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    Example: Creating a BGP Session Between the CE Router and the Parent VR

    The following example creates a BGP session from the VRF to the CE router to advertise routes in the VRF to the CE router.

    Figure 1: BGP Session Between CE Router and Parent VR

    BGP Session Between CE Router and Parent

    The following commands configure a shared IP interface in the parent VR and point a static route for the loopback in the CE router to it:

    host1(config)#virtual-router pe1 host1:pe1(config)#interface ip ce1-cust host1:pe1(config-if)#ip share-interface atm2/0.1 host1:pe1(config-if)#ip address host1:pe1(config-if)#exit host1:pe1(config)#ip route ip ce1-cust

    The following commands make the loopback in the parent VR reachable from the VRF by means of a global import map:

    host1(config)#virtual-router pe1 host1:pe1(config)#prefix-list VRloop permit host1:pe1(config)#route-map globimaploop host1:pe1(config-route-map)#match ip address prefix-list VRloop host1:pe1(config-route-map)#exit host1:pe1(config)#ip vrf pe11 host1:pe1(config-vrf)#rd 100:1 host1:pe1(config-vrf)#route-target both 100:1 host1:pe1(config-vrf)#global import map globimaploop

    The following commands create a BGP session between the CE router and the parent VR.

    On host 1, VR PE 1:

    host1(config)#virtual-router pe1 host1:pe1(config)#router bgp 100 host1:pe1(config-router)#neighbor remote-as 200 host1:pe1(config-router)# neighbor ebgp-multihop host1:pe1(config-router)#neighbor update-source loopback1 host1:pe1(config-router)#exit

    On host 2, VR CE 1:

    host2(config)#virtual-router ce1 host2:ce1(config)#interface loopback 1 host2:ce1(config-if)#ip address host2:ce1(config-if)#exit host2:ce1(config)#ip route atm2/1.1 host2:ce1(config)#router bgp 200 host2:ce1(config-router)#neighbor remote-as 100 host2:ce1(config-router)#neighbor ebgp-multihop host2:ce1(config-router)#neighbor update-source loopback1 host2:ce1(config-router)#exit

    You must also configure either fallback global or a default route to a manually created shared interface in the VRF. See Example: Configuring a Fallback Global Option or Example: Configuring a Default Route to a Shared Interface for details.

    You can use the BGP session between the CE router and the parent VR to enable the CE router to advertise prefixes within the VPN site that can be reachable from the global Internet. An alternative configuration is to use a global export map as described in Understanding Route Distribution for a VRF using Maps.

    Published: 2014-08-18