H3C Technologies H3C S10500 Series Switches - Manual (Page 130)

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To do… Use the command… Remarks
Use MPLS LSP tracert to locate
errors of an MPLS TE tunnel
tracert lsp [ -a source-ip | -exp
exp-value | -h ttl-value | -r
reply-mode |-t time-out ] * te
interface-type interface-number
Required
Available in any view
Configuring BFD for an MPLS TE Tunnel
You can configure BFD for an MPLS TE tunnel to implement fast detection of the connectivity of the tunnel.
After you configure BFD for an MPLS TE tunnel, a BFD session will be established between the ingress
and egress of the tunnel, and the ingress will add the label for the tunnel into a BFD control packet,
forward the BFD control packet along the tunnel, and determine the status of the tunnel according to the
BFD control packet received from the egress. Upon detecting an MPLS TE tunnel failure, BFD triggers
protection switching to switch traffic to another tunnel.
A BFD session for MPLS TE tunnel detection can be static or dynamic.
• Static: If you specify the local and remote discriminator values by using the discriminator keyword
when configuring the mpls te bfd enable command, the BFD session will be established with the
specified discriminator values. Such a BFD session can detect the connectivity of a pair of MPLS TE
tunnels in opposite directions (one from local to remote, and the other from remote to local) between
two devices.
• Dynamic: If you do not specify the local and remote discriminator values when configuring the mpls
te bfd enable command, the MPLS LSP ping will be run automatically to negotiate the discriminator
values and then the BFD session will be established based on the negotiated discriminator values.
Such a BFD session can detect the connectivity of a unidirectional (from the local device to the
remote device) MPLS TE tunnel between two devices.
After you enable BFD and configure the mpls te failure-action teardown command for an MPLS TE tunnel,
once an RSVP-TE tunnel failure occurs, BFD can detect the failure, and if RSVP does not re-establish the
tunnel within a specified period of time, MPLS TE will remove the failed RSVP-TE tunnel and then
re-establish it.
Configuration prerequisites
• The source address of the BFD session is the MPLS LSR ID. Before configuring BFD to inspect an
MPLS TE tunnel, make sure that there is a route on the peer device to the MPLS LSR ID. You can also
configure the BFD session parameters on the tunnel interface as needed. For more information
about BFD, see High Availability Configuration Guide.
• To establish a static BFD session to inspect an MPLS TE tunnel, make sure that there is already an LSP
from the local device to the remote device and an LSP from the remote device to the local device.
Configuring BFD for an MPLS TE tunnel
Follow these steps to configure BFD for an MPLS TE tunnel:
To do… Use the command… Remarks
Enter system view system-view —
Enable LSP verification and enter
MPLS LSPV view
mpls lspv
Required
By default, LSP verification is
disabled.
Return to system view quit —