X.25 vs. Frame Relay packet switching

Both X.25 and Frame Relay provide connection-oriented packet switching, also known as virtual circuit switching. A major difference between X.25 and Frame Relay packet switching are that X.25 is a reliable protocol, based on node-to-node automatic repeat request, while Frame Relay is a non-reliable protocol, maximum packet length is 1000 bytes. Any retransmissions must be carried out by higher layer protocols. The X.25 protocol is a network layer protocol, and is part of the X.25 protocol suite, also known as the OSI protocol suite. It was widely used in switching networks during the 1980s and early 1990s, for example as an alternative to circuit mode terminal switching, and for automated teller machines                                                                                                                                                                                                                 . Frame relay is a further development of X.25.