Dual stack IPv6 for IPv4 depletion

Fri Jul 17 18:26:49 UTC 2015

On Wed, 15 Jul 2015 19:54:37 -0400, Joe Maimon said:

> This objection hinges on the assumption that if there is even ONE host
> on the network that will not accept that address, then the entire effort
> was a waste.

"if there's even ONE host" isn't the assertion, so do us a favor and don't
claim it is.

The problem is that *successfully* using the class E space for anything depends
on it having pretty damned ubiquitous support.

Statistics problem for you:  Assuming an average hop count of 14, what
percentage of intermediate routers need to support it in order to provide
a 90% chance that a connection will make it through?

Answer: 99.3% have to upgrade.

Statistics problem 2:  Assuming a 90% upgrade and 14 hops, what's the chance
that a given connection works?

Answer: Only 22.8%. (Yea, 0.9**14 nosedives pretty quickly).

Are you starting to see the problem here?

> Because there would then be no difference to the many many IPv4 (and
> IPv6) updates that were made with no guarantee of universal adoption.

The difference is that pretty much all of those other IPv4 updates were
designed in such a way that failure to implement them just means failure
to use *that feature*, and you could still talk unless using that feature
was deemed critical to the connection.

Somebody doesn't do ECN? You still talk, just without being able to use ECN.
Somebody doesn't do QoS tagging? You still talk, just without being able to use QoS.
Somebody doesn't do SACK?  You still talk, just without being able to use SACK.
Somebody doesn't do Class E? You still talk, just without being able to use Class E.

Do you remember on Sesame Street, the game "one of these things is not
like the others?"

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