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From: FEffenberger@xxxxxxxxxxxxxxxxx [mailto:FEffenberger@xxxxxxxxxxxxxxxxx]
Sent: Wednesday, May 08, 2002 10:46 AM
To: Larry.Rennie@nsc.com; firstname.lastname@example.org
Subject: RE: [EFM] FEC needs a good discussion home!Larry,First of all, I am a supporter of FEC, and think that we should continue working on it.However, I would not favor moving the FEC topic out of the optics track. The primaryapplication of FEC is to make up for shortcomings in the optics. Therefore, where betterto discuss it than the optics track? There is no doubt that FEC will be located insidethe PHY layer, and not in the MAC layers (it is unfeasible, otherwise). Hence, the opticstrack is where it belongs.Regarding the priority of FEC inside the optics track... regrettably, there are some veryimportant issues that have yet to be solved (the P2P wavelength choice being the mostobvious one). While these other issues rank higher than FEC, I, for one, do not believethat that will rule out the inclusion of FEC in the standard, pending a full examination ofthe evidence. I'm sure that Vipul would agree with this basic approach.The task force chair is occasionally emphatic at times about "baseline now!" and"minimum number of PHYs!", but I do not believe it is the chair's intention to throw outvalid topics of consideration purely on the grounds that it doesn't fit his schedule.The IEEE process has no pre-ordained schedule. If it takes an extra meeting,then so be it.On the actual work, what I've seen is that there have been two proposals regarding theapplication of FEC. I authored one, and Lior from Passave authored the other. On theirface, they both use the same base code, RS(255,239,8), and promise the same sortof performance boost. The differences between these two systems has to do with howto protect the framing control codes, and how to insert the parity symbols. I havebeen looking forward to a conversation regarding these issues, but to date nobodyhas offered to organize such a thing. We should start this soon, with the goal of reachinga more coherent picture by mid-summer.Sincerely,Frank Effenberger.-----Original Message-----FEC needs a good home with EFM for discussion purposes. Right now FEC is being discussed in the optics track but it has the least priority. Is this still the correct track ? As has been presented in several previous presentations, FEC can reasonably be added just after the GMII interface. Therefore, it is a valid consideration for discussion issue within the EFM TF. As some have said, "if the payload warrants FEC let the upper layers decide on whether or not to include FEC". I don't believe this is the correct way to treat FEC for EFM. The addition of FEC can bring substantial benefits to our EFM standard. These have been discussed in prior presentations (increased range, link quality monitoring, relaxation of BER spec for PMD, etc.).
From: larry rennie [mailto:Larry.Rennie@xxxxxxx]
Sent: Wednesday, May 08, 2002 1:04 PM
Subject: [EFM] FEC needs a good discussion home!