[8023-10GEPON] [FEC] Notes from 12/14 telecon
Notes from the telecon are below. Please let me know if there's something misstated.
BRs,
- Jeff
1. Participants:
Jeff Mandin
Glen Kramer
Fumio Daido
Pat Thaler
Enis Akbaba
Frank Chang
Frank Effenberger
Ryan Hirth
Shoichiro Seno
2. Frank Effenberger presented roughly the first half of his slides on upstream synchronization. These were the slides that dealt with the proposed "leader frame" and the transmitter/receiver behaviour. Frank experienced technical problems and was disconnected before he could present the slides on derivation of the delimiter sequence.
Discussion highlights: Frank Chang, Glen Kramer, and Jeff Mandin expressed the view that the "leader frame" scheme involved what could be regarded as layering violations. Frank E. agreed and is amenable to using a scheme where the PCS layer generates the synchronization-related data to the PMA. Frank's proposal also advocates using "one-stage" synchronization (ie. a single method which simultaneously establishes both FEC codeword and 66b block alignment), using repeated 0x55 as the "sync pattern", and using a "golden block" which maintains large Hamming distance from shifts of itself as the delimiter.
3. Glen Kramer presented his reply contribution on upstream synchronization. In Glen's proposal the OLT first establishes delineation of 66b blocks and subsequently receives sync patterns and the data delimiter in newly defined 66b control words.
Discussion highlights: Jeff spoke in favor of "one stage" synchronization, and also asked why the sync pattern and delimiter were encoded in 66b blocks rather than be transmitted by the PCS as serial data (and then beginning the transmission of the FEC codewords following the data delimiter). Glen and Pat Thaler provided explanations. Pat noted that if the 2 bit sync header of the 66b word is not used for synchronzation then it is not needed at all.
4. Next steps: the adhoc will continue the harmonization of the schemes offline and via the reflector