Frame Relay definition
Frame Relay is a wide-area network (WAN) protocol that operates at the data link layer of the OSI (Open Systems Interconnection) model. While popular in the late 20th century, it has been largely replaced by modern technologies like MPLS and Ethernet.
How Frame Relay works
Frame Relay encapsulates data into frames, which act as containers for network packets. Once the encapsulation is complete, the protocol establishes a logical connection between the endpoints using virtual circuits and transmits the frames over a packet-switched network.
To identify the required virtual circuits, Frame Relay uses Data Link Connection Identifiers (DLCI). Each DLCI is associated with a specific destination address, enabling the network to route frames to the correct endpoint. Multiple virtual circuits can be multiplexed onto a single physical link, allowing organizations to share a network infrastructure.
MPLS (Multiprotocol Label Switching) has largely replaced Frame Relay over time due to offering more flexibility and better support for IP-based services. MPLS also allows for a smoother transition to more modern networking technologies. Frame Relay is largely confined to legacy systems and IT history classrooms, where it is studied as a trailblazer of packet-switched WAN technology.