best effort

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

best effort

   <networking> A classification of low priority network traffic,
   used especially the {Internet}.

   Different kinds of traffic have different priorities.
   {Videoconferencing} and other types of {real-time}
   communication, for example, require a certain minimum
   guaranteed {bandwidth} and {latency} and so must be given a
   high priority.  {Electronic mail}, on the other hand, can
   tolerate an arbitrarily long delay and is classified as a
   "best-effort" service.

   [Scientific American, Nov. 1994, pp. 83-84].

   (1995-04-04)