Frame Relay links are more flexible than point-to-point links, because multiple links can be terminated at a single interface in a router. This opens up design possibilities allowing connectivity to multiple sites at a significant cost savings over point-to-point circuits.
Figure 23-5 shows three sites networked together with Frame Relay. On the left, Router B and Router C are both connected to Router A, but are not connected to each other. This design is often referred to as a partial mesh or hub and spoke network. In this network, Router B can communicate to Router C only through Router A.
Figure 23-5. Meshed Frame Relay networks
On the right side of Figure 23-5 is an example of a fully meshed network. The difference here is that all sites are connected to all other sites. Router B can communicate directly with Router C in the fully meshed network.
Meshed networks are not strictly the domain of Frame Relay. As you can see in Figure 23-6, a fully meshed network can easily be created with point-to-point T1s.
Figure 23-6. Frame Relay versus point-to-point T1 meshed networks
In a Frame Relay network like the one shown on the left side of Figure 23-6, each location needs a router that can support a single T1. Each PVC can be configured as a separate virtual interface ...