Subject: [AVT] RFC3711: Srtp Parameters for Rx/Tx ?

From: "milo diurn" <[email-masked]>
Date: Fri, 19 Nov 2004 15:10:43 +0000

Karl, and Srtp community,

In RFC3711, I do not see any clear way of setting the Srtp parameters (chap 
8.2)
for both ways of the session:
- Transmit : need the Srtp parameters for Encryption (to be sent to the 
network)
- Receive: need the Srtp parameters for Decryption (to be received from the 
network).

Could you, please, clarify this point ?

Thanks

Regards

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From: "David A. McGrew" <[email-masked]>
Date: Fri, 19 Nov 2004 07:54:47 -0800

Hi Milo,

On Nov 19, 2004, at 7:10 AM, milo diurn wrote:

> In RFC3711, I do not see any clear way of setting the Srtp parameters 
> (chap 8.2)
> - Transmit : need the Srtp parameters for Encryption (to be sent to 
> the network)
> - Receive: need the Srtp parameters for Decryption (to be received 
> from the network).

essentially, the parameters are established out-of-band for SRTP.  The 
transmit/receive issue doesn't affect this point; either SRTP endpoint, 
or a third-party device (e.g. a call controller) could set the 
parameters.  In this respect, SRTP is like RTP: it relies on another 
protocol to signal the context information needed to get it going.  
MIKEY and the SDP Security Descriptions are two standards-track ways of 
signaling SRTP.

David