v6 multihoming (Re: The Choice: IPv4 Exhaustion or Transition to IPv6)

Donald Stahl don at calis.blacksun.org
Fri Jun 29 14:53:13 UTC 2007

> If you took everything on v4 today and migrated it to v6 tomoro the 
> routing table would not grow - actually by my calculation it should 
> shrink (every ASN would only need one prefix to cover its current and 
> anticipated growth). So we'll see 220000 routes reduce to 25000.
Even if you gave everyone 2 or 3 bits to deaggregate with for TE purposes 
the table would _still_ be smaller. As the majority of people multihoming 
would never use more than 1 bit for TE purposes you would only end up with 
50k routes.

TCAM's and routers in general have always been able to keep up with table 
growth. As long as we don't do anything mind numbingly stupid they will 
continue to keep up. They won't be able to keep up, however, if we run out 
of addresses and ISP's start getting allocations of 200 separate /24's or 
if we need to start announcing /25's and longer.


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