Subject: [Sipping] Question on draft-ejzak-sipping-p-em-auth-01.txt

From: Gonzalo Camarillo <[email-masked]>
Date: Fri, 07 Jul 2006 12:58:25 +0300

Hi,

the draft now talks a great deal about how the network will open and 
close its gates to authorized and unauthorized early media respectively. 
However, it seems that you can implement this gating function in every 
scenario at the terminating side without any extension:

1) if an INVITE arrives to an IMS terminal, the terminal's P-CSCF will 
make sure that the PCRF does not allow early media in any direction.

2) if an INVITE arrives to a PSTN gateway, the gateway will allow early 
media in both directions.

3) if an INVITE arrives to an AS, the AS will allow early media in 
whatever direction it needs.

4) if an INVITE leaves the IMS network (i.e., the trusted domain), the 
I-BCF will not allow early media in any direction.

Could you please clarify in which scenarios this extension is needed in 
order to perform the gating function?

Thanks,

Gonzalo

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---

From: Dean Willis <[email-masked]>
Date: Thu, 13 Jul 2006 09:53:12 -0500

On Jul 7, 2006, at 4:58 AM, Gonzalo Camarillo wrote:

>
> 4) if an INVITE leaves the IMS network (i.e., the trusted domain),  
> the I-BCF will not allow early media in any direction.
>

This precludes having an IMS terminal place a call to outside the IMS  
domain that then gets routed to a PSTN gateway and terminated on a  
destination that requires early media.

Early media is broken. Bandaids will not fix it, and will assure an  
increase of this sort of interoperability problem.

--
Dean