Frame Relay is a wide area network technology which is used to specify the physical and data link layers of digital telecommunications channels using packet switching.
Frame Relay was originally designed for transport across ISDN (Integrated Services Digital Network) infrastructure but nowadays it can also be used with many other network interfaces.
It is usually implemented by network providers as a voice and data encapsulation technique that is used between LANs (Local Area Networks) and WANs (Wide Area Networks).
Configuring user equipment within a frame Relay network is very simple and is one the main reasons it is so popular in telecommunication networks around the world.
Frame Relay works by putting data in variable-size units which are called “frames” and leaves any necessary error-correction (such as retransmission of data) up to the end-points, which speeds up overall data transmission.
In most cases, the network provider will offer a PVC (Permanent Virtual Circuit) to the customer, which allows them to see a continuous, dedicated connection without the need to pay for full-time leased lines. This then allows the service-provider to charge the user based on the route each frame travels to reach its destination.
By being able to prioritize some frames and make others less important, customers are able to choose a level of service quality, depending on their specific requirements.
Frame relay is capable of running on fractional E1 or full E-carrier systems (T1 or full T-carrier in the Americas). It provides a mid-range service between basic rate ISDN (128kbit/s) and ATM (Asynchronous Transfer Mode, 155 to 622mbit/s).
It is a fast packet switching technology, which operates over links which have a very low chance of transmission error (practically lossless like PDH). When a frame relay detects an error in a frame, it simply drops that frame. The end points will then detect the dropped frame and retransmit.