Subject: [Simple] COMEDIA vs MSRP Relays: COMEDIA-TLS

From: Ben Campbell <[email-masked]>
Date: Mon, 20 Jul 2009 16:16:34 -0500

(As individual)

We've had quite a bit of discussion about how the Transport Connection  
Addressing Section (draft-ietf-simple-msrp-acm-00 section 4.2) may or  
may not work with MSRP relays. I'd like to make sure we're not  
neglecting how the COMEDIA Usage section (Section 4.1 and children)  
interact with MSRP relays.

I think there are some open questions. Since each one seems likely to  
generate a thread of discussion, I'm sending them separately:

How does COMEDIA-TLS work with MSRP relays? (There has been some  
discussion on this one, but I don't recall any conclusions)

If I understand correctly, RFC 4572 is really only designed for the  
use of self-signed TLS certs. At least, it states parties to a TLS  
session MUST provide certificate fingerprints. This is an issue for  
MSRP relays, as relays are not involved in the SDP offer/answer, and  
the endpoints are not going to necessarily know the fingerprints of  
certificates used by a relay. Also, it's quite likely that an MSRP  
relay will use a cert signed by a well-known CA, where a fingerprint  
would not add much value.

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From: Hadriel Kaplan <[email-masked]>
Date: Tue, 21 Jul 2009 18:17:34 -0400

Yup, I noted that issue in one of the earlier emails (long ago): that if we use the fingerprint with MSRP Relays, then we need a way for a UA to learn the fingerprint of its Relay(s). (presumably through the MSRP messaging it uses to get the use-path MSRP URI from such Relay(s)?)

-hadriel

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From: "Christer Holmberg" <[email-masked]>
Date: Wed, 22 Jul 2009 01:03:49 +0200

Hi,
 
This is listed as an open issue in my presentation. 
 
The currently available solution proposal is to send the information in the MSRP message itself.
 
Regards,
 
Christer

________________________________

From: [email-masked] on behalf of Hadriel Kaplan
Sent: Wed 22/07/2009 00:17
To: Ben Campbell; Simple WG
Subject: Re: [Simple] COMEDIA vs MSRP Relays: COMEDIA-TLS

-hadriel