Reference Guide

Border Gateway Protocol IPv4 (BGPv4) | 235
Use the following command in EXEC and EXEC Privilege mode to view statistics on route flapping.
By default, the path selection in FTOS is deterministic, that is, paths are compared irrespective of the order
of their arrival. You can change the path selection method to non-deterministic, that is, paths are compared
in the order in which they arrived (starting with the most recent). Furthermore, in non-deterministic mode,
the software may not compare MED attributes though the paths are from the same AS.
Use the following command in CONFIGURATION ROUTER BGP mode to change the path selection
from the default mode (deterministic) to non-deterministic.
Change BGP timers
Use either or both of the following commands in the CONFIGURATION ROUTER BGP mode to
configure BGP timers.
Command Syntax Command Mode Purpose
show ip bgp flap-statistics
[ip-address [mask]] [filter-list
as-path-name] [regexp
regular-expression]
EXEC
EXEC Privilege
View all flap statistics or for specific routes meeting the
following criteria:
• ip-address [mask]: enter the IP address and mask
• filter-list as-path-name: enter the name of an
AS-PATH ACL.
• regexp regular-expression: enter a regular express
to match on.
Command Syntax Command Mode Purpose
bgp non-deterministic-med
CONFIG-ROUTER-
BGP
Change the best path selection method to
non-deterministic.
Note: When you change the best path selection method, path selection for existing paths remains
unchanged until you reset it by entering the clear ip bgp command in EXEC Privilege mode.
Command Syntax Command Mode Purpose
neighbors {ip-address |
peer-group-name} timers keepalive
holdtime
CONFIG-ROUTER-
BGP
Configure timer values for a BGP neighbor or peer
group.
• keepalive range: 1 to 65535. Time interval, in
seconds, between keepalive messages sent to the
neighbor routers. (Default: 60 seconds)
• holdtime range: 3 to 65536. Time interval, in
seconds, between the last keepalive message and
declaring the router dead. (Default: 180 seconds)