[comp.dcom.lans] 802.3 vs ethernet

storm@nas.nasa.gov (Steve Storm) (06/21/91)

I have been asked some questions about my machines that I have
no answer for.  Maybe some kind soul out there can give me some
info about this or some pointers to info.

The issue concerns 802.3 and ethernet packets.  Recently, we tried 
bring up some machines at a remote site and among the other confusions
of a new site, we found that their hosts were talking 802.3 only.
Some of our hosts didn't understand at all.  Others seemed to understand
the 802.3, but insisted on replying in ethernet mode.  The answer we
came up with was to have the remote hosts switch to ethernet.  (Which
took them a while since they weren't too knowledgeable about their
systems.)

The point that was brought up is...they shouldn't have to do that.
In the best of all possible worlds, we should be able to reply in
the same dialect that we receive.  If a host starts up in 802.3,
we should answer in 802.3.  If the host starts talking to us in ethernet,
we can reply in ethernet.  If our host starts the conversation our
host gets to choose.  One of my questions is...is this unreasonable?
Does this exist anywhere?

Another question is, which hosts actually support 802.3 packets?
How can I tell?  How do I test this?  Anybody got any clues.

I'll gice you one thing I have found that is amusing.  One of our
machine types is SGI workstations.  Checking the docs reveals this
information.  Yes, their chip set understands 802.3.  No, their software
doesn't understand 802.3.  Where does this leave me?  (Waiting for the
next release, that's where.)

If anyone can get me anywhere on this little puzzle, I offer my
heartfelt gratitude and appreciation.  (In other words, thanks
in advance!)

-storm

-- 

As we endure storms,     |  storm@smaug.nas.nasa.gov
So we receive rainbows.  |  (415) 604-4334

DISCLAIMER:  Even my wife doesn't agree with everything I
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nearly as much as she does.  Draw your own conclusions.

rpw3@rigden.wpd.sgi.com (Rob Warnock) (06/22/91)

In article <1991Jun21.162957.24583@nas.nasa.gov> storm@nas.nasa.gov
(Steve Storm) writes:
+---------------
| I'll gice you one thing I have found that is amusing.  One of our
| machine types is SGI workstations.  Checking the docs reveals this
| information.  Yes, their chip set understands 802.3.  No, their software
| doesn't understand 802.3.  Where does this leave me?  (Waiting for the
| next release, that's where.)
+---------------

As far as I know, we have no plans for *ever* talking 802.3-style TCP, in
the next release or any other. The 802.2 SAP for TCP was deprecated at the
first TCP/IP Interoperability Conference, and anyone who is still using
it is out of step, not us. We use Ethernet encapuslation on Ethernets, and
RFC 1103 802.2/SNAP/"Ethernet" encapsulation on FDDI.

Obviously, if we were to offer an ISO protocol product at some point, it
would use 802.3 encapsulation for the ISO packets [with the appropriate 802.2
SAP(s)]. But TCP would continue to use Ethernet encapsulation.


-Rob

-----
Rob Warnock, MS-1L/515		rpw3@sgi.com		rpw3@pei.com
Silicon Graphics, Inc.		(415)335-1673		Protocol Engines, Inc.
2011 N. Shoreline Blvd.
Mountain View, CA  94039-7311