STP计算失效导致环路的解决过程
STP计算失效导致环路的解决过程
作者：魏帅创建时间：2020-08-12 21:34:27浏览次数：31 次
一、组网描述
二、故障现象
1. 整个网段的业务全断，发现这个网段的四台交换机CPU 都是100%左右，Console口也进不了，和核心交换机级联的10.93.33.28的 G0/1有端口安全抑制报错信息，初步判断是这个网段产生了环路导致：
Nov 20 09:27:29: %PORT_SECURITY-2-PSECURE_VIOLATION: Security violation occurred, caused by MAC address 54e1.ad58.3fb5 on port FastEthernet0/24.
Nov 20 09:27:35: %PORT_SECURITY-2-PSECURE_VIOLATION: Security violation occurred, caused by MAC address 54e1.ad58.3fb5 on port FastEthernet0/24.
Nov 20 09:27:40: %PORT_SECURITY-2-PSECURE_VIOLATION: Security violation occurred, caused by MAC address 54e1.ad58.3fb5 on port FastEthernet0/24.
Nov 20 09:27:45: %PORT_SECURITY-2-PSECURE_VIOLATION: Security violation occurred, caused by MAC address 54e1.ad58.3fb5 on port FastEthernet0/24.
Nov 20 09:27:53: %PORT_SECURITY-2-PSECURE_VIOLATION: Security violation occurred, caused by MAC address 54e1.ad58.3fb5 on port FastEthernet0/24.
LCMA-MIS-2960-333#
三、处理过程
1. 由于Console口进去还是无法操作，三点三十几插拔了一下10.93.33.28 G0/1端口，交换机CPU立即恢复正常。
Nov 20 15:33:14: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/39, changed state to up
Nov 20 15:34:23: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/1, changed state to down
Nov 20 15:34:24: %LINK-3-UPDOWN: Interface GigabitEthernet0/1, changed state to down
Nov 20 15:34:28: %LINK-3-UPDOWN: Interface GigabitEthernet0/1, changed state to up
Nov 20 15:34:30: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/1, changed state to up
LCMA-MIS-2950-333#
2. 插拔后，10.93.33.28的G0/1成为Block端口，STP生效，环路取消。
LCMA-MIS-2950-333#sh spanning-tree blockedports
Name Blocked Interfaces List
-------------------- ------------------------------------
VLAN0033 Gi0/1
Number of blocked ports (segments) in the system : 1
LCMA-MIS-2950-333#
3. 解决方法：根据端口安全日志说明是端口自环或者终端环路导致STP失效，三点三十多插拔10.93.33.28的G0/1端口，STP重新收敛计算，10.93.33.28的 G0/1成为Block端口，交换机立即恢复正常，业务恢复；后期经过排查，发现是因为终端有一台voice语音电话的网线插错，产生环路，导致级联端口STP计算失效，进而导致整个网段环路。
四、总结及建议
1. 导致环路的原因就是STP计算失效，整个链路没有Block端口，导致整个vlan的环路，进而导致交换机CPU 100%，类似死机，插拔了一下级联端口让交换机重新计算STP，计算出Block端口即可 。
2. 遇到影响业务的故障，要想方设法的先恢复客户的业务，然后恢复业务后再去排查具体的故障原因，并做总结和汇报。