SDH开销字节汇.ppt

SDH 开销字节 Provide a frame alignment pattern 提供帧定位类型 A1 = A2 = Format: 3N 格式： 3N A1 A1 A1 A2 A2 A2 J0 F1 D3 B1 D1 E1 D2 H1 H2 H3 B2 K1 K2 J1 B3 C2 G1 F2 H4 F3 K3 N1 D4 D7 D10 S1 D5 Z1 Z2 D8 D11 D6 D9 D12 M1 E2 Framing Bytes A1, A2 帧定位字节 Transmits a fixed pattern repetitively 反复传送一个固定类型 Used by the section receiver to verify its continued connection to the intended transmitter 用于段接收机向发送机确认它 的继续连接性 Format: 1 格式： 1 A1 A1 A1 A2 A2 A2 J0 F1 D3 B1 D1 E1 D2 H1 H2 H3 B2 K1 K2 J1 B3 C2 G1 F2 H4 F3 K3 N1 D4 D7 D10 S1 D5 Z1 Z2 D8 D11 D6 D9 D12 M1 E2 Regenerator Section Trace J0 中继段跟踪 Provides an 8-bit wide bit- interleaved even parity check for error performance monitoring at the regenerator section level 在中继段级别上，为误码性能监测 提供8个比特位的偶校验 The parity check is computed for all bytes of the previous STM-N frame after scrambling 对扰码后的前个STM-N所有字节 进行奇偶校验 The computed value is placed in this byte before scrambling 在扰码前将检验结果存于该字节 Format: 1 格式： 1 A1 A1 A1 A2 A2 A2 J0 F1 D3 B1 D1 E1 D2 H1 H2 H3 B2 K1 K2 J1 B3 C2 G1 F2 H4 F3 K3 N1 D4 D7 D10 S1 D5 Z1 Z2 D8 D11 D6 D9 D12 M1 E2 8-bit Parity Check B1 8比特奇偶校验 Provide a local orderwire channel for voice communication 为语音通信提供本地公务信道 E1 may be accessed by regenerators 中继器可以访问E1 E2 may be accessed by multiplexers 复用器可以访问E2 Format: 1 格式： 1 A1 A1 A1 A2 A2 A2 J0 F1 D3 B1 D1 E1 D2 H1 H2 H3 B2 K1 K2 J1 B3 C2 G1 F2 H4 F3 K3 N1 D4 D7 D10 S1 D5 Z1 Z2 D8 D11 D6 D9 D12 M1 E2 Orderwire Channels E1, E2 公务信道 Allocated for user’s purposes 为用户目的分配的信道 Terminated at all regenerator section-level equipment 在所有的中继段级别设备终止