Chapter 12 – Frame Relay
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Publisher Summary
The chapter examines various concepts related to frame relay from both conceptual and technical perspectives. Frame relay has emerged as a popular and robust standalone technology. It is a public, wide area networks (WAN) packet-switching protocol that provides LAN-to-LAN connectivity. It relays frames across a network between two sites. Frame relay is economical and efficient and provides a single point of network access for multiple LAN-to-LAN connections. This feature offers considerable savings on local loop charges. Frame relay also can be implemented using existing bridges or routers. Prior to frame relay's development, dedicated leased lines using point-to-point protocols or X.25 primarily interconnected local area networks (LANs). This design was acceptable if only one or two LANs required interconnectivity. However, as internetworking became more prevalent, multi-port routers were needed to provide multi-LAN connectivity, and additional dedicated leased lines had to be installed. LAN-to-LAN connectivity became a more expensive endeavor with the addition of each dedicated circuit. These costs were further escalated, and the network design became more complex, when a partially or fully meshed network design was needed. In addition, unlike traditional private leased line service, frame relay's circuit costs are not distance based and the circuits themselves do not necessarily have to be permanent. This led to frame relay being offered and further developed as a separate protocol.