On Wed, Oct 24, 2012 at 02:43:14PM -0400, Simon Perreault wrote: > What you need to multihome is either BGP or NAT. Exactly as in IPv4. > Nothing has changed. The only new thing with IPv6 is that there's > more bits. Oh? I have two internet connections plugged directly into my desktop box at home, it is multihomed and there is no BGP or NAT. This does need some policy routing to work with uRPF filtered access lines.
With IPv6 multihoming should work trivially: plug two access lines into a switch, get RAs from both, get addresses from both on your end-host, and your end-host needs to select the proper route for each source address. Again, no NAT or BGP. Applications will need to support hosts having multiple addresses in the future, and happy eyeballs seems to have made browsers do that. There is also a considerable advantage against "multihoming" where hosts only have 1 address configured: if the application tries to use all source addresses available, you can get to google even if one of your access lines has no connectivity to them; with BGP multihoming you will not, with v4 NAT style multihoming you possibly can if it does round-robin and you try again. Add SCTP to this puzzle, and you should be able to roam seamlessly from WLAN to 3G to WLAN without your ssh sessions breaking. mosh already more or less does this. With multiple addresses and default routes per host, and SCTP or multipath TCP, you should also be able to load-share one connection among multiple internet connections. End hosts need to get smarter, instead of the network adapting to their stupidity. But I'm not holding my breath.
