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The BFD Multihop Support for IPv4 Static Routes feature enables detection of IPv4 network failure between paths that are not directly connected. If a Bidirectional Forwarding Detection (BFD) session is up (that is, the next-hop destination is reachable), IPv4 static routes that are associated with IPv4 static BFD configuration are added to a routing table. If the BFD session is down, the routing table removes all associated static routes from the routing table.
This feature is applicable on different kinds of interfaces such as physical, subinterface, and virtual tunnels and across intra-area and interarea topologies.
Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
In Bidirectional Forwarding Detection for IPv4 (BFDv4) associated mode, an IPv4 static route is automatically associated with an IPv4 static BFDv4 multihop destination address if the static route next hop exactly matches the static BFDv4 multihop destination address.
The state of the BFDv4 session is used to determine whether the associated IPv4 static routes are added in the IPv4 routing information base (RIB). For example, static routes are added in the IPv4 RIB only if the BFDv4 multihop destination is reachable, and the static routes are removed from the IPv4 RIB if the BFDv4 multihop destination subsequently becomes unreachable.
In Bidirectional Forwarding Detection for IPv4 (BFDv4), an IPv4 static BFD multihop destination can be configured in unassociated mode. In unassociate mode, a BFD neighbor is not associated with a static route, and the BFD sessions are requested if the IPv4 static BFD is configured.
Unassociated mode is useful in the following scenario:
1.
enable
2.
configure terminal
3.
ip route
prefix mask ip-address
4.
ip route static bfd
multihop-destination-address multihop-source-address
5.
ip route static bfd
multihop-destination-address multihop-source-address
unassociate
6.
end
The following show commands can be used to verify IPv4 static routes for BFD multihop:
1.
show
bfd
neighbor
2.
show
ip
static
route
bfd
Related Topic | Document Title |
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Cisco IOS commands |
|
IP Routing: Protocol Independent commands |
Standard/RFC | Title |
---|---|
RFC 5883 | BFD for Multihop Paths |
Description | Link |
---|---|
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Device> enable Device# configure terminal Device(config)# bfd map ipv4 192.0.2.1/32 10.1.1.1/32 test Device(config)# bfd-template multi-hop test Device(config-bfd)# interval min-tx 51 min-rx 51 multiplier 3 Device(config-bfd)# exit Device(config)# ip route 192.0.2.0 255.255.255.0 10.1.1.2 Device(config)# interface GigabitEthernet 1/1 Device(config-if)# ip address 10.1.1.1 255.255.0.0 Device(config-if)# exit Device(config)# ip route static bfd 192.0.2.1 10.1.1.1 Device(config)# end
Device> enable Device# configure terminal Device(config)# bfd map ipv4 192.0.2.1/32 10.1.1.1/32 test Device(config)# bfd-template multi-hop test Device(config-bfd)# interval min-tx 51 min-rx 51 multiplier 3 Device(config-bfd)# exit Device(config)# ip route 192.0.2.0 255.255.255.0 10.1.1.2 Device(config)# interface GigabitEthernet 1/1 Device(config-if)# ip address 10.1.1.1 255.255.0.0 Device(config-if)# exit Device(config)# ip route static bfd 192.0.2.1 10.1.1.1 unassociate Device(config)# end
The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Feature Name |
Releases |
Feature Information |
---|---|---|
BFD Multihop Support for IPv4 Static Routes |
15.2(3)S 15.3(3)M 15.2(1)SY |
The BFD Multihop Support for IPv4 Static Routes feature enables detection of IPv4 network failure between paths that are not directly connected. If a Bidirectional Forwarding Detection (BFD) session is up (that is, the next-hop destination is reachable), IPv4 static routes that are associated with IPv4 static BFD configuration are added to a routing table. If the BFD session is down, the routing table removes all associated static routes from the routing table. The following commands were modified: ip route static bfd and show ip static route bfd. |