BFD for Static Routes

Unlike routing protocols such as OSPF and BGP, static routing has no method of fault detection or peer discovery. BFD for IPv4 and
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IPv6 static routes provides rapid detection of failure in the bidirectional forwarding path between BFD peers.

When a static route is configured with the BFD option, the BFD session state for the configured next hop is checked. If the BFD session is up, the static route is installed in the Routing Table Manager (RTM). If the BFD session is not up, the route is not installed in the RTM. BFD can remove the associated static route from the routing table if the next hop becomes unreachable.

When BFD is configured for a static route next hop, the creation of a BFD session is initiated. Similarly, when BFD is unconfigured from the static route next hop, the BFD session is torn down.

Consider the following when configuring BFD for static routes:

  • When a session state changes to up, the route is added to the RTM and is used for routing traffic.
  • When a session state changes to admin down, no action is taken.
  • When a session state changes to down, the static route is removed from the RTM and is not used for routing traffic.
  • If the holdover timer is configured, the static route is not immediately notified about the down state and the holdover timer begins. If the configured holdover timer expires and the BFD session is not up, static routes are removed from the RTM.
  • A BFD enabled static route is installed in the RTM only when the BFD session is up.

For detailed configuration examples for both single-hop and multihop sessions for an IP static route, refer to BFD Configuration Examples.

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In this section:

  1. Configuring BFD for an IP Static Route
    BFD can be configured globally on IP static routes. The following task enables BFD and configures BFD session parameters on an IP static route where the destination IP address is 10.2.2.0/24 and the next-hop IP address is 10.0.0.2. BFD session timer values are also configured.
  2. Configuring BFD for an IPv6 Static Route
    BFD can be configured globally on IPv6 static routes. The following task configures BFD session parameters on an IPv6 static route where the destination IPv6 address is 2001:2018::8192:125/64 and the next IP address is 2001:1::3:1. BFD session timer values are also configured.
Parent topic: BFD