27
Layer 3 forwarding failure
Symptom
Packet loss occurs when the switch forwards packets to a different network.
Troubleshooting flowchart
Figure 8 Troubleshooting a Layer 3 forwarding failure
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 "
Layer 2 forwarding failure
" to troubleshoot the problem.
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
the problem.
−
If the switch learns no ARP entries, you can execute the
arp static
command to
configure static ARP entries.
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:
The port is faulty?
No
Yes
Yes
Troubleshoot the
port
End
No
Yes
Layer 3 packet loss
ARP entries are correct?
Troubleshoot ARP
entries
Route entries are correct?
No
Yes
Resolved?
No
No
No
Yes
Yes
Resolved?
Resolved?
Contact the support
Troubleshoot
route entries
