To: Mark_Sankey@3mail.3com.com
Cc: p8021@nic.hep.net
Subject: [Mark Sankey/US/3Com: gigabit enet and vlan]
Date: Sat, 13 Apr 1996 14:36:00 -0700
From: Mick Seaman <mjs@NSD.3Com.COM>


Mark,

Interesting question. My instinctive answer is NO (declaring support
of the VLAN spec should not be part of the autonegotiaition process):

    1. "Lower" layers should not attempt management/negotiation on
       behalf of "higher" layers unless there is a chicken-and-egg
       initial communication problem to be resolved. That should not
       occur here.

    2. If there were to be any negotiation that needed to take place
       for .1Q might be complex, is likely to be multi-party (for
       shared media), and is as yet completely undefined. It would not
       be wise (I believe) to bundle these in to .3z.

    3. I do not envisage any such basic negotiation taking place.
       There may be protocol to resolve/assign/associate IDs with
       VLANs but these should be part of continuous VLAN management
       not part of initial startup.

    4. Currently .1 believes that each VLAN will have a unique
       representation on a given segment (i.e. all frames for a given
       VLAN will be explicitly tagged OR all frames for that VLAN will
       be implictly tagged - just as sent/received without the
       addition of extra VLAN fields) but that different VLANs may
       have different representations on the same segment (the frames
       for one VLAN may be explicitly tagged - with the VLAN
       header/insert BUT frames for another VLAN may be implicitly
       tagged).

       This means that it is always possible to transmit a frame
       without a VLAN header which should be understandable by
       other bridges/switches on the same segment. Hence there is not
       a need for a VLAN or NOT VLAN decision at startup.

I'm forwarding this onto the 802.1 mailer to give other working group
members a chance to comment.

Mick


------- Forwarded Message

To: Mick Seaman/HQ/3Com <Mick_Seaman@hqmail.ops.3com.com>
From: Mark Sankey/US/3Com <Mark_Sankey@hqmail.ops.3com.com>
Date: 11 Apr 96 17:28:18 EDT
Subject: gigabit enet and vlan

Mick:

I am a new member of the 802.3z High Speed Study Group (Gigabit
Ethernet).  As my first task, I am to answer the following question:

Should declaring support of the proposed 802.1 VLAN spec be a part of the 
Autonegotiation process??

Any other impacts of 802.1 VLAN spec on the new gigabit spec that you
can think of???  (I know about the frame length impact).

Mark