疑难解答SONET链路误码率的错误

http://www.cisco.com/en/US/tech/tk482/tk607/technologies_tech_note09186a0080094a79.shtml

 

目录

Introduction 简介
Prerequisites 先决条件
Requirements 需求
Components Used 使用的组件
Conventions 公约
Background Information 背景资料
BIP-8 Bytes in SONET Overhead BIP - 8在SONET开销字节
When Do Particular BIP Errors Occur? 特别是BIP的错误是什么时候发生的？
BER 误码率
Set BER Thresholds 设置的BER阈值
Report BIP Errors 报告的BIP错误
How Does a Router Respond to BIP Errors? 路由器是如何响应的BIP错误？
Steps to Troubleshoot 步骤来解决
Bit Errors on ATM Interfaces ATM接口的误码
Cisco Support Community - Featured Conversations 思科支持社区-特色
Related Information 相关信息

Introduction 简介

This document explains bit interleaved parity (BIP-8) checks on frames that a packet over SONET (POS) router interface transmits.本文档介绍了位交叉奇偶校验（BIP - 8）帧检查，超过SONET（POS）的路由器接口发送的数据包。

Prerequisites 先决条件

Requirements 需求

Cisco recommends that you have knowledge of these topics:思科建议您有这些题目的知识：

• SONET (Synchronous Optical NETwork). SONET（同步光网络）。
• GSR (Gigabit Switch Router). GSR（千兆位交换路由器）。
• ESR (Edge Services Router). ESR（边缘路由器）。

Components Used 使用的组件

This document is not restricted to specific software and hardware versions.本文件并不限于特定的软件和硬件版本。

The information in this document was created from the devices in a specific lab environment.在这个文件中的信息是从在一个特定的实验室环境的设备。 All of the devices used in this document started with a cleared (default) configuration.在本文档中使用的所有设备都开始与清零（默认）配置。 If your network is live, make sure that you understand the potential impact of any command.如果您的网络生活，确保您了解所有命令的潜在影响。

Conventions 公约

Refer to Cisco Technical Tips Conventions for more information on document conventions.关于文件惯例的更多信息，请参阅Cisco技术提示惯例。

Background Information 背景资料

When the number of BIP errors crosses a threshold that you can configure, the router reports log messages similar to this:当的BIP错误的数量超出阈值，您可以配置路由器报告类似的日志消息：

 Feb 22 08:47:16.793: %LINEPROTO-5-UPDOWN: Line protocol on Interface POS3/0, 2月22日08:47:16.793：％LINEPROTO - 5上下按钮：POS3 / 0接口上的线路协议， 
changed state to down下来的状态发生变化 
Feb 22 08:47:16.793: %OSPF-5-ADJCHG: Process 2, Nbr 12.122.0.32 on POS3/0 2月22日08:47:16.793：％OSPF - 5 - ADJCHG：进程2，NBR POS3 / 0 12.122.0.32 
from FULL to DOWN, Neighbor Down从全下来，邻居下降 
Feb 22 08:48:50.837: %SONET-4-ALARM: POS3/0: SLOS 2月22日08:48:50.837：％SONET - 4 -报警：POS3 / 0：联络主任 
Feb 22 08:48:52.409: %LINK-3-UPDOWN: Interface POS3/0, changed state to down 2月22日08:48:52.409：％LINK - 3 -上下按钮：界面POS3 / 0，状态发生了改变向下 
Feb 22 08:50:47.845: %SONET-4-ALARM: POS3/0: B1 BER exceeds threshold, 2月22日08:50:47.845：％SONET - 4 -报警：POS3 / 0：B1误码率超过阈值，  
 TC alarm declared 声明训练班报警  
 Feb 22 08:50:47.845: %SONET-4-ALARM: POS3/0: B2 BER exceeds threshold, 2月22日08:50:47.845：％SONET - 4 -报警：POS3 / 0：B2误码率超过阈值，  
 TC alarm declared 声明训练班报警  
 Feb 22 08:50:47.845: %SONET-4-ALARM: POS3/0: B3 BER exceeds threshold, 2月22日08:50:47.845：％SONET - 4 -报警：POS3 / 0：B3误码率超过阈值，  
 TC alarm declared 声明训练班报警
Feb 22 08:50:52.922: %SONET-4-ALARM: POS3/0: SLOS cleared 2月22日08:50:52.922：％SONET - 4 -报警：POS3 / 0：SLO来清除 
Feb 22 08:50:54.922: %LINK-3-UPDOWN: Interface POS3/0, changed state to up 2月22日08:50:54.922：％LINK - 3 -上下按钮：界面POS3 / 0，状态发生了改变起来 

This document provides tips on how to troubleshoot threshold-crossing (TC) bit error rate (BER) alarms.本文档提供了关于如何解决门槛交叉（TC），误码率（BER）报警提示。

BIP-8 Bytes in SONET Overhead BIP - 8在SONET开销字节

SONET is a protocol that uses an architecture of layers: section, line and path. SONET是一种协议，它使用层的结构部分，线和路径。 Each layer adds some number of overhead bytes to the SONET frame, as illustrated here:每一层都增加了一些开销字节的SONET帧，如下所示：

				Path Overhead 通道开销
Section Overhead 段开销	A1 Framing A1帧	A2 Framing A2的帧	A3 Framing A3的帧	J1 Trace J1的跟踪
	B1 BIP-8 B1的BIP - 8	E1 Orderwire E1的勤务	E1 User E1的用户	B3 BIP-8 B3的BIP - 8
	D1 Data Com D1的数据通信	D2 Data Com COM D2的数据	D3 Data Com D3的数据COM	C2 Signal Label C2信号标签
Line Overhead 线路开销	H1 Pointer H1的指针	H2 Pointer H2的指针	H3 Pointer Action H3的指针行动	G1 Path Status G1路径状态
	B2 BIP-8 B2的BIP - 8	K1 K1	K2 K2	F2 User Channel F2用户通道
	D4 Data Com D4数据通信	D5 Data Com D5的数据COM	D5 Data Com D5的数据COM	H4 Indicator H4的指标
	D7 Data Com D7数据COM	D8 Data Com D8的数据COM	D9 Data Com D9数据COM	Z3 Growth Z3的增长
	D10 Data Com D10的数据COM	D11 Data Com D11的数据COM	D12 Data Com D12的数据COM	Z4 Growth Z4的增长
	S1/Z1 Sync Status/Growth S1/Z1同步状态/增长	M0 or M1/Z2 REI-L Growth M0或M1/Z2 REI - L的增长	E2 Orderwire E2的勤务	Z5 Tandem Connection Z5的串联连接

Importantly, each layer uses a single, interleaved parity byte to provide error monitoring across a particular segment, along the end-to-end SONET path.更重要的是，每一层都使用一个单一的，交错的校验字节提供一个特定的市场上的错误监测以及终端到终端的SONET路径。 This parity byte is known as BIP-8, which is an abbreviation for bit interleaved parity.这被称为BIP - 8，这是一个缩写位交叉奇偶校验字节。 BIP-8 performs an even-parity check on the previous Synchronous Transport Signal level 1 (STS-1) frame. BIP - 8执行以前的同步传输信号电平1（STS - 1）帧的偶数奇偶校验。

During the parity check, the first bit of the BIP-8 field is set so that the total number of ones in the first bit of all octets of the previously scrambled STS-1 frame is an even number.在奇偶校验，第一位的BIP - 8场设置，使那些在以前所有字节的第一个位总数炒STS - 1帧是一个偶数。 The second bit of the BIP-8 field is used exactly the same way, except that this bit performs a check on the second bits of each octet, and so on.第二位的BIP - 8场是用完全相同的方式，除该位执行检查每个八位位组的第二位，等。

The Bellcore GR-253 standard for SONET networks defines the bytes over which a particular parity error is calculated.符合Bellcore GR - 253 SONET网络标准定义了一个特定的奇偶校验错误计算的字节。 This table describes the portion of the SONET frame that a particular BIP byte covers:此表描述了SONET帧，一个特定的BIP字节涵盖的部分：

