Polycom® RMX 1800 Administrator’s Guide
4-28 Polycom, Inc.
—All media channels are encrypted: video, audio and FECC.
—Collaboration Server SRTP implementation complies with Microsoft SRTP
implementation.
—LPR is not supported with SRTP.
—The ENABLE_SIRENLPR_SIP_ENCRYPTION System Flag enables the SirenLPR
audio algorithm when using encryption with the SIP protocol. The default value of
this flag is NO meaning SirenLPR is disabled by default for SIP participants in an
encrypted conference. To enable SirenLPR the System Flag must be added to
system.cfg and its value set to YES.
—The SEND_SRTP_MKI System Flag enables or disables the inclusion of the MKI
field in SRTP packets sent by the Collaboration Server. The default value of the flag
is YES. Add the flag to system.cfg and set its value set to NO to disable the inclusion
of the MKI field in SRTP packets sent by the Collaboration Server when using
endpoints that cannot decrypt SRTP-based audio and video streams if the MKI
(Master Key Identifier) field is included in SRTP packets sent by the Collaboration
Server. This System Flag should not be set to NO when HDX endpoints, Microsoft
Office Communicator and Lync Clients. For more information, see "Modifying System
Flags” on page20-1 .
Mixing Encrypted and Non-encrypted Endpoints in one Conference
Mixing encrypted and non-encrypted endpoints in one conference is possible, based on the
Encryption option “Encrypt When Possible” in the Conference Profile - Advance dialog box.
The option “Encrypt When Possible” enables the negotiation between the MCU and the
endpoints and let the MCU connect the participants according to their capabilities, where
encryption is the preferred setting. Defined participants that cannot connect encrypted are
connected non-encrypted, with the exception of dial-out SIP participants.
The same system behavior can be applied to undefined participants, depending on the
setting of the System Flag
FORCE_ENCRYPTION_FOR_UNDEFINED_PARTICIPANT_IN_WHEN_AVAILABLE_MODE:
• When set to NO and the conference encryption in the Profile is set to “Encrypt When
Possible”, both Encrypted and Non-encrypted undefined participants can connect to the
same conferences