在 Catalyst 9000 系列交换机上排查端口摆动问题

简介

本文档介绍如何在 Catalyst 9000 交换机上识别、收集有用的日志并排查可能出现的端口摆动问题。

先决条件

要求

本文档没有任何特定的要求。

使用的组件

本文档中的信息基于所有Catalyst 9000系列交换机。

本文档中的信息都是基于特定实验室环境中的设备编写的。本文档中使用的所有设备最初均采用原始（默认）配置。如果您的网络处于活动状态，请确保您了解所有命令的潜在影响。

背景信息

本文由Leonardo Pena Davila供稿。

端口摆动（通常称为链路摆动）是指交换机上的物理接口连续上下移动的情况。常见原因通常与电缆不良、不受支持或非标准、小型封装热插拔(SFP)或其他链路同步问题有关。链路抖动的原因可能是间歇性的或永久性的。

由于链路抖动通常是物理干扰，本文档说明了诊断、收集有用日志以及排除Catalyst 9000交换机上端口抖动可能发生的问题的步骤。

故障排除

您可以检查以下事项：如果您对交换机有物理访问权限，可以确保正确安装网络模块、电缆和SFP:

网络模块安装

下表介绍在Catalyst 9000系列交换机中安装网络模块的最佳实践：

检验电缆和连接的两端

下表介绍了可能导致链路抖动的一些电缆问题。 

验证SFP和SFP+兼容性

Cisco 热插拔接口组合在速度、协议、到达和支持的传输介质方面提供了丰富的选择。

您可以使用Catalyst 9000系列交换机设备支持的SFP或SFP+收发器模块的任意组合。唯一的限制是，每个端口必须与电缆另一端的波长规格相匹配，并且电缆不得超过规定的电缆长度，以实现可靠通信。

在思科设备上仅使用思科SFP收发器模块。每个SFP或SFP+收发器模块均支持思科质量标识(ID)功能，允许思科交换机或路由器识别和验证收发器模块是否经过思科认证和测试。

提示：要验证Cisco光纤到设备兼容性表，请参阅此链接

确定端口摆动

使用命show logging令识别链路抖动事件。此示例显示带有接口TenGigabitEthernet1/0/40的链路抖动事件的部分交换机系统日志消息：

Switch#show logging | include changed
Aug 17 21:06:08.431 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/0/40, changed state to down
Aug 17 21:06:39.058 UTC: %LINK-3-UPDOWN: Interface TenGigabitEthernet1/0/40, changed state to down
Aug 17 21:06:41.968 UTC: %LINK-3-UPDOWN: Interface TenGigabitEthernet1/0/40, changed state to up
Aug 17 21:06:42.969 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/0/40, changed state to up
Aug 17 21:07:20.041 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/0/40, changed state to down
Aug 17 21:07:21.041 UTC: %LINK-3-UPDOWN: Interface TenGigabitEthernet1/0/40, changed state to down
Aug 17 21:07:36.534 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/0/40, changed state to up
Aug 17 21:08:06.598 UTC: %LINK-3-UPDOWN: Interface TenGigabitEthernet1/0/40, changed state to up
Aug 17 21:08:07.628 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/0/40, changed state to down
Aug 17 21:08:08.628 UTC: %LINK-3-UPDOWN: Interface TenGigabitEthernet1/0/40, changed state to down
Aug 17 21:08:10.943 UTC: %LINK-3-UPDOWN: Interface TenGigabitEthernet1/0/40, changed state to up
Aug 17 21:08:11.944 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/0/40, changed state to up

提示：如果分析系统消息日志，您必须注意端口抖动的时间戳，因为它允许您比较该特定端口上的同时事件并验证是否预期会发生链路抖动(例如：睡眠设置或其他“正常”原因未必是问题)。

接口Show命令 

show interface命令为您提供大量信息，有助于识别可能导致链路抖动事件的第1层问题：

Switch#show interfaces tenGigabitEthernet 1/0/40
TenGigabitEthernet1/0/40 is up, line protocol is up (connected) 
Hardware is Ten Gigabit Ethernet, address is 00a5.bf9c.29a8 (bia 00a5.bf9c.29a8)
  MTU 1500 bytes, BW 10000000 Kbit/sec, DLY 10 usec, 
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive not set
  Full-duplex, 10Gb/s, link type is auto, media type is SFP-10GBase-SR   <-- SFP plugged into the port
  input flow-control is on, output flow-control is unsupported 
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:03, output 00:00:00, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0  
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     670 packets input, 78317 bytes, 0 no buffer              
     Received 540 broadcasts (540 multicasts)
     0 runts, 0 giants, 0 throttles                           
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored     
     0 watchdog, 540 multicast, 0 pause input                 
     0 input packets with dribble condition detected          
     1766 packets output, 146082 bytes, 0 underruns           
     0 Output 0 broadcasts (0 multicasts)
     0 output errors, 0 collisions, 0 interface resets        
     0 unknown protocol drops                                 
     0 babbles, 0 late collision, 0 deferred                  
     0 lost carrier, 0 no carrier, 0 pause output
     0 output buffer failures, 0 output buffers swapped out   

