Page 1206 - 5G Basics - Core Network Aspects

2 Transport aspects

The OPUk overhead for these multiplexed signals consists of a payload type (PT), the multiplex structure
identifier (MSI), the OPU4 multiframe identifier (k=4), the OPUk tributary slot overhead carrying the ODTU
overhead and depending on the ODTU type one or more bytes reserved for future international
standardization.

19.3.1 ODTU12 mapping into one OPU2 tributary slot

A byte of the ODTU12 payload signal is mapped into a byte of an OPU2 2.5G TS #i (i = 1,2,3,4) payload area,
as indicated in Figure 19-7 (left). A byte of the ODTU12 overhead is mapped into a TSOH byte within
column 16 of the OPU2 2.5G TS #i.
A byte of the ODTU12 signal is mapped into a byte of one of two OPU2 1.25G TS #A,B (A,B = 1,2,..,8)
payload areas, as indicated in Figure 19-7 (right). A byte of the ODTU12 overhead is mapped into a TSOH
byte within column 16 of the OPU2 1.25G TS #a,b.
The remaining OPU2 TSOH bytes in column 15 are reserved for future international standardization.

MFAS 1 2 3 4 5 6 7 8 952 MFAS 1 2 3 4 5 6 7 8 952
bits bits
78 1 678 1
2 2
00 000
3 3
4 4
ODTU12 ... ODTU12 ...

1 1
2 2
11 111
3 3
4 4

OPU2 1.25G TS #A OPU2 1.25G TS #B
OPU2 2.5G TS #i
1 1 1
2 000 2 2
00
3 3 3
4 4 4
... ... ...

1 1 1
2 2 2
11 111
Column 16 3 Column 16 3 3
OPU2 4 4 4
TSOH OPU2
of TS #i 1 2 952 TSOH 1 2 476 1 2 476
of TS #A,
#B
G.709-Y.1331(12)_F19-7

Figure 19-7 – Mapping of ODTU12 into one OPU2 2.5G tributary slot (left)
and two OPU2 1.25G tributary slots (right)

19.3.2 ODTU13 mapping into one OPU3 tributary slot

A byte of the ODTU13 signal is mapped into a byte of an OPU3 2.5G TS #i (i = 1,2,..,16) payload area, as
indicated in Figure 19-8 (left). A byte of the ODTU13 overhead is mapped into a TSOH byte within column
16 of the OPU3 2.5G TS #i.
A byte of the ODTU13 signal is mapped into a byte of one of two OPU3 1.25G TS #A, B (A,B = 1,2,..,32)
payload areas, as indicated in Figure 19-8 (right). A byte of the ODTU13 overhead is mapped into a TSOH
byte within column 16 of the OPU3 1.25G TS #a,b.
The remaining OPU3 TSOH bytes in column 15 are reserved for future international standardization.

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