¶ … Frame Relay

is one of the oldest packet-switched services available. Common carriers initiated its development in the 1970s (x.25 overview). According to this source, the standard was developed to address a need for WAN protocols capable of providing connectivity across public data networks. The standard is current administered by ITU-T, a body that produces global telecommunication standards. Frame Relay was later developed to address the need for higher performance and greater transmission efficiency required for WAN applications, such as LAN interconnection, than x.25 offered (Frame relay). Although Frame Relay proposals were presented to the Consultative Committee on International Telephone and Telegraph (CCITT) in 1984, lack of standardization and interoperability slowed significant deployment until the 1990s (Frame Relay). Adoption was accelerated when Cisco, Digital Equipment Corporation, Northern Telecom and StrataCom formed a development consortium that extended the protocol with additional features for complex internetworking environments referred to as Local Management Interface (LMI) (Frame Relay).

There are three main differences between x.25 and Frame Relay (Frame Relay vs. x.25). First, x.24 performs packet switching on OSI Layer 3 while Frame Relay is strictly an OSI Layer 2 protocol (Frame Relay vs. x.25). This is what allows Frame Relay to offer more reliable connection services and a higher degree of reliability (Frame Relay). X.25's call control also involves more overhead than does Frame Relay because it uses the same virtual channel for connection establishment and release use in band-signaling for data transmission (Frame Relay vs. x.25). Frame Relay, on the other hand, has call control that uses separate virtual channels using the LMI protocol. Frame Relay reduces network overhead by implementing error checking rather than error correction (Frame Relay). This is attributable to the fact that Frame Relay was designed for use on links with error-rates lower than when X.25 was designed. Thus, X.25 routers have to acknowledge each frame and when there are frame errors frames the frames have to be retransmitted and acknowledged (Frame Relay vs. x.25).

Bibliography

Frame relay. http://www.cisco.com/en/U.S./docs/internetworking/technology/handbook/Frame-Relay.html#wp1020552

Frame Relay vs. X.25. http://www.synwiki.de/ban/HTML/P_LAYER2/Eng/P_lay264.html

x.25 overview. http://www.cisco.com/en/U.S./docs/internetworking/technology/handbook/X25.html