On Wed, 2005-06-01 at 12:16, Soliman, Hesham wrote:
> => How do you know if you have no route to the destination?

You consult your forwarding table.

> Could it not be on one of the links?

It could be if you have a forwarding table entry that points to one or
more of your local interfaces.

>  The difference is that
> this case does not _assume_ that the destination is on-link, which
> was there before. 

I does assume that that the destination is on-link.  In outbound packet
processing, you don't attempt to do link-layer address resolution until
you've done the forwarding table lookup and done on-link determination.

> 
> In any case, this issue was discussed with Jinmei last week and 
> here is the suggested text that we agreed on. Please let me know
> if you have a comment:
> 
> >> 1) If no Router Advertisement is received on any interfaces, a
> >> multihomed host will have no way of knowing which 
> >> interface to
> >> send packets out on, even for on-link destinations.  One
> >> possible approach for a multihomed node would be to 
> >> attempt to
> >> perform address resolution on all interfaces.  The same
> >> argument applies to a singlehomed node that does not receive
> >> any Router Advertisement, but the step in the multihomed case
> >> involves significant complexity.

The same argument does not apply to single homed nodes.  The point of
removing the on-link assumption was to make sure the node does _not_ do
address resolution in the absence of a route to the destination.  Are
you saying that it's ok to do that if you have more than one network
interface?  That's how I read this text.

-Seb



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