An alternative to dedicated, expensive, leased WAN lines is Frame Relay. Frame Relay is a high-performance WAN protocol that operates at the physical and data link layers of the OSI reference model. Although newer services such as broadband and metro Ethernet have reduced the need for Frame Relay in many locations, Frame Relay is still a viable option in many locales around the world. Frame Relay provides a cost-efficient solution for communications between multiple remote sites by using a single access circuit from each site to the provider.
This chapter introduces the fundamental concepts of Frame Relay. It also covers Frame Relay configuration, verification, and troubleshooting tasks.