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Such a BFD session is used for connectivity detection of an LSP from the local device to the
remote device.
Configuration prerequisites
Before enabling BFD for an LSP, complete the following tasks:
•
Configure an IP address for the loopback interface, and configure the IP address as the MPLS
LSR ID of the device.
•
Configure BFD session parameters on the loopback interface.
The device uses the BFD session parameters configured on the loopback interface to establish a
BFD session, and it uses the MPLS LSR ID as the source address of the BFD packets. For more
information about BFD, see
High Availability Configuration Guide
.
To establish a static BFD session, make sure there is already an LSP from the local device to the
remote device and an LSP from the remote device to the local device.
Configuration guidelines
•
You cannot establish both a static BFD session and a dynamic BFD session for the same LSP.
•
After a static BFD session is established, you cannot modify the discriminator values of the BFD
session.
•
In a BFD session for detecting LSP connectivity, the ingress node always operates in active
mode and the egress node always operates in passive mode. The
bfd session init-mode
command does not take effect on the ingress and egress nodes of such a BFD session. Even if
you configure the two nodes to both operate in passive mode, the BFD session can still be
established successfully.
•
BFD for MPLS LDP is for detecting the IP connectivity between two remote LDP peers. BFD for
LSP is for detecting the connectivity of LSPs.
Configuration procedure
To configure BFD for LSPs:
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enable LSP verification and
enter the MPLS LSPV view.
mpls lspv
Not enabled by default.
3.
Configure BFD to detect the
LSP connectivity.
bfd enable
destination-addressmask-length
[
nexthop
nexthop-address
[
discriminator local
local-id
remote
remote-id
] ]
Not configured by default.
Configuring periodic LSP tracert
The periodic LSP tracert function is for locating faults of an LSP periodically. It detects the
consistency of the forwarding plane and control plane and records detection results into logs. You
can check the logs to know whether an LSP has failed.
If you configure BFD as well as periodic tracert for an LSP, once the periodic LSP tracert function
detects an LSP fault or inconsistency of the forwarding plane and control plane, the BFD session for
the LSP is deleted and a new BFD session is established according to the control plane.
To configure the periodic LSP tracert function: