Re: [RRG] A new draft about Hierarchical Routing Architecture

["Stephen Sprunk" <stephen@sprunk.org>]

Thus spake louise.burness@bt.com
> But there is quite a lot of v6 support in hosts, perhaps more so than
> in networks?

The vast majority of hosts today have an IPv6 stack, with around half having 
it enabled by default and that'll rise to near totality within a few years.

ISP core networks also have IPv6 running, for the most part.  It's not 
generally pushed out to the edges, but that's more a matter of demand than 
capability these days.

The deployment problem is that most leaf networks, particularly the 
middleboxes at their borders, do not have IPv6 stacks or do not have them 
enabled.  The problem seems to afflict all leaf networks, whether consumers, 
content providers, enterprises, etc.

> One of the tricks with migration is that there is a benefit to the
> person who migrates. A crytpo ID gives potentially some security
> related benefits (whether they are wanted or not is another
> question) therefore there may be a motivation to add that to a host.

It took a decade to get IPv6 implemented and on by default in Windows.  It 
is reasonable to expect it'll take a similar amount of time to get any other 
major host stack changes made and deployed.  We don't have that much time 
left, therefore solutions that require changes to host stacks are 
interesting but (IMHO) not useful at this point.

> On the other hand, the tunnel proposals seem to require end sites
> (or providers on their behalf) to do a lot of work so that the core
> routing system can scale better?

One of the major causes of core routing scalability problems is end-sites 
wanting PI space for multihoming or portability.  Currently, the cost of 
each PI prefix is paid by everyone _except_ the party that benefits.  LISP 
seeks to move the cost to the site that benefits without affecting anyone 
else: if you want PI space, you deploy an ETR and register your EID-to-RLOC 
mapping.  Who exactly deploys ITRs is an interesting question, but that's a 
fixed cost regardless of how many people deploy LISP, which makes the 
economics less challenging.  Since one would expect all ETRs to also be 
ITRs, if LISP is reasonably successful the ITR problem will mostly solve 
itself.

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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