Checking Whether the Loop Prevention Protocol Flaps

Procedure

1. Check whether a loop prevention protocol, such as STP, is enabled and is flapping. If the protocol flaps, ICMP forwarding and processing are affected.

   <HUAWEI> display stp brief
   MSTID      Port                   Role  STP State     Protection
   0        GigabitEthernet1/0/24    ALTE  DISCARDING      NONE
   0        GigabitEthernet1/0/35    ROOT  FORWARDING      NONE

2. Check the loop prevention protocol status repeatedly during ping packet loss to confirm whether the protocol flaps:

   01MSTP/6/SET_PORT_DISCARDING(l)[182103]:In MSTP process 0 instance 0, MSTP set port Eth-Trunk2 state as discarding.
   MSTP/6/SET_PORT_LEARNING(l)[182104]:In process 0 instance 0, MSTP set port Eth-Trunk2 state as learning.

   Check whether the interface status frequently changes according to Checking Whether the Link Flaps.