ns to 25 ps when the multiplexing is achieved up to STM-256. Clearly show the bit speed of each SDH hierarchy.

STM-1 ------ STM-4 ------- STM-16 -------- STM-64 ------- STM-256

Time duration for 1 byte in STM-1 = 1/155.52*106 = 6.4ns
Time duration for 1 byte in STM-4 = 1.61ns
Time duration for 1 byte in STM-16 = 0.4ns
Time duration for 1 byte in STM-64 = 0.1ns
Time duration for 1 byte in STM-256 = 0.025ns = 25ps

Bit speeds:

STM-1 155.52Mbit/s ~ 155 Mbits/s
STM-4 622.08Mbit/s ~ 622 Mbits/s
STM-16 2.488Gbit/s ~ 2.5 Gbits/s
STM-64 9.953Gbit/s ~ 10 Gbits/s
STM-256 39.8Gbit/s ~ 40 Gbits/s