Network Router User Manual

5 VPLS troubleshooting
Nortel Secure Router 8000 Series
Troubleshooting - VPN
5-14 Nortel Networks Inc. Issue 5.3 (30 March2009)
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The IP address of the specified peer is incorrect.
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The address of the peer is not the peer LSR-ID. The LDP session cannot establish.
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The LSR-ID of the peer is redefined. Then the LDP session cannot be set up.
To enable the VSI status to be Up, at least two ACs must be Up, or at least one AC Up and one
PW Up.
To locate this type of problem, begin by checking the status of the AC and that of the PW.
To enable an AC to be Up, you must bind the AC with an interface, and the current state of the
interface must be Up.
The problem often occurs on the PW. To let a PW go Up, ensure that the MTU, encapsulation
type, VSI ID, and remote peer configuration are correct. The key is that the local and remote
ends can receive labels from each other.
You can use the display vsi remote { ldp | bgp } command to check them. You can judge which
router has a configuration error based on whether it receives the label.
5.3.2 Packets cannot forward successfully between two PEs
though VSI is up
Fault symptom
After the configuration of the VPLS, check the status of the VSI on PE. You will find the VSI is
Up but the packets cannot forward successfully between two PEs.
Fault analysis
Step 1 Check whether the PW exists.
Use the display vsi verbose command to check whether the PW exists.
If the PW does not exist, it indicates the PW information is not delivered to the interface board.
If the PW exists, check whether the delivering status of the PW is OK.
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If not, it means the forwarding information is not delivered to the interface board, which
leads to the failure of the forwarding.
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If the status is OK, check the operating status of the interface board.
Step 2 Check the MAC limit.
If the PW exists, packets cannot forward between PEs. Use the display current-configuration
| begin vsi vsi-name command to check the MAC limit. If the MAC address entries exceed the
MAC limit, reconfigure the MAC limit.
Step 3 Check whether the BGP peer is being re-established.
If the MAC address entries do not exceed the MAC limit, use the display bgp peer
peer-address command to check whether the BGP peer is set up. When the BGP peer is being
re-established, the VSI state remains Up for a very short period.
Step 4 Check the encapsulation modes of PEs on both ends.