Panasonic NN46240-710 - Manual (Page 92)

Nortel Secure Router 8000 Series
Troubleshooting - VPN___________ 3 BGP/MPLS IP VPN troubleshooting
Step 3 Check that an LSP is established between PEs.
Network traffic on the MPLS VPN is transferred to the remote through LSPs on the public
network. In actual configuration, the next hop of the private network route must be bound with
the LSP.
• In case the LSPs are generated first, the binding can be queried against the tunnel
management (TNLM) by the Routing Management (RM) according to the IP address of
the next hop of the private network route.
• In the case that routes are learned first and then LSPs are generated, the TNLM notifies the
RM of the destination IP address of the LSP. According to the IP address, the RM finds the
associated private network route, and performs iteration.
• Therefore, check if an LSP establishes between PEs.
• Use the display mpls Isp include ip-address mask command on PE. In this command,
ip-address is the IP address of the next hop of the private network route. If you find that the
LSP that uses the next hop of the private network route as the destination is not set up,
follow these steps.
• Verify that an LDP session establishes.
Use the display mpls Idp session command to check whether an LDP session establishes.
Common causes of failure to set up LDPs are as follows:
- LSR ID configuration error: Remote PE cannot find the route to the LSR ID, leading to
setup failure. Nortel recommends that you set the IP address of the loopback interface
as the LSR ID. The IP address is advertised through the routing protocol and static
route.
- LSR ID configuration error and no mpls ldp transport-address configuration: If the
mpls ldp transport-address command is not configured on the interface, PE will use
the LSR ID to set up an LDP session with the remote PE. If the LSR ID is incorrect, the
LDP session cannot establish successfully. To avoid this problem, run the mpls ldp
transport-address command on the interface.
• Check that a TCP connection establishes for LDP sessions.
Use the display tcp status command to view the TCP connection.
If the routing information is correct, you can find that the TCP connection is already set up.
The State in the output must be Established. If the TCP connection is not established,
check for IP connectivity.
• Check that LDP parameters are consistent on both the ends of an LSP
LDP parameters must be consistent on both the ends of an LSP
If parameters are not consistent, for example, the label distribution mode is DOD on one
end and DU on the other end, an LDP session fails to establish.
• Check that the policy to set up the LSP is configured.
By default, a policy is adopted by which only the host address is triggered to set up LSP
To trigger all the routes to set up LSP, configure the lsp-trigger all command in MPLS.
• Check the status of interfaces enabled with MPLS LDP
Use the display mpls interface command and the display mpls ldp interface command
to check whether the interfaces are Up or Active.
If the status of the interface is Down or Inactive, use the shutdown command, and the
undo shutdown command in the interface view. If the interface remains Down, check the
physical link.
Issue 5.3 (30 March 2009) Nortel Networks Inc. 3-13