OTN标准简介V1.0
Column #1123456789101112公开▲（保密期）
13141516Frame alignment overheadOTUk overheadRow #234ODUk overheadMapping&concatenationspecificPSI01PTMapping& concatenationspecific255G.709/Y.1331_F15-23图18 OPUk的开销 5.3.1.1 OPUk payload structure identifier（PSI） 此开销长度为一个字节，位置为字节（4,15）。此字节位于连续256个帧中，和ODUk的复帧MFAS对齐，MFAS=0时对应的PSI开销为PSI[0]，MFAS=255时对应PSI[255]。PSI[0]定义为净荷类型PT(payload type)，PSI[1]-PSI[25]用于级联和映射信息（PSI[0]=1或者PSI[0]=0x80-0x8f时除外）。PSI[0]即PT的定义如表11所示。 表11 PT的取值定义 MSB 1 2 3 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 0 0 1 0 0 1 0 1 0 1 1 0 1 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 LSB 5 6 7 8 0 0 0 1 0 0 1 0 0 0 1 1 0 1 0 0 0 1 0 1 0 1 1 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1 0 1 0 1 1 0 x x x x 1 1 0 1 1 1 1 0 1 1 1 1 Hex code (Note 1) 01 02 03 04 05 06 10 11 20 55 66 80-8F FD FE FF Interpretation Experimental mapping (Note 3) Asynchronous CBR mapping, see 17.1 Bit synchronous CBR mapping, see 17.1 ATM mapping, see 17.2 GFP mapping, see 17.3 Virtual Concatenated signal, see clause 18 (Note 5) Bit stream with octet timing mapping, see 17.5.1 Bit stream without octet timing mapping, see 17.5.2 ODU multiplex structure, see clause 19 Not available (Note 2) Not available (Note 2) Reserved codes for proprietary use (Note 4) NULL test signal mapping, see 17.4.1 PRBS test signal mapping, see 17.4.2 Not available (Note 2) 本文中的所有信息归中兴通讯股份有限公司所有，未经允许，不得外传 第 23 / 41 页
OTN标准简介V1.0
公开▲（保密期）
NOTE 1 – There are 226 spare codes left for future international standardization. Refer to Annex A/G.806 for the procedure to obtain one of these codes for a new payload type. NOTE 2 – These values are excluded from the set of available code points. These bit patterns are present in ODUk maintenance signals. NOTE 3 – Value \de