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Re: [BP] Data Presented in Goergen_02_0904



Joel,

 

The channels submitted in goergen_02_0709 and goergen_02_0904 certainly do have great value and should be used by the working group for further work.  However, they should not be used to the exclusion of other channels that represent complete channels.  Both the signaling work and the setting of the channel limit should be based on a wide selection of data and must include data that represents real channels.  I submit the following reasons to support this conclusion.

 

1)       A connector agnostic test system is a worthy goal.  However, this is not achieved by omitting the connectors.  Additionally, each connector is accompanied by two via fields with their associated breakouts.  This is not well represented by a single via transition.

2)       A test system does not necessarily take into account the tradeoffs that inevitably occur in the design of a cost-effective, high density system.

3)       We can only compare the public data and there are significant differences.  It is difficult to predict how these differences will impact the performance for any particular line code / equalization as illustrated in sinsky_01_0904.

 

 Again, the test board data from goergen_02_0709 and goergen_02_090 should be considered, but must be put into perspective.  We cannot rely exclusively on incomplete test systems or contrived models however valuable they may be.

 

-Bill Peters

 


From: owner-stds-802-3-blade@listserv.ieee.org [mailto:owner-stds-802-3-blade@listserv.ieee.org] On Behalf Of Joel Goergen
Sent: Friday, October 01, 2004 4:27 PM
To: STDS-802-3-BLADE@listserv.ieee.org
Subject: [BP] Data Presented in Goergen_02_0904

 

Fellow collegues,

During the back plane meeting this week in Ottawa, it was pointed out on several occasions by one colleague that the channels submitted for review and simulation as reported in goergen_02_0709 and goergen_02_0904 are not real channels and therefore, should not be used by the working group in any capacity.  I've studied this concern at length and defend my work in whole as follows.

1) The intent of a connector-less test card was agreed to in part by the members of the channel ad-hoc.  It's creation, though not a new concept at all, was to prevent a common set of test cards from becoming connector evaluation boards by the industry.  My understanding of the ATCA platform is that this MSA has agreed to 'ONE' connector.  Therefore, evaluating comparative back planes in an ATCA environment is easy.  It does not address the diverse nature of the telecom segment, which is the primary intent of the connector-less cards.

2) I've examined all the channel data presented to the public, as well as that submitted to me in private.  All of the public data submitted to IEEE as presentations, and all of the private data sent to me directly correlates to the data from the connector-less back plane cards.  Do the comparison yourself ... Look at every channel and compare it to all the data submitted and you will see the same likeness.  The data speaks for itself.  All the effects form various degrees of inferior channel design are included, certainly not excluding any of those seen in Peters_01_0904.

Therefore, if my data is not valid to consider, then what data 'IS' valid for consideration?  It's clearly acceptable to simulate a channel and then measure the likeness to real before continuing with the remaining simulations/approximations.  These test back planes correlate perfectly and I stand by the design, implementation, and data collected.  If the majority body feels the data is not valid, I am perfectly fine with recalling the data and the cards.  It's cheaper for me.

Joel Goergen