Two Networks Connected by Point-to-Point Link

You can use PPP to connect two separate networks through a point-to-point link, with one system on each network serving as an endpoint. These endpoints communicate through modems and phone lines, essentially in the same fashion as shown in Figure 21-1. But in this setup, the endpoints, modems, and PPP software become routers for their physical networks. Using this type of configuration scheme, you can create an internetwork with wide geographic reach.

The following figure shows two networks in different locations connected by a point-to-point link.

Figure 21-3 Two Networks Connected by a PPP Link

In this example, endpoints A and B, their modems, public telephone lines, and the PPP software act as a router between the networks. These networks might have other hosts serving as routers between physical networks. Sometimes, the host functioning as the PPP router might have an additional network interface board, thus also serving as a router for a physical network.