Chapter 4: Frame Relay
Exam Objectives
Understanding Frame Relay WAN connections
Examining permanent and switched virtual circuits
Defining link status control and LMI
Controlling congestion using DE, FECN, and BECN
Introducing Frame Relay address resolution using Inverse ARP
Managing Frame Relay
Configuring Cisco interfaces using Frame Relay
Monitoring and troubleshooting Frame Relay
Configuring Frame Relay using the Cisco SDM GUI
Introducing Frame Relay
Frame Relay is an efficient, high-performance, Layer 2 packet-switched WAN technology that shares available bandwidth among users on a packet-switched network medium. Like Point-to-Point Protocol (PPP) and High-Level Data Link Control (HDLC), Frame Relay operates at the physical and data link layers of the OSI model and relies on upper-layer protocols to provide the mechanism for data error correction and flow control. For instance, TCP — not Frame Relay — is responsible for providing the error-checking functionality for IP-based packets. The Frame Relay protocol is also considered to be a replacement for network layer X.25 technology and was originally designed for use with Integrated Services Digital Networks (ISDNs). Today, Frame Relay is a widely popular standard used over a variety of network interfaces and is preferred to X.25 technology. It is a more streamlined, bandwidth-efficient method of connecting local-area networks (LANs) together via wide-area networks (WANs). Frame Relay also provides virtual circuit multiplexing ...
