BFD In OSPF

With BFD usage in OSPF, the failover mechanism is greatly improved by detecting the loss of remote OSPF neighbors. Instead of relying on standard hello mechanisms, BFD permits faster convergence. To get more information on BFD, please see BFD.

BFD Configuration And Monitoring In OSPF

A BFD peer session context is created, along with discovering OSPF neighbors. Due to the nature of OSPF, all created BFD peer contexts are single-hop.

vrf customer1
   routing ospf
      router-id 10.125.0.1
      .. ..
   routing interface eth1_0
      ip ospf area 0.0.0.1
      ip ospf track bfd

Then you can continue the configuration as usual. For timer settings, the default emission and reception settings are set to 300000 microseconds, which may not be what is wished. In that case, it is possible to override default timers, by configuring general timer settings. More information is given in Configuring general BFD settings.

vsr> show ospf interface eth1_0 vrf customer1
eth1_0 is up
   ifindex 2, MTU 1500 bytes, BW 10000 Mbit <UP,BROADCAST,RUNNING,MULTICAST>
   Internet Address 10.125.0.1/24, Broadcast 10.125.0.255, Area 0.0.0.1
   MTU mismatch detection: enabled
   Router ID 10.125.0.1, Network Type BROADCAST, Cost: 10
   Transmit Delay is 1 sec, State DR, Priority 1
   Backup Designated Router (ID) 10.125.0.2, Interface Address 10.125.0.1
   Multicast group memberships: OSPFAllRouters OSPFDesignatedRouters
   Timer intervals configured, Hello 10s, Dead 40s, Wait 40s, Retransmit 5
     Hello due in 5.710s
   Neighbor Count is 1, Adjacent neighbor count is 1
   BFD: Detect Multiplier: 3, Min Rx interval: 600, Min Tx interval: 600

vsr> show ospf neighbor vrf customer1
Neighbor ID     Pri State           Dead Time Address         Interface            RXmtL RqstL DBsmL
10.125.0.2      1 Full/Backup       38.091s 10.125.0.2      eth1_0:10.125.0.1       0     0     0

vsr> show ospf database vrf customer1 router 10.125.0.2
VRF Name: r2-cust1

    OSPF Router with ID (10.254.254.2)


             Router Link States (Area 0.0.0.1)

 LS age: 70
 Options: 0x2  : *|-|-|-|-|-|E|-
 LS Flags: 0x3
 Flags: 0x2 : ASBR
 LS Type: router-LSA
 Link State ID: 10.125.0.2
 Advertising Router: 10.125.0.2
 LS Seq Number: 80000004
 Checksum: 0xb65d
 Length: 36

  Number of Links: 1

   Link connected to: a Transit Network
    (Link ID) Designated Router address: 10.125.0.2
    (Link Data) Router Interface address: 10.125.0.2
      Number of TOS metrics: 0
       TOS 0 Metric: 10


 LS age: 70
 Options: 0x2  : *|-|-|-|-|-|E|-
 LS Flags: 0x6
 Flags: 0x2 : ASBR
 LS Type: router-LSA
 Link State ID: 10.125.0.2
 Advertising Router: 10.125.0.2
 LS Seq Number: 80000003
 Checksum: 0x9a79
 Length: 36

  Number of Links: 1

   Link connected to: a Transit Network
    (Link ID) Designated Router address: 10.0.3.1
    (Link Data) Router Interface address: 10.0.3.1
     Number of TOS metrics: 0
      TOS 0 Metric: 10

vsr> show bfd vrf customer1 session single-hop destination 10.125.0.2
 BFD Peer:
   peer 10.125.0.2 interface eth1_0
     ID: 322201613
     Remote ID: 2746639856
     Status: up
     Uptime: 9 minute(s), 49 second(s)
     Diagnostics: ok
     Remote diagnostics: ok
     Local timers:
       Receive interval: 300ms
       Transmission interval: 300ms
       Echo transmission interval: 50ms
     Remote timers:
       Receive interval: 300ms
       Transmission interval: 300ms
       Echo transmission interval: 50ms

By default this tracks the default profile set in BFD. It is possible to track another profile which was set in bfd settings as seen in Configuring general BFD settings.

vrf customer1
   routing ospf
      router-id 10.125.0.1
      .. ..
   routing interface eth1_0
      ip ospf area 0.0.0.1
      ip ospf track bfd-profile-peer1