On 05 Jan 2011, at 15:15 , Brian E Carpenter wrote: > On 2011-01-06 02:15, RJ Atkinson wrote: > ... >> A) Prohibiting new IPv6 Extension Headers outright, >> as Joel has repeatedly suggested. This removes the >> narrow case where RFC-2460 allows Extension Headers, >> so the I-D would be an Update to RFC-2460. > > My reaction is that this is going too far, and isn't actually > necessary. We have words in 2460 that already make it quite hard > to define a new header. We have running code proof (in the form of > non-existent IPv4 options) that it's in practice impractical to > deploy such things, for exactly the reasons we've been discussing > (routers are not forward-compatible, and firewalls block unknowns > by default, both being partially embedded in silicon). > > But who knows what the future may bring, in 20 or 40 years from now?
There is a kind of procedural elegance lurking here that is worth highlighting. While you probably realise this due to your IESG experience, perhaps others on the list haven't considered the implications resulting from IETF processes. If some future instance of the IETF really believes they need to change things away from an outright prohibition on new IPv6 related extension headers, then revising the prohibition (e.g. to allow for some hypothetical legitimate need) is precisely the same process (i.e. standards action) as Suresh's proposed restraint upon creating IPv6 enhancements using a new header. Put another way, no current IETF action can really prohibit the future IETF from undertaking something that the future IETF really thinks ought to be undertaken. The practical difference is that the IETF will think VERY carefully about reversing a previous decision, whereas it might not apply the same level of thought about allowing a new enhancement where the standards-track documents explicitly allow that. Some of us think it would be valuable to have maximum thought before allowing any new IPv6 headers to be created. Cheers, Ran -------------------------------------------------------------------- IETF IPv6 working group mailing list [email protected] Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
