Route Manipulation Using Soo Match Condition - Cisco ASR 9000 Series Configuration Manual

Implementing EIGRP
When BGP and EIGRP peers that support the SoO extended community receive these routes, they also
receive the associated SoO values and pass them to other BGP and EIGRP peers that support the SoO
extended community. This filtering is designed to prevent transient routes from being relearned from
the originating site, which prevents transient routing loops from occurring.
In conjunction with BGP cost community, EIGRP, BGP, and the RIB ensure that paths over the MPLS
VPN core are preferred over backdoor links.
For MPLS and IP VPN and SoO configuration information, see Implementing MPLS Layer 3 VPNs in
the Cisco ASR 9000 Series Aggregation Services Router MPLS Configuration Guide.

Route Manipulation using SoO match condition

The SoO configuration in EIGRP network can be used to manipulate routes using the SoO match condition
in the routing policy. The egress interface of a PE router is used to compare and manipulate routes based on
the SoO configuration on the remote PE router.
Topology
In the following topology, CE1, CE2 and CE3 are the customer edge routers. PE1 and PE2 are the provider
edge routers. By default, CE1 will use PE1->PE2 to reach CE3.To configure CE1 to use CE2 to reach CE3,
the metric advertised by PE1 must be increased.
The routing policy on PE1 manipulates routes received from CE3 via PE2, by using the SoO match condition.
With this feature added, PE1 can increase the metric while advertising routes to CE1.
Configuration:
/*SoO tag is assigned on PE2 router*/
router(config)#interface GigabitEthernet0/0/0/11
router (config-if)#site-of-origin 33.33.33.33:33
OL-30423-03
◦ If a route is received without a SoO value, the route is accepted into the EIGRP topology table,
and the SoO value from the interface that is used to reach the next-hop CE router is appended to
the route before it is redistributed into BGP.
Cisco ASR 9000 Series Aggregation Services Router Routing Configuration Guide, Release 5.1.x
EIGRP Layer 3 VPN PE-CE Site-of-Origin
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