Re: Preserving established communications (was RE: about draft-nordmark-multi6-noid-00)

[Erik Nordmark <Erik.Nordmark@sun.com>]

> But we don't have to go this far. We know that if a source address tied 
> to ISP A is used, there is no use in forwarding the packet to ISP B, 
> and the other way around. So there is no need to even check whether the 
> destination is even reachable through the ISP indicated by the source 
> address as there is no alternative course of action to forwarding the 
> packet to that ISP and hope for the best. So essentially we're just 
> taking default routes.

But to solve Macelo's example where packets to destination PC:X and PD:X
both exit Y's site over the same link/ISP (and it takes a long time to
discover that that link/ISP has failed), you would actually
need something stronger. For instance something along the lines
of being able to configure the routers so
that packets with the source prefix PA all-other-things-being-equal(?) exit 
via ISP A and source prefix PB exit via ISP B. That
way the sender can explore the two ISPs by changing the source locator.

  Erik