SLIP

1.The IP datagram is terminated by the special character called END (0xc0)

  Also,to prevent any line noise before this datagram from being

  interpreted as part of this datagram ,most implementation transmit an 

  END character at the beginning of the datagram too .(If there was some

  line noise ,this END terminated that erroneous datagram ,allowing the

  current datagram to be transmitted.That erroneous datagram will be

  thrown away by a higher layer when its contents are detected to be

  garbage) .

2.If a byte of the IP datagram equals the END character,the 2-byte

  sequence 0xdb ,0xdc is transmitted instead.This special character ,0xdb

  is called the SLIP ESC character ,but its value is different from the

  ASCII ESC character(0x1b) .

3.If a byte of the IP datagram equals the SLIP ESC character ,the 2-byte

  sequence 0xdb ,0xdd is transmitted instead .