Page 1241 - 5G Basics - Core Network Aspects

Transport aspects 2

Column
Row 15 16 17 3821 3822 3823 3824
1 JC4 JC1

2 JC5 JC2 OPUC payload
(4 3808 bytes)
3 JC6 JC3
4 PSI OMFI

1 2 3 4 5 6 7 8
OMFI 0 0 0 MSB LSB
OPUC #1 OPUC #2..#n
0 PT = 22 Reserved 3 4 5 6 7 8
1 Reserved Reserved
2 JC1 C1 C2 C3 C4 C5 C6 10-bit C (m=128 M)
m
MSI MSI
41 JC2 C7 C8 C9 C10 II DI
42
JC3 CRC-6 Decrement indicator
Increment indicator
Reserved Reserved
1 2 3 4 5 6 7 8 1 2
JC4 RES D1 D2 D3 D4 D5 D6 D7 D8 D9 JC1 Client
255 specific
JC5 RES D10 D11 D12D13D14D15D16D17 D18 JC2 18-bit C 8D
JC6 OP CRC-9 JC3 G.709-Y.1331(16)_F20-7

Figure 20-7 – OPUCn multiplex overhead (payload type = 22)

20.4.1 OPUCn multiplex structure identifier (MSI)
The OPUCn multiplex structure identifier (MSI) overhead, which encodes the ODU multiplex structure in the
OPU, is located in the mapping specific area of the PSI signal (refer to Figure 20-7 for the MSI location in
OPUCn with PT=22. The MSI has a fixed length of 40n bytes and indicates the ODTU content of each
tributary slot (TS) of an OPUCn. Two bytes are used for each TS.

20.4.1.1 OPUCn multiplex structure identifier (MSI) – Payload type 22
For the 20n OPUCn 5G tributary slots n times 40 bytes of the PSI are used (named PSI[x.y] where x = 1…n
and y = 2…41, that is PSI[1.2], PSI[1.3],…PSI[1.41], PSI[2.2], PSI[2.3],…, PSI[2.41], PSI[3.2],…,PSI[n-1.41],
PSI[n.2]…, PSI[n.41]) as MSI bytes as shown in Figure 20-7. The MSI indicates the ODTU content of each
tributary slot of an OPU. Two bytes are used for each tributary slot as illustrated in Figure 20-8 and the
encoding of the fields of each MSI instance is illustrated in Figure 20-9.
– The TS availability bit 1 indicates if the tributary slot is available or unavailable.
– The TS occupation bit 9 indicates if the tributary slot is allocated or unallocated.
– The tributary port # in bits 2 to 8 and 10 to 16 indicates the port number of the ODTUCn.ts that is
being transported in this TS; a flexible assignment of tributary port to tributary slots is possible.
ODTUC.ts tributary ports are numbered 1 to 10n. The value is set to all-0s when the occupation bit
has the value 0 (tributary slot is unallocated).

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