IPv6 Confusion

Owen DeLong owen at delong.com
Tue Feb 17 19:48:49 UTC 2009

On Feb 17, 2009, at 11:28 AM, Tony Hain wrote:

> While people frequently claim that auto-config is optional, there are
> implementations (including OS-X) that don't support anything else at  
> this
> point. The basic message is that you should not assume that the host
> implementations will conform to what the network operator would  
> prefer, and
> you need to test.

I can configure OS-X statically, so, that simply isn't true.

What is true is that there are many implementations which do not (yet)
support DHCPv6.  That is not the same as "don't support anything

> One last comment (because I hear "just more bits" a lot in the *nog
> community)... Approach IPv6 as a new and different protocol. If you  
> approach
> it as "IPv4 with more bits", you will trip over the differences and be
> pissed off. If you approach it as a "different protocol with a name  
> that
> starts with IP" and runs alongside IPv4 (like we used to do with  
> decnet,
> sna, appletalk...), you will be comforted in all the similarities.  
> You will
> also hear lots of noise about 'lack of compatibility', which is just  
> another
> instance of refusing to recognize that this is really a different  
> protocol.
> At the end of the day, it is a packet based protocol that moves  
> payloads
> around.
The problem here, IMHO, stems from the fact that unlike DECnet,
Appletalk, SNA, et. al., IPv6 is intended as a replacement for
IPv4. (None of the other protocols was ever intended to replace
any of the others).

As a replacement, the IETF realized that at the current scale of the
internet when they began designing IPv6, a flag day conversion
(like what happened when we went to IPv4) was not possible.
Unfortunately, the migration plan set forth by the IETF made many
assumptions (especially on vendor preparedness and rate of
adoption prior to IPv4 runout) that have not proven out, so, the
"Everyone who has IPv4 starts running dual-stack before we
need any IPv6 only connectivity" plan is not going to prove out.

More unfortunately, there is no real contingency plan for how
migration happens absent that scenario and we are, therefore,
in for some interesting times ahead.


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