Frame Relay is the standard of the WAN Wide Area Network technology that will specify the physical and the logical link of the channels by using a packet switching technique.

Frame Relay is a scalable WAN solution that is often used as an alternative to leased lines when leased lines prove to be cost unaffordable.

With Frame Relay, you can have a single serial interface on a router connecting into multiple remote sites through virtual circuits.

Network providers commonly implement Frame Relay for voice (VoFR) and data as an encapsulation technique, used between local area networks (LANs) over a wide area network (WAN). Each end-user gets a private line  to a Frame Relay node.

Protocol data unit

Each Frame Relay protocol data unit (PDU) consists of the following fields:

Flag Field.

Address Field.

Information Field.

Frame Check Sequence (FCS) Field

Frame Relay is  used as a low cost carrier to replace the networks of leased lines previously used to connect ATM machines, POS terminals and other legacy devices to head office mainframes.

Many Frame Relay connections are used for high-end Internet connections.