In private email I was asked to review the "tape" of the IPv6 discussion in San Francisco. ftp://limestone.uoregon.edu/pub/videolab/video/ietf56/ietf56%20-%2003202003%20-%20INT%20ipv6.rm The SL discussion starts at 1:02 into the session. The chairs first presented a set of slides talking about various SL related options. The presentation was interrupted with questions from the floor quite a few times during the discussion of the "exclusive" model (wherein a v6 node would be a SL node of a global addressing node) - it was clear to me that there was quite a bit of confusion about this model. There were few interruptions during the discussions about the other models. The chairs opened the floor for general discussion at 1:39 into the session. The discussion was careful and extensive. After a while it became clear, as noted by Thomas, that more people were arguing for eliminating SL than had been the case in the past and few people were arguing for SL addressing. Those that were arguing in favor of SL mostly said that SL and v6 NATs were going to happen anyway but no one seemed all that concerned that the IETF define such addresses (e.g. Deno pointed out that people would just pick their own if the IETF did not.) At 2:07 into the session the chairs conferred and said that they would ask a simple yes or no question (in reality they asked two questions) about deprecating IPv6 SL addresses. (Not eliminate them in that the sense that the prefix would not be reassigned for other uses.) Margaret noted that the simple questions covered a lot of details that were not called out. After 10 minutes of discussion to clarify the intent of the questions Margaret asked for a show of hands for: 1/ how many people want to deprecate the use of IPv6 SL addresses? 2/ how many people do not want to deprecate the use of IPv6 SL addresses? She asked the first question twice so they could get a count of hands the second time. The result was 102 hands in favor of deprecating and 20 opposed. The chairs declared that there was rough consensus in the session to deprecate the use of IPv6 SL addressing but that this consensus would now be taken to the list to verify. After my review of the tape I have come to the following conclusions: 1/ there was a lot of confusion over the details of at least the exclusive model for the use of SL 2/ it was a clear sense of the people who chose to express their opinion in favor of deprecating IPv6 addresses (I have no way of knowing what fraction of the room chose to express an opinion because the IETF web site says that no meeting report was received so I have no way to know how many people were in the room.) RFC 2418 says: ... Decisions reached during a face-to-face meeting about topics or issues which have not been discussed on the mailing list, or are significantly different from previously arrived mailing list consensus MUST be reviewed on the mailing list. and In the case where a consensus which has been reached during a face- to-face meeting is being verified on a mailing list the people who were in the meeting and expressed agreement must be taken into account. If there were 100 people in a meeting and only a few people on the mailing list disagree with the consensus of the meeting then the consensus should be seen as being verified. I followed the discussion on the mailing list. In my opinion, there was considerable less clarity of view on the list than in the meeting. I know of no way to figure out what overlap there was between the people expressing their opinions on the list and those who expressed their opinion during the face-to-face session but it seems likely that the ratio of opinion is somewhere between 3/4 (the ratio reported by Margaret about the mailing list discussion) and 4/5 (the ration in the meeting). While I would rather see rough consensus not wind up with 20 or more percent of the IETF community (or at least the part of the community that expressed an opinion) disagreeing with a decision. (That many people may have input that the rest of the community dismisses at its peril.) I have to support the working group chair's assertion that rough consensus was found in this case. I will follow up this note with two others later today but I wanted to limit this note to the specific topic of the level of consensus and confusion. Scott