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AW: [bp] BER Objective for BPE




Gadi,

we are giving a paper at the DesignCon on Wednesday concerning the StatEye,
so as soon as that is done I guess we can distribute the paper?

Cheers,

Anthony


>-----Ursprüngliche Nachricht-----
>Von: Gadi Lahat [mailto:Gadi@TERA-CHIP.COM] 
>Gesendet: Sonntag, 1. Februar 2004 10:00
>An: DAmbrosia, John F; Sanders Anthony (COM ON CE); 
>IEEE@nc.rr.com; ahealey@agere.com; stds-802-3-blade@ieee.org
>Betreff: RE: [bp] BER Objective for BPE
>
>
>John
>Till then can you send a link pointing to a good introduction 
>? Thanks Gadi
>
>-----Original Message-----
>From: DAmbrosia, John F [mailto:john.dambrosia@tycoelectronics.com] 
>Sent: Friday, 30 January, 2004 07:33
>To: anthony.sanders@infineon.com; IEEE@nc.rr.com; 
>ahealey@agere.com; stds-802-3-blade@ieee.org
>Subject: RE: [bp] BER Objective for BPE
>
>
>Anthony,
>While many of us are aware of the StatEye methodology from OIF 
>efforts, it is fair to say that there are a number of people 
>who aren't.  With that said, perhaps we can get time at the 
>next plenary to do our DesignCon paper to introduce it to more people?
>
>John
>
>-----Original Message-----
>From: owner-stds-802-3-blade@majordomo.ieee.org
>[mailto:owner-stds-802-3-blade@majordomo.ieee.org] On Behalf 
>Of anthony.sanders@infineon.com
>Sent: Thursday, January 29, 2004 6:19 PM
>To: IEEE@nc.rr.com; ahealey@agere.com; stds-802-3-blade@ieee.org
>Subject: AW: [bp] BER Objective for BPE
>
>
>Adam, Jeff,
>
>a good thread to start.
>
>I think option.2 seems to be the best way to go i.e. 
>calculating the system requirements for a 1e-15 ber, and 
>through over-stressed jitter tolerance measurements at 1e-12, 
>and bathtub extrapolation gaurentee 1e-15.
>
>For the calibration of the over-stressed ejitter tolerance I 
>believe that the StatEye Channel measurement methodology can 
>accurately predict the overstressing requirements. And for 
>output transmitters the extrapolation of the output jitter is 
>also accurate.
>
>Where I believe problems may occur is in the final system 
>itself. This is agreeing with your issue of noise floors. I 
>believe the link in presence of the complete system e.g. power 
>supply glitches, could be limited in terms of BER. Not sure 
>how to deal with this yet.
>
>Cheers,
>
>Anthony
>
>
>
>-----Ursprüngliche Nachricht-----
>Von: owner-stds-802-3-blade@majordomo.ieee.org
>[mailto:owner-stds-802-3-blade@majordomo.ieee.org] Im Auftrag 
>von Jeff Warren
>Gesendet: Donnerstag, 29. Januar 2004 01:15
>An: Healey, Adam B (Adam); stds-802-3-blade@ieee.org
>Betreff: Re: [bp] BER Objective for BPE
>
>
>Adam,
>
>Correct I did intend for this to be a general discussion 
>topic, especially the 'experts' from OIF and UXPi because both 
>of these 10G technical specifications require a 10EE-15 BER. 
>The 1st approach you've described which includes all elements 
>of the BPE standard (transmitter, channel,
>receiver) with a systems compliance test at 10EE-12 combined 
>with additional margin to guarantee 10EE-15 seems like a 
>reasonable way to go. 
>
>Hopefully subsequent BPE reflector traffic will include 
>input(s) from the OIF and UXPi experts that established their 
>respective 10EE-15 BER
>requirements for 10G backplane applications.          
>
>       - Jeff
>----- Original Message -----
>From: Healey, Adam B (Adam)
>To: Jeff Warren ; stds-802-3-blade@ieee.org
>Sent: Wednesday, January 28, 2004 6:27 PM
>Subject: RE: [bp] BER Objective for BPE
>
>
>Jeff,
>
>Although you addressed this directly to me, I assume that you 
>put this topic to the reflector for general discussion.
>
>As you know, this proposal needs to be brought forward to the 
>study group and agreed to by at least a 75% majority before it 
>become an objective.  I encourage you to make such a motion at 
>our next meeting if you feel that this is a necessary change.
>
>Since you directed the message to me, I'll also make some 
>remarks as a citizen of 802.3 and not SG chair:
>
>My personal opinion is that it would help if you elaborated on 
>what this objective would mean in practice (especially for 
>those who do not participate in the OIF).  
>
