Subject: RE: [RRG] Renumbering...

From: "Tony Li" <[email-masked]>
Date: Wed, 3 Sep 2008 15:57:13 -0700

|OK, I now understand that when you say PI you mean a globally routed,
|non-aggregated address prefix.  Yes?

Yes, that's where the conversation started.

|However, I think the essential point here is not "PI" (provider
|independence).  Rather, it's the trade-off between non-aggregation and
|being globally routed.  One or the other needs to be controlled by some
|means.  Even PA prefixes should either be aggregated or have their
|routing constrained.

I hope everyone here agrees that the only way to achieve scalability is
through aggregation.  ;-)

|We can look at the different classes of approach to limiting one or the
|other, to see which one causes the least pain.  I believe that anything
|that requires *site* renumbering in order to switch upstream providers
|is going to be hard to swallow.  

Our current consensus poll would seem to agree with you.

|That includes any approach 
|that uses PA
|addresses within a site, i.e. any approach that aggregates instead of
|limiting scope, and where an endpoint knows an external prefix 
|for itself.

Yes, but can we please stop saying 'address' unless we truly _mean_ a
classical address, with both identifier and location semantics?

|At first glance that would mean at least Handley/Trilogy/Multipath
|(unless modified) and the IPv6 loc/id split ones except GSE where the
|"routing goop" in incoming packets is zeroed out at the network edge.

More precisely, a loc/id split solution where the host must know its own
locators is going to have an issue.  Agree on the transport solutions.

|Once you have decided to limit routing scope, there is no reason for
|your site-internal addressing not to be "provider-independent" (strict
|meaning).

That depends on the limits of the scope.  If the scope is still global in
some way, then you continue to have scalability issues.  For example, if you
have a VPN that is full of unaggregated site prefixes, you'll still have
scalability issues.  If you limit your scope further, such as to the site
(ala RFC 1918 addressing), then yes, you're effectively
"provider-indepenent".

Tony

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