WANs are commonly interconnected using the following physical topologies:
- Point-to-Point: This is the simplest topology which consists of a permanent link between two endpoints. For this reason, this is a very popular WAN topology.
- Hub and Spoke: A WAN version of the star topology in which a central site interconnects branch sites using point-to-point links.
- Mesh: This topology provides high availability, but requires that every end system be interconnected to every other system. Therefore the administrative and physical costs can be significant. Each link is essentially a point-to-point link to the other node. Variations of this topology include a partial mesh where some but not all of end devices are interconnected.
The three common physical WAN topologies are illustrated in the figure.