Re: draft-ietf-multi6-multihoming-requirements-06.txt

[Cedric de Launois <delaunois@info.ucl.ac.be>]

> > A general principle would be :
> > 
> >   IF a host receives prefix PA in a router advertisement coming from 
> >   router RA THEN choose src address PA if the host sends a packet with 
> >   RA as the first hop toward the destination (i.e. the packet is sent
> >   through ISPA).
> > 
> > I would insert this rule just after the 7th rule in RFC3484.
> 
> This doesn't help in the most typical case, where there is a single router 
> advertising both prefixes. (It would only help when there are two routers 
> advertising two different prefixes to the host.)

When there is a single router, source-based routing can be used. The
router routes all packets with src address PA through ISPA.

> Basically the simplest fix is using policy-based routing in your site
> border routers.  Not typically implemented for IPv6, but should be quite
> straightforward.

Agreed. But if there are two routers, packets addressed to the wrong
router need to be redirected in some way to the right router. The basic
src address selection mechanism I propose just helps to avoid the
redirection in this case. This is an heuristic that could help and that
don't cost a lot...

> See draft-savola-bcp38-multihoming-update-00.txt for more thoughts on
> this.

Thanks, I'll read it.