Page 1204 - 5G Basics - Core Network Aspects

2 Transport aspects

NOTE – The 1.25G and 2.5G tributary slot versions of an ODTU12 are identical when the two 1.25G tributary slots
carrying the ODTU12 are TSa and TSa+4. The 1.25G and 2.5G tributary slot versions of an ODTU13 are identical when
the two 1.25G tributary slots carrying the ODTU12 are TSa and TSa+16. The 1.25G and 2.5G tributary slot versions of
an ODTU23 are identical when the eight 1.25G tributary slots carrying the ODTU23 are TSa, TSb, TSc, TSd, TSa+16,
TSb+16, TSc+16 and TSd+16.

ODTUjk . . . . . . . . . . . . . . .
overhead 1 2 3 c-1 c
1 1
2
3

.
. .
. ODTUjk payload .
. .
.
ts .
.

r-1
r
jk = 01, 12, 13, 23 G.709-Y.1331(12)_F19-5

Figure 19-5 – ODTUjk frame formats

Table 19-5 – ODTUjk characteristics for 2.5G and 1.25G tributary slots

ODTUjk payload ODTUjk overhead
2.5G TS c r ts
bytes bytes
ODTU12 952 16 1 15232 1 x 4
ODTU13 238 64 1 15232 1 x 4
ODTU23 952 64 4 60928 4 x 4

ODTUjk payload ODTUjk overhead
1.25G TS c r ts
bytes bytes
ODTU01 1904 8 1 15232 1  4
ODTU12 952 32 2 30464 2  4
ODTU13 238 128 2 30464 2  4
ODTU23 952 128 8 121856 8  4

Optical data tributary unit k.ts
The optical data tributary unit k.ts (ODTUk.ts) is a structure which consists of an ODTUk.ts payload area and
an ODTUk.ts overhead area (Figure 19-6). The ODTUk.ts payload area has j x ts columns and r rows (see
Table 19-6) and the ODTUk.ts overhead area has one times 6 bytes. The ODTUk.ts is carried in "ts" 1.25G
tributary slots of an OPUk.

The location of the ODTUk.ts overhead depends on the OPUk tributary slot used when multiplexing the
ODTUk.ts in the OPUk (see clauses 19.1.1, 19.1.2, 19.1.4). The single instance of an ODTUk.ts overhead is
located in the OPUk TSOH of the last OPUk tributary slot allocated to the ODTUk.ts.

The ODTUk.ts overhead carries the GMP justification overhead as specified in clause 19.4.

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