Subject: [SIP] SIP URLs in Contact

From: "Deepak Mohan" <[email-masked]>
Date: 7 Jun 2001 08:03:18 -0000

Hi,
2.2 of bis-03 says that Contact in OPTIONS should have only SIP URLs, but 10.14 says that "For OPTIONS, Contact provides a hint where future SIP requests can be sent or the user can be contacted via non-SIP means.

Clarifications?

Regards,
Deepak

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From: Jonathan Rosenberg <[email-masked]>
Date: Mon, 11 Jun 2001 00:54:48 -0400

> -----Original Message-----
> From: Deepak Mohan [mailto:[email-masked]]
> Sent: Thursday, June 07, 2001 4:03 AM
> To: [email-masked]
> Subject: [SIP] SIP URLs in Contact
> 
> 
> Hi,
> 2.2 of bis-03 says that Contact in OPTIONS should have only 
> SIP URLs, but 10.14 says that "For OPTIONS, Contact provides 
> a hint where future SIP requests can be sent or the user can 
> be contacted via non-SIP means.
> 
> Clarifications?

The right answer depends on the interpretation of the Contact in the OPTIONS
response. Really, Contact has two separate meanings. The one in INVITE and
INVITE-200 are signaling addresses, which always need to be one single SIP
URL. The Contact in 3xx, REGISTER, and REGISTER-200 are alternate names for
a user, which can be non-SIP URLs, and there can be more than one. The
distinction is subtle (and this is why its one header), but I have become
convinced that they are distinct.

Now, which of these two do we want in OPTIONS? If we are trying to obtain a
direct address for signaling for INVITE, then we want the first
interpretation, in which case it needs to be a single SIP URL. If its a set
of alternate names for a user, then it can be multiple non-SIP URLs. I'm
inclined to think its the latter.

-Jonathan R.

---
Jonathan D. Rosenberg, Ph.D.                72 Eagle Rock Ave.
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