Vyatta NOS documentation

Learn how to install, configure, and operate Vyatta Network Operating System (Vyatta NOS), which helps to drive our virtual networking and physical platforms portfolio.

Configuring BFD for OSPFv2 on a virtual link by using IPv4 addressing

To configure BFD for OSPFv2 neighbors on a virtual link, you must first configure the virtual link between the disconnected backbone area routers and then enable BFD on the virtual link.

Consider a scenario in which you have two systems, R1 and R2. R1 and R2 share an OSPFv2 session, sharing a virtual link, as illustrated in the reference network diagram. The following list provides the addresses of R1 and R2.
  • R1 router-id—1.1.1.1
  • R2 router-id—2.2.2.2
  • R1 interface address facing R2—10.1.1.1
  • R2 interface address facing R1—10.1.1.2
Figure 1. Configuring BFD for OSPFv2 on a virtual link by using IPv4 addressing

Virtual link is configured in a transit area. A virtual link chooses any address to reach other virtual link end points in the same transit area. Therefore, the source and destination addresses in a three-router configuration or a more-complex configuration are selected dynamically. You must ensure that you select the correct source and destination addresses for your BFD commands for OSPFv2 and OSPFv3 virtual links. To configure a BFD session between R1 and R2, perform the following steps in configuration mode.

Table 1. Configuring BFD for OSPFv2 on a Virtual Link 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 10.1.1.2 source 10.1.1.1 template test
R1 Register R2 as a BFD neighbor.
vyatta@R1# set protocols ospf area 1 virtual-link 2.2.2.2 fall-over bfd
R1 Commit the configuration.
vyatta@R1# commit
R1 Save the configuration.
vyatta@R1# save
R1 Display the configuration.
vyatta@R1# show protocols ospf
 ospf {
        area 1 {
                network 10.1.1.0/24
                virtual-link 2.2.2.2 {
                        fall-over {
                                bfd
                        }
                }
        }
        parameters {
                router-id 1.1.1.1
        }
 }


vyatta@R1# show protocols bfd 
 bfd {
        destination 10.1.1.2 {
                source 10.1.1.1 {
                   template test
                }
        }
        template test {
                auth {
                        simple {
                                key "********"
                        }
                }
                minimum-rx 300
                minimum-tx 300
                multiplier 3
        }
 }
R2 Create a BFD template called test. See section Configuring the BFD template.
R2 Associate the BFD test template with the destination address of R1 and the source address of R2.
vyatta@R2:~$ set protocols bfd destination 10.1.1.1 source 10.1.1.2 template test
R2 Register R1 as a BFD neighbor.
vyatta@R2# set protocols ospf area 1 virtual-link 1.1.1.1 fall-over bfd
R2 Commit the configuration.
vyatta@R2# commit
R2 Save the configuration.
vyatta@R2# save
R2 Display the configuration.
vyatta@R2# show protocols ospf
 ospf {
        area 1 {
                network 10.1.1.0/24
                virtual-link 1.1.1.1 {
                        fall-over {
                                bfd
                        }
                }
        }
        parameters {
                router-id 2.2.2.2
        }
 }


vyatta@R2# show protocols bfd 
  bfd {
        destination 10.1.1.1 {
                source 10.1.1.2{
                   template test
                }
        }
        template test {
                auth {
                        simple {
                                key "********"
                        }
                }
                minimum-rx 300
                minimum-tx 300
                multiplier 3
        }
 }