Serial Line Internet Protocol (SLIP)

Serial Line Internet Protocol (SLIP) is a simple protocol that works with TCP/IP for communication over serial ports and routers. They provide communications between machines that were previously configured for direct communication with each other.

For example, a client may be connected to the Internet service provider (ISP) with a slower SLIP line. When a service is required, the client places a request to the ISP. The ISP responds to the request and passes it over to the Internet via high speed multiplexed lines. The ISP then sends the results back to the client via the SLIP lines.

SLIP was developed by Rick Adams in 1984. It is documented in RFC 1055.

SLIP Frame

SLIP frame has a very simple format, comprising of payload and a flag that acts as an end delimiter. The flag is generally a special character equivalent to decimal 192. If this flag is present in the data, then an escape sequence precedes it, so that the receiver does not consider it as the end of the frame.

Advantages of SLIP

• It has a very small overhead. So, it is suitable for usage in microcontrollers.

• It reuses the existing dial-up connections and telephone lines.

• It supports the most widely used protocol, Internet Protocol (IP). So, there is ease of deployment.