From: gregh@cserver.plexus.com (Greg Hawley)
Newsgroups: comp.dcom.lans,comp.realtime
Subject: Embedded Systems Networking Systems
Summary: Request for Information on Embedded Systems Networks
Keywords: Echelon, LonWorks, Networks, X.25
Date: 26 Aug 92 14:59:46 GMT
Article-I.D.: cserver.gregh.714841186
Organization: Plexus Corp. -- Neenah Wisconsin


Maybe the net can help us...

OVERVIEW
--------

We am evaluating third-party network hardware and software 
for an embedded systems application.  While many systems are
on the market for embedded system operating systems, we have 
seen precious little about over-the-counter embedded system
interconnection products.

Many of the protocols today are designed for moving as much
information from point A to point B with only secondary
concern for unit cost.  Their primary purpose is 
high-speed communications.  Typically these systems cost
more than our application can absorb and are not suitable
for embedded systems.  During my days in college I was 
happy to get a low-end ethernet card for $150.  This was 
good for a PC, but for the applications we are involved in, 
this is too expensive.  Ethernet also provides far more 
transmission capacity than we need.  

By purchasing a third-party product we hope to reduce the 
development time of interconnecting several systems.  We 
don't however wish to lock ourselves into a proprietary
third-party system.  We have the ability to build our own
system; we just don't have the budget.

CRITERIA
--------

In choosing a networking product we have the following 
criteria. 

    1. Reliability is a larger concern than speed.
       A system with sustained throughput of 10 kbps would
       be adequate.
    2. An open protocol is desired.  
    3. Support less than 100 nodes (but more than *2*).  
       No internetworking capability is necessary.
    4. Distributed control of network is preferable.
       No single node should control the network's
       operation.
    5. Must have industrial environment capability.
       This includes wide temperature range, high
       electrical noise resistance, etc.
    6. Wire or fiber media are acceptable.


QUESTIONS
---------

1.  We have spent some time reading the literature from Echelon 
    about their LONWorks product.  Aside from Echelon's products, 
    what other companies are competing for the market?  What 
    advantages or disadvantages do other company's products have?
    We have heard very little about any competition.  Does anyone
    have experience with the Echelon Neuron chip?

2.  Is there any reason we should constrain ourselves to a wire media?
    Has fiber proven itself in industrial situations?

3.  Are there open standards (IEEE, etc.) that exist for protocols
    like what we am looking for.  Have third party's developed
    implementations of these protocols?  All of the standards we
    have seen are for high capacity systems.  What about lower
    speed stuff.  What we are really looking for is a multi-drop
    X.25/HDLC protocol.  We think.  

4.  Are there are other questions we should be asking?  Are there
    any general comments we should hear?  Are we on the right track?

---Greg

+---------------------------+----------------------------+-----------------+
|  __     __          ___   |  Greg Hawley               |  Expressed      |
| /  \|  /   \ / |  | \     |  Technology Group Inc.     |  Opinions are   |
| +--/|  +--  X  |  |  \    |  55 Jewelers Park Drive    |  mine and not   |
| |   \__\__ / \ \__/ __\   |  Neenah WI 54956           |  of Technology  |
|                           |  gregh@cserver.plexus.com  |  Group Inc. or  |
|  Technology Group Inc.    |  414-722-8748              |  Plexus Corp.   |
+---------------------------+----------------------------+-----------------+
Newsgroups: comp.dcom.lans,comp.sys.dec,comp.dcom.lans.ethernet