Re: [AVT] Re: [MMUSIC] RE: Draft -04 of Comedia over TLS submitted.Ready for WGLC?

[Magnus Westerlund <magnus.westerlund at ericsson.com>]

Hi Jonathan,

Can you please remind where and when the decision was taken to not 
define TCP/TLS/RTP/AVP? All I find is some loose discussion without 
conclusion about the topic, but nothing I can interpret as an WG 
consensus on this.

I am in favor of defining both TCP/TLS/RTP/AVP and TCP/TLS/RTP/AVPF. I 
would also consider if TCP/TLS/RTP/SAVP is a good idea or not. I would 
consider TCP/TLS/RTP/SAVP a possibility in cases that requires a secure 
TCP/TLS connection, for example due to end point authentication, which 
however is a gateway to an SRTP session. If that is relevant or not is 
another matter.

I also agree with Lazzaro that with the current IETF lead time the only 
reasonable way of providing for future use cases the market wants to 
select it to have it ready. I don't want to be the part blocking actual 
deployment of security. Thus I think we should consider both 
TCP/RTP/SAVP and TCP/TLS/RTP/AVP.

As I see it TCP/RTP/SAVP and TCP/TLS/RTP/AVP have somewhat different 
security properties. TLS provides a secured transport channel with 
possibility to end-point authentication. The SRTP based solution 
provides instead group security and can be done without a trusted 
gateway. So they definitely are applicable in different use cases.

Jonathan Lennox wrote:
> I also noticed that the recent AVT recharter contained the bullet point:
>
>   - to provide a framing mechanism for RTP over TCP and TLS
>
> Was inserting TLS just someone's "this seems like a good idea" as part of
> describing draft-ietf-avt-rtp-framing-contrans for the charter, or did was
> this decision actually made at some point?

Again doing some searching in the archives I find that this formulation 
was part of the proposed charter update I sent out 2003-09-02. It is 
probably something we who wrote it felt was an good idea and reflected 
our understanding of what was going to happen.

I would interpret such that we are allowed and expected to do what the 
charter says. However if we do have motivation why we wouldn't, we 
probably can get away without doing the work.

My conclusion is that we need to discuss this topic again.

Cheers

Magnus Westerlund

Multimedia Technologies, Ericsson Research EAB/TVA/A
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