If Two Sites Are Good, Three (or More) Must Be Better

If Two Sites Are Good, Three (or More) Must Be Better

Although you might have found the past few pages fascinating, the real advantage that Frame Relay holds over leased lines isn't obvious until you see an example with at least three Frame Relay sites. With Frame Relay, a router can use its single physical access link to forward traffic to multiple remote routers. If you're hanging with me on the analogy with Ethernet switches, that's an easy concept because the same thing happens with Ethernet. With Ethernet, a PC sends frames with varying destinations, over the one Ethernet cable that connects it to the LAN switch, and the LAN switch forwards the frames based on the destination MAC address. With Frame Relay, the same thing happens, except the Frame Relay switch forwards the frames based on the DLCI. Figure 15-3 shows the basic concept.