[Perc] Double Encryption and header extensions issue

[Sergio Garcia Murillo <[e-mail]>]

Hi all,

I have been reviewing the documentation for double encryption and I have 
serious doubts about how the header extensions are handled.

If I have understood it (please correct me if I am wrong) the MD must 
rely all the header extensions present before the OHB to the other peers:

       The Media Distributor MUST NOT delete any header extensions before
       the OHB, but MAY add, delete, or modify any that follow the OHB.

This is an obvious requirement, as to be able to decrypt the inner 
crypto, the end receiver must have the same original rtp packet, which 
includes header extensions.

My concerns is that there are scenarios in which this is not possible:

  * Sender and receiver may not support same set of header extensions
  * Sender and receiver may have negotiated a different id for same
    header extension

In any of the previous scenarios, the receiver will not be able to parse 
the packet correctly, and at best case scenario, it will ignore the 
header extension.

Is there anything that I missing?

Best regards
Sergio