Re: [Sip] Comparison of retargeting proposals

[Hadriel Kaplan <HKaplan at acmepacket.com>]

> -----Original Message-----
> From: Dean Willis [mailto:dean.willis at softarmor.com]
>
> On Apr 2, 2008, at 6:05 PM, Hadriel Kaplan wrote:
>
> > Routing is when a proxy routes.  I believe the intention was that
> > this mean the proxy does not touch the req-uri, but my guess is
> > that's not agreed is reality. (more on that later)
>
> In RFC 2543, routing always required changing the ReqURI.  RFC 3261
> loose-routing changed this, and proxies only change the Request URI
> when changing the target. RFC 3261 does not distinguish between target
> changes that change the identity of the target and those that do not,
> hence the new terms "rerouting" and "retargeting".

Sorry I should have been clearer.  I didn't mean it was in question what rfc3261 meant, I meant it was in question what "proxies" actually do.  Now the quick answer is, if they don't do what 3261 says, those ain't "proxies".  And I agree that I'm using a bad term here - I think the issue at hand is actually what real sip hops do in the real world, even those claiming to be a "proxy", not what rfc3261 Proxies (with a capital P) do.


> I'd call that operation rerouting, not routing. It is the functional
> equivalent of replacing the request-URI with a Contact -- it's just
> that the new request-URI is determined by some means other than
> registration against the AOR. This might be, for example, via static
> provisioning, or by matching against a TRIP routing table.

Or based on an ENUM response...

> The fact
> that the userparts encode phone numbers is essentially irrelevant to
> the question of what type of operation (routing, rerouting,
> retargeting) is used, although it might be very important to how the
> proxy might decide which operation to use and which destination to
> encode.

Yes, exactly.  And yet that proxy has absolutely no idea if it's re-routed or re-targeted by changing the hostpart.

-hadriel
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