排除Catalyst 9000交换机上的端口抖动故障
问题
本文档介绍如何排除一个或多个交换机接口在打开和关闭之间反复改变状态（端口摆动或链路摆动）而导致连接中断的故障。
环境
Cisco Catalyst 9000系列交换机，带铜缆或光纤上行链路/下行链路。此问题可能发生在接入端口、上行链路和（如果存在）可移动网络模块端口上。物理路径可以包括配线面板、终端设备和光纤收发器。
- 介质适用性：TDR仅适用于铜缆接口；DOM仅适用于支持的光纤收发器。
- 接口类型：独立固定端口和模块端口属于范围；对任一操作使用相同的工作流程。
- 光纤支持：仅使用平台和软件版本支持的光纤。
原因
常见原因包括布线错误或不受支持、小型封装热插拔(SFP)或增强型小型封装热插拔(SFP+)收发器不受支持或出现故障、双工或协商不匹配、终端节电行为以及其他物理层故障。
分辨率
按照本文中的故障排除工作流程确认日志中的抖动，验证物理连接和光纤，检查接口计数器，并在适用情况下运行纯铜缆TDR或纯光纤DOM检查。
先决条件
要求
本文档没有任何特定的要求。
使用的组件
本文中的信息基于 Cisco 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
当交换机上的物理接口反复开启和关闭时，端口抖动（也称为链路抖动）就会发生。常见原因包括布线错误、不受支持或不标准、小型封装热插拔(SFP)收发器不受支持以及其他链路同步问题。条件可以是间歇性或永久性。
由于链路摆动往往是物理问题，本文档介绍如何诊断Cisco Catalyst 9000系列交换机上的问题、收集有用的日志以及排除端口摆动故障。
故障排除工作流程
使用此工作流程可以隔离端口抖动的最常见原因。从第1步开始，按顺序继续。仅当链路类型和症状匹配时，才运行可选步骤。
- 确认日志中的摆动。使用show logging确认重复的up/down事件并捕获时间戳。
- 检查物理连接性和光纤。检验布线、配线面板和支持的收发器；重新拔插或换用已知良好的组件。
- 检查接口计数器和硬件统计信息。使用show interfaces和控制器计数器识别第1层错误（CRC、符号错误、FCS错误）。
- 运行TDR（仅限铜缆链路）。 使用TDR检测OPEN/SHORT条件和近似故障距离。
- 选中DOM（仅光纤链路）。 根据数据表阈值查看光纤功率/温度/电压。
- 验证FEC（仅支持的光纤）。 确认Forward Error Correction 设置和兼容性（如果适用）。
- 仅在问题仍然存在时，才使用debug命令。在复制窗口期间收集目标的debug输出，并在捕获后立即禁用。
每个部分都包含一个简短注释，指示何时使用它。
物理访问可用时，请使用此部分。检查计数器或运行其他诊断程序之前，请验证网络模块、电缆以及SFP或SFP+收发器是否正确安装。
网络模块安装参考
当存在可移动网络模块时，请使用此参考。下表介绍了在Cisco Catalyst 9000系列交换机中安装网络模块的最佳实践：
| Platform |
URL |
| Catalyst 9200 系列交换机 |
|
| Catalyst 9300 系列交换机 |
|
| Catalyst 9400 系列交换机 |
|
| Catalyst 9500 系列交换机 |
|
| Catalyst 9600 系列交换机 |
检验电缆和连接的两端
在日志中确认抖动后，使用此部分。这些表介绍了链路抖动常见的电缆相关原因以及建议的恢复操作。
| 原因 |
恢复操作 |
| 电缆损坏 |
将可疑电缆换成已知良好的电缆。查找连接器的引脚是否损坏或丢失。 |
| 连接松动 |
重新拔插电缆。卸下接头并重新插入，确保它完全就位。 |
| 配线面板 |
消除接线板连接故障。如果可能，请绕过配线面板，将其排除。 |
| SFP错误或错误（特定于光纤） |
将怀疑SFP更换为已知良好的SFP。验证此类SFP的硬件和软件支持。 |
| 错误的端口或模块端口 |
将电缆移至已知良好的端口，对可疑端口或模块进行故障排除。 |
| 错误的或旧的终端设备 |
将电话、扬声器或其他终端与已知良好的设备或更新设备交换。 |
| 设备睡眠模式 |
这可以是一个预期的折翼。检查端口抖动的时间戳。将其与其他同时发生的事件进行比较。然后确定原因是否在于睡眠设置。 |
验证SFP和SFP+兼容性
当抖动链路使用光纤收发器时，请使用此部分。思科热插拔接口产品组合提供了一系列速度、协议、连接和支持传输介质选择。
使用Cisco Catalyst 9000系列交换机支持的SFP或SFP+收发器模块的任意组合。每个端口必须与电缆另一端的波长规格相匹配。电缆不能超过支持的电缆长度，以实现可靠通信。
在Cisco设备上仅使用Cisco 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。此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。
确定端口摆动
先决条件:对设备系统日志缓冲区或远程系统日志的特权EXEC访问（例如，enable）和访问。
预期结果：同一接口在短时间窗口内重复的up/down消息可确认抖动情况。
首先使用此部分可以确认是否出现阀瓣。运行命令show logging | include changed，确定链路抖动事件。此示例显示接口TenGigabitEthernet1/0/40上链路抖动事件的部分交换机系统日志消息：
