HP 12500 Series Configuration Manual page 35

a BFD control packet, forward the BFD control packet along the LSP to the egress, and determine the
status of the LSP according to the reply received. Upon detecting an LSP failure, BFD triggers a traffic
switchover.
A BFD session for LSP connectivity detection can be static or dynamic.
Static: If you specify the local and remote discriminator values by using the discriminator keyword
•
when configuring the bfd enable command, the BFD session will be established with the specified
discriminator values. Such a BFD session is used to detect the connectivity of a pair of LSPs in
opposite directions (one from local to remote, and the other from remote to local) between two
switches.
• Dynamic: If you do not specify the local and remote discriminator values when configuring the 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 is used for connectivity detection of an LSP from the local switch to the remote switch.
Configuration prerequistes
The BFD session parameters configured on the loopback interface whose IP address is configured
•
as the MPLS LSR ID are used, and the BFD packets use the MPLS LSR ID as the source address.
Therefore, before enabling BFD for an LSP, you need to configure an IP address for the loopback
interface and configure the IP address as the MPLS LSR ID. You can also configure BFD session
parameters for the loopback interface as needed. For more information about BFD, see High
Availability Configuration Guide.
• To establish a static BFD session, make sure that there is already an LSP from the local switch to the
remote switch and an LSP from the remote switch to the local switch.
Configuring BFD for LSPs
To configure BFD for LSPs:
To do...
Enter system view
Enable LSP verification and enter
the MPLS LSPV view
Configure BFD to check the
connectivity of an LSP to the
specified FEC destination
NOTE:
• You cannot establish both a static BFD session and a dynamic BFD session for the same LSP.
After a static BFD session is established, it is not allowed to modify the discriminator values of the BFD
•
session.
In a BFD session for detecting LSP connectivity, the ingress node always works in active mode and the
•
egress node always works 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 work in
passive mode, the BFD session will 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.
Use the command...
system-view
mpls lspv
bfd enable destination-address
mask-length [ nexthop
nexthop-address [ discriminator
local local-id remote remote-id ] ]
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Remarks
—
Required
Not enabled by default
Required
Not configured by default