Communities - Cisco ASR 9000 Series Routing Configuration Manual

Implementing BGP
Command or Action
Step 14
route-policy route-policy-name out
Example:
RP/0/RSP0/CPU0:router(config-bgp-nbr-af)#
route-policy pe-pe-vpn-out out
Step 15
commit
Configuring Route Reflector to Hold Routes That Have a Defined Set of RT Communities
A provider edge (PE) needs to hold the routes that match the import route targets (RTs) of the VPNs configured
on it. The PE router can discard all other VPNv4 routes. But, a route reflector (RR) must retain all VPNv4
routes, because it might peer with PE routers and different PEs might require different RT-tagged VPNv4
(making RRs non-scalable). You can configure an RR to only hold routes that have a defined set of RT
communities. Also, a number of the RRs can be configured to service a different set of VPNs (thereby achieving
some scalability). A PE is then made to peer with all RRs that service the VRFs configured on the PE. When
a new VRF is configured with an RT for which the PE does not already hold routes, the PE issues route
refreshes to the RRs and retrieves the relevant VPN routes.
Note that this process can be more efficient if the PE-RR session supports extended community outbound
Note
route filter (ORF).
Perform this task to configure a reflector to retain routes tagged with specific RTs.
SUMMARY STEPS
1. configure
2. router bgp as-number
3. address-family vpnv4 unicast
4. retain route-target { all | route-policy route-policy-name }
5. commit
DETAILED STEPS
Command or Action
Step 1 configure
Step 2 router bgp as-number
Example:
RP/0/RSP0/CPU0:router(config)# router bgp
120
Cisco ASR 9000 Series Aggregation Services Router Routing Configuration Guide, Release 5.3.x
Configuring a VPN Routing and Forwarding Instance in BGP
Purpose
Specifies a routing policy for an outbound route. The
policy can be used to filter routes or modify route
attributes.
Purpose
Specifies the autonomous system number and enters the BGP
configuration mode, allowing you to configure the BGP routing
process.
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