RE: Clause 46 - Preamble
By removing the restriction of preamble size the standard would come close
to reality. I am doubtful if after 10Base2/5 anyone designed a MAC which
all seven octets of preamble.
90 Great Oaks Blvd #206
San Jose, Ca 95119
> -----Original Message-----
> From: owner-stds-802-3-hssg@xxxxxxxx
> [mailto:owner-stds-802-3-hssg@xxxxxxxx]On Behalf Of Sanjeev Mahalawat
> Sent: Friday, February 16, 2001 11:44 AM
> To: Grow, Bob; 'Gareth Edwards'; HSSG
> Subject: RE: Clause 46 - Preamble
> Hi Bob,
> At 10:36 AM 02/16/2001 -0800, Grow, Bob wrote:
> >There is nothing that a conforming implementation with the
> current PHY types
> >will do to change the preamble length, but why add an unnecessary
> >restriction to eliminate future options.
> I would think keeping an option to change the preamble size
> by a PHY may lead to confusion and PHY/RS/MAC un-interoperable
> implementations. It is not a restriction but an explicit specification
> that would keep all the PHYs and RS implementations STANDARD.
> >--Bob Grow
> >-----Original Message-----
> >From: Gareth Edwards [mailto:Gareth.Edwards@xxxxxxxxxx]
> >Sent: Friday, February 16, 2001 7:56 AM
> >To: HSSG
> >Subject: Clause 46 - Preamble
> >Afternoon all,
> >Shimon raised a comment against D2.0 SC 22.214.171.124 (#252) asking for the
> >removal of the requirement that the preamble be a fixed length on
> >receive; this was accepted in principle. However, I seem to remember in
> >the discussion on this comment at Irvine that there was agreement that
> >the Start control code and SFD couldn't appear in the same RXD column;
> >there would be one or more clock edges between the Start code and SFD.
> >The new text (in D2.1 SC 126.96.36.199) does not explicitly rule in or out
> >the appearance of the SFD in the same column as the Start code; this is
> >consistent with Shimon's original suggested remedy.
> >Is this something that has slipped through the rewrite or has False
> >Memory Syndrome struck again?
> >/ /\/\ Gareth Edwards mailto:gareth.edwards@xxxxxxxxxx
> >\ \ / Design Engineer
> >/ / \ System Logic & Networking Phone: +44 131 666 2600 x234
> >\_\/\/ Xilinx Scotland Fax: +44 131 666 0222