Hi Marc,
-----Original Message-----From: avt-bounces at ietf.org [mailto:avt-bounces at ietf.org] On Behalf Of MarcPetit-Huguenin Sent: Monday, October 19, 2009 4:05 PM To: avt at ietf.org Subject: [AVT] SRTP with layered encodingI was not able to find guidelines on how to use SRTP with multicast layered encoding. As all the layers share the same SSRC, the same master key cannotbe shared between them.
right.
Using the same master key for all the layers would be great though, so I was thinking that a way to do this would be to redefine the label byte so the 5first bits are used for the layer number (from 0 to 31).
That seems like a reasonable use of the label byte.The tricky part here is that the receiver would need to know the correspondence between the layer number and the RTP session. This would need to be communicated via signaling, presumably, and then stored/used by all of the session participants.
Any thoughts on this? Should I write an I-D?
How much savings will this key-sharing method bring? Each of the RTP sessions will have some amount of state associated with it. Is the savings of not storing a key or two per session really that valuable?
David
Thanks. -- Marc Petit-Huguenin Personal email: marc at petit-huguenin.org Professional email: petithug at acm.org Blog: http://blog.marc.petit-huguenin.org _______________________________________________ Audio/Video Transport Working Group avt at ietf.org https://www.ietf.org/mailman/listinfo/avt
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