8.1 Frame Relay
8.1.1 What is Frame Relay?
Frame Relay is an International Telecommunication Union Telecommunication Standardization Sector (ITU-T; formerly the Consultative Committee for International Telegraph and Telephone [CCITT]) and American National Standards Institute (ANSI) standard that defines the process for sending data over a public data network (PDN). It is a connection-oriented, data-link technology that is streamlined to provide high performance and efficiency, as shown in the Figure. It relies on upper-layer protocols for error correction, and todays more dependable fiber and digital networks. It uses the services of many different physical-layer facilities at speeds that typically range from 56 Kbps up to 2 Mbps.

Note that Frame Relay defines the interconnection process between your customer premises equipment (CPE-also known as data terminal equipment [DTE]), such as a router, and the service provider’s local access-switching equipment (known as data communications equipment or data circuit-terminating equipment [DCE]). It does not define the way the data is transmitted within the service provider’s Frame Relay cloud.

Frame Relay differs significantly from X.25 in its functionality and format. In particular, Frame Relay is a more streamlined protocol. It does not have the windowing and retransmission strategies of X.25. This simplicity facilitates higher performance and greater efficiency that is appropriate for use over faster, less-error-prone networks. As a result, Frame Relay is appropriate for uses that require high throughput, such as LAN interconnection. The network providing the Frame Relay service can be either a carrier-provided public network or a network of privately owned equipment serving a single enterprise.