RE: [Sip] SIP Identity using Media Path

["Dan Wing" <dwing@xxxxxxxxx>]

> > Yes, I agree that will give the best chance.  Of course, it is
> > always possible for an SBC (or firewall) to block such messages 
> > anyway (as has been discussed on the RTPSEC mailer).
> 
> But that would at least mean that the SBC would have to look 
> inside the media stream to see that not everything in it is 
> (S)RTP, instead of just looking at the source and destination. 

Many SBCs, and some firewalls, include "RTP inspection".  They drop
packets that aren't RTP packets (such as ICE packets, DTLS-SRTP
packets [draft-ietf-avt-dtls-srtp], and RTCP packets
[draft-ietf-avt-rtp-and-rtcp-mux].

> It may happen, of course, but at least it's less likely. When it does
> appear, it would require an SBC that can recognize the security
> interchange for what it is and allow it to pass even though it isn't
> media. I'm not sure if that can reasonably be done.

Unless or until another solution to providing Identity is proposed,
I think it'll be necessary.  Identity is important so 
that the industry can build reliable and useful whitelists, 
blacklists, and reputation systems -- which are all necessary for 
call routing and mitigating spam.

-d