Prerequisites - Cisco Catalyst 4500 Series Configuration Manual

Chapter 37 Configuring Bidirection Forwarding Detection
the forwarding path on the remote (neighbor) system without involving the remote system, there is an
opportunity to improve the interpacket delay variance, thereby achieving quicker failure detection times
than when using BFD Version 0 with BFD control packets for the BFD session.
Echo mode is described as without asymmetry when it is running on both sides (both BFD neighbors are
running echo mode).

Prerequisites

BFD must be running on all participating switches.
Before using BFD echo mode, you must disable the sending of Internet Control Message Protocol
(ICMP) redirect messages by entering the no ip redirects command, in order to avoid high CPU
utilization.
The baseline parameters for BFD sessions on the interfaces over which you want to run BFD sessions to
BFD neighbors must be configured. See the
section on page 37-8
Restrictions
BFD echo mode which is supported in BFD Version 1.
This section contains the following configuration tasks for BFD echo mode:
•
•
BFD echo mode does not work in conjunction with Unicast Reverse Path Forwarding (uRPF)
Note
configuration. If BFD echo mode and uRPF configurations are enabled, then the sessions will flap.
Configuring the BFD Slow Timer
The steps in this procedure show how to change the value of the BFD slow timer. Repeat the steps in this
procedure for each BFD switch.
To configure the BFD slow timer, perform this task:
Command or Action
Step 1
enable
Switch> enable
Step 2
configure terminal
Switch# configure terminal
Step 3
bfd slow-timer milliseconds
Switch(config)# bfd slow-timer 12000
Step 4
end
Switch(config)# end
OL-25340-01
for more information.
Configuring the BFD Slow Timer, page 37-15
Disabling BFD Echo Mode Without Asymmetry, page 37-16
How to Configure Bidirectional Forwarding Detection
"Configuring BFD Session Parameters on the Interface"
Purpose
Enables privileged EXEC mode.
•
Enters global configuration mode.
Configures the BFD slow timer.
Exits global configuration mode and returns
the switch to privileged EXEC mode.
Software Configuration Guide—Release IOS XE 3.3.0SG and IOS 15.1(1)SG
Enter your password if prompted.
37-15