>I am personally aware of system requirements for 1E-15 and 
>below, but as you imply in the phrasing of the proposed 
>objective, it is prohibitive to measure such low error rates.  
>The specific language you use implies that we will define a 
>system that is guaranteed to work at a BER of 1E-15 but we 
>will only verify its performance by measuring the BER to 
>1E-12.  Giving this topic only limited thought, I see a couple 
>of ways to approach this:
>
>1.  Define the system (transmitter, channel, receiver) such 
>that simulated performance is 1E-15, but in compliance test 
>performance is only verified to 1E-12.  Presumably, parametric 
>values specified in the standard include margin to account for 
>the difference in what was simulated at 1E-15 and what can 
>actually be measured 1E-12.  For a quick example, consider 
>random jitter.  If the link is defined such the peak-peak 
>random jitter at 1E-15 is 0.15UI, then the specification would 
>presumably incorporate a specification for peak-peak random 
>jitter at 1E-12 of 0.133UI.
>
>2.  Define a system for performance to 1E-15, and as part of 
>compliance test rely on extrapolation of measured data (for 
>example, bathtub curves along the vertical or horizontal axis) 
>to derive values for 1E-15 that can be compared with the 
>specified values.
>
>One interesting observation regarding (1) is that, if we were 
>to have a closed eye system (i.e. the solution relies heavily 
>on receiver-based equalization, in that the eye at the 
>receiver input is closed), I would expect receiver compliance 
>to be based on "operation at a given BER when driven by 
>compliant driver through a compliant channel."  This is the 
>model that has been employed in 100/1000M twisted pair links 
>and in 10GBASE-CX4. Using the model defined in (1), we would 
>drive a compliant channel with a compliant driver and ensure 
>that receiver BER performance was better than 1E-12.  I would 
>argue that this says nothing about the receiver's ability to 
>operate at 1E-15.  Some additional impairment (worse than 
>worst-case transmitter or channel) needs to be included to 
>ensure that the appropriate margin is in the receiver design.
>
>With regards to (2), we would run the risk of having a hole in 
>the specification (solutions that are both perceived to be 
>compliant but are not
>interoperable) since error floors below 1E-12 would be 
>undetected and extrapolation would provide misleading results.
>
>In summary, I do not debate that some applications would like 
>to see BER exceed 1E-12 (and in some cases, exceed 1E-15).  
>With regards to your proposed objective, I think it would be 
>useful to get a better understanding of how a Backplane 
>Ethernet standard could be judged to have met such an objective or not.
>
>I think members of the OIF community who also participate in 
>the SG could share some insight here.  I welcome them to do so.
>
>
>Thank you,
>-Adam
>
>-----Original Message-----
>From: Jeff Warren [mailto:IEEE@nc.rr.com]
>Sent: Wednesday, January 28, 2004 11:43 AM
>To: stds-802-3-blade@ieee.org
>Subject: [bp] BER Objective for BPE
>
>
>Adam,
>
>During the recent IEEE Backplane Ethernet (BPE) study group 
>(SG) interim meeting in Vancouver, BC. Canada a BER objective 
>of 10EE-12 was voted into the initial set of BPE objectives by 
>a vote of 32-yes / 3-no / 1-abstain. 
>
>I was one of the three negative votes. My reason was simple; 
>because these future 10G backplane links in a modular chassis 
>are critical network links and the environment (inside the 
>box) is much more noisy than external links.
>
>
>I felt the same approach as the OIF CEI implementers agreement 
>makes sense; they require a BER of 10EE-15 per lane with the 
>test requirement of 10EE-12.
>
>
>I suspect that system vendors will have the same concern with 
>this 10EE-12 BER objective for backplane applications and 
>voice their concerns when this objective reaches the 802.3 WG 
>so it might be better to fix this objective now rather than later. 
>
>I would propose a new BER objective, here's some suggested text:
>
>"Support a BER of 10EE-15 or better with the test requirement 
>set at 10EE-12". 
>
>Cheers, 
>
>   - Jeff Warren 
>
>
>