Re: on-/off-board protocol processing


Wayne Hathaway (ultra!petruchio!wayne@ames.arc.nasa.gov)
Thu, 24 Mar 88 08:47:01 PST


One problem with offloading protocols which has not yet been mentioned
has to do with the "locked-up" nature of commercial on-board protocol
implementations. A specific example from a place I used to be
associated with: They used intelligent Ethernet cards (brand name
irrelevant) quite successfully -- until they extended their Ethernet
to the East Coast with a satellite link. Needless to say, the
on-board Ethernet software was hardly tuned to the extra delay, and
the throughput was abysmal. But since the on-board software was
proprietary there was nothing the host administrator could do, and
while the card manufacturer was sympathetic, tuning his software for
such a "strange" environment was very low priority. The solution?
The satellite link was replaced with a slower (bandwidth) but faster
(throughput) land line!

Of course, this is nothing unique to network protocols; any
"intelligent controller" could have the same problem. In the case of
something like a disk controller, however, one is considerably less
likely to suddenly add some 40,000 miles to the length of the cable!

      Wayne Hathaway ultra!wayne@Ames.ARPA
      Ultra Network Technologies
      2140 Bering drive with a domain server:
      San Jose, CA 95131 wayne@Ultra.COM



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