Dial-in Server With Dynamic Point-to-Point Link

The endpoint machine on the network shown in Figure 7-2 functions as a dial-in server with dynamic point-to-point links. It is called a dial-in server because remote machines can dial in to it to reach the network. When the server receives a request to dial in from a machine, the server allocates the PPP link to the machine on an as-needed basis.

A dial-in server can communicate with the remote hosts through a dynamic point-to-point link or through a multipoint link, as explained in "Multipoint Communications Links". The dynamic point-to-point link has the advantages of point-to-point communications: RIP can run over the link, and broadcasting is enabled. Perhaps most importantly, more than one machine on the physical network can function as the dial-in server. This allows you to configure backup servers, thus enabling redundancy and easier administration. Although the machines in Figure 7-2 can directly communicate with the network endpoint, they cannot directly communicate with each other. They must pass information to each other through the dial-in server endpoint.