RE: Chapter 46: preamble length
I think Sanjiv has very good point. It is regressive to go back and make
preamble open
for PHY layers. After we have entered in continuous transmission mode (idle
or data),
I do not see any reasoning of allowing "option" in preamble field.
Regards,
Devendra Tripathi
VidyaWeb, Inc
90 Great Oaks Blvd #206
San Jose, Ca 95119
Tel: (408)226-6800,
Direct: (408)363-2375
Fax: (408)226-6862
> -----Original Message-----
> From: owner-stds-802-3-hssg@xxxxxxxx
> [mailto:owner-stds-802-3-hssg@xxxxxxxx]On Behalf Of Sanjeev Mahalawat
> Sent: Tuesday, March 27, 2001 6:08 PM
> To: Grow, Bob; 'Danielle Lemay'; stds-802-3-hssg@xxxxxxxx
> Subject: RE: Chapter 46: preamble length
>
>
>
> Hi Bob,
>
> At 02:21 PM 03/27/2001 -0800, Grow, Bob wrote:
> >
> >On transmit, a conforming implementation will send seven
> preamble plus the
> >SFD.
> >
> >On receive, there is no current function that will change that
> length, but
> >the concensus of the committee was to keep the option open. (In
> 802.3z we
> >did change preamble length for idle alignment.) The D3.0 text
> should make
> >it clear that an implementation should be tolerant to changes in preamble
> >length, though it can still rely on lane alignment (Start in
> lane 0, SFD in
> >lane 3). Text was added to warn that the Start and SFD could
> appear in the
> >same column.
>
> What is the reasoning behind letting a layer lower than
> MAC to touch the preamble?
>
> Since preamble is coded as data it belongs to MAC
> and no lower layer should be allowed to change
> and/or remove the length of preamble.
>
> Thanks,
> Sanjeev
>
>
> >
> >--Bob Grow
> >
> >-----Original Message-----
> >From: Danielle Lemay [mailto:dlemay@xxxxxxxxxxxxxxxxx]
> >Sent: Monday, March 12, 2001 10:38 AM
> >To: stds-802-3-hssg@xxxxxxxx
> >Subject: Chapter 46: preamble length
> >
> >
> >
> >
> >
> >Is it possible for the preamble+SFD to be less than 8 bytes ?
> >
> >thanks,
> >Danielle
> >
> >
> >
> >*******************************************
> >Danielle Lemay
> >Design Engineer, Nishan Systems
> >dlemay@xxxxxxxxxxxxxxxxx
> >408-519-3985
> >
>