Frame Relay

One of the most popular WAN technologies is Frame Relay. Technology improvements and support for Frame Relay has made this WAN technology as prevalent as ATM and its use is growing. Frame Relay is being used to connect remote offices to extend the LAN and replace dial-up connections. Because Frame Relay is cost-effective and because you pay for your usage of the bandwidth, people use the Frame Relay network to deliver services such as the Internet to remote offices.

Figure 5-4 shows an example of a network that uses a Frame Relay WAN for connection to remote offices. Note that the Frame Relay network is portrayed as a cloud. The cloud is used to illustrate a network that does not use the same path between two end points. That means that the packets between the remote offices and the corporate network will most likely take different paths within the Frame Relay network.

Frame Relay is a common WAN solution for small to medium businesses because of its lower costs and scalability. Frame Relay uses a method called packet switching to transport data and operates on Layers 1 and 2 of the OSI model. Packet switching takes data and formats it into small chunks, called packets or frames, which allows you to transport different data packets over the same physical data path. A main difference between X.25 technology and Frame Relay is latency and overhead. X.25 technology assumes that the physical line is unreliable and therefore X.25 uses error checking, whereas Frame Relay does not, thereby achieving greater speeds with minimal latency.

More information on Frame Relay can be found in the section "Provisioning a Frame Relay Network" later in this chapter.

Figure 5-4 Using A Frame Relay Network to Connect Remote Offices

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