Virtual Networks

You can use PPP to set up a virtual network wherein the modems, PPP software, and telephone wires become the "virtual" network media. In a physical network, such as Ethernet or Token Ring, computers are directly cabled to the network media. In a virtual network, no true network media exist.

Machines become peer hosts on the virtual network when you configure each with a multipoint communications link. Then each host can dial out through its modem over phone lines to reach another endpoint machine. Each computer also functions as a dial-in machine, permitting its peer hosts on the virtual network to dial in to it.

Figure 7-5 depicts a virtual network consisting of nomadic computers connected to each other through modems and telephone lines.

Figure 7-5 Virtual Network of Nomadic Computers

Each machine exists in a different office, perhaps in a different town from other members of the virtual network. However, each machine can establish communications with its peer hosts over its multipoint communications links.