Subject: RE: [Sip] SIPS question

From: "Peterson, Jon" <[email-masked]>
Date: Wed, 30 Oct 2002 11:21:26 -0500

I agree that I don't see any immediate use for this, but I also don't see
any danger that would mandate forbidding it. Was there anything you had in
mind?

Jon Peterson
NeuStar, Inc.

-----Original Message-----
From: Christer Holmberg [mailto:[email-masked]]
Sent: Wednesday, October 30, 2002 5:22 AM
To: [email-masked]
Subject: [Sip] SIPS question

Hi,

The RFC says that if the INVITE Contact header contained a SIPS-URI, the
200 Contact header must also contain a SIPS-URI.

However, I can't find anywhere said if it's allowed  to put a SIPS-URI
in the 200 Contact header if the INVITE Contact header contained a
SIP-URI. Don't know if it would make much sense, but still...

Regards,

Christer Holmberg
Ericsson Finland

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_______________________________________________
Sip mailing list  https://www1.ietf.org/mailman/listinfo/sip
This list is for NEW development of the core SIP Protocol
Use [email-masked] for questions on current sip
Use [email-masked] for new developments on the application of sip

---

From: Christer Holmberg <[email-masked]>
Date: Wed, 30 Oct 2002 20:37:48 +0200

Hi,

> any danger that would mandate forbidding it. Was there anything you had in

Assuming the UAS does insert a SIPS-URI in the Contact, let's have a look at
the following scenario:

UA1 ------------- P1 -------------- UA2

Now, UA1 sends an INVITE to UA2, via P1:

- UA1 inserts a SIP-URI in the Request-URI

- P1 inserts a Record-Route header with a SIP-URI

- UA2 sends 200 with a Contact header with a SIPS-URI

Q1:  Now, UA2 indicates that requests from P1 to UA2 shall be sent using TLS,
due to the SIPS-URI in the Contact. However, requests from UA2 to P1 would be
sent using let's say UDP, due to the SIP-URI in the Record-Route.

Q2: Now, if P1 supports loose routing, when UA1 sends another request within
the session, it will look like:

Request-URI: SIPS-URI: UA2
Route:SIP-URI: P1;lr

Now, according to chapter 26.2.2 in RFC3261, if the Request-URI contains a
SIPS-URI, TLS shall be used. However, the request is not sent to the
Request-URI, but to the top Route, which contains a SIP-URI. So, since P1
record routed with a SIP-URI, and that route is used to route the request, why
shall UA1 make the transport decission based on the SIPS-URI in the
Request-URI??? UA1 doesn't even know if P1 supports TLS or not, and UA1 may
not support TLS, so....

Regards,

Christer Holmberg
Ericsson Finland