Subject: [Sip] Open Issue #88: Addressing OPTIONS to a proxy/redirect server

From: Jonathan Rosenberg <[email-masked]>
Date: Wed, 5 Dec 2001 17:17:47 -0500

Issue:

How do you address an OPTIONS to a specific proxy/redirect server? The spec
simply says that the R-URI indicates the server, but doesn't say how to do
it.

Discussion:

This is a fairly minor issue. Given the infrequency of OPTIONS in general,
and the even more infrequency of OPTIONS to servers, its not a big deal. But
its an easy one anyway.

Proposal:

The domain in the request-URI would look like it does for REGISTER. So, if
you want to get the extensions supported by the proxy for foo.com:

OPTIONS sip:foo.com SIP/2.0

The mechanism of using Max-Forwards to query a specific proxy on the path
would also remain.

-Jonathan R.

---
Jonathan D. Rosenberg, Ph.D.                72 Eagle Rock Ave.
Chief Scientist                             First Floor
dynamicsoft                                 East Hanover, NJ 07936
[email-masked]                     FAX:   (973) 952-5050
http://www.jdrosen.net                      PHONE: (973) 952-5000
http://www.dynamicsoft.com

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---

From: "Jo Hornsby" <[email-masked]>
Date: Thu, 6 Dec 2001 13:22:54 -0000

> Issue:
> 
> How do you address an OPTIONS to a specific proxy/redirect 
> server? The spec simply says that the R-URI indicates the
> server, but doesn't say how to do it.
> 
> Discussion:
> 
> This is a fairly minor issue. Given the infrequency of 
> OPTIONS in general, and the even more infrequency of
> OPTIONS to servers, its not a big deal. But its an easy
> one anyway.
> 
> Proposal:
> 
> The domain in the request-URI would look like it does for 
> REGISTER. So, if you want to get the extensions supported
> by the proxy for foo.com:
> 

Agreed.

> The mechanism of using Max-Forwards to query a specific proxy 
> on the path would also remain.

Yes..., I noticed the resurrection of said mechanism.

I thought we decided to remove it ages ago; what was
the motivation for bringing him back?

 - Jo.

---

From: Jonathan Rosenberg <[email-masked]>
Date: Tue, 18 Dec 2001 14:35:45 -0500

>>OPTIONS sip:foo.com SIP/2.0

This issue was presented at IETF 52, and there were no objections. 
Therefore, I will consider it closed.

> the motivation for bringing him back?

Actually, my recollection is that we agreed to do it. THe main 
motivation, I think, was to discover the capabilities of all proxies 
along the path from you to the desired UAS, allowing a sort of sip 
capability traceroute. Since you don't know the set of proxies, or their 
domains, you can't target the OPTIONS at them explicitly with a domain 
name. I should probably add some verbiage along those lines.

Thanks,

Jonathan R.

-- 
Jonathan Rosenberg, PhD                 72 Eagle Rock Avenue
Chief Scientist                         First Floor
dynamicsoft                             East Hanover, NJ 07936
[email-masked]                 FAX: (973) 952-5050
http://www.jdrosen.net                  PH: (973) 952-5000
http://www.dynamicsoft.com