API Guide
History entry Entry that stores information about a downed route.
Dampened path Path that is no longer advertised.
Penalized path Path that is assigned a penalty.
1. Enable route dampening in ROUTER-BGP mode.
dampening [half-life | reuse | max-suppress-time]
● half-life — Number of minutes after which the penalty decreases (1 to 45, default 15). After the router assigns a
penalty of 1024 to a route, the penalty decreases by half after the half-life period expires.
● reuse — Number compares to the flapping route’s penalty value. If the penalty value is less than the reuse value, the
flapping route again advertises or is no longer suppressed (1 to 20000, default 750). Withdrawn routes are deleted from
the history state.
● suppress — Number compares to the flapping route’s penalty value. If the penalty value is greater than the suppress
value, the flapping route no longer advertises and is suppressed (1 to 20000, default 2000).
● max-suppress-time — Maximum number of minutes a route is suppressed (1 to 255, default is four times the half-
life value or 60 minutes).
2. View all flap statistics or for specific routes meeting the criteria in EXEC mode.
show ip bgp flap-statistics [ip-address [mask]]
● 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.
When you change the best path selection method, path selections for the existing paths remain unchanged until you reset it by
using the clear ip bgp command in EXEC mode.
Configure values to reuse or restart route
OS10(config)# router bgp 102
OS10(conf-router-bgp-102)# address-family ipv4 unicast
OS10(conf-router-bgpv4-af)# dampening 2 2000 3000 10
View dampened (nonactive) routes
OS10# show ip bgp flap-statistics
BGP local router ID is 13.176.123.28
Status codes: s suppressed, S stale, d dampened, h history, * valid, > best
Origin codes: i - IGP, e - EGP, ? - incomplete
Network
From Reuse Path
Total number of prefixes: 0
View dampened paths
OS10# show ip bgp dampened-paths
BGP local router ID is 80.1.1.1
Status codes: s suppressed, S stale, d dampened, h history, * valid, > best
Origin codes: i - IGP, e - EGP, ? - incomplete
Network From Reuse Path
d* 3.1.2.0/24 80.1.1.2 00:00:12 800 9 8 i
d* 3.1.3.0/24 80.1.1.2 00:00:12 800 9 8 i
d* 3.1.4.0/24 80.1.1.2 00:00:12 800 9 8 i
d* 3.1.5.0/24 80.1.1.2 00:00:12 800 9 8 i
d* 3.1.6.0/24 80.1.1.2 00:00:12 800 9 8 i
Total number of prefixes: 5
Layer 3
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