🚀 go-pugleaf

From article <32y8PB1w164w@Control.Com>, by ics.ralph@Control.Com (Ralph Mackiewicz):
> In response to Ran (atkinson@itd.nrl.navy.mil):
> The simple truth is:  MMS is currently the only non-
> proprietary device to computer networking protocol that has been implmented
> in any commercially available products.  It is in use today.  It works.
> And it uses OSI technology.  This last fact doesn't make MMS useless. It
> just makes it harder to sell because uninformed people will assume that 
> just because TCP/IP, Novell, Banyan, etc. do a better job at file transfer,
> E-Mail, etc. than OSI, then TCP/IP must also do a better job for reading
> and writing variables in a controller, uploading and downloading programs
> in a controller and reporting device faults....and this is not true.

Why isn't it true? I don't understand this logic.

Let's not mix apples and oranges. MMS is an _application_ level
protocol, like FTP, telnet or FTAM, whereas TCP/IP is a _transport_ and
_network_ level protocol. I don't see why TCP/IP can't be used instead
of OSI layers for MMS. If TCP/IP is smaller, faster and lower weight
than OSI, it seems to me that it is *better* for real time device
control.

I agree that no other standard protocol
exists at the application layer that does what MMS does, and one reason
why is that MMS suffers from kitchen-sink syndrome. It may work, but
the cost in resources is pretty horrendous. It takes a lot of memory
and processing power to support a full OSI stack, whereas I can
run my TCP/IP stack on an embedded system in 40 Kb of memory on a
7 Megahertz 68000 (and that's using what some people believe is the
bloated BSD code) over 802.4 token bus and still get tens or hundreds
of Kbytes throughput.

> If anyone other than my company would commit to supporting MMS over TCP/IP
> using RFC 1006, only then would TCP/IP become a viable alternative to OSI
> for performing these device communications functions in a non-proprietary
> manner.

Standardisation by fiat can fail miserably; IMHO MAP/MMS is a classic
committee designed solution that was frozen prematurely. I believe
protocols should evolve and reach maturity *before* they become
standards.

> Ralph Mackiewicz, SISCO Inc.
> 2943439@mcimail.com or ics.ralph@ics.org

Interesting discussion. These are difficult issues.

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