Byte字节	Portion of Frame Covered框架部分涵盖	Span Monitored跨度监视	Error Indication错误指示
B1 B1	Entire frame, after scrambling.整个画面，后争先恐后。	Monitors bit errors between two adjacent STEs (Section Terminating Equipment), such as a regenerator.显示器之间的两个相邻的国营贸易企业（组端接设备），如再生器，位错误。	Differences indicate the occurrence of section-level bit errors.差异表明科级位错误的发生。
B2 B2	Line overhead and synchronous payload envelope (SPE) (including path overhead and payload), before scrambling.架空线和同步有效载荷信封（SPE）（包括路径开销和净荷），前争先恐后。	Monitors bit errors between two adjacent LTEs (Line Terminating Equipment), such as an Add/Drop Multiplexer (ADM) or DCS.监控两个相邻LTEs（线路终端设备），如添加/插复用器（ADM）或DCS之间的位错误。	Differences indicate the occurrence of line-level bit errors.差异表明线路电平位错误的发生。
B3 B3	SPE (including path overhead and payload), before scrambling. SPE（包括路径开销和净荷），前争先恐后。	Monitors bit errors between two adjacent Path Terminating Equipments (PTEs), such as two router POS interfaces.两个相邻的路径终端设备（PTE）的，如两个路由器的POS接口之间的监视器位错误。	Differences indicate the occurrence of path-level bit errors.差异表明路径级位错误的发生。

When Do Particular BIP Errors Occur? 特别是BIP的错误是什么时候发生的？

Under some conditions, the output of the show controllers pos command reports only one level of BIP errors.在某些情况下， 显示控制器POS命令的输出报告只有一个级别的BIP错误。 The reason is that the reported BIP errors vary depending on where the code violation or bit flip actually occurs.原因是报告的BIP错误不同，根据实际发生的代码违反或位翻转。 In other words, parity bytes monitor and detect errors over different parts of a SONET frame.换句话说，校验字节的监测和检测过的SONET帧的不同部分中的错误。 A BIP error can occur anywhere in the frame.帧中的一个的BIP错误可以发生在任何地方。

This diagram illustrates a typical SONET network:此图说明了一个典型的SONET网络：

When you connect two router POS interfaces point to point, over a dense wavelength division multiplexing (DWDM) link without intermediate SONET or Synchronous Digital Hierarchy (SDH) equipment, all three BIP mechanisms monitor the same segment, and typically detect the same errors.当您连接两个路由器POS接口指向一个密集波分复用多路复用（DWDM）无中间SONET或同步数字系列（SDH）设备的链接，点满，所有三个BIP机制监测在同一网段，通常检测到同样的错误。 However, in this configuration, B2 must provide the most accurate bit error count.然而，在此配置中，B2的，必须提供最准确的位错误计数。

An increment in B1 and B2 errors, without an increment in B3 errors is statistically improbable.在B1和B2错误的增量，没有增量的B3错误，统计学上是不可能的。 This condition occurs only if the errors affect parts of the frame that the B3 byte does not monitor.出现这种情况只有当错误影响的框架，B3字节不监视的部分。 Recall that the B3 byte covers the path overhead and payload section.回想一下，B3字节覆盖路径开销和有效载荷部分。

An increment in B3 errors points to a corrupt SPE or payload portion.在B3的错误的增量点，一个腐败的SPE或有效载荷部分。 The path overhead does not change until a remote PTE terminates the SONET frame.路径开销不会改变，直到远程PTE终止SONET帧。 ADMs and regenerators do not terminate the path overhead and must not report B3 errors. ADMS和再生不终止的路径开销，不得B3的错误报告。 Thus, a condition in which B3 errors increase only indicates that either the local or remote router interface corrupts the path overhead or payload.因此，这种情况，失误增多，其中B3仅表示，无论在本地或远程路由器接口腐化的路径开销或有效载荷。

In addition, when the B3 check covers the longest span, the chance of bit flips is greater.此外，当B3的检查覆盖跨度最长，位机会翻转更大。 Typically, the end-to-end path spans a few monitored segments between LTEs.通常情况下，终端到终端的路径跨越几个监测段之间LTEs。 The B2 parity check must monitor these segments. B2奇偶校验必须监视这些细分市场。

SONET interfaces must not report an increase in BIP errors during a loss of signal or loss of frame alarm condition. SONET接口必须在增加过程中的信号损失或丢失帧报警条件的BIP错误报告。 However, a burst of B1 errors can occur during the time the interface takes to declare the alarm.然而，一阵B1的错误可能会出现在界面时需要申报的报警。 This burst can last for up to 10 seconds, which is the interval at which the line cards in the Cisco 12000 and 7500 router series report statistics to the central route processor.这种爆发可以持续长达10秒，这是在Cisco 12000和750​​0系列路由器报告统计的中央路由处理器的线路卡的时间间隔。

