Re: [Simple] MSRP-ACM compatibility

[Ben Campbell <ben at nostrum.com>]

(as individual)

On Apr 29, 2009, at 1:11 PM, Christer Holmberg wrote:

> Hi,
>
> In fact, chapter 4.1.2 talks about TLS, and already says that RFC  
> 4572 (which defines the fingerprint attribute) shall be used.
>
> But, I guess we can add some additional text which describes what we  
> have been discussing.

To make this interop with MSRP relays, we would need more work. Relays  
are not involved in the SIP signaling, so there's no opportunity for  
them to send a fingerprint. We would need some way for endpoints to  
get fingerprints from the relays, and include them in the signaling.

There's also the fact that any fingerprint mechanism will require at  
least integrity protection of the fingerprint, which is showing itself  
to be controversial in the RFC4479 discussions in the other work groups.

I think that to have a useful discussion about this, we will need a  
proposal covering this end-to-end. That doesn't necessarily mean it  
all ends up living in the final ACM draft, but we at least need to  
understand if we have a workable architecture.


> Regards,
>
> Christer
>
> -----Original Message-----
> From: simple-bounces at ietf.org [mailto:simple-bounces at ietf.org] On  
> Behalf Of Christer Holmberg
> Sent: Wednesday, April 29, 2009 3:55 PM
> To: Hisham Khartabil; Simple WG
> Subject: Re: [Simple] MSRP-ACM compatibility
>
>
> Hi,
>
> > 1) We seem to have consensus that it must be possible for MSRP  
> > devices
> > using ACM to talk to devices using relays.
> >
> > We don't have consensus on how far we are willing to update
> > RFC4975/4976 to accomplish this. We don't have consensus around any
> > currently proposed mechanism to accomplish the requirement.
>
> As far as I know, the only proposed mechanism is to change the  
> session mapping procedure, to only take the user part into account.
>
> But, that proposal is related to the TLS issue, so we we need to  
> move that forward before we can make a decission.
>
> Regards,
>
> Christer
>
>
>
>
> > 2009/4/1 Hisham Khartabil <hisham.khartabil at gmail.com>:
> > > The MSRP-ACM draft has an open requirements question on backwards
> > > compatibility with endpoints that use MSRP relays. In San Francisco
> > > some 20 or so people raised their hands one way or another on this
> > > question, yet only a much smaller number have engaged in the list
> > > discussion.
> > >
> > > Please offer your opinions on the following questions. We'd
> > appreciate
> > > the reasoning behind your opinions, rather than just yes or
> > no votes.
> > > We'd really like to hear from every person who raised a hand in San
> > > Francisco. If you stated an opinion at the microphone,
> > please restate
> > > it here.
> > >
> > > 1) Is there a requirement for an endpoint that uses the C-line
> > > addressing mechanism in the MSRP-ACM draft to be able to talk to an
> > > endpoint that uses an MSRP relay (RFC 4976).
> > >
> > > 2) If you said yes to 1), is it acceptable to update RFC
> > 4975 and/or
> > > RFC 4976 to achieve compatibility?  If so, how extensively?
> > >
> > > Much appreciated,
> > > Hisham
> > _______________________________________________
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