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RE: [RPRWG] Destination Address of RPR control messages


Beg to differ. Zero is "officially" owned by Xerox,
although commonly used by other standards to represent
a NULL value.

Check it out at:

However, there is an pending action request to the
IEEE from its MSC committee to make zero a NULL value.


David V. James, PhD
Chief Architect
Network Processing Solutions
Data Communications Division
Cypress Semiconductor, Bldg #3
3901 North First Street
San Jose, CA 95134-1599
Work: +1.408.545.7560
Cell: +1.650.954.6906
Fax:  +1.408.456.1962
Work: djz@xxxxxxxxxxx
Base: dvj@xxxxxxxxxxxx

> -----Original Message-----
> From: owner-stds-802-17@xxxxxxxxxxxxxxxxxx
> [mailto:owner-stds-802-17@xxxxxxxxxxxxxxxxxx]On Behalf Of Tom Alexander
> Sent: Thursday, May 30, 2002 12:15 PM
> To: 'Anoop Ghanwani'; 'stds-802-17@xxxxxxxx'
> Subject: RE: [RPRWG] Destination Address of RPR control messages
> I believe there was some discussion on this topic in relation
> to a comment at the last meeting. The point was brought up that
> all-zeros is an illegal value for a MAC address. Essentially,
> an all-zeros address is a globally-administered (universal)
> address, for which an OUI must have been supplied by the IEEE
> Registration Authority. To the best of my knowledge, no OUI
> of all-zeros has been issued. Unless P802.17 wishes to request
> the Registration Authority to issue them the all-zeros OUI,
> use of an all-zeros MAC address is illegal.
> Best regards,
> - Tom Alexander
> Chief Editor, P802.17
> -----Original Message-----
> From: Anoop Ghanwani [mailto:anoop@xxxxxxxxxxxxxx]
> Sent: Thursday, May 30, 2002 11:30 AM
> To: 'stds-802-17@xxxxxxxx'
> Subject: [RPRWG] Destination Address of RPR control messages
> According to Clause 8 in D0.2, the destination address
> is set to "all zeros" for hop-by-hop control packets,
> and "all ones" for broadcast control packets.
> Other IEEE 802 MACs use reserved multicast addresses to
> identify MAC control frames.  For example, IEEE 802.3
> flow control frames are sent with a destination address 
> of 01-80-C2-00-00-01.  These frames are only sent on
> full-duplex Ethernet links and must not be forwarded
> by the MAC.
> Is there any reason for deviating from the standard
> practice?
> -Anoop
> --
> Anoop Ghanwani - Lantern Communications - 408-521-6707