Default Bfd Configuration Guidelines; Configuring Bfd Session Parameters On An Interface - Cisco 3845 - Security Bundle Router Software Manual

Chapter 29 Configuring IP Unicast Routing

Default BFD Configuration Guidelines

The switch supports a maximum of 28 BFD sessions at one time.
To run BFD on a switch:
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We recommend that you configure the BFD interval parameters on an interface before configuring the
Note
routing protocol commands, especially when using EIGRP.
Confirm that CEF is enabled on participating switches (the default) as well as IP routing.
BFD is supported on physical interfaces that are configured as routing interfaces. It is not supported on
Layer 2 interfaces, pseudowires, static routes, SVI interfaces, or port channels.
Although you can configure BFD interface commands on a Layer 2 port, BFD sessions do not operate
on the interface unless it is configured as a Layer 3 interface (no switchport) and assigned an IP address.
In HSRP BFD, standby BFD is enabled globally by default and on all interfaces. If you disable it on an
interface, you then must disable and reenable it globally for BFD sessions to be active.
When using BFD echo mode (the default), you should disable sending of ICMP redirect messages by
entering the no ip redirects interface configuration command on the BFD interface.

Configuring BFD Session Parameters on an Interface

Before you can start a BFD session on an interface, you must put the interface into Layer 3 mode and
set the baseline BFD parameters on it.
Note Although you can configure BFD on Layer 2 interfaces, a BFD session cannot start until both interfaces
are in Layer 3 mode and routing is enabled on the switch.
Beginning in privileged EXEC mode, follow these steps to configure BFD parameters on any interface
participating in a BFD session:
Command
Step 1
configure terminal
Step 2
interface interface-id
Step 3
no switchport
Step 4 ip address ip-address subnet-mask
OL-23400-01
Configure basic BFD interval parameters on each interface over which you want to run BFD
sessions.
Enable routing on the switch. You can configure BFD without enabling routing, but BFD sessions
do not become active unless routing is enabled on the switch and on the BFD interfaces.
Enable one or more one routing protocol clients for BFD. You should implement fast convergence
for the routing protocol that you are using. See the IP routing documentation in this chapter or in the
Cisco IOS IP Configuration Guide, Release 12.2, for information on configuring fast convergence.
Purpose
Enter global configuration mode.
Specify an interface for a BFD session, and enter interface configuration
mode. Only physical interfaces support BFD.
Remove the interface from Layer 2 configuration mode.
Configure the IP address and IP subnet mask.
Cisco ME 3800X and 3600X Switch Software Configuration Guide
Configuring BFD
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