Dell Force10 S4810P Configuration Manual page 159

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 usually 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.
On C-Series and E-Series only, you can configure BFD for BGP on the following types of interfaces:
physical port (10GE or 40GE), port channel, and VLAN.
To establish a BFD session with one or all BGP neighbors, follow these steps:
Step Task
1 Enable BFD globally.
2 Specify the AS number and enter ROUTER
BGP configuration mode.
3 Add a BGP neighbor or peer group in a
remote AS.
4 Enable the BGP neighbor.
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.
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.
- 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.
Disabling BFD for BGP
To disable a BFD for BGP session with a specified neighbor, enter the
peer-group-name} bfd disable
Command Syntax
bfd enable
router bgp as-number
neighbor {ip-address | peer-group
name} remote-as as-number
neighbor {ip-address |
peer-group-name} no shutdown
bfd all-neighbors [interval millisecs
min_rx millisecs multiplier value role
{active | passive}]
OR
neighbor {ip-address |
peer-group-name} bfd
command in
ROUTER BGP
neighbor {ip-address |
configuration mode.
Bidirectional Forwarding Detection (BFD) | 159
Command Mode
CONFIGURATION
CONFIGURATION
CONFIG-ROUTER-
BGP
CONFIG-ROUTER-
BGP
CONFIG-ROUTER-
BGP