ABSTRACT
X.25 is often regarded as the forerunner of frame relay. It is a communications packet switching protocol designed for the exchange of data over a wide area network (WAN). X.25 was designed to provide error-free delivery using high-error-rate links. It was developed when analog transmission and copper media were the predominant technologies. Frame relay takes advantage of the new, lower-error-rate links made of optical fiber, enabling it to eliminate many of the services provided by X.25. The elimination of functions and fields, combined with digital links, enables frame relay to operate at speeds 20 times greater than X.25. In frame relay, frames are switched to their destination with only a few byte times’ delay, as opposed to several hundred milliseconds’ delay on X.25.
