Frame Relay is a packet switching methodology that is designed in the late 1980s and widely deployed in the 1990s. Frame Relay uses virtual circuits. These virtual circuits can be set up for each session (switched virtual circuits) or set up permanently (permanent virtual circuits). Frame Realy is designed for fiber optic cables with a very low bit error rate. Frame Realy has no error recovery and no flow control. Whenever a Frame Relay switch detects an error in a packet, it just discard the data. This results in a network with a low processing overhead and high transmission rates. The end system will have to take care of the data integrity.
Frame Relay is extensively used today in large corporations to interconnect the LANs between buildings. Frame Relay offers a corporation an alternative to sending its intra IP traffic over the public Internet, for which the corporation may have concerns about the reliability or the security. In this case the virtual circuits will be permanent.