Perhaps foolishly stepping in here when I am behind in other work :) ... I agree that both the issue of being able to distinguish an unknown EH from an unknown upper layer header and having a uniform start to extension headers are important and both must be in place in order to get the full value. However, I am fine with these being resolved separately.
Since the distinction between an unknown extension header or an unknown next layer protocol is important, let me informally propose a solution... -- My suggestion for how to solve this problem lies in setting aside a next header range for future extension headers. For example set aside the range 240-247. Within that, I'd suggest reserving 247 as a special case, to allow for expansion. This following probably wouldn't be officially defined now, but my idea there is that if "next header=247", then the 3rd octet (or 3rd and 4th octet) of the extension header would further define which extension header this is. Also, we might want to make 246 (or 240-243) a special value to indicate that this extension header "transforms" the rest of the packet in a way that will make it impossible to meaningfully parse the header and what follows. If it didn't already have a next header value, ESP would be an example of this. A mechanism like I suggested for 247 could make up for the fact that this is a limited range. Of course, the 3 ranges/subranges I mention could be different sizes than I suggested and could be distinct ranges. (Eventually you may have to deal with running out of values for upper layer protocols, but I'm not going into that.) -- Feel free to pick away... -- Jim On 3/20/08 1:21 PM, "Markku Savela" <[EMAIL PROTECTED]> wrote: > This seems moot all text in the draft... -------------------------------------------------------------------- IETF IPv6 working group mailing list [email protected] Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
