Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!cs.utexas.edu!sun-barr!sun!imagen!atari!portal!cup.portal.com!John_Robert_Breeden
From: John_Robert_Breeden@cup.portal.com
Newsgroups: comp.dcom.lans
Subject: Re: Starlan/Ethernet compatibility
Message-ID: <19449@cup.portal.com>
Date: 14 Jun 89 00:55:03 GMT
References: <2009@wasatch.utah.edu>
Organization: The Portal System (TM)
Lines: 57

>We're in the market for Ethernet over twisted pair products.  The
>guys from AT&T want to sell us Starlan-10 (surprise!) but I have a few
>questions about compatibility with Ethernet in general and 10BASET in
>particular:
>
>1) Are there any compatibility issues that arise if I use existing
>   Ethernet interfaces through AT&T's AUI adapters into Starlan hubs?
>
No, you should have no problem (you need an AUI port on your ethernet
interface).
 
>2) How big are the differences between Starlan and the forthcoming 10BASET,
>   ie. if I buy a Starlan now, how well will it interoperate with the
>   Brand X 10BASET products I buy next year?
>
 
 
As long as the OTHER vendors are 10baseT compatable (see note below), they
will interoperate. As a matter of fact, two other vendors besides AT&T
conform to the March '88 10baseT draft, Hewlett Packard and Ungermann Bass
and you can mix and match the three vendors' HUBS, AUI's and NICs (AT&T by
far is the least expensive of the three).
 
NOTE: AT&T, HP and UB where the only three 10baseT draft compliant vendors
as of the 1988 summer draft. At the December meeting, a new feature was
proposed but not included in the draft (it is expected to be included in the
draft when the IEEE meets this summer) and that's the"link status" packet,
it tells the network that the device is there and up. It is expected that
the draft will become a standard in the first quarter of 1990 - what this
means is that the major parts of the protocol is for all intents and
purposes set in concrete ie; there won't be any major changes in the draft
that would make either AT&T, HP or UP non-compatable with the standard.
 
What about the "status packet"? No vendor today supports it (it's not even
in the draft yet). But if it becomes part of the draft, AT&T, HP, and UB
will produce product that support it. Does this mean that anything I have
prior to the new product goes out the window - the fork lift upgrade to make
it work? No - that's the issue between compliant and compatable. A vendor
could support the "link status" packet and have a switch on a hub's port
to turn the packet OFF - then anything downstream could be a 10baseT
product that doesn't support "link status" - ie: not 100% compliant with
the standard, but 100% compatable  (one must remember that "link
status" is'nt required to make the ethernet function - it's really a
management issue).
 
The bottom line is that you can mix and match products from different
vendors today and tomorrow, you're not stuck with a single vendor's
proprietary solution - like Cabletron or Synoptics (that should ruffle
some feathers).
 
 
>Thanks in advance for any information.

>Walt Hass

"I'm prejudice because it's true"
John Breeden - uunet!john_robert_breeden@portal.com