Configuring BFD Parameters on the Egress Node of the Tunnel
Context
The BFD parameters configured on the egress node include the local and remote discriminators, local intervals at which BFD packets are sent and received, and BFD detection multiplier, which determine the establishment of a BFD session.
Perform the following configurations on the egress node of an MPLS TE tunnel.
If a one-arm BFD echo session is established on the ingress node, this configuration is not required.
Procedure
- Run system-view
The system view is displayed.
- Configure a reverse tunnel to inform the ingress node of
a fault if the fault occurs. The reverse tunnel can be the IP link, LDP LSP, or CR-LSP. To ensure
that the forward and reverse paths are over the same link, an CR-LSP
is preferentially selected to notify the ingress node of an LSP fault.
Run the following commands as required.
For an IP link, run bfd session-name bind peer-ip ip-address [ vpn-instance vpn-name ] [ source-ip ip-address ]
For the LDP LSP, run bfd session-name bind ldp-lsp peer-ip ip-address nexthop ip-address [ interface interface-type interface-number ]
For a CR-LSP, run bfd session-name bind mpls-te interface tunnel interface-number te-lsp [ backup ]
- Run discriminator local discr-value
The local discriminator is set.
By default, the local discriminator is not set.
- Run discriminator remote discr-value
The remote discriminator is set.
By default, the remote discriminator is not set.
- (Optional) Run min-tx-interval interval
The local interval at which BFD packets are sent is set.
By default, the value is 1000 milliseconds. The default value is recommended.
- (Optional) Run min-rx-interval interval
The local interval at which BFD packets are received is set.
By default, the value is 1000 milliseconds. The default value is recommended.
- (Optional) Run detect-multiplier multiplier
The local detection multiplier is adjusted.
By default, the local detection multiplier is 3.
Actual local sending interval = MAX { Configured local sending interval, Configured remote receiving interval }
Actual local receiving interval = MAX { Configured remote sending interval, Configured local receiving interval }
Actual local detection interval = Actual local receiving interval x Configured remote detection multiplier
For example:
The local sending and receiving intervals are set to 200 ms and 300 ms respectively and the detection multiplier is set to 4.
The remote sending and receiving intervals are set to 100 ms and 600 ms respectively and the detection multiplier is set to 5.
Then,
Actual local sending interval = MAX {200 ms, 600 ms} = 600 ms; Actual local receiving interval = MAX {100 ms, 300 ms} = 300 ms; Actual local detection interval is 300 ms x 5 = 1500 ms.
Actual remote sending interval = MAX {100 ms, 300 ms} = 300 ms; Actual remote receiving interval = MAX {200 ms, 600 ms} = 600 ms; Actual remote detection interval is 600 ms x 4 = 2400 ms.
- Run commit
The configuration is committed.