flapping router

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

flapping router
route flapping

   <networking> A {router} that transmits routing updates
   alternately advertising a destination network first via one
   route, then via a different route.

   Flapping routers are identified on more advanced {protocol
   analysers} such as the Network General (TM) Sniffer.

   (1999-08-24)