In computer networks, frame relay is an efficient, reasonably cheap, and fast way to transfer data. It is usually used to organize data exchange between local area networks (LANs) through a wide area network (WAN). Each user with a dedicated line connects directly to his relay node, but such a connection is transparent, that is, it is displayed as a direct connection with the destination.
In the relay process, data is placed in blocks of different sizes called frames. Moreover, the usual information for error correction is not included in the frame, due to which an increase in the data exchange rate is achieved. In most cases, the network organizes permanent virtual channels (PVCs) in one physical line, so for the subscriber the connection looks like a dedicated direct channel directly to the remote point. Although in fact the existing line of communication is shared by several users.
Packet relay works at the second data link layer of the OSI model. Frames may include packets of different protocols, for example, Ethernet and X.25. Frames of different protocols differ in size.
Frame Relay operates at the following speeds: 56, 64, 128, 256, 512 kbps, 1.5 and 2 Mbps. Frame relay is actually a cross between ISDN (128 kbit / s) and asynchronous transfer mode (ATM), operating on approximately the same principles as frame relay, only at speeds from 155.520 Mbit/s to 622.080 Mbit/s. When designing the frame relay protocol, the old X.25 packet switching technology used to transmit analog data, such as voice, was taken as the basis. But, unlike X.25, frame relay offers fast packet technology that does not use error correction. If an error is detected in the frame, this frame is simply discarded and transmitted again (it should be noted that in digital networks the percentage of errors is much smaller than in analog).
Frame relay is not the most ideal option for streaming video or voice, as continuous support for an active connection is required here, and when relaying frames, the communication channel in the line is allocated only when it becomes necessary to send / receive information.
Now networks with frame relay are gradually beginning to be replaced by IP networks. With the advent of multiservice networks, cable and DSL modems, the frame relay protocol has faded into the background.