Re: [10GBT] Question about previous analysis of codes and undetected errors.
Sailesh -
Can you summarize the analysis that led you to determine that the
undetected frame error rate for 1000BASE-T would be so much better than
T2? How did you account for the multiple errors coming out of the
Viterbi decoder.
A major component of most undetected error analyses referenced to date
relies on looking at the independent error probabilities of individual
bits and therefore taking the 4th power of the BER to get beyond the CRC
distance for data bits. While 1000BASE-T takes extra pains to protect
the control symbols, data symbols would appear to be governed by the BER
and independence mathematics. With coded systems, such as 1000BASE-T,
as you know, we get error bursts, so multiple bit errors in a frame are
not independent. As such, at a first level, it is difficult to see how
the coded 1000BASE-T would have to be "several orders of magnitude"
better than a similar uncoded system with essentially the same line
coding for undetected error rates.
This is of course very important to us in 10GBASE-T, because we are
using a very powerful code, and there are no good references (that I've
been able to find) for predicting the undetected error rate of these
codes. Simulation is impractical, and even very small undetected error
rates (well beyond what is simulatable) would swamp anything from the
constellation or mapping.
This is the issue I'd left you a voicemail on a few days ago to discuss.
-george
-----Original Message-----
From: stds-802-3-10gbt@IEEE.ORG [mailto:stds-802-3-10gbt@IEEE.ORG] On
Behalf Of Pat Thaler
Sent: Tuesday, October 12, 2004 10:06 AM
To: STDS-802-3-10GBT@listserv.ieee.org
Subject: Re: [10GBT] Question about previous analysis of codes and
undetected errors.
Does anyone have this presentation? The 100BASE-T work falls before the
archives on the IEEE 802.3 site.
-----Original Message-----
From: stds-802-3-10gbt@IEEE.ORG [mailto:stds-802-3-10gbt@IEEE.ORG]On
Behalf Of sailesh rao
Sent: Tuesday, 12 October, 2004 7:18 AM
To: STDS-802-3-10GBT@listserv.ieee.org
Subject: Re: [10GBT] Question about previous analysis of codes and
undetected errors.
Pat,
The 1000BASE-T signaling was essentially derived from 100BASE-T2. In
802.3ab, a group of us got together and determined that the undetected
frame
error rate for 1000BASE-T was orders of magnitude lower than that for
100BASE-T2, and thus met the requirement for Ethernet.
The undetected frame error rate analysis for 100BASE-T2 was presented to
802.3y by John Creigh, then of IBM.
Regards,
Sailesh.
srao@phyten.com
>From: Pat Thaler <pat_thaler@AGILENT.COM>
>Reply-To: pat_thaler@AGILENT.COM
>To: STDS-802-3-10GBT@listserv.ieee.org
>Subject: Re: [10GBT] Question about previous analysis of codes and
>undetected errors.
>Date: Mon, 11 Oct 2004 10:36:18 -0600
>
>I believe that there was, but I didn't follow 1000BASE-T as closely so
it
>would take time for me to find the relevant presentations. For 802.3ae,
I
>recalled who the presenter and I knew approximately which meeting
archives
>to look at which speeded the search a lot. It would be helpful if
someone
>else can provide the references to the 1000BASE-T error analysis.
>
>Regards,
>Pat
>
>-----Original Message-----
>From: stds-802-3-10gbt@IEEE.ORG [mailto:stds-802-3-10gbt@IEEE.ORG]On
Behalf
>Of Jose Tellado
>Sent: Thursday, 07 October, 2004 3:40 PM
>To: STDS-802-3-10GBT@listserv.ieee.org
>Subject: Re: [10GBT] Question about previous analysis of codes and
>undetected errors.
>
>
>Thanks Pat,
>
>This material is very relevant for understanding undetected error rate
for
>802.3ae and will aid in our 802.3an analysis.
>Is there a similar analysis for the 1000Base-T project?
>
>Regards,
>Jose
>
> _____
>
>From: stds-802-3-10gbt@IEEE.ORG [mailto:stds-802-3-10gbt@IEEE.ORG] On
>Behalf Of Pat Thaler
>Sent: Thursday, September 30, 2004 8:33 AM
>To: STDS-802-3-10GBT@listserv.ieee.org
>Subject: [10GBT] Question about previous analysis of codes and
undetected
>errors.
>
>
>Hugh and I were asked for references showing how undetected error rate
was
>analyzed in previous 802.3 projects. Here is some of the material for
the
>64b/66b code in IEEE p802.3ae.
>
>For 64b/66b, one analysis of the scrambler non-effect on CRC error
>detection can be found in:
>http://ieee802.org/3/10G_study/public/jan00/walker_1_0100.pdf
>
>This presentation estimates mean time to false packet acceptance:
>http://ieee802.org/3/ae/public/mar00/walker_1_0300.pdf
>
>This presentation discusses how the sync state and BER monitor machines
>react to drop sync when BER is high:
>http://ieee802.org/3/ae/public/jul00/walker_1_0700.pdf
>
>Regards,
>Pat <http://ieee802.org/3/ae/public/may00/walker_1_0500.pdf>
>
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