RE: [RRG] Moving forward... IPv4 now, IPv6 less urgent and perhaps more ambitious

["Tony Li" <tony.li@tony.li>]

Robin,

|There is currently only one routing scaling problem - in the IPv4
|Internet.  There's no hurry about solving the IPv6 routing scaling
|problem because it will only occur if and when IPv6 is widely adopted.


I have a lot of sympathy for where you're coming from, but I have to
disagree.  Yes, we have one routing scaling problem, but it's the IP routing
architecture, and it's common for both v4 and v6 because both use exactly
the same routing architecture.  There's no hurry to fixing it for IPv4
because frankly, we can scale the hardware to support the usual PI prefix
sizes (/24 -> 2^24 routes == 16M routes).  Yes, it will cost a bit more, but
over the long run, that's probably a lot cheaper than upgrading every CPE or
PE router.

Where we have major issues is (and, admittedly, if we transition to) v6.
Since the canonical PI prefix is a /48, we will have a very serious problem
on our hands.  Now, I'm no lover of v6 and I think my views on it are pretty
well known.  While you may not take v6 very seriously, there are those that
do, and frankly it's our joint responsibility to plan for its adoption.  We
have had one 'success disaster' with v4 and we need to prevent the same
thing from happening to our grandchildren.  I'll happily stipulate that we
don't know when a solution will be necessary.  V6 deployment has been about
15 years running so far and shows no signs of reaching critical mass anytime
soon.  However, this is also partly why this is considered a _research_
topic, not an engineering one.  


|However, I can't rule out that there may be some fancier, better and
|more ambitious approaches to solving the IPv6 routing scaling
|problem.  This includes fundamentally different approaches,
|especially if we contemplate changing the IPv6 protocols.


... And that's exactly what we are chartered to explore.

Tony


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