Reference Guide

Border Gateway Protocol IPv4 (BGPv4) | 419
BGP Extended Communities (RFC 4360)
BGP Extended Communities, as defined in RFC 4360, is an optional transitive BGP attribute. It
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.
The BGP Extended Community commands are:
• deny
• deny regex
• description
• ip extcommunity-list
• match extcommunity
• permit
• permit regex
• set extcommunity rt
• set extcommunity soo
• show ip bgp ipv4 extcommunity-list
• show ip bgp paths extcommunity
• show ip extcommunity-list
• show running-config extcommunity-list
deny
c e s
Use this feature to reject (deny) from the two types of extended communities, Route Origin (rt) or
Site-of-Origin (soo).
Syntax
deny {rt | soo} {as4 ASN4:NN | ASN:NNNN | IPADDR:NN}
To remove (delete) the rule, use the no deny {rt | soo} {as4 ASN4:NN | ASN:NNNN |
IPADDR:NN} command.
Parameters
Defaults
Not configured
Command Modes
CONFIGURATION (conf-ext-community-list)
rt Enter the keyword rt to designate a Route Origin community
soo Enter the keyword soo to designate a Site-of-Origin community (also known as
Route Origin).
as4 ASN4:NN Enter the keyword as4 followed by 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)
.
IPADDR:NN
Enter the IP address specific extended community in the format IPADDR:NN
(4-Byte IPv4 Unicast Address:2-Byte community value)