Juniper JUNOSE 11.2.X BGP AND MPLS Configuration Manual page 463

Example:
Hub-and-Spoke VPN
Copyright © 2010, Juniper Networks, Inc.
To configure route targets for this fully meshed scenario, you specify the same route
target for the import list and export list on all VRFs in VPN A. The VRFs in VPN B use a
different route target, but it is the same for the import list and export list for all.
Route-target configuration on PE 1:
host1(config)#virtual-router newyork
host1:newyork(config)#ip vrf vrfA
host1:newyork(config-vrf)#route-target both 777:1
host1:newyork(config-vrf)#exit
host1:newyork(config)#ip vrf vrfB
host1:newyork(config-vrf)#route-target both 777:2
Route-target configuration on PE 2:
host2(config)#virtual-router boston
host2:boston(config)#ip vrf vrfC
host2:boston(config-vrf)#route-target both 777:1
host2:boston(config-vrf)#exit
host2:boston(config)#ip vrf vrfD
host2:boston(config-vrf)#route-target both 777:2
Route-target configuration on PE 3:
host3(config)#ip vrf vrfE
host3(config-vrf)#route-target both 777:1
host3(config-vrf)#exit
host3(config)#ip vrf vrfF
host3(config-vrf)#route-target both 777:2
In one type of a hub-and-spoke design, only the hub site can reach every site in the VPN.
All other sites—spokes—can reach only the hub site. (More complex hub-and-spoke
designs are possible, but require additional configuration and route targets to achieve.)
In Figure 90 on page 428, Customer Site 1 is the hub site for VPN A. As such it can reach
both spokes, Customer Sites 2 and 3 through VRF A. Customer Site 2 can reach only the
hub, customer 1, through VRF C. Customer Site 3 can reach only the hub, customer 1,
through VRF E.
BGP sessions exist between PE 1 and PE 2 and between PE 1 and PE 3. In most situations,
BGP itself is fully meshed, but that level of complexity is not necessary for this example.
The MPLS paths through the service provider core are omitted for clarity.
To configure route targets for this hub and spoke, you specify different import and export
route targets on the hub VRF. On the spoke VRFs, you switch these route targets.
Route-target configuration on PE 1:
host1(config)#virtual-router newyork
host1:newyork(config)#ip vrf vrfA
host1:newyork(config-vrf)#route-target export 777:25
host1:newyork(config-vrf)#route-target import 777:50
Chapter 6: Configuring BGP-MPLS Applications
427