Administrator Guide

Establishing Sessions for Static Routes for Default VRF
Sessions are established for all neighbors that are the next hop of a static route on the default VRF.
Figure 12. Establishing Sessions for Static Routes
To establish a BFD session, use the following command.
● Establish BFD sessions for all neighbors that are the next hop of a static route.
CONFIGURATION mode
ip route bfd [prefix-list prefix-list-name] [interval interval min_rx min_rx multiplier
value role {active | passive}]
To verify that sessions have been created for static routes, use the show bfd neighbors command.
R1(conf)#ip route 2.2.3.0/24 2.2.2.2
R1(conf)#ip route bfd
R1(conf)#do show bfd neighbors
* - Active session role
Ad Dn - Admin Down
C - CLI
I - ISIS
O - OSPF
R - Static Route (RTM)
LocalAddr RemoteAddr Interface State Rx-int Tx-int Mult Clients
2.2.2.1 2.2.2.2 Tf 1/1 Up 200 200 4 R
To view detailed session information, use the show bfd neighbors detail command.
Establishing Static Route Sessions on Specific Neighbors
You can selectively enable BFD sessions on specific neighbors based on a destination prefix-list.
When you establish a BFD session using the ip route bfd command, all the next-hop neighbors in the static route become
part of the BFD session. Starting with Dell EMC Networking OS release 9.11.0.0, you can enable BFD sessions on specific
next-hop neighbors. You can specify the next-hop neighbors to be part of a BFD session by including them in a prefix-list.
Prefix lists are used in route maps and route filtering operations. You can use prefix lists as an alternative to existing access lists
(ACLs). A prefix is a portion of the IP address. Prefix lists constitute any number of bits in an IP address starting from the far
left bit of the far left octet. By specifying the exactly number of bits in an IP address that belong to a prefix list, the prefix list
can be used to aggregate addresses and perform some functions; for example, redistribution.
You can use the following options to enable or disable the BFD session:
● Permit – The permit option enables creation of a BFD session on the specified prefix list or prefix list range. The no permit
option enables tear down of the BFD session if and only if the ACL has no permit entry that shares the same neighbor.
● Deny – The deny option prevents BFD sessions from getting created for the specified prefix list or prefix list range.
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Bidirectional Forwarding Detection (BFD)