Limits to SRTP implementation

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SUMMARY: GVP implementation of SRTP has some limitations not fully documented. (GVP-21356)

The next publication of the GVP 8.5 User's Guide will include this revision:

CHAPTER: Appendix I: Specifications and Standards
SECTION: Related Standards
ADD THIS NOTE below the line "RFC 3711 The Secure Real-Time Protocol (SRTP)":
Notes:

• The Media Server (MS) does not support some options in the SRTP specification, including: the Master Key Index (MKI), key derivation rates other than zero, the cipher F8, anti-replay lists with sizes other than 128, the use of the packet index to select between master keys.
• MS does not support the FEC_ORDER and FEC_KEY session parameters.
  …where FEC stands for Forward Error Correction. Refer to Section 6 of RFC 4568 for details.
• MS ignores the WSH (Window Size Hint) parameter and assumes a value of 128.
• MS supports only the default master key lifetime.
• MS rejects the media line containing the crypto: attribute if the RTP profile that was signaled is not RTP/SAVP.
• MS rejects the media line if the keying method is not inline: (the only keying method that is specified in RFC 4568).