Administrator Guide

Establishing Sessions for IPv6 Static Routes for Nondefault VRF
You can also create nondefault VRFs and establish sessions for all neighbors that are the next hop of a static route.
To establish a BFD session for nondefault VRFs, use the following command.
● Establish BFD sessions for all IPv6 neighbors that are the next hop of a static route.
CONFIGURATION mode
ipv6 route bfd vrf vrf-name [prefix-list prefix-list-name] [interval interval min_rx
min_rx multiplier value role {active | passive}]
Example Configuration and Verification
The following example contains static routes for both default and nondefault VRFs.
Dell#show run | grep bfd
bfd enable
ipv6 route bfd prefix-list p6_le
ipv6 route bfd vrf vrf1
ipv6 route bfd vrf vrf2
ipv6 route bfd vrf vrf1 prefix-list p6_le
The following example shows that sessions are created for static routes for the default VRF.
The following example shows that sessions are created for static routes for the nondefault VRFs.
Changing IPv6 Static Route Session Parameters
BFD sessions are configured with default intervals and a default role.
The parameters you can configure are: Desired TX Interval, Required Min RX Interval, Detection Multiplier, and system role.
These parameters are configured for all static routes. If you change a parameter, the change affects all sessions for static
routes.
To change parameters for static route sessions, use the following command .
● Change parameters for all static route sessions.
CONFIGURATION mode
ipv6 route bfd [vrf vrf-name][prefix-list prefix-list-name] interval milliseconds min_rx
milliseconds multiplier value role [active | passive]
To view session parameters, use the show bfd neighbors detail command, as shown in the examples in
Configure BFD for OSPF
When using BFD with OSPF, the OSPF protocol registers with the BFD manager. BFD sessions are established with all
neighboring interfaces participating in OSPF. If a neighboring interface fails, the BFD agent on the line card notifies the BFD
manager, which in turn notifies the OSPF protocol that a link state change occurred.
NOTE:
If you enable BFD after OSPF with a large number (more than 100) of OSPF neighbors on a VLAN port-channel and if the
VLAN has more than one port-channel, BFD does not come up immediately. (This behavior occurs only if you enable BFD
after connections with all OSPF neighbors are fully established.)
BFD does not come up for 5 to 6 minutes in a scenario when all the following conditions are met:
● A large number of BFD neighbors are present.
● The neighbors are reachable over a VLAN through a port-channel and the VLAN has multiple port-channels as members.
● BFD is enabled after all the OSPF neighbors are in an established state.
This delay should not be seen after a reload because OSPF will throttle neighbor establishment.
Bidirectional Forwarding Detection (BFD) 147