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Re: A simple question

2003-04-19 16:21:15
 Site local addressing in IPv6 is a concept which has been 
mentioned in RFC 1884, 2373 and 3513, the progression of Proposed 
Standards. This is a string of documents dating back to 1995. For eight 
years this concept was apparently considered a good thing. 

it is indeed unfortunate that it took several years before there was serious
consideration to the impact of site-local on networks, DNS, and applications. 
I view this as an indication of serious failures in our process - IPv6 was
approved (under pressure, it must be said) by the working group and IESG
despite serious technical omissions.  fortunately proposed standards are not
carved in stone, and these particular omissions are easy to fix.

I'd like to know why it's taken eight years for folks to decide it's 
bad.

because few serious applications people were in the discussion, and there
wasn't enough review by those people during Last Call.  most apps people
probably assumed that the changes between IPv4 and IPv6 would be transparent
to them, other than having to use a different size for the address.

also IPv6 took so long getting out the door that it was widely viewed as
on a distant horizon - something that could be dealt with when it finally
arrived (if that ever happened).

Is it that folks are just now implementing IPv6?

no, but most of the early apps that were ported to IPv6 were two-party apps,
often apps that were used in conjunction with either a v4-v6 translator or
proxy.  many problems with SLs don't show up for these apps; they show up for
multi-party apps.  also, even though there were v6 stacks there were probably
not many early networks that made heavy use of both SLs and globals.

It is not unprecedented to change or remove a feature as a document 
advances through the standards track. Such changes, however, can have 
significant impact on already-implemented and deployed solutions. Such 
matters should be considered carefully in that light. Perhaps removal of 
features should receive substantially more scrutiny after publication on 
the standards track.

I don't disagree.  but surely the months of discussion on this topic qualify
as a substantial amount of scrutiny.  and surely you'd agree that features in
published documents that appear to cause problems should also receive a
substantial amount of scrutiny before advancing those documents?