EXCELAN TCIP

[Milo Medin]

Well, the excelan product may be ok for your particular set-up, but
its given us here a real haedache.  The problem is, (at least with our
version of the software) that the Excelan IP doesn't know about
internet routing!  Now, if you have everything hooked on a single
cable, this won't bother you, but if you'd like to use a gateway
to talk to something like the MILNET, you lose big.  At least the
present version of software doesn't crash the machine when it got something
from an address it didn't know about like older versions did (specifically
for the IRIS workstation).  It prints a message on the console saying that
it doesnt know who the other guy is and ignores the packet.
This is true for intel boards on 310 systems and hypercubes, SGI
IRIS workstations, and IBM PC's.  I don't know about VMS but I'd
suspect its the same way there.  

Also, some other folks here at Ames used the boards over a sky link
between 2 vitalink boxes and discovered that the TCP on the board
only lets one packet or so be outstanding without an ack, now
this isn't too bad on direct ether links, but over satellite
links you get massacred by the long transit time.  You'd probably
notice this too on the MILNET, but since you can't use gateways
anyway, it probably doesn't matter.

I know CMC makes these type of boards too, but I'm not sure that
they do routing either.  If you folks who build these things
are out there, PLEASE FIX THIS PROBLEM!  Even the ability
to use a default route and do the rest with ICMP redirects would
be decent.  Its really not that hard to do.

$Flame on$

I really get tired of people making silly mistakes like this when
there are so many examples of how to do it right around.  Many
people just don't want to learn from the experiences of the
arpanet people.  I had some folks over from Intel awhile ago
peddling their ISO wares, and I asked them, "Do you handle internet
routing?"  They didn't know what I was talking about.  I had to 
explain to them what a gateway was and what it did, and the reason why
you need gateways in the first place.  I am very pessimistic about
how interoperable these ISO products are going to be when you have
a bunch of amateurs building all this stuff.  Oh well, at least
we have something that works.

$Flame off$

				Milo Medin
				NASA Ames Research Center