What Happens During Leased-Line Communications

On most types of leased lines, peers do not actually dial each other. Rather, a company purchases a leased-line service to explicitly connect between two fixed locations. Sometimes the two peers at either end of the leased line are at different physical locations of the same company. Another scenario is a company that sets up a router on a leased line that is connected to an ISP.

Leased lines are less commonly used than dial-up links, though the hardwired links are easier to set up. Hardwired links do not require chat scripts. Authentication is often not used because both peers are known to each other when a line is leased. After the two peers initiate PPP over the link, it stays active unless the leased line fails or either peer explicitly terminates the link.

A peer on a leased line that runs Solaris PPP 4.0 uses most of the same configuration files that define a dial-up link.

The following process occurs to initiate communication over the leased line:

1. Each peer machine runs the pppd command as part of the booting process or other administrative script.

2. The peers read their PPP configuration files.

3. The peers negotiate communications parameters.

4. An IP link is established.