Re: Chapter 46: preamble length
Hi Ben,
At 01:00 PM 03/29/2001 -0500, Ben Brown wrote:
>I think this same idea exists in 10G. No implementation should
>ever remove any bytes of preamble so a MAC designed to expect no
>fewer than 8 (or even exactly 8) should be fine. If it stops working
>because someone else's PHY removes bytes of preamble, than it should
>be easy to show that PHY is non compliant.
I completely agree with you.
Thanks,
Sanjeev
>
>>
>> As for where in the draft, I don't think there is any text that directly
>> tells you how to do preamble shrinkage. There is text that describes the
>> occurrence of preamble shrinkage (hence this thread). Another question
>> would be: is there any text in the draft that strictly forbids preamble
>> shrinkage?
>
>There is also no text in the draft that says a PHY can't perform
>clock tolerance by discarding data from the packet. However, a PHY
>that did so, even if it corrected the CRC somehow, would immediately
>be considered non compliant. The way we're handling preamble in
>these PHYs is identical to the way we're handling data. It should
>never be touched. Therefore, a MAC designed to only expect 8
>bytes of preamble should never be deemed non compliant.
>
>Regards,
>Ben
>
>>
>> Cheers,
>> Brad
>>
>> -----Original Message-----
>> From: Ben Brown [mailto:bbrown@xxxxxxxx]
>> Sent: Wednesday, March 28, 2001 10:44 PM
>> To: stds-802-3-hssg@xxxxxxxx
>> Subject: Re: Chapter 46: preamble length
>>
>> Brad,
>>
>> In my opinion, after reading the drafts, I would say that an
>> implementation which chose to change the length of the
>> preamble,
>> for any reason, would be non compliant. I think you would
>> disagree with this statement. I wonder how many others would
>> disagree with it. Also, where in the draft does it allow an
>> implementation to change the length of the preamble?
>>
>> Ben
>>
>>
>
>
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