Switch#show logging | include changed
August 17 21:06:08.431 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/0/40, changed state to down
August 17 21:06:39.058 UTC: %LINK-3-UPDOWN: Interface TenGigabitEthernet1/0/40, changed state to down
August 17 21:06:41.968 UTC: %LINK-3-UPDOWN: Interface TenGigabitEthernet1/0/40, changed state to up
August 17 21:06:42.969 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/0/40, changed state to up
August 17 21:07:20.041 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/0/40, changed state to down
August 17 21:07:21.041 UTC: %LINK-3-UPDOWN: Interface TenGigabitEthernet1/0/40, changed state to down
August 17 21:07:36.534 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/0/40, changed state to up
August 17 21:08:06.598 UTC: %LINK-3-UPDOWN: Interface TenGigabitEthernet1/0/40, changed state to up
August 17 21:08:07.628 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/0/40, changed state to down
August 17 21:08:08.628 UTC: %LINK-3-UPDOWN: Interface TenGigabitEthernet1/0/40, changed state to down
August 17 21:08:10.943 UTC: %LINK-3-UPDOWN: Interface TenGigabitEthernet1/0/40, changed state to up
August 17 21:08:11.944 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/0/40, changed state to up
- 确定每个启动/关闭转换的时间戳。
- 将时间戳与同一接口上的其他事件（例如，终端省电行为）进行比较。
- 确定抖动是预期的还是表示物理层的问题。
Interface show命令
适用场合:确认重复的up/down事件并验证物理路径后。
命令:受影响接口的show interfaces和show controllers ethernet-controller interface。
预期结果：错误计数器（CRC、符号错误、FCS）在正常情况下保持稳定或缓慢增加。
异常时的下一步操作：交换电缆/光缆，移至已知良好的端口，并重新检查计数器；如果适用，请继续执行TDR（铜缆）或DOM（光纤）。
确认抖动并检查物理路径后，可使用此部分。show interfaces命令提供的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 interfaces命令的一些计数器：
| 计数器 |
有关错误计数器递增的问题和常见原因 |
| CRC |
大量循环冗余校验(CRC)错误通常是冲突的结果。它还可能表示物理问题，例如布线、SFP、接口故障或网络接口卡(NIC)。 它也可能表示双工不匹配。 |
| 输入错误 |
这包括残帧、巨型帧、无缓冲区、CRC、帧、溢出和忽略的计数。其他与输入相关的错误也会增加输入错误计数。 |
| 输出错误 |
当输出队列过小或接口超订用时，输出错误可能会增加。 |
| 总输出丢弃数 |
输出丢弃通常是由多对一流量模式或10 Gbps到1 Gbps传输引起的接口超订用造成的。接口缓冲区是有限的资源，最多只能吸收一点突发量。在此之后，数据包开始丢弃。缓冲器可以调整以提供一些缓冲，但无法保证零输出丢弃。 |
| 未知协议丢弃 |
当接收接口未配置该协议或交换机无法识别协议时，会发生未知协议丢弃。例如，如果两台交换机已连接，并且在一个交换机接口上禁用了思科发现协议(CDP)，则该接口上会出现未知协议丢弃。CDP数据包不再被识别，交换机将丢弃这些数据包。 |
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。历史记录可以维护为每秒位(bps)或每秒数据包数(pps)，如下例所示：
Switch(config-if)#history ?