In addition, you must understand that BIP errors have different error detection resolutions, which are explained here:此外，你必须明白的BIP错误，不同错误检测的决议，这里解释：

• B1 : B1 can detect up to eight parity errors per frame. B1：B1可以检测出每帧8个奇偶校验错误。 This level of resolution is not acceptable at OC-192 rates.这一级别的分辨率在OC - 192的价格是不能接受的。 Even-numbered errors can elude the parity check on links with high error rates.偶数的错误，可以躲避的高错误率的链路上的奇偶校验。
• B2 : B2 can detect a far higher number of errors per frame. B2：B2，可以检测出每帧错误的数量远远高于。 The exact number increases as the number of STS-1s (or STM-1s) increases in the SONET frame. SONET帧的STS - 1（或STM - 1）增加数量的确切数量的增加。 For example, an OC-192/STM-64 produces a 192 x 8 = 1536 bit-wide BIP field.例如，一个OC-192/STM-64的产生一个192 × 8 = 1536位宽BIP的领域。 In other words, B2 can count up to 1536 bit errors per frame.换句话说，B2可以计数到1536每帧位错误。 There is considerably less chance of an even-numbered error that eludes the B2 parity calculation.有偶数不到B2奇偶校验计算的错误的机会大大减少。 B2 offers superior resolution when compared to B1 or B3.相比，B1或B3，B2提供优越的分辨率。 Therefore, a SONET interface can report B2 errors only for a particular monitored segment.因此，SONET接口可以报告，只在一个特定监测段B2的错误。
• B3 : B3 can detect up to eight parity errors in the entire SPE. B3：B3可以检测多达8个奇偶校验错误，在整个SPE。 This number produces acceptable resolution for a channelized interface because, (for example) each STS-1 in an STS-3 has a path overhead and B3 byte.这个数字产生通道接口接受的解决办法，因为（例如）在STS - 3的每个STS - 1的路径开销和B3字节。 However, this number produces poor resolution over concatenated payloads in which a single set of path overhead must cover a relatively large payload frame.然而，这个数字产生串联的有效载荷，其中一个单一的路径开销必须覆盖一个比较大的有效载荷帧，分辨率较差。
  Note: When you initiate an IOS reload or a microcode reload, the POS interface is reset, and so is the framer. 注意：当您启动IOS加载或重新加载微码，POS接口复位，等成帧器。 The reset downloads the microcode on the interface again.下载界面上的微码再次复位。 In some cases, this process can generate a small burst of bit errors.在某些情况下，这个过程可以生成一个位错误的小爆发。

BER 误码率

The BER counts the number of detected BIP errors. BER计数检测到的BIP错误。 In order to calculate this value, compare the number of bit errors to the total number of bits transmitted per unit of time.为了计算这个值，单位时间内传输的比特总数比较数位错误。

Set BER Thresholds 设置的BER阈值

POS interfaces use the BER to determine whether a link is reliable. POS接口使用的误码率，以确定是否是可靠的链接。 The interface changes the state to down if the BER exceeds a threshold that you can configure.接口变化的状态，如果系统的误码率超过阈值，您可以配置。

All three SONET layers use a default BER value of 10e-6. SONET的所有三个层使用一个默认10E - 6 BER值。 The show controllers pos command displays the current values. 显示控制器POS命令显示当前值。

 RTR12410-2# show controllers pos 6/0 RTR12410 - 2＃ 显示控制器POS 6 / 0
POS6/0 POS6 / 0 
SECTION第 
  LOF = 0 LOS = 2 BIP(B1) = 63 LOF = 0的LOS = 2 的BIP（B1）= 63 
LINE线 
 AIS = 0 RDI = 1 FEBE = 1387 BIP(B2) = 2510 AIS = 0的RDI = 1 FEBE = 1387 BIP（B2）= 2510 
PATH PATH 
  AIS = 0 RDI = 1 FEBE = 17 BIP(B3) = 56 AIS = 0的RDI = 1 FEBE = 17 BIP（B3）= 56
  LOP = 2 NEWPTR = 0 PSE = 0 NSE = 0 LOP = 2 NEWPTR = 0的PSE = 0 NSE = 0 
Active Defects: None主动缺陷：无 
Active Alarms: None活动报警：无 
Alarm reporting enabled for: SF SLOS SLOF B1-TCA B2-TCA PLOP B3-TCA报警报告：SF联络主任SLOF的B1 - TCA B2 - TCA PLOP B3 - TCA的启用 
Framing: SONET帧结构：SONET 
APS黄芪多糖 
  COAPS = 8 PSBF = 1 COAPS = 8 PSBF = 1 
  State: PSBF_state = True国家：PSBF_state = TRUE 
  ais_shut = FALSE ais_shut = FALSE 
  Rx(K1/K2): 00/00 S1S0 = 00, C2 = CF RX（K1/K2）：00/00 S1S0 = 00，C2 = CF 
  Remote aps status working; Reflected local aps status non-aps远程APS状态工作;反映了当地的APS地位的非- APS 
CLOCK RECOVERY时钟恢复 
  RDOOL = 0 RDOOL = 0 
  State: RDOOL_state = False状态：RDOOL_state = FALSE 
PATH TRACE BUFFER : STABLE路径跟踪缓冲区：稳定 
  Remote hostname : 12406-2远程主机名：12406-2 
  Remote interface: POS2/0远程接口：POS2 / 0 
  Remote IP addr : 48.48.48.6远程IP地址：48.48.48.6 
  Remote Rx(K1/K2): 00/00 Tx(K1/K2): 00/00远程RX（K1/K2）：00/00 TX（K1/K2）：00/00 
BER thresholds: SF = 10e-3 SD = 10e-6 误码率阈值：SF = 10E - 3 SD = 10E - 6  
 TCA thresholds: B1 = 10e-6 B2 = 10e-6 B3 = 10e-6 TCA的阈值：B1 = 10E - 6 B2 = 10E - 6 B3 = 10E - 6

Use the pos threshold command to adjust the threshold values from the defaults.使用的POS阈值 “命令，调整阈值从默认。

 router(config-if)# pos threshold ?路由器（配置如果）＃POS门槛 ？ 
  b1-tca B1 BER threshold crossing alarm B1 - TCA B1误码率超过阈值报警 
  b2-tca B2 BER threshold crossing alarm B2 - TCA B2误码率超过阈值报警 
  b3-tca B3 BER threshold crossing alarm B3 - TCA B3误码率超过阈值报警 
  sd-ber set Signal Degrade BER threshold SD - BER设置信号降级的BER阈值 
  sf-ber set Signal Fail BER threshold SF - BER设置信号故障误码率门槛 

Signal failure (SF) BER and signal degrade (SD) BER are sourced from B2 BIP-8 error counts (as is B2-TCA).来自B2的BIP - 8错误计数（B2 - TCA）信号失效（SF）的BER和信号降低（SD）的BER。 However, SF-BER and SD-BER feed into the automatic protection switching (APS) machine, and can lead to a protection switch (if you have configured APS).然而，进入自动保护切换（APS）机SF - BER和SD - BER饲料，并可能导致一个保护开关（如果您有配置的APS）。

B1 BER Threshold Crossing Alert (B1-TCA), B2-TCA, and B3-TCA only print a log message to the console if you have enabled reports for them. B1误码率超过阈值警报（B1 - TCA），B2的TCA，和B3​​ - TCA只打印日志信息到控制台，如果您已启用为他们的报告。

Report BIP Errors 报告的BIP错误

The pos report {b1-tca | b2-tca | b3-tca } command allows you to configure the SONET alarms that you want to report. POS报告{B1 - TCA | B2 - TCA | B3 - TCA}命令允许您配置的，你要报告的SONET警报。 A router common reports TC alarms when the router declares a path-level or line-level alarm.一个路由器常见的报告TC报警当路由器宣告的路径级或行级警报。

This sample output shows how a POS interface on a Cisco router reports a high BER.此示例输出显示了如何在Cisco路由器上的POS接口报告高BER。

 Aug 7 04:32:41 BST: %SONET-4-ALARM: POS4/6: B1 BER exceeds threshold, 8月7日4点32分41秒BST：％SONET - 4 -报警：POS4 / 6：B1误码率超过阈值， 
TC alarm declared声明训练班报警 
Aug 7 04:32:41 BST: %SONET-4-ALARM: POS4/6: B2 BER exceeds threshold, 8月7日4点32分41秒BST：％SONET - 4 -报警：POS4 / 6：B2误码率超过阈值， 
TC alarm declared声明训练班报警 
Aug 7 04:32:41 BST: %SONET-4-ALARM: POS4/6: SD BER exceeds threshold, 8月7日4点32分41秒BST：％SONET - 4 -报警：POS4 / 6：SD误码率超过阈值， 
TC alarm declared声明训练班报警 
Aug 7 04:32:41 BST: %SONET-4-ALARM: POS4/6: B3 BER exceeds threshold, 8月7日4点32分41秒BST：％SONET - 4 -报警：POS4 / 6：B3误码率超过阈值， 
TC alarm declared声明训练班报警 
Aug 7 04:32:44 BST: %SONET-4-ALARM: POS4/6: SLOF cleared 8月7日4时32分44秒BST：％SONET - 4 -报警：POS4 / 6：SLOF清除 
Aug 7 04:32:44 BST: %SONET-4-ALARM: POS4/6: PPLM cleared 8月7日4时32分44秒BST：％SONET - 4 -报警：POS4 / 6：PPLM清除 
Aug 7 04:32:44 BST: %SONET-4-ALARM: POS4/6: LRDI cleared 8月7日4时32分44秒BST：％SONET - 4 -报警：POS4 / 6：LRDI清除 
Aug 7 04:32:44 BST: %SONET-4-ALARM: POS4/6: PRDI cleared 8月7日4时32分44秒BST：％SONET - 4 -报警：POS4 / 6：PRDI清除 
Aug 7 04:32:46 BST: %LINK-3-UPDOWN: Interface POS4/6, changed state to up 8月7 4点32分46秒BST：％LINK - 3 -上下按钮：界面POS4 / 6，改变状态最多 
Aug 7 04:32:47 BST: %LINEPROTO-5-UPDOWN: Line protocol on Interface POS4/6, 8月7 4时32分47秒BST：％LINEPROTO - 5 -上下按钮：POS4 / 6接口上的线路协议， 
changed state to up最多的状态发生变化 

How Does a Router Respond to BIP Errors? 路由器是如何响应的BIP错误？

When a Cisco POS interface detects a BIP error, the interface does not discard the frame.当Cisco POS接口检测到的BIP错误，接口不丢弃该帧。 The reason is that the BIP value carried in the current frame is the value calculated on the previous frame.原因是，在当前帧进行BIP的价值是对前一帧的计算值。 In order to calculate the BIP value on the entire frame, the entire frame needs to be created.为了计算对整个帧的BIP值，整个画面的需要创建。 At SONET speeds, a frame is quite large and would occupy a large amount of buffer resources. SONET的速度，是相当大的一个框架，将占用大量的缓冲资源。 The actual approach is to avoid any delay in sending the frame that normally occurs until the parity calculation.实际的做法是为了避免在发送帧直到平价计算通常发生的任何延迟。 This approach minimizes buffer requirements.这种方法最大程度地减少缓冲要求。 Parity calculation occurs after the actual transmission of the frame.奇偶校验计算后发生的实际传输的帧。

For example, the parity value for frame 100 is placed in the BIP field of frame 101.例如，100帧校验值是摆在101帧的BIP领域。

As long as the SONET framer can maintain frame alignment, the frame is sent to the layer-2 protocol.只要在SONET成帧器可以保持帧对齐，帧被发送到第2层协议。 If the layer-2 data within the frame is corrupt, the frame is dropped as a cyclic redundancy check (CRC).如果框架内的第2层数据是腐败的，车架是下降的循环冗余检查（CRC）。

Steps to Troubleshoot 步骤来解决

Use these steps to troubleshoot the SONET alarms and defects that this document describes:使用这些步骤来解决本文件中所描述的SONET警报和缺陷：

• Check the optical power levels.检查光功率水平。 Ensure that the link has sufficient attenuation.确保链路具有足够的衰减。
• Ensure that bad or dirty fiber does not cause the bit errors.确保坏或脏的纤维不会导致位错误。 Complete these steps:完成以下步骤：
  1. Clean the physical fiber and the interfaces.清洁的物理光纤接口。
  2. Swap the cables.交换的电缆。
  3. Check any patch panels.检查所有的配线架。
• Ensure proper clock settings.确保适当的时钟设置。
• Draw out the topology, and check for any transport devices or signal regenerators in between the two ends.绘制出拓扑结构，并检查任何运输设备或在两端之间的信号再生。 Check and clean these devices also.检查并清洁，这些器件还。
• Perform hard loopback tests.执行硬环回测试。 Loop a single strand of fiber into the transmit and receive connectors of the interface.循环的接口发送和接收连接器的光纤的单链。 Then ping the IP address of the interface to ensure that the interface is capable of actual data flow.然后ping接口的IP地址，以确保该接口是实际的数据流的能力。 For more information, refer to Understanding Loopback Modes on Cisco Routers .欲了解更多信息，请参阅了解思科路由器的环回模式。
• When you contact the Cisco Technical Assistance Center (TAC):当您联系思科技术支持中心（TAC）：
  1. Collect output from the show running-config command.收集从输出显示运行配置命令。
  2. Collect output from the show controllers pos details command.收集从输出显示控制器POS细节命令。 Determine the number of SONET-level bit errors.确定SONET级位错误。
  3. Execute the clear counters command.执行命令的明确柜台 。
  4. Wait a few minutes.等待几分钟。
  5. Capture the output of show controllers pos details command again for the same interface.再次捕捉的输出显示控制器，POS细节命令相同的接口。

Here is a table that appears in the Cisco 10000 Series ESR Troubleshooting Guide.下面是一个表，出现在Cisco 10000系列ESR故障排除指南。 This table provides the steps to troubleshoot BIP TC alarms.此表提供的步骤来解决的BIP训练班报警。

Note: A known issue with Gigabit Switch Router (GSR) POS cards is that a hard loop results in ping loss because the GSR rate-limits packets are pushed to the Gigabit Route Processor (GRP). 注：千兆位交换路由器（GSR）的POS卡的一个已知问题是，在平亏损的硬盘循环的结果，因为GSR的速率限制的包都推到千兆路由处理器（ GRP）。 For more information, refer to Cisco bug ID CSCea11267 ( registered customers only ) .欲了解更多信息，请参阅Cisco Bug ID中CSCea11267 （ 注册只客户 ）。

Alarm Type and Severity报警类型和严重程度	Alarm Symptoms报警症状	Recommendation建议
TCA_B1 TCA_B1 Threshold crossing alarm - B1超出阈值报警 - B1 Minor 小	For alarm types:报警类型： TCA_B1 TCA_B1 TCA_B2 TCA_B2 TCA_B3 TCA_B3 Alarm messages appear in the CLI and logs. CLI和记录报警信息出现在。	In all cases, test the quality of the cables and connections.在所有情况下，测试的电缆和连接的质量。
TCA_B2 TCA_B2 Threshold crossing alarm - B2超出阈值报警 - B2 Minor 小	- -	Same as TCA_B1. TCA_B1相同。
TCA_B3 TCA_B3 Threshold crossing alarm - B3超出阈值报警 - B3 Minor 小	- -	Same as TCA_B1. TCA_B1相同。
BER_SF BER_SF Signal Fail condition信号故障条件 Minor 小	BER_SF and BER_SD alarms result in APS cutovers. BER_SF和BER_SD报警的APS cutovers的结果。	In both cases, test the quality of the cables and connections.在这两种情况下，测试的电缆和连接的质量。
BER_SD BER_SD Signal degrade condition信号降解条件 Minor 小	- -	You can specify these BER thresholds.您可以指定这些BER阈值。

Bit Errors on ATM Interfaces ATM接口的误码

Campus ATM switches, for example, the LightStream 1010 and Catalyst 8500, do not support a command to configure the TC alarm value on ATM over SONET interfaces.校园ATM交换机，例如，LightStream 1010和Catalyst 8500，不支持命令配置在ATM TC报警值超过SONET接口。

 Sep 19 02:21:44: %SONET-4-ALARM: ATM11/0/0: B1 BER below threshold, 09月19日2时21分44秒：％SONET - 4 -报警：ATM11/0/0：B1误码率低于阈值， 
TC alarm cleared清除训练班报警 
Sep 19 02:21:44: %SONET-4-ALARM: ATM11/0/0: B2 BER below threshold, 09月19日2时21分44秒：％SONET - 4 -报警：ATM11/0/0：B2的误码率低于阈值， 
TC alarm cleared清除训练班报警 

Troubleshoot TC alarms on ATM switches with the same steps as on POS interfaces. ATM交换机上的TC报警排除POS接口相同的步骤。 Bit errors point to a physical layer problem between the ATM switch and other devices in the path.位错误的指向路径ATM交换机和其他设备之间的物理层问题。

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