下表列出了show interface命令的一些计数器：

history命令允许接口以类似于CPU历史记录的图形格式维护使用率历史记录。此历史记录可以按每秒位(bps)或每秒数据包(pps)进行维护，如以下示例所示：

Switch(config-if)#history ?
 bps Maintain history in bits/second
 pps Maintain history in packets/second

除速率外，用户可以监控各种接口计数器：

Switch(config-if)#history [bps|pps] ?
  all                                Include all counters
  babbles                            Include ethernet output babbles - Babbl
  crcs                               Include CRCs - CRCs 
  deferred                           Include ethernet output deferred - Defer
  dribbles                           Include dribbles - Dribl
  excessive-collisions               Include ethernet excessive output collisions -
                                     ExCol
  flushes                            Include flushes - Flush
  frame-errors                       Include frame errors - FrErr
  giants                             Include giants - Giant
  ignored                            Include ignored - Ignor
  input-broadcasts                   Include input broadcasts - iBcst
  input-drops                        Include input drops - iDrop
  input-errors                       Include input errors - iErr
  interface-resets                   Include interface resets - IRset
  late-collisions                    Include ethernet late output collisions - LtCol
  lost-carrier                       Include ethernet output lost carrier - LstCr
  multi-collisions                   Include ethernet multiple output collisions -
                                     MlCol
  multicast                          Include ethernet input multicast - MlCst
  no-carrier                         Include ethernet output no-carrier - NoCarr
  output-broadcasts                  Include output broadcasts - oBcst
  output-buffer-failures             Include output buffer failures - oBufF
  output-buffers-swapped-out         Include output buffers swapped out - oBSwO
  output-drops                       Include output drops - oDrop
  output-errors                      Include output errors - oErr
  output-no-buffer                   Include output no buffer - oNoBf
  overruns                           Include overruns - OvrRn
  pause-input                        Include ethernet input pause - PsIn
  pause-output                       Include ethernet output pause - PsOut
  runts                              Include runts - Runts
  single-collisions                  Include ethernet single output collisions - SnCol
  throttles                          Include throttles - Thrtl
  underruns                          Include underruns - UndRn
  unknown-protocol-drops             Include unknown protocol drops - Unkno
  watchdog                           Include ethernet output watchdog - Wtchdg
  <cr>                               <cr>
SW_1(config-if)#

与CPU历史记录一样，也有过去60秒、过去60分钟和过去72小时的图表。输入和输出直方图会维护单独的图表：

Switch#sh interfaces gigabitEthernet 1/0/2 history ?
 60min    Display 60 minute histograms only
 60sec    Display 60 second histograms only
 72hour   Display 72 hour histograms only
 all      Display all three histogram intervals
 both     Display both input and output histograms
 input    Display input histograms only
 output   Display output histograms only
 |        Output modifiers
  

------ Sample output ---------

Switch#show interfaces tenGigabitEthernet 1/0/9 history 60sec  



   10 
    9 
    8 
    7 
    6 
    5 
    4 
    3 
    2 
    1 
    0....5....1....1....2....2....3....3....4....4....5....5....6
              0    5    0    5    0    5    0    5    0    5    0
     TenGigabitEthernet1/0/9 input rate(mbits/sec) (last 60 seconds)


   10 
    9 
    8 
    7 
    6 
    5 
    4 
    3 
    2 
    1 
    0....5....1....1....2....2....3....3....4....4....5....5....6
              0    5    0    5    0    5    0    5    0    5    0
     TenGigabitEthernet1/0/9 output rate(mbits/sec) (last 60 seconds)

使用show controllers ethernet-controller{interface{interface-number}}显示从硬件读取的每个接口（Transmit和Receive）流量计数器和错误计数器统计信息。使用phy关键字显示接口内部寄存器，或使用port-info关键字显示有关端口ASIC的信息。

