Locating a Fault on a PW

Procedure

1. Run the system-view command to enter the system view of the U-PE.
2. Run the pw-template pw-template-name command to enter the PW template view.
3. Run the control-word command to enable the control word function.
4. Run either of the following commands to collect information about each LSR along the PW and information about the egress PE.

   • tracert vc pw-type pw-id [ -exp exp-value | -f first-ttl | -m max-ttl | -r reply-mode | -t timeout-value ] ^* control-word [ draft6 ] [ full-lsp-path ] [ pipe | uniform ]

   • tracert vc pw-type pw-id [ -exp exp-value | -f first-ttl | -m max-ttl | -r reply-mode | -t timeout-value ] ^* control-word remote remote-ip-address [ ptn-mode | full-lsp-path ] [ pipe | uniform ]

   • tracert vc pw-type pw-id [ -exp exp-value | -f first-ttl | -m max-ttl | -r reply-mode | -t timeout-value ] ^* control-word remote remote-pw-id draft6 [ full-lsp-path ] [ pipe | uniform ]

   • tracert vc pw-type pw-id [ -exp exp-value | -f first-ttl | -m max-ttl | -r reply-mode | -t timeout-value ] * label-alert [ remote remote-ip-address ] [ full-lsp-path ] [ draft6 ]
   • tracert vc pw-type pw-id [ -exp exp-value | -f first-ttl | -m max-ttl | -r reply-mode | -t timeout-value ] * normal [ remote remote-ip-address ] [ full-lsp-path ] [ draft6 ]

   When running the tracert vc command to locate a PW fault, pay attention to the following points:

   • The SPEs do not support this command. You can run this command on UPEs only.

   • You can use this command to tracert a single-segment PW and a multi-segment PW created using LDP.

   • When tracerting a multi-segment PW, specify the remote PW ID in addition to the local PW ID and PW type.

   When the tracert vc command is run, the tracert operation is terminated in the following cases:

   • The PE that initiates tracert receives an MPLS Echo Reply packet from the egress PE.

   • The TTL in the label of the previous MPLS Echo Request packet sent by the PE that initiates tracert reaches the configured or default maximum number of hops.

   • A user presses Ctrl+C on the PE that initiates tracert.