Frame Relayy

The Frame Relay protocol is quite simple compared to X.25 because the error correction functions
have been removed. This enables the protocol to scale up to 45Mbps in currently available
offerings, although this is more a practical limit than a technology-based one. The greatest benefit
of Frame Relay is its availability and its low cost over long distances at high bandwidths.
The protocol itself is used to define virtual circuits, which adds an additional benefit to
Frame Relay: a single physical port can terminate numerous logical virtual circuits. This can
greatly reduce the hardware costs associated with an installation. Each virtual circuit is defined
with a DLCI.

Frame Relay is formally presented in Chapter 29, but in the context of this chapter, the protocols
of this international standard should be noted. The specifics of the protocol are defined
in the following standards:
 ANSI T1.617
 ITU-T Q.933
 ITU-T Q.922