IGP

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

Interior Gateway Protocol
IGP

   (IGP) An {Internet} {protocol} which distributes {routing}
   information to the {routers} within an {autonomous system}.
   The term "{gateway}" is historical, "router" is currently the
   preferred term.

   See also {Exterior Gateway Protocol}, {Open Shortest Path
   First}, {Routing Information Protocol}.

   (1994-11-09)

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

IGP
       Integrated Graphics Processor (IC, Nvidia)

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

IGP
       Interior Gateway Protocol