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All, Here is a short summary of the call that on FEC. The attendees were: Ryan Hirth, Frank Chang, Roger Berrel, Jeff Mandin, and Frank Effenberger. Frank Chang kindly provided the conference call number. Frank E. prepared a short slideset to discuss some of the byte/block/codeword alignment issues (see first attached preso). These slides served as a sort of conversation starter... The main topics of discussion were: 1. The topic of FEC can be broken into two parts: the FEC algorithm and its effect on the optical performance, and the framing of FEC into the 10G Ethernet signal. The slides coming into the meeting focused on the framing aspects. Frank Chang offered to prepare some slides on the algorithm/performance topic. In fact, Frank C. has done this, which is the second file attachment. 2. It seemed agreed that FEC needs to be at the lowest layer, and that the 64b code blocks should fit evenly into the FEC code input (in other words, the FEC input should be a multiple of 66bits or 65bits). 3. Time quanta - there was a variety of opinions on whether the time quanta should stay the same as 1G EPON (16 ns), or if it should be changed to fit the new speed better. No conclusions were drawn on this issue on the call, although some people on the call needed to do more work on the topic. 4. The line rate - there was a divergence of opinions on this issue, too. The original slideset presented the super-rate approach, where the MAC rate stays at 10Gb/s, and the optics are speed-up to permit space for the parity. On deciding this super-rate, there were a variety of values, some based on numerical theory and others on practical availability of serdes parts. Others on the call suggested that the PHY should stay at 10.3125 Gb/s, and the MAC should be slowed down. It was also noted that increasing the data rate will also increase receiver noise, so that must be balanced against the bandwidth and architectural advantages. Once again, a question to be discussed more. 5. 66b versus 65b coding - The first presentation presents the use of 66 bit versus 65 bit representation as a question. It seems that some people like to stay with 66b code (for familiarity sake), and others see the efficiency advantage of 65b representation. 6. Synchronization patterns - The first presentation illustrates a few synchronization patterns that are intended for continuous synch. State machine. It was noted that in the upstream, a special 'leader' pattern would likely be needed to get FEC codeword delimitation quickly, so that the state-machine could be kick-started. The length and operation of these patterns was another issue that needs more work. 7. Layer-scope question - There was some disagreement on what is in or out of scope of the current work, with some people claiming that it was 'easy' to change parameters of the MAC, while others claiming the opposite. This certainly will be an ongoing area of contention. 8. Agreed path forward - the involved parties agreed that it would be good to re-draft the collected materials into a sort of presentation which presented each design issue as a question, and avoided making a position statement on any of the issues. This was seen as helping bring the whole group up to speed on the topics. Frank C. and Ryan H. would volunteer additional materials to the effort. Thanks, Frank Effenberger -----Original Message----- From: Glen Kramer [mailto:glen.kramer@teknovus.com] Sent: Friday, September 08, 2006 1:08 PM To: 'Frank Effenberger'; STDS-802-3-10GEPON@listserv.ieee.org Subject: RE: [8023-10GEPON] Presentation on FEC for 10G Frank, Thank you for organizing the FEC discussions. Few people have asked me for a summary of the FEC call. Would you please, post to the reflector a short overview of the call: what was discussed and any steps planned next. Also, if you plan another conf call, please announce it on the reflector, so that those who are interested, but missed the first call could join this time. I also want to remind everybody that the Ethernet Alliance has offered 10GEPON group a sponsorship in a form of hosting conference calls. Please, let me know if you would like to have a conference call in preparation for the September meeting. Regards, Glen
2006sept-FEClinecoding-DRAFT.ppt