raffic often represents variable delays across the network. It is a data-link layer approach around 80% of a network's capacity while data is only about 20%. (level 2 of OSI) and as such depends on the end systems supporting However, many data applications are growing at 30% to 40% per the Frame Relay protocol. These properties make Frame Relay best year, while voice applications are growing at only 5%. This change suited to non-delay-sensitive information transfer, such as data in focus means that a communications network must meet today's communications or still image. heavy voice demands, yet be able to adapt to increasing data Cell Relay on the other hand uses a fixed length frame or packet demands. For example, with the introduction of Local Area Net- to carry information, and as such does not create variable delays work (LAN) applications and ever more powerful client/server across the network. It is a physical layer approach and consequently workstations, the large amounts of data which must be transferred is protocol independent. These properties make Cell Relay suitable will become a critical issue in a company's overall communications for transfer of delay sensitive information such as live speech. network. Fast Packet Switching is sometimes regarded as similar to CCITT X.25 packet switching, but the two techniques must not be con- Frame Relay fused, despite having a common name. Both methods take trans- missions from user devices, partition them into packets and route CCITT recommendation I.122 'Framework for providing addi- them over a backbone of network switches until they arrive at the tional Packet Mode Bearer Services', describes the architectural right destination. However, due to its protocol transparent nature a framework for two types of Frame Relay service. The frames are Fast Packet Switch (FPS) approach uses technology which can based on Recommendation 1.441. Frame Relay is proving to be the CONCEPT: FAST PACKET SWITCHING FRAME TECHNOLOGY: RELAY RELAY Q 931 IEE 802.6 STANDARDS: (PVC) (SVC)