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Path: utzoo!henry
From: henry@utzoo.UUCP (Henry Spencer)
Newsgroups: comp.dcom.lans
Subject: Re: Smart Ethernet boards
Message-ID: <8212@utzoo.UUCP>
Date: Sat, 27-Jun-87 22:08:29 EDT
Article-I.D.: utzoo.8212
Posted: Sat Jun 27 22:08:29 1987
Date-Received: Sat, 27-Jun-87 22:08:29 EDT
References: <283@sering.cwi.nl>
Organization: U of Toronto Zoology
Lines: 32

> WE want to know about experiences with "smart" Ethernet boards, like
> the Interlan (Micom) NP100 or the Excelan Exos 204.

I have no direct experience with these things, but I asked a similar
question a while ago; perhaps a quick summary of the replies I got will
suffice for this one.

The general consensus was that, barring the special situation of a dumb
operating system which cannot be fitted with its own networking code,
the benefits of "smart" boards are doubtful.  Those boards usually use
relatively poor processors, e.g. the 80186, which are quite slow compared
to the host.  The overhead of communicating with the smart board can be
quite high, to the point where it approaches the overhead of running the
simpler protocols in the host itself.  The protocol implementations
supplied for the smart board are usually rather bare-bones versions and
often have bugs.  Provisions for gatewaying and internetworking are rare.
You don't get sources, or the cross-compilation system you would need to
make use of them.  Finally, if you are running non-standard protocols as
well as standard ones, the board will have to just pass the non-standard
stuff through to the host, and the smart boards often don't do this very
well (i.e., expect poor performance).

In general, the idea seems good but the practical realizations tend to be
pretty poor.  They can work okay in simple situations, but they are unsuited
to complex networks, and even in simple cases their throughput is often
inferior to that of simple interfaces plus networking code in the host.
Try (and measure) before buying.  Insist on getting sources and the software
needed to use them.  Don't expect too much unless you're willing to add it
yourself.
-- 
Mars must wait -- we have un-         Henry Spencer @ U of Toronto Zoology
finished business on the Moon.     {allegra,ihnp4,decvax,pyramid}!utzoo!henry