2.8 PPP and SLIP Architecture

The PPP architecture has been redesigned in the ChorusOS 4.0 operating system, making its use and operation much closer to that used in BSD UNIX. There is no longer a specific API to dynamically manage serial lines as there was in the ChorusOS 3.2 operating system.

The IOM actor now includes standard tty line discipline functionalities, as well as support for pseudo ttys, which are devices that are not associated with any real hardware. They are used to simulate the functions of a real tty. A tty line can be opened in raw mode, then switched to PPP or SLIP line discipline using standard ioctl() calls. This is used by the PPP or SLIP daemon to configure the serial line for the PPP or SLIP protocol.

The ChorusOS 4.0 PPP daemon is an improved version of the BSD daemon, which is able to handle multiple serial lines by assigning a separate thread to each one. All the usual PPP functions, including dial-up on demand, are supported through the pppd options.

The PPP API is provided by the actor pppstart and three C_INIT commands, pppd, pppstop, and pppclose. See the pppstart(1M), pppd(1M), pppstop(1M), and the pppclose(1M) man pages, and "Setting Up PPP" in ChorusOS 4.0 Network Administration Guide for more information.