Administrator Guide

Layer 3 Routing Commands 1274
The site of origin (SOO) extended communities attribute is configured with
the soo keyword. This attribute uniquely identifies the site from which the
provider edge (PE) router learned the route. All routes learned from a
particular site must be assigned the same site of origin extended community
attribute, regardless if a site is connected to a single PE router or multiple PE
routers. Configuring this attribute prevents routing loops from occurring
when a site is multihomed. The SOO extended community attribute is
configured using a route map in both outbound and inbound directions. The
SOO should not be configured for stub sites or sites that are not multi-homed
Command History
Introduced in version 6.3.0.1 firmware.
Example
The following example shows the creation of an extended community list
that permits routes from route target 1:1 and site of origin 2:2 and denies
routes from route target 3:3 and 4:4.
(R1)(Config)# ip extcommunity-list 10 permit rt 1:1
(R1)(Config)# ip extcommunity-list 10 permit rt 2:2
(R1)(Config)# ip extcommunity-list 20 deny rt 3:3 rt 4:4
List 10 shows a logical OR condition which means the first match is
processed.
List 20 shows a logical AND condition which means all the community values
must match in order for list 20 to be processed.
The following example show how the extended communities list is used by
route-maps.
(R1)(config)# route-map SEND_OUT permit 10
(R1)(config-route-map)# match extcommunity 10
(R1)(config-route-map)# set extcommunity rt:10:10 additive
(R1)(config-route-map)# exit
The following example shows the usage of extended communities attribute in
BGP configuration mode and sending of the extended communities attribute
to external peer at 1.1.1.1.
(R1)(Config)# router bgp 1
(R1)(Config-router)# address-family vpnv4 unicast
(R1)(Config-router)# neighbor 1.1.1.1 remote-as 2
(R1)(Config-router-af)# neighbor 1.1.1.1 send-community extended
2CSNXXX_SWUM204.book Page 1274 Monday, January 25, 2016 1:25 PM