Subject: Re: policy domains

From: "Stephen Sprunk" <[email-masked]>
Date: Tue, 29 Apr 2003 18:09:04 -0500

Thus spake "S Woodside" <[email-masked]>
> Then if you conclude that policy domains are a Good Thing, or at least
> Necessary Evil, then why is there all this talk to design a network
> that can somehow route around them?

There's reasonable arguments against private addresses, but unless
allocation policies are radically different than IPv4 practice, expecting a
public address for every host is a pipe dream.

Sidebar: a thread has recently popped up on nanog regarding the practice of
assigning public addresses to unconnected networks or hosts behind
firewalls.  It's not clear whether those for or against are in the majority,
but the mere presence of the debate is rather telling.

> My point is that A sends B a third-party address C, and the policy of
> the domain is "you can't route that outside my domain" then it doesn't
> matter whether C is site local, global, uses DNS, or whatever. Policy
> says it still won't route!

The expected usage model was that all hosts would have a site-local address
as well as zero to many global addresses.  Since we don't yet know how to
handle multiple addresses per host cleanly, the removal of site-locals is
thought to reduce the problem's complexity since site-locals are for some
reason assumed to have different semantics than globals.

S

Stephen Sprunk         "God does not play dice."  --Albert Einstein
CCIE #3723         "God is an inveterate gambler, and He throws the
K5SSS        dice at every possible opportunity." --Stephen Hawking

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From: Eliot Lear <[email-masked]>
Date: Tue, 29 Apr 2003 16:44:59 -0700

Stephen,

I'm glad you sent this note.  One of us is under a serious 
misconception, and if it's you, I suspect there are a lot more like you.

> public address for every host is a pipe dream.

Tell me if http://www.arin.net/policy/ipv6_policy.html addresses your 
concern.  Particularly section 3.2.  The policy, as I read it, gives 
just about everyone a /48.  When counting subnets and interfaces on 
routers, consider that the equivalent of an IPv4 /16.  That's a lot of 
space.  According to the above document, there's no real experience of 
someone having hit that point yet.

Eliot