who gets a /32 [Re: IPV6 renumbering painless?]

Mon Nov 29 18:03:07 UTC 2004

> > i have long wished for and sometimes needed a way to renumber a host
> > w/o killing or restarting its active tcp flows.  this isn't a
> > layering violation.  tcp should be able to know about
> > endpoint-renumber events.
> 
> This is a layering violation and has endless security implications.

as i told someone in private e-mail earlier this morning, tcp's notion
of a flow-identifying tuple includes network addresses, and so, the
ability to change these on the fly will absolutely affect tcp.  when
you bind a session to an address, as tcp currently does, you cause the
community to waste ipv4 /32's or ipv6 /128's as loopback aliases just
to have something they can virtualize, manage, move around, play with.

let me put that another way, in case it's not clear enough as stated:

tcp's existing reference to network addresses are a layering violation,
and so anything we do to improve the situation will also be a layering
violation, but what of it?  deciding against making tcp "less pure" is
not going to meet the needs and demands of the community -- and those
needs and demands WILL be met, and probably in even less pure ways.
google for a product or feature called "3TCP" to see what i mean.

> You can solve the renumber thingie by having all TCP connecting
> to/from an official IP on the loopback interface.  Then the routing
> code could do its work and route the packets through some some other
> or renumbered interface.

see above.  we do that now.  however, it limits the scope of mobility to
"same autonomous system" and often "same campus" so it's not useful for
any wide area purpose.  the internet's target area is very wide indeed.

> Try to get your TCP automatic renumbering stuff implemented from spec
> by five different people in five different codebases in a compatible
> way within two month time... No way.

where i come from that's called "the fallacy of the straw man" and is
not a well respected technique for debate or discussion.  the process
i'm thinking of would take years to reach deployability, and more years
to reach wide scale deployment.

> KISS KISS KISS KISS !!!
> 
> Why is the telephone (POTS/Mobile) so popular?  Easy answer: Even the
> most stupid person on earth capable of correctly reading digits is able
> to punch in a number.  As simple as it gets.

i guess i was expecting smart people to write kernels and "lusers" to
just run working code.  this seems to work for apple and suse and redhat
and sun and microsoft.  or is this another straw man thing?  certainly
my kids think their mac/os/x machine is as easy to use as a telephone,
and if you asked them how the routing table worked they wouldn't care.
-- 
Paul Vixie