Re: NHRP question

[Yakov Rekhter <[e-mail]>]

Eric,

> 	The redundancy between these bits is largely an issue of usage.  The
> fact that a query source is a host (or a router) is significant in
> determination of whether or not the information contained in a request
> is "stable" (at least to some implementations) but is none-the-less a
> fact that might be worth knowing.  The same thing applies to whether or
> not _each_ destination in a response is a host or router.  The issue of
> stability verses source/destination type should be treated as orthogonal
> and the bits retained - after all, the minute someone comes up with an
> example of why the information MUST be treated as orthogonal, the bits
> will neeed to re-inserted and this would be likely to be an issue with
> future backward compatibility.

If we step back for a second, we could realise, that just like an NHRP
Reply carries a set of destinations for which the originator of the
Reply could act as the end of a shortcut, an NHRP Request could also
carry a set of destinations for which the originator of the Request
could act as the end of a shortcut (recent message from Joel alluded to
this possibility). And in this case we only need to know whether the
set of destinations, for which an originator of a message (whether
Request or Reply) could provide a shortcut, could be viewed as "safe"
("stable"). This, in turn, would eliminate certain asymmetry (arguably
artificial) that is present in the current spec. It would also make it
better aligned with the router-router spec, as there is no reason
to preserve this artificial asymmetry in the router-router case.

Yakov.