bps Maintain history in bits/second
pps Maintain history in packets/second
除速率外，还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，图形在最近60秒、最近60分钟和最近72小时内可用。输入和输出直方图会维护单独的图表：
Switch#show 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{interface-number}}命令可显示从硬件读取的每个接口（传输和接收）流量计数器和错误统计信息。使用phy关键字显示接口内部寄存器。使用port-info关键字可显示有关端口特定应用集成电路(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
使用show platform pm interface-flaps {interface{interface-number}}命令可显示接口关闭的次数：
以下是show platform pm interface-flaps {interface{interface-number}}针对特定接口的输出示例：
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
当必须验证光纤运行状况时，请将此部分用于光纤链路。使用show idprom interface {interface-number}命令显示指定接口中安装的收发器的IDPROM信息。使用detail关键字显示详细的十六进制IDPROM字段。
此示例显示特定接口的show idprom {interface{interface-number}}命令的输出。此命令输出中列出的High和Low Warning|Alarm 阈值值是正常运行的光纤收发器参数。这些值可以在特定光学器件的数据表中进行验证。请参阅Cisco光纤收发器模块文档。
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) = SERIALNUMBER
Vendor Name = CISCO-FINISAR
Vendor OUI (IEEE company ID) = 00.90.65 (36965)
Common Language Equipment Identifier (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
下表列出了可用于排除链路抖动故障的命令。推荐的使用顺序：show logging、show interfaces、show controllers ethernet-controller、show platform pm interface-flaps，然后根据需要使用光纤特定命令或铜缆特定命令。
| 命令 |
目的 |
| show interfaces counters error |
显示接口错误计数器。 |
| show interfaces capabilities |
显示特定接口的功能。 |
| show interface tranceivers（光纤或SFP特定） |
显示启用数字光纤监控(DOM)的光收发器的相关信息。 |
| show interface link |
显示链路级别信息。 |
| show interface {interface{interface-number}}平台 |
显示接口平台信息。 |
| show controllers ethernet-controller {interface{interface-number}} port-info |
显示其他端口信息。 |
| show controllers ethernet-controller {interface{interface-number}}链路状态详细信息 |
显示链路状态。 |
| show errdisable flap-values |
显示允许在errdisable状态之前出现的摆动数。 |
| clear counters |
使用此命令将流量和错误计数器清零，以便您查看问题是否只是暂时的，或者计数器是否继续增加。 |
| clear controllers ethernet-controller |
使用此命令可清除硬件发送和接收计数器。 |
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}。
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
TDR准则
以下指南适用于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：
| 步骤 |
命令或操作 |
目的 |
| 第 1 步 |
enable 示例： Switch > Enable |
启用物理执行模式。 根据提示输入密码。 |
| 第 2 步 |
configure terminal 示例： switch#configure terminal |
进入全局配置模式。 |
| 第 3 步 |
收发器类型all 示例： switch(config)#transceiver type all |
进入收发器类型配置模式。 |
| 第 4 步 |
监控 示例： switch(config)#monitoring |
启用对所有光纤收发器的监控。 |
使用show interfaces {interface{interface-number}} transceiver detail命令可显示收发器信息：
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
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.
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--
调试命令
下表列出了可用于调试端口抖动的各种命令
| 命令 | 目的 |
| debug pm | 端口管理器调试 |
| debug pm port | 端口相关事件 |
| debug platform pm | NGWC平台端口管理器调试信息 |
| debug platform pm l2-control | NGWC L2控制基础设施调试 |
| debug platform pm link-status | 接口链路检测事件 |
| debug platform pm pm-vectors | 端口管理器矢量功能 |
| debug condition interface <interface name> | 选择性地启用特定接口的调试 |
| debug interface state | 状态转换 |
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
| Cisco Bug ID |
描述 |
| Cisco Bug ID CSCvu13029 |
mGig Cat9300交换机上的间歇性链路摆动到支持mGig的终端。 |
| Cisco Bug ID CSCvt50788 |
其他mGig设备的Cat9400 mGig互操作问题会导致链路抖动。 |
| Cisco Bug ID CSCvu92432 |
CAT9400:具有Mgig AP的Mgig接口抖动。 |
| Cisco Bug ID CSCve65787 |
100G/40G/25G Cu收发器的自动支持。 |
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
修订历史记录
| 版本 | 发布日期 | 备注 |
|---|---|---|
3.0 |
09-Sep-2026
|
重新认证 — 更新的问题、SEO、机器翻译、样式要求和格式。 |
2.0 |
13-Mar-2024
|
重新认证 |
1.0 |
04-Nov-2022
|
初始版本 |
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