nanog mailing list archives

Re: Another v6 question


From: bmanning () vacation karoshi com
Date: Tue, 25 Jan 2011 20:03:47 +0000

Second, as I was crunching a few numbers to get a rough estimate of what a
global table would look like in say 3 or 5 years after v4 is exhausted (I
understand that it's completely unpredictable to do this, but curiosity
killed the cat I guess), and in a few cases, I stopped due to the shear size
of the amount of prefixes I was coming with. Where i'm getting with this is
has anyone done any crunching on prefix count for v6 (as in estimates of
global table usage with the various prefix lengths seen above _based_ on the
initial allocation of the v6 space (not the entire v6 space itself)). I'm

You really can't map prefix availability to prefix usage.

        this is so true. and yet you proceed, in your next few sentences
        to do -exactly- that. :)

There are 4 billion IPv4 /32s. There aren't 4 billion LIRs that will get /32s.

        presuming the LIR model holds...

There are 256 trillion IPv4 /48s (roughly). There are not 256 trillion
end sites that will apply for /48s.

        apply to whom? the RIR/LIR model is not the only place/venue
        for getting a /48.

The whole point of IPv6 is that the number of prefixes vastly exceeds
the number of applicants that will use them.

        not sure I buy that arguement.  

To measure the likely content of the IPv6 global table, then, we need
to look at the number and type of users rather than looking at the
maximum available number of prefixes.

        if there is a global table that is interesting (debatable point)
        then I'd be more interested in curn rates and overlapping announcements.



I haven't had trouble reaching anything I care about from my /48
advertised through Hurricane Electric and Layer 42.

interested to see how long before we have 96Gb's of TCAM/Memory (take you
vendor of choice) in our routers just to take a full table. (Not to mention
still having all of the ipv4 de-agg crazyness going on today. Seriously, who
lets /28 and /32's in their tables today? And this will only get worse as v4
fades away).

Yeah, that's not likely to happen. TCAM doesn't scale that way. As to the
IPv4 de-agg, I think that's going to be one of the primary causes for
an accelerated deprecation of IPv4 once IPv6 starts to become more
ubiquitous.

Owen




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