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 _______________________________________________ rrg mailing list rrg@irtf.org http://www.irtf.org/mailman/listinfo/rrg