To expand on this from a programmers perspective, usually at the kernel/network stack level, a "patricia" radix-style trie is used for fast ipv6 lookups.
The benefit of the patricia trie being that if you only have a difference keylength of 8 bits (/120) then the ip lookup only takes 8 steps in a worst-case scenario. The same concept applies to ipv4 cidr as well, but it is less obvious. William ------Original Message------ From: Adrian Chadd To: Jeroen Massar Cc: North American Network Operators Group Subject: Re: IPv6 could change things - Was: DMCA takedowns of networks Sent: Oct 27, 2009 10:39 AM On Tue, Oct 27, 2009, Jeroen Massar wrote: > But yes, the network stack itself is a different question, then again, > you can just route a /64 into the loopback device and let your apache > listen there... (which also allows you to do easy-failover as you can > move that complete /64 to a different box ;) Funny you should mention that. A couple of tricks I've seen: * instead of a linked list and O(n) searching of interface aliases, use some kind of tree to map local IP -> interface. * hacks to do a "bind to all damned IP addresses and let userspace sort it out". I've done the former for a few thousand aliases with no degredation in performance. The hacks available for freebsd-4.x for the Web Polygraph software did something similar. 2c, Adrian -- William Pitcock SystemInPlace - Simple Hosting Solutions 1-866-519-6149