以下是show controllers ethernet-controller 针对特定接口的输出示例：

Switch#show controllers ethernet-controller tenGigabitEthernet 2/0/1
Transmit                  TenGigabitEthernet2/0/1               Receive                 
        61572 Total bytes                      282909 Total bytes              
            0 Unicast frames                      600 Unicast frames           
            0 Unicast bytes                     38400 Unicast bytes            
          308 Multicast frames                   3163 Multicast frames         
        61572 Multicast bytes                  244509 Multicast bytes          
            0 Broadcast frames                      0 Broadcast frames         
            0 Broadcast bytes                       0 Broadcast bytes          
            0 System FCS error frames               0 IpgViolation frames      
            0 MacUnderrun frames                    0 MacOverrun frames        
            0 Pause frames                          0 Pause frames             
            0 Cos 0 Pause frames                    0 Cos 0 Pause frames       
            0 Cos 1 Pause frames                    0 Cos 1 Pause frames       
            0 Cos 2 Pause frames                    0 Cos 2 Pause frames       
            0 Cos 3 Pause frames                    0 Cos 3 Pause frames       
            0 Cos 4 Pause frames                    0 Cos 4 Pause frames       
            0 Cos 5 Pause frames                    0 Cos 5 Pause frames       
            0 Cos 6 Pause frames                    0 Cos 6 Pause frames       
            0 Cos 7 Pause frames                    0 Cos 7 Pause frames       
            0 Oam frames                            0 OamProcessed frames      
            0 Oam frames                            0 OamDropped frames        
          193 Minimum size frames                3646 Minimum size frames      
            0 65 to 127 byte frames                 1 65 to 127 byte frames    
            0 128 to 255 byte frames                0 128 to 255 byte frames   
          115 256 to 511 byte frames              116 256 to 511 byte frames   
            0 512 to 1023 byte frames               0 512 to 1023 byte frames  
            0 1024 to 1518 byte frames              0 1024 to 1518 byte frames 
            0 1519 to 2047 byte frames              0 1519 to 2047 byte frames 
            0 2048 to 4095 byte frames              0 2048 to 4095 byte frames 
            0 4096 to 8191 byte frames              0 4096 to 8191 byte frames 
            0 8192 to 16383 byte frames             0 8192 to 16383 byte frames
            0 16384 to 32767 byte frame             0 16384 to 32767 byte frame
            0 > 32768 byte frames                   0 > 32768 byte frames      
            0 Late collision frames                 0 SymbolErr frames         <-- Usually indicates Layer 1 issues. Large amounts of symbol errors can indicate a bad device, cable, or hardware. 
            0 Excess Defer frames                   0 Collision fragments      <-- If this counter increments, this is an indication that the ports are configured at half-duplex.
            0 Good (1 coll) frames                  0 ValidUnderSize frames    
            0 Good (>1 coll) frames                 0 InvalidOverSize frames   
            0 Deferred frames                       0 ValidOverSize frames     
            0 Gold frames dropped                   0 FcsErr frames           <-- Are the result of collisions at half-duplex, a duplex mismatch, bad hardware (NIC, cable, or port)
            0 Gold frames truncated    
            0 Gold frames successful   
            0 1 collision frames                    
            0 2 collision frames       
            0 3 collision frames       
            0 4 collision frames       
            0 5 collision frames       
            0 6 collision frames       
            0 7 collision frames       
            0 8 collision frames       
            0 9 collision frames       
            0 10 collision frames      
            0 11 collision frames      
            0 12 collision frames      
            0 13 collision frames      
            0 14 collision frames      
            0 15 collision frames      
            0 Excess collision frames  

LAST UPDATE 22622 msecs AGO

提示：您还可以使用show interfaces {interface{interface-number}} controller命令显示从硬件读取的每个接口的Transmit和Receive统计信息。

使用show platform pm interface-flaps{interface{interface-number}}  要显示接口关闭的次数，请执行以下操作：

这是show platform pm interface-flaps的输出示例{interface{interface-number}}对于特定接口：

Switch#show platform pm interface-flaps tenGigabitEthernet 2/0/1 

  Field                     AdminFields          OperFields
===============================================================
  Access Mode               Static               Static
  Access Vlan Id            1                    0
  Voice Vlan Id             4096                 0
  VLAN Unassigned                                0
  ExAccess Vlan Id          32767                
  Native Vlan Id            1                    
  Port Mode                 dynamic              access
  Encapsulation             802.1Q               Native
  disl                      auto                 
  Media                     unknown              
  DTP Nonegotiate           0                    0
  Port Protected            0                    0
  Unknown Unicast Blocked   0                    0
  Unknown Multicast Blocked 0                    0
  Vepa Enabled              0                    0
  App interface             0                    0
  Span Destination          0                    

  Duplex                    auto                 full 
  Default Duplex            auto                 
  Speed                     auto                 1000
  Auto Speed Capable        1                    1
  No Negotiate              0                    0
  No Negotiate Capable      1024                 1024
  Flow Control Receive      ON                   ON
  Flow Control Send         Off                  Off
  Jumbo                     0                    0
  saved_holdqueue_out       0                    
  saved_input_defqcount     2000                 
  Jumbo Size                1500                 

  Forwarding Vlans : none
  Current Pruned Vlans : none
  Previous Pruned Vlans : none


  Sw LinkNeg State : LinkStateUp
  No.of LinkDownEvents :    12                            <--  Number of times the interface flapped    
  XgxsResetOnLinkDown(10GE):
  Time Stamp Last Link Flapped(U) : Aug 19 14:58:00.154   <-- Last time the interface flapped
  LastLinkDownDuration(sec) 192                           <-- Time in seconds the interface stayed down during the last flap event      
  LastLinkUpDuration(sec):  2277                          <-- Time in seconds the interface stayed up before the last flap event  

使用show idprom{interface{interface-number}}  命令（不带关键字），以显示特定接口的IDPROM信息。与detail关键字一起使用可显示详细的十六进制IDPROM信息。

这是show idprom的输出示例{interface{interface-number}} 用于特定接口。此命令输出中列出的High和Low Warning|Alarm 阈值是正常运行的光纤收发器参数。这些值可以从特定光学器件的数据表中进行验证。请参阅思科光纤数据表 

