Vyatta Network OS Documentation

Learn how to install, configure and operate the Vyatta NOS, which helps drive our virtual networking & physical platforms portfolio.

Configuring a BFD helper session by using IPv4 addressing

You can configure a static route from a router R1 to another router R2, without configuring another static route from R2 to R1. In such a case, you can enable BFD only from R1 to R2 with static route as the client. BFD must be configured at both routers for it to be operational, you can use a helper session to compensate the lack of a static route from R2 to R1.

Consider two routers R1 and R2. There is a static route from R2 to R1, and but no static route from R1 to R2. You can enable BFD for R1.
Note: The source any parameter is not supported for the helper session command.
The helper session is supported for both IPv4 and IPv6 addresses. The following list provides the addresses of R1 and R2.
  • R1 interface address facing R2—10.10.10.1
  • R2 interface address facing R1—10.10.10.2
Figure 1. Configuring a BFD helper session by using IPV4 addressing
To configure BFD by using a helper session, perform the following steps in configuration mode.
Note: Instead of specifying the source IP address in this example, you can also use the source any parameter to associate the BFD template with all BFD sessions that have the specific destination. For more information, refer to BFD Commands.
Table 1. Configuring a BFD Helper Session by Using IPV4 Addressing
Router Step Command
R1 Create a BFD template called test. See section Configuring the BFD template.
R1 Associate the BFD test template with the destination address of R2 and the source address of R1.
vyatta@R1# set protocols bfd destination 10.10.10.2 source 10.10.10.1 template test
R1 Register R2 as a BFD neighbor.
vyatta@R1# set protocols bfd destination 10.10.10.2 source 10.10.10.1 helper-session
R1 Commit the configuration.
vyatta@R1# commit
R1 Save the configuration.
vyatta@R1# save
R1 Display the configuration.
vyatta@R1# show protocols bfd 
 protocols {
                        bfd {
                            destination 10.10.10.2  {
                                source 10.10.10.1 {
                                    template test
                                    helper-session
                                 }
                               
                      }
                        minimum-rx 300
                        minimum-tx 300
                        multiplier 3
           }
            
}