CSLIP

from The Free On-line Dictionary of Computing (8 July 2008)

Compressed SLIP
CSLIP

   <networking> (CSLIP) {VanJacobsen TCP header compression}.  A
   version of {SLIP} using {compression}.  CSLIP has no effect on
   the data portion of the {packet} and has nothing to do with
   compression by {modem}.  It does reduce the {TCP} header from
   40 bytes to 7 bytes, a noticeable difference when doing
   {telnet} with lots of little packets.  CSLIP has no effect on
   UDP, only TCP.

   (1995-05-28)

from V.E.R.A. -- Virtual Entity of Relevant Acronyms (June 2006)

CSLIP
       Compressed [headers] Serial Line Internet Protocol (SLIP, IP)