Switch#show idprom interface Twe1/0/1 

IDPROM for transceiver TwentyFiveGigE1/0/1 :
  Description                               = SFP or SFP+ optics (type 3)
  Transceiver Type:                         = GE CWDM 1550 (107)
  Product Identifier (PID)                  = CWDM-SFP-1550  <-- 
  Vendor Revision                           = A
  Serial Number (SN)                        = XXXXXXXXXX   <-- Cisco Serial Number
  Vendor Name                               = CISCO-FINISAR
  Vendor OUI (IEEE company ID)              = 00.90.65 (36965)
  CLEI code                                 = CNTRV14FAB
  Cisco part number                         = 10-1879-03
  Device State                              = Enabled.
  Date code (yy/mm/dd)                      = 14/12/22
  Connector type                            = LC.
  Encoding                                  = 8B10B (1)
  Nominal bitrate                           = OTU-1 (2700 Mbits/s)
  Minimum bit rate as % of nominal bit rate = not specified
  Maximum bit rate as % of nominal bit rate = not specified
  The transceiver type is 107
  Link reach for 9u fiber (km)              = LR-2(80km) (80)
                                              LR-3(80km) (80)
                                              ZX(80km) (80)
  Link reach for 9u fiber (m)               = IR-2(40km) (255)
                                              LR-1(40km) (255)
                                              LR-2(80km) (255)
                                              LR-3(80km) (255)
                                              DX(40KM) (255)
                                              HX(40km) (255)
                                              ZX(80km) (255)
                                              VX(100km) (255)
  Link reach for 50u fiber (m)              = SR(2km) (0)
                                              IR-1(15km) (0)
                                              IR-2(40km) (0)
                                              LR-1(40km) (0)
                                              LR-2(80km) (0)
                                              LR-3(80km) (0)
                                              DX(40KM) (0)
                                              HX(40km) (0)
                                              ZX(80km) (0)
                                              VX(100km) (0)
                                              1xFC, 2xFC-SM(10km) (0)
                                              ESCON-SM(20km) (0)
  Link reach for 62.5u fiber (m)            = SR(2km) (0)
                                              IR-1(15km) (0)
                                              IR-2(40km) (0)
                                              LR-1(40km) (0)
                                              LR-2(80km) (0)
                                              LR-3(80km) (0)
                                              DX(40KM) (0)
                                              HX(40km) (0)
                                              ZX(80km) (0)
                                              VX(100km) (0)
                                              1xFC, 2xFC-SM(10km) (0)
                                              ESCON-SM(20km) (0)
  Nominal laser wavelength                  = 1550 nm.
  DWDM wavelength fraction                  = 1550.0  nm.
  Supported options                         = Tx disable
                                              Tx fault signal
                                              Loss of signal (standard implementation)
  Supported enhanced options                = Alarms for monitored parameters
  Diagnostic monitoring                     = Digital diagnostics supported
                                              Diagnostics are externally calibrated
                                              Rx power measured is "Average power"
  Transceiver temperature operating range   = -5 C to 75 C (commercial)
  Minimum operating temperature             = 0 C
  Maximum operating temperature             = 70 C
  High temperature alarm threshold          = +90.000 C
  High temperature warning threshold        = +85.000 C
  Low temperature warning threshold         = +0.000 C
  Low temperature alarm threshold           =  -4.000 C
  High voltage alarm threshold              = 3600.0 mVolts
  High voltage warning threshold            = 3500.0 mVolts
  Low voltage warning threshold             = 3100.0 mVolts
  Low voltage alarm threshold               = 3000.0 mVolts
  High laser bias current alarm threshold   = 84.000 mAmps
  High laser bias current warning threshold = 70.000 mAmps
  Low laser bias current warning threshold  = 4.000 mAmps
  Low laser bias current alarm threshold    = 2.000 mAmps
  High transmit power alarm threshold       =  7.4 dBm
  High transmit power warning threshold     =  4.0 dBm
  Low transmit power warning threshold      = -1.7 dBm
  Low transmit power alarm threshold        = -8.2 dBm
  High receive power alarm threshold        = -3.0 dBm
  Low receive power alarm threshold        = -33.0 dBm
  High receive power warning threshold        = -7.0 dBm
  Low receive power warning threshold        = -28.2 dBm
  External Calibration: bias current slope  = 1.000
  External Calibration: bias current offset = 0

提示：确保设备的硬件和软件版本与已安装的SFP/SFP+思科光纤到设备兼容性列表兼容

下表列出了可用于排除链路抖动故障的各种命令：

使用时域反射器(TDR)验证电缆状态

时域反射计(TDR)功能允许您确定电缆在出现故障时是打开还是短路。使用TDR，您可以检查Catalyst 9000系列交换机上端口铜缆的状态。TDR使用通过电缆发送的信号检测电缆故障，并读取反射回的信号。由于电缆存在缺陷，信号的所有或部分都可以反射回来

