Cisco ASR 9000 Series Routing Configuration Guide

Configuring the Route Distinguisher
The route distinguisher (RD) makes prefixes unique across multiple VPN routing and forwarding (VRF)
instances.
In the L3VPN multipath same route distinguisher (RD)environment, the determination of whether to install
a prefix in RIB or not is based on the prefix's bestpath. In a rare misconfiguration situation, where the best
pah is not a valid path to be installed in RIB, BGP drops the prefix and does not consider the other paths. The
behavior is different for different RD setup, where the non-best multipath will be installed if the best multipath
is invalid to be installed in RIB.
Perform this task to configure the RD.
SUMMARY STEPS
1.
configure
2.
router bgp as-number
3.
bgp router-id ip-address
4.
vrf vrf-name
5.
rd { as-number : nn | ip-address : nn | auto }
6.
Do one of the following:
•
end
•
commit
DETAILED STEPS
PurposeCommand or Action
configure
Step 1
Enters BGP configuration mode allowing you to configure the BGP
routing process.
router bgp as-number
Example:
RP/0/RSP0/CPU0:router(config)# router bgp
120
Step 2
Configures a fixed router ID for the BGP-speaking router.
bgp router-id ip-address
Example:
RP/0/RSP0/CPU0:router(config-bgp)# bgp
router-id 10.0.0.0
Step 3
Configures a VRF instance.
vrf vrf-name
Example:
RP/0/RSP0/CPU0:router(config-bgp)# vrf
vrf_pe
Step 4
Configures the route distinguisher.
rd { as-number : nn | ip-address : nn | auto }
Step 5
Cisco ASR 9000 Series Aggregation Services Router Routing Configuration Guide, Release 5.3.x
139
Implementing BGP
Configuring a VPN Routing and Forwarding Instance in BGP

Cisco ASR 9000 Series Specifications

General

Brand	Cisco
Model	ASR 9000 Series
Category	Network Router
Language	English