Checking Whether the Link Flaps

Procedure

1. If the interface through which ping packets pass alternate between Up and Down, ping packets will be lost. Run the terminal debugging and terminal monitor commands in the user view to enable debugging:

   <HUAWEI> terminal debugging
   <HUAWEI> terminal monitor

2. Check whether the interface alternates between Up and Down, and then disable debugging:

   Sep  9 2009 14:57:29 HUAWEI %%01IFNET/4/IF_STATE(l): Interface
   GigabitEthernet1/0/24 has turned into UP state.
   Sep  9 2009 14:56:54 HUAWEI %%01IFNET/4/IF_STATE(l): Interface
   GigabitEthernet1/0/24 has turned into DOWN state.
   <HUAWEI> undo terminal debugging
   <HUAWEI> undo terminal monitor

   If the interface status changes, check whether the interface rate and duplex mode are correct and whether the attributes on connected interfaces are consistent. Try to remove or replace the Ethernet cable or optical module to solve the problem. For details, see Interconnected Optical Ports Cannot Go Up or Interconnected Electrical Interfaces Cannot Go Up.

   You can run the display interface interface-type interface-number command to view the interface status.

   <HUAWEI> display interface gigabitethernet 0/0/24
   
   GigabitEthernet0/0/24 current state : UP
   Line protocol current state : UP
   Description:117.40.161.123
   Switch Port, PVID :  625, TPID : 8100(Hex), The Maximum Frame Length is 9216
   IP Sending Frames' Format is PKTFMT_ETHNT_2, Hardware address is fce3-3cb0-adf0
   Last physical up time   : 2015-08-09 21:41:37 UTC+08:00
   Last physical down time : 2015-08-09 21:41:35 UTC+08:00
   Current system time: 2015-08-11 09:57:58+08:00
   Port Mode: COMMON COPPER
   Speed : 100,    Loopback: NONE
   Duplex: FULL,   Negotiation: ENABLE
   Mdi   : AUTO,   Flow-control: DISABLE
   ... ...