使用test cable-diagnostics tdr {interface{interface-number} }启动TDR测试，然后使用show cable-diagnostics tdr{interfaceinterface-number}。 

提示：有关详细信息，请参阅检查端口状态和连接

示例显示了接口Tw2/0/10的TDR测试结果：

Switch#show cable-diagnostics tdr interface tw2/0/10
TDR test last run on: November 05 02:28:43
Interface Speed Local pair  Pair length         Remote pair Pair status
--------- ----- ---------- ------------------ ----------- --------------------
Tw2/0/10 1000M Pair A       1     +/- 5 meters  Pair A      Impedance Mismatch
               Pair B       1     +/- 5 meters  Pair B      Impedance Mismatch
               Pair C       1     +/- 5 meters  Pair C      Open
               Pair D       3     +/- 5 meters  Pair D      Open

提示：在Catalyst 9300系列交换机上，仅检测到以下电缆故障类型 — OPEN、SHORT和IMPEDANCE MISMATCH。如果电缆端接正确，则会显示Normal状态，此过程出于说明目的。

TDR准则

本指南适用于TDR的使用：

• 在TDR测试运行时，请勿更改端口配置。
• 如果在TDR测试期间将端口连接到启用了Auto-MDIX的端口，则TDR结果可能无效。
• 如果在TDR测试期间将端口连接到100BASE-T端口（例如设备上的端口），则未使用的对（4-5和7-8）将报告为故障，因为远程终端不会终止这些对。
• 由于电缆的特征，您必须多次运行TDR测试才能得到准确的结果。
• 请勿更改端口状态（例如，拔下近端或远端的电缆），因为结果可能不准确。
• 如果测试电缆从远程端口断开，则TDR的工作效果最佳。否则，您就很难正确解释结果。
• TDR在四根电线之间运行。根据电缆状况，状态可显示一个线对为OPEN或SHORT，而其他所有线对均显示为故障。此操作是可接受的，因为只要一对电线开或短，您就可以断定电缆有故障。
• TDR的目的是确定电缆的运行情况如何，而不是定位有故障的电缆。
• 当TDR找到有故障的电缆时，您仍然可以使用离线电缆诊断工具来更好地诊断问题。
• 由于TDR实施的分辨率不同，Catalyst 9300系列交换机不同交换机型号上的TDR结果可能不同。发生这种情况时，必须参考离线电缆诊断工具。

数字光纤监控(DOM)

数字光纤监控(DOM)是行业标准，旨在定义访问实时参数的数字接口，例如：

• 温度
• 收发器电源电压
• 激光偏置电流
• 光发射功率
• 光Rx功率

如何启用DOM

下表列出了可用于为系统中所有类型的收发器打开/关闭DOM的命令：

使用show interfaces {interface{interface-number}} transceiver detail命令显示收发器信息：

Switch#show interfaces hundredGigE 1/0/25 transceiver detail 
ITU Channel not available (Wavelength not available),
Transceiver is internally calibrated.
mA: milliamperes, dBm: decibels (milliwatts), NA or N/A: not applicable.
++ : high alarm, + : high warning, - : low warning, -- : low alarm.
A2D readouts (if they differ), are reported in parentheses.
The threshold values are calibrated.

                                  High Alarm  High Warn  Low Warn   Low Alarm
               Temperature        Threshold   Threshold  Threshold  Threshold
Port           (Celsius)          (Celsius)   (Celsius)  (Celsius)  (Celsius)
---------      ----------------- ----------   ---------   --------- ---------
Hu1/0/25       28.8                   75.0       70.0        0.0       -5.0

                                 High Alarm   High Warn  Low Warn   Low Alarm
              Voltage            Threshold    Threshold  Threshold  Threshold
Port          (Volts)            (Volts)      (Volts)    (Volts)    (Volts)
---------     ----------------- ----------    ---------  ---------  ---------
Hu1/0/25      3.28                   3.63        3.46      3.13         2.97

                                 High Alarm   High Warn  Low Warn   Low Alarm
                Current          Threshold    Threshold  Threshold  Threshold
Port      Lane  (milliamperes)   (mA)         (mA)       (mA)       (mA)
--------- ----  ---------------  ----------   ---------  ---------  ---------
Hu1/0/25   N/A   6.2                  10.0        8.5        3.0        2.6

                 Optical         High Alarm   High Warn  Low Warn   Low Alarm
                 Transmit Power  Threshold    Threshold  Threshold  Threshold
Port      Lane   (dBm)           (dBm)        (dBm)      (dBm)      (dBm)
--------- ----   --------------- ----------   ---------  ---------  ---------
Hu1/0/25  N/A    -2.2                 1.7        -1.3       -7.3      -11.3

                 Optical          High Alarm  High Warn   Low Warn   Low Alarm
                 Receive Power    Threshold   Threshold   Threshold  Threshold
Port      Lane   (dBm)            (dBm)       (dBm)       (dBm)      (dBm)
--------- ----   ---------------  ----------  ---------   ---------  ---------
Hu1/0/25  N/A    -16.7                2.0        -1.0        -9.9      -13.9
 

提示：要确定光收发器是否工作在适当的信号电平，请参阅Cisco Optics数据表

数字光纤监控系统日志消息

本节介绍最相关的阈值违规系统日志消息：

SFP光纤的温度水平

• 说明:当温度低或超过正常光纤工作值时，会生成以下日志消息：

%SFF8472-3-THRESHOLD_VIOLATION: Te7/3: Temperature high alarm; Operating value: 88.7 C, Threshold value: 74.0 C.
%SFF8472-3-THRESHOLD_VIOLATION: Fo1/1/1: Temperature low alarm; Operating value: 0.0 C, Threshold value: 35.0 C.

