SLIP

SLIP is short for Serial Line Internet Protocol. It is a protocol for establishing a connection to Internet through a dial up connection. It is originally designed in the 1980s at a time when communication through modem was limited to 2400 bps. SLIP was designed for a simple communication over the serial lines.

SLIP can also be utilized on RS-232 serial ports. It also supports asynchronous links.

Point to POInt Protocol (PPP) is a more common protocol which is much more faster and reliable too. It supports functions which usually SLIP do not support.

Generally, the ISP’s (Internet Service Providers) offer merely one protocol although yet some support both of the protocols.