On 2010-02-26 09:40, Joel M. Halpern wrote:
...
>> Most of this document does not distinguish between IPv4 and
>> IPv6. The overall routing archtecture for the two protocols is the
>> same. Consequently, most of the issues in this document apply
>> equally to IPv4 and IPv6. Any behavior that places pressure on IPv4
>> routing is likely to also exert the same pressure on IPv6.
>> Deployment of IPv6 will not lessen these pressures in most cases.
>>
>
> What you propose to add is good. But, the text in 4.6 as written claims
> "It is possible to extrapolate what the size of the IPv6 routing table
> would be if wide spread adoption of IPv6 occurred..." Unfortunately,
> the extrapolation that then takes place assumes that the same factors
> that currently constrain IPv4 sizes would constrain IPvb6 sizes, and
> that seems extremely unlikely. Hence, this extrapolation is very
> optimistic, and misleading to the reader.
Joel, as you know, it isn't the length of the announced prefixes
that really matters, but the number of non-aggregated prefixes.
So the question is, what constrains the growth in that number?
That is of course very debatable, and there is a lot of research
literature about it. If current trends persist, for example,
you can conclude that a network of 10 billion hosts would
generate just over one million BGP4 routes.
(That is making a scientifically unjustified extrapolation
of the graphs in my CCR paper). But if the rate of multihoming
increases by a factor ten, and if multihoming continues to
require de-aggregation, we'd get ~10 million routes in BGP.
Numbers beyond that imply a much bigger deviation from current
practice than seems likely to me, since it's clear that the
majority of mobility needs will be met using captive-customer
addresses that are intrinsically PA.
My conclusion is that we can hope for 1 million routes but
should have a solution for 10 million. I don't think there is
anything in the data or technology that tells us we will
need a solution for 100 million or more.
All IMHO of course.
Thomas just wrote:
> NEW:
>
> It is possible to extrapolate what the size of the IPv6 Internet
> routing table might look like today, from the current IPv4 Internet
> routing table, if widespread IPv6 adoption were to occur
> "instantaneously",
>
> Then, at the end of the paragraph add something like:
>
> Of course, this estimate is based on a current snapshot of IPv4
> routing activity. Unless the pressures described elsewhere in this
> document are reduced, the actual table size would be larger.
I don't think that quite covers the very reasonable speculation
that the Internet will grow to around ten billion publicly-
addressable hosts under IPv6, and that this is part of the
problem. So I think we need to be clear that significantly
larger numbers are in our future.
Brian
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