SFP光纤的电压电平

• 说明:当电压低或超过正常光纤工作值时，会生成以下日志消息：

%SFF8472-3-THRESHOLD_VIOLATION: Gi1/1/3: Voltage high warning; Operating value: 3.50 V, Threshold value: 3.50 V.
%SFF8472-5-THRESHOLD_VIOLATION: Gi1/1: Voltage low alarm; Operating value: 2.70 V, Threshold value: 2.97 V.

SFP光纤的轻量级

• 说明:当光功率低或超过光操作值时，会生成以下日志消息：

%SFF8472-3-THRESHOLD_VIOLATION: Gi1/0/1: Rx power high warning; Operating value: -2.7 dBm, Threshold value: -3.0 dBm.
%SFF8472-5-THRESHOLD_VIOLATION: Te1/1: Rx power low warning; Operating value: -13.8 dBm, Threshold value: -9.9 dBm.

提示：有关DOM的详细信息，请参阅数字光纤监控

思科光纤和前向纠错(FEC)

FEC技术用于检测和纠正比特流中的一定数量的错误，并在传输之前将冗余比特和错误检查代码附加到消息块中。作为模块制造商，思科将认真设计收发器以符合规范。当光纤收发器在Cisco主机平台中运行时，默认情况下会根据主机软件检测到的光纤模块类型启用FEC（请参阅此可下载表）。在绝大多数情况下，FEC实施取决于光纤类型支持的行业标准。 

对于某些自定义规格，FEC实施各不相同。有关详细信息，请参阅了解Cisco Optics中的FEC及其实施文档。

示例展示如何配置FEC和一些可用选项：

switch(config-if)#fec?
  auto Enable FEC Auto-Neg
  cl108 Enable clause108 with 25G
  cl74 Enable clause74 with 25G
  off Turn FEC off

Use the show interface command to verify FEC configuration:

TwentyFiveGigE1/0/13 is up, line protocol is up (connected)
  Hardware is Twenty Five Gigabit Ethernet, address is 3473.2d93.bc8d (bia 3473.2d93.bc8d)
  MTU 9170 bytes, BW 25000000 Kbit/sec, DLY 10 usec,
      reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Full-duplex, 25Gb/s, link type is force-up, media type is SFP-25GBase-SR
  Fec is auto     < -- The configured setting for FEC is displayed here
  input flow-control is on, output flow-control is off
  ARP type: ARPA, ARP Timeout 04:00:00 
--snip--

注意：链路的两端必须启用相同的FEC算法encoding，链路才能进入工作状态。

调试命令

下表列出了可用于调试端口抖动的各种命令

注意:请谨慎使用debug命令。请注意，许多debug命令会影响实时网络，因此建议仅在重现问题时在实验室环境中使用。                                                        ;

以下是表中列出的debug命令的部分输出示例：

SW_2#sh debugging 
PM (platform):          
 L2 Control Infra debugging is on   <-- debug platform pm l2-control
 PM Link Status debugging is on     <-- debug platform pm link-status
 PM Vectors debugging is on         <-- debug platform pm pm-vectors
Packet Infra debugs:

Ip Address Port
------------------------------------------------------|----------

