Configuration manual

BFD for BGP is supported only on directly-connected BGP neighbors and only in BGP IPv4 networks.
As long as each BFD for BGP neighbor receives a BFD control packet within the configured BFD interval
for failure detection, the BFD session remains up and BGP maintains its adjacencies. If a BFD for BGP
neighbor does not receive a control packet within the detection interval, the router informs any clients of
the BFD session (other routing protocols) about the failure. It then depends on the individual routing
protocols that uses the BGP link to determine the appropriate response to the failure condition. The
typical response is to terminate the peering session for the routing protocol and reconverge by bypassing
the failed neighboring router. A log message is generated whenever BFD detects a failure condition.
You can configure BFD for BGP on the following types of interfaces: physical port (10GE or 40GE), port
channel, and VLAN.
1. Enable BFD globally.
CONFIGURATION mode
bfd enable
2. Specify the AS number and enter ROUTER BGP configuration mode.
CONFIGURATION mode
router bgp as-number
3. Add a BGP neighbor or peer group in a remote AS.
CONFIG-ROUTERBGP mode
neighbor {ip-address | peer-group name} remote-as as-number
4. Enable the BGP neighbor.
CONFIG-ROUTERBGP mode
neighbor {ip-address | peer-group-name} no shutdown
5. Configure parameters for a BFD session established with all neighbors discovered by BGP. OR
Establish a BFD session with a specified BGP neighbor or peer group using the default BFD session
parameters.
CONFIG-ROUTERBGP mode
bfd all-neighbors [interval millisecs min_rx millisecs multiplier value role
{active | passive}]
OR
neighbor {ip-address | peer-group-name} bfd
NOTES:
• When you establish a BFD session with a specified BGP neighbor or peer group using the
neighbor bfd command, the default BFD session parameters are used (interval: 100
milliseconds, min_rx: 100 milliseconds, multiplier: 3 packets, and role: active).
• When you explicitly enable or disable a BGP neighbor for a BFD session with the neighbor bfd
or neighbor bfd disable commands, the neighbor does not inherit the BFD enable/disable
values configured with the bfd all-neighbors command or configured for the peer group to
which the neighbor belongs. Also, the neighbor only inherits the global timer values configured
with the
bfd all-neighbors command (interval, min_rx, and multiplier).
6. Repeat Steps 1 to 5 on each BGP peer participating in a BFD session.
Bidirectional Forwarding Detection (BFD)
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