Solution; Related Commands; Protocol Flapping; Symptom - H3C S5150-EI Series Troubleshooting Manual

Solution

To resolve the problem:
1. Verify that the port is not faulty (due to hardware or configuration problems).
If the port is faulty, follow the solution in
2. Verify that ARP entries are correct:
a. Execute the display arp command to verify that ARP entries are correct.
− If incorrect ARP entries exist, execute the debugging arp packet command to locate
− If the switch learns no ARP entries, you can execute the arp static command to
b. Execute the display mac-address command to verify that the output interfaces in the MAC
address entries and ARP entries are the same by using the display mac-address
command.
If the output interfaces are not the same, execute the reset command to clear the ARP
entries. Then the switch can learn ARP entries again.
3. Verify that route entries are correct:
a. Execute the display ip routing-table command to verify that route entries are correct.
If incorrect route entries exist, troubleshoot the protocol that learns the route entries.
b. Execute the display fib command to verify that the output interfaces in the FIB entries and
route entries are the same.
If the output interfaces are not the same, execute the reset command to clear the route
entries. Then the switch can learn route entries again.
4. If the problem persists, contact H3C Support.

Related commands

This section lists the commands that you might use for troubleshooting Layer 3 forwarding failure.
Command
debugging arp packet
display arp
display fib
display ip routing-table
display mac-address

Protocol flapping

Symptom

The switch cannot send or receive protocol packets.
the problem.
configure static ARP entries.
"Layer 2 forwarding failure" to troubleshoot the problem.
Description
Enables ARP packet debugging.
Displays ARP entries.
Displays FIB entries.
Displays brief information about active routes in the routing
table.
Displays MAC address entries.
29