Port Manager:
  Port events debugging is on        <-- debug pm port

Condition 1: interface Te1/0/2 (1 flags triggered)
Flags: Te1/0/2

------ Sample output ---------

*Aug 25 20:01:05.791: link up/down event : link-down on Te1/0/2
*Aug 25 20:01:05.791: pm_port 1/2: during state access, got event 5(link_down)   <-- Link down event (day/time)
*Aug 25 20:01:05.791: @@@ pm_port 1/2: access -> pagp
*Aug 25 20:01:05.792: IOS-FMAN-PM-DEBUG-PM-VECTORS: Success sending PM tdl message
*Aug 25 20:01:05.792: IOS-FMAN-PM-DEBUG-PM-VECTORS: Success sending PM tdl message
*Aug 25 20:01:05.792: IOS-FMAN-PM-DEBUG-PM-VECTORS: Success sending PM tdl message
*Aug 25 20:01:05.792: IOS-FMAN-PM-DEBUG-PM-VECTORS: Vp Disable: pd=0x7F1E797914B0 dpidx=10 Te1/0/2
*Aug 25 20:01:05.792: IOS-FMAN-PM-DEBUG-PM-VECTORS: Success sending PM tdl message
*Aug 25 20:01:05.792: IOS-FMAN-PM-DEBUG-PM-VECTORS: Success sending PM tdl message
*Aug 25 20:01:05.792: Maintains count of VP per Interface:delete, pm_vp_counter[0]: 14, pm_vp_counter[1]: 14
*Aug 25 20:01:05.792: *** port_modechange: 1/2 mode_none(10)
*Aug 25 20:01:05.792: @@@ pm_port 1/2: pagp -> dtp
*Aug 25 20:01:05.792: stop flap timer : Te1/0/2 pagp
*Aug 25 20:01:05.792: *** port_bndl_stop: 1/2 : inform yes
*Aug 25 20:01:05.792: @@@ pm_port 1/2: dtp -> present
*Aug 25 20:01:05.792: *** port_dtp_stop: 1/2
*Aug 25 20:01:05.792: stop flap timer : Te1/0/2 pagp
*Aug 25 20:01:05.792: stop flap timer : Te1/0/2 dtp
*Aug 25 20:01:05.792: stop flap timer : Te1/0/2 unknown
*Aug 25 20:01:05.792: *** port_linkchange: reason_link_change(3): link_down(0)1/2  <-- State link change 
*Aug 25 20:01:05.792: pm_port 1/2: idle during state present
*Aug 25 20:01:05.792: @@@ pm_port 1/2: present -> link_down    <-- State of the link
*Aug 25 20:01:06.791: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/0/2, changed state to down
*Aug 25 20:01:07.792: %LINK-3-UPDOWN: Interface TenGigabitEthernet1/0/2, changed state to down
*Aug 25 20:01:11.098: IOS-FMAN-PM-DEBUG-LINK-STATUS: Received LINKCHANGE in xcvr message, if_id 10 (TenGigabitEthernet1/0/2)

