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1、1,2,Provide a frame alignment pattern 提供帧定位类型 A1=11110110 A2=00101000 Format:3N 格式：3N,Framing Bytes A1,A2帧定位字节,3,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,Regenerator
2、 Section Trace J0中继段跟踪,4,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 v
3、alue 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：1,8-bit Parity Check B18比特奇偶校验,5,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E1E2 may be accessed by multiplexers 复用器可以访问E2Format:1 格式：1,Orderwire Channels E1
4、,E2公务信道,6,Allocated for users 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Format:1 格式：1,User Channel F1用户信道,7,Provide a message-based data communications channel,including administration,monitor,alarm and maintenance functions 提供包括管理、监测、告警和维护等功能的信息数据通信信道D1-D
5、3 define a 192 kbit/schannel in the RSOH 定义D1-D3为192kbit/s的信道D4-D12 define a 576 kbit/s channel in the MSOH 定义D4-D12为576kbit/s的信道Format:1 格式：1,Datacom Channel(DCC)D1-D3,D4-D12数据通信信道,8,Provide indications and flags regarding the frame contents 提供帧内容的指示和标记Define the start position of the VC-4 within t
6、he STM-1 frame 定义VC-4在STM-1帧内的起始位置Provide a method of the VC-4 floating within the AU-4 frame提供VC-4在AU-4帧内浮动的方法Provide an indication of AU-4 concatenation 提供AU-4串联指示Format:3N 格式：3N,AU Pointer Bytes H1-H3管理单元指针字节,9,Link Between Section Overhead and VC段开销与虚容器的联系,10,AU-4 Pointer Adjustment Operation-Po
7、sitive JustificationAU-4 指针调节-正向调节,11,AU-4 Pointer Adjustment Operation-Negative JustificationAU-4 指针调节-逆向调节,12,Include a 24-bit wide bit-interleaved even parity check,for error performance monitoring at the multiplexer section level 在复用段级别上，为误码性能监测提供24个比特位的偶校验The check is computed for all bytes of
8、the previous STM-N frame,except those located in the RSOH 对前一个STM-N除RSOH外所有字节进行检验Format:3N 格式：3N,24-bit Parity Check B224比特奇偶校验,13,Provides MPS signalling between multiplexer section terminating equipment 在复用段设备之间，提供MPS信令 Format:1 格式：1,Multiplexer Protection Switching(MPS)K1复用器保护倒换,14,Used to return
9、 an indication to the transmit end that the received end has detected an incoming section defect or is receiving AIS 接收端在收到AIS或当接收段故障时向发送端反馈的指示 Format:1 格式：1,Remote Defect Indication(RDI)K2远端故障指示,15,Indicates the type of clock source used to time the transmitted signal 指示传送信号定时的时钟源种类The indications
10、are one of the four synchronization levels agreed to by the ITU-T,or patterns to indicate that the quality is unknown or should not be used 包括ITU-T协议所规定的4个同步 级别中的一种，或指示质量不知 道以及不可用Format:1 格式：1,Quality of Synchronization S1同步质量,16,Used to send error performance information from multiplexer section re
11、ceiving equipment to the originating equipment 复用段接收机向发射机反馈的 误码性能信息 Conveys the count of interleaved bit blocks detected in error by the B2 byte 传达B2检测出的错误比特块数量 Format:1 格式：1,Remote Error Indication(REI)M1远端错误指示,17,Provides a unique message set up for each path in the SDH network 为SDH网络中的每个通道提供 唯一性信
12、息Supports continuity testing between any location on a transmission path 支持传输通道任意端点间的连续性测试Format:1N 格式：1N,Path Trace Byte J1通道跟踪,18,Includes an 8-bit wide bit-interleaved parity check that provides error performance monitoring at the VC-4 level 在VC-4级别上，为误码性能监测 提供8个比特位的奇偶校验The parity check is comput
13、ed for all bytes of the previous VC-4 before scrambling 对扰码前的前个VC-4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,8-bit Parity Check B38比特奇偶校验,19,Provides an indication of the payload construction 提供净负荷结构指示Indicates the type of payloads which are mapped into the vir
14、tual container 说明映射于虚容器中净负荷的种类,Signal Label C2信号卷标,20,Sends status and performance monitoring information from the receiving terminating equipment to the originating equipment 接收机向发射机反馈的性能监测 及状态信息Bits 1-4 convey the count of errors detected by B3 1-4比特传达B3检测出错误数量Bit 5 indicates a path RDI 第5比特表示通道的远
15、端故障指示,Path Status G1通道状态,21,Allocated for network operator communication between path terminations 在通道结点间分配给网络操作员的通信字节,User Channel F2,F3用户信道,22,Identifies the present frame within the multi-frame of the current VC-4 表示该帧在当前VC-4多帧中的 位置 The TU overhead is distributed over four TU frames comprising th
16、e TU multi-frame 支路单元开销分成四个支路单元帧而形成支路单元多帧,Multi-frame H4多帧,23,Example of TUs Multi-frame Indication Using H4 ByteH4指示支路单元多帧实例,24,Used to provide path-level protection switching on individual VC-4 paths 提供通道级别单个VC-4通道的 保护倒换,Automatic Protection Switch(APS)Byte K3自动保护倒换字节,25,Supports end-to-end perfor
17、mance monitoring of a tandem connection 支持通路连接中端到端的性能监测Bits 1-4 used as incoming error count 1-4比特用于接收错误计数Bits 5-8 used as a communication channel，communicates the number of B3 errors 5-8比特用于通信信道，传送B3 错误数量,Tandem Connection Byte N1通路连接字节,26,TUs Multi-frame支路单元多帧,27,Bits 1-2 are used for a bit interl
18、eaved parity(BIP)check on the previous VC-n 1-2比特为前一个VC-n作比特间插奇偶校验Bit 3 is a path Remote Error Indicator(REI)第3比特为通道远端错误指示Bit 4 is a path Remote Failure Indicator(RFI)第4比特为通道远端失败指示Bits 5-7 provide a VC-n signal label 5-7比特为VC-n提供信号卷标Bit 8 is a path Remote Defect Indicator(RDI)第8比特为通道远端故障指示,Error Che
19、cking,Signal Label,Path Status Byte V5误码检验，信号卷标，通道状态,28,Used to transmit repetitively an identifier,so that a path receiving terminal can verify its continued connection to the intended transmitter 反复传送一个识别码，用于通道接收机与发送机证实 其间的继续连接性Used in the same way as J0 in the SOH 与SOH中的J0使用方法相同,Path Trace J2通道跟踪
20、,29,Bits 1-2 are used as an even BIP-2 check for the Tandem Connection(TC)1-2比特为通路连接作比特间插偶校验Bit 4 operates as an incoming AIS indicator 第4比特用于接收AIS指示Bit 5 indicates error blocks within the TC 第5比特指示在通路连接中的误码块Bit 6 indicates error blocks of the egressing VC-n第6比特指示发送VC-n中的误码块Bits 7-8 operate in multi-frame as defect indicators 7-8比特用于多帧故障指示,Tandem Connection Byte N2通路连接字节,30,Bits 1-4 are allocated for APS signalling for protection at the lower order path level 1-4比特为低阶通道级别保护倒换分配APS信令,Automatic Protection Switching(APS)Byte K4自动保护倒换字节,
