Hub-And-Spoke Vpns; Figure 83: Route Target Configuration For A Full-Mesh Vpn; Figure 84: Site Connectivity In A Hub-And-Spoke Vpn - Juniper BGP - CONFIGURATION GUIDE V 11.1.X Configuration Manual

Chapter 5: Configuring BGP-MPLS Applications

Figure 83: Route Target Configuration for a Full-Mesh VPN

Hub-and-Spoke VPNs

In a hub-and-spoke VPN, the spoke sites in the VPN can communicate only with the
hub sites; they cannot communicate with other spoke sites, as shown in Figure 84
on page 407.

Figure 84: Site Connectivity in a Hub-and-Spoke VPN

Figure 85 on page 408 shows how to configure the VRF import and export route
targets to build a hub-and-spoke VPN. Each spoke VRF has the same export route
target, 100:12. The hub VRF has its import route target set to 100:12, so it accepts
only routes from the spoke VRFs. Each spoke VRF has the same import route target,
100:11. Every route advertised by any spoke has an attached route target of 100:12.
Because that route target does not match the import route target of any spoke, the
spokes cannot accept any routes from another spoke. However, the hub VRF has an
export route target of 100:11, so routes advertised by the hub do match the import
target of each spoke and are accepted by all of the spokes.
407
Using Route Targets to Configure VPN Topologies