*Aug 25 20:01:11.098: IOS-FMAN-PM-DEBUG-LINK-STATUS: if_id 0xA, if_name Te1/0/2, link up <-- Link became up
*Aug 25 20:01:11.098: link up/down event: link-up on Te1/0/2
*Aug 25 20:01:11.098: pm_port 1/2: during state link_down, got event 4(link_up)
*Aug 25 20:01:11.098: @@@ pm_port 1/2: link_down -> link_up
*Aug 25 20:01:11.098: flap count for link type : Te1/0/2 Linkcnt = 0 
*Aug 25 20:01:11.099: pm_port 1/2: idle during state link_up
*Aug 25 20:01:11.099: @@@ pm_port 1/2: link_up -> link_authentication
*Aug 25 20:01:11.099: pm_port 1/2: during state link_authentication, got event 8(authen_disable)
*Aug 25 20:01:11.099: @@@ pm_port 1/2: link_authentication -> link_ready
*Aug 25 20:01:11.099: *** port_linkchange: reason_link_change(3): link_up(1)1/2 
*Aug 25 20:01:11.099: pm_port 1/2: idle during state link_ready
*Aug 25 20:01:11.099: @@@ pm_port 1/2: link_ready -> dtp
*Aug 25 20:01:11.099: IOS-FMAN-PM-DEBUG-PM-VECTORS: Set pm vp mode attributes for Te1/0/2 vlan 1
*Aug 25 20:01:11.099: IOS-FMAN-PM-DEBUG-PM-VECTORS: Success sending PM tdl message
*Aug 25 20:01:11.099: IOS-FMAN-PM-DEBUG-PM-VECTORS: Success sending PM tdl message
*Aug 25 20:01:11.099: IOS-FMAN-PM-DEBUG-PM-VECTORS: Success sending PM tdl message
*Aug 25 20:01:11.099: pm_port 1/2: during state dtp, got event 13(dtp_complete)
*Aug 25 20:01:11.099: @@@ pm_port 1/2: dtp -> dtp
*Aug 25 20:01:11.099: IOS-FMAN-PM-DEBUG-PM-VECTORS: Set pm vp mode attributes for Te1/0/2 vlan 1
*Aug 25 20:01:11.099: IOS-FMAN-PM-DEBUG-PM-VECTORS: Success sending PM tdl message
*Aug 25 20:01:11.099: DTP flapping: flap count for dtp type: Te1/0/2 Dtpcnt = 0 
*Aug 25 20:01:11.099: pm_port 1/2: during state dtp, got event 110(dtp_done)
*Aug 25 20:01:11.099: @@@ pm_port 1/2: dtp -> pre_pagp_may_suspend
*Aug 25 20:01:11.099: pm_port 1/2: idle during state pre_pagp_may_suspend
*Aug 25 20:01:11.099: @@@ pm_port 1/2: pre_pagp_may_suspend -> pagp_may_suspend
*Aug 25 20:01:11.099: pm_port 1/2: during state pagp_may_suspend, got event 33(pagp_continue)
*Aug 25 20:01:11.099: @@@ pm_port 1/2: pagp_may_suspend -> start_pagp
*Aug 25 20:01:11.099: pm_port 1/2: idle during state start_pagp
*Aug 25 20:01:11.099: @@@ pm_port 1/2: start_pagp -> pagp
*Aug 25 20:01:11.100: IOS-FMAN-PM-DEBUG-PM-VECTORS: Success sending PM tdl message
*Aug 25 20:01:11.100: IOS-FMAN-PM-DEBUG-PM-VECTORS: Success sending PM tdl message
*Aug 25 20:01:11.100: IOS-FMAN-PM-DEBUG-PM-VECTORS: Set pm vp mode attributes for Te1/0/2 vlan 1
*Aug 25 20:01:11.100: IOS-FMAN-PM-DEBUG-PM-VECTORS: Success sending PM tdl message
*Aug 25 20:01:11.100: IOS-FMAN-PM-DEBUG-PM-VECTORS: Success sending PM tdl message
*Aug 25 20:01:11.100: IOS-FMAN-PM-DEBUG-PM-VECTORS: Success sending PM tdl message
*Aug 25 20:01:11.100: *** port_bndl_start: 1/2
*Aug 25 20:01:11.100: stop flap timer : Te1/0/2 pagp
*Aug 25 20:01:11.100: pm_port 1/2: during state pagp, got event 34(dont_bundle)
*Aug 25 20:01:11.100: @@@ pm_port 1/2: pagp -> pre_post_pagp
*Aug 25 20:01:11.100: pm_port 1/2: idle during state pre_post_pagp
*Aug 25 20:01:11.100: @@@ pm_port 1/2: pre_post_pagp -> post_pagp
*Aug 25 20:01:11.100: IOS-FMAN-PM-DEBUG-PM-VECTORS: Success sending PM tdl message
*Aug 25 20:01:11.100: IOS-FMAN-PM-DEBUG-PM-VECTORS: Success sending PM tdl message
*Aug 25 20:01:11.100: pm_port 1/2: during state post_pagp, got event 14(dtp_access)
*Aug 25 20:01:11.100: @@@ pm_port 1/2: post_pagp -> access
*Aug 25 20:01:11.100: IOS-FMAN-PM-DEBUG-PM-VECTORS: Success sending PM tdl message
*Aug 25 20:01:11.100: IOS-FMAN-PM-DEBUG-PM-VECTORS: Success sending PM tdl message
*Aug 25 20:01:11.100: IOS-FMAN-PM-DEBUG-PM-VECTORS: Success sending PM tdl message
*Aug 25 20:01:11.100: IOS-FMAN-PM-DEBUG-PM-VECTORS: Set pm vp mode attributes for Te1/0/2 vlan 1
*Aug 25 20:01:11.100: IOS-FMAN-PM-DEBUG-PM-VECTORS: Success sending PM tdl message
*Aug 25 20:01:11.100: Maintains count of VP per Interface:add, pm_vp_counter[0]: 15, pm_vp_counter[1]: 15
*Aug 25 20:01:11.100: IOS-FMAN-PM-DEBUG-PM-VECTORS: vlan vp enable for port(Te1/0/2) and vlan:1
*Aug 25 20:01:11.101: IOS-FMAN-PM-DEBUG-PM-VECTORS: VP ENABLE: vp_pvlan_port_mode:access for Te1/0/2 
*Aug 25 20:01:11.101: IOS-FMAN-PM-DEBUG-PM-VECTORS: VP Enable: vp_pvlan_native_vlanId:1 for Te1/0/2 
*Aug 25 20:01:11.101: IOS-FMAN-PM-DEBUG-PM-VECTORS: Success sending PM tdl message
*Aug 25 20:01:11.101: IOS-FMAN-PM-DEBUG-PM-VECTORS: Success sending PM tdl message
*Aug 25 20:01:11.101: *** port_modechange: 1/2 mode_access(1)
*Aug 25 20:01:11.101: IOS-FMAN-PM-DEBUG-PM-VECTORS: The operational mode of Te1/0/2 in set all vlans is 1 
*Aug 25 20:01:11.101: IOS-FMAN-PM-DEBUG-PM-VECTORS: Success sending PM tdl message
*Aug 25 20:01:11.101: IOS-FMAN-PM-DEBUG-PM-VECTORS: vp_pvlan port_mode:access vlan:1 for Te1/0/2 
*Aug 25 20:01:11.101: IOS-FMAN-PM-DEBUG-PM-VECTORS: vp_pvlan port_mode:access native_vlan:1 for Te1/0/2 
*Aug 25 20:01:11.102: IOS-FMAN-PM-DEBUG-PM-VECTORS: Success sending PM tdl message
*Aug 25 20:01:13.098: %LINK-3-UPDOWN: Interface TenGigabitEthernet1/0/2, changed state to up
*Aug 25 20:01:14.098: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/0/2, changed state to up

相关的思科漏洞

相关信息

思科光纤到设备兼容性矩阵

适用于千兆以太网应用的思科SFP模块产品手册

25GE和100GE — 通过投资保护实现企业内更高速度白皮书

Cisco CWDM SFP解决方案产品手册

支持创新：Cisco TAC如何转变文档和简化自助服务

思科技术支持和下载