RE: Chapter 46: preamble length
Hi Pat,
At 04:53 PM 03/28/2001 -0700, pat_thaler@agilent.com wrote:
>At 10 Gig, it would
>require deleting 3 characters of preamble and we decided it would be better
>to change the IPG and preserve the full preamble.
Lets keep it this way (allow IPG to shrink and preserve full preamble) and it helps.
Thanks,
Sanjeev
>
>Regards,
>Pat
>
>-----Original Message-----
>From: Sanjeev Mahalawat [mailto:sanjeev@cisco.com]
>Sent: Tuesday, March 27, 2001 6:08 PM
>To: Grow, Bob; 'Danielle Lemay'; stds-802-3-hssg@ieee.org
>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@nishansystems.com]
>>Sent: Monday, March 12, 2001 10:38 AM
>>To: stds-802-3-hssg@ieee.org
>>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@NishanSystems.com
>>408-519-3985
>>
>