Users Guide

Usage
Information
To determine a BGP session flap, both a route-down event and a subsequent route-up event
corresponding to a single route are considered. As a result, a flap event is penalized only one time during
the route-down event. The subsequent route-up event corresponding to the same route is not considered
as a flap and is not penalized.
The history paths that the show ip bgp command displays contain only the prefix and the next-hop
information. The next-hop information shows the ip address of the neighbor. It does not show the actual
next-hop details.
The following describes the show ip bgp damp command shown in the following example.
Field Description
Network Displays the network ID to which the route is dampened.
From Displays the IP address of the neighbor advertising the dampened route.
Reuse Displays the hour:minutes:seconds until the dampened route is available.
Path Lists all the ASs the dampened route passed through to reach the destination
network.
Example
DellEMC# show ip bgp dampened-paths
BGP local RIB : Routes to be Added 0, Replaced 0, Withdrawn 0
BGP local router ID is 192.168.11.5
Status codes: s suppressed, S stale, d dampened, h history, * valid, >
best
Path source: I - internal, a - aggregate, c - confed-external, r -
redistributed
n - network, D - denied, S - stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network From Reuse Path
d 55.0.0.0/24 172.16.0.2 00:36:23 200
DellEMC#
BGP Extended Communities (RFC 4360)
BGP Extended Communities, as defined in RFC 4360, is an optional transitive BGP attribute.
BGP Extended Communities provides two major advantages over Standard Communities:
● The range is extended from 4-octet (AA:NN) to 8-octet (Type:Value) to provide enough number communities.
● Communities are structured using a new “Type” field (1 or 2-octets), allowing you to provide granular control/filter routing
information based on the type of extended communities.
set extcommunity rt
To set Route Origin community attributes in Route Map, use this feature.
Syntax
set extcommunity rt {as4 ASN4:NN [non-trans] | ASN:NNNN [non-trans] |
IPADDR:NN [non-trans]} [additive]
To delete the Route Origin community, use the no set extcommunity command.
Parameters
as4 ASN4:NN Enter the keyword as4 then the 4-octet AS specific extended community number
in the format ASN4:NN (4-byte AS number:2-byte community value).
ASN:NNNN Enter the 2-octet AS specific extended community number in the format
ASN:NNNN (2-byte AS number:4-byte community value).
456 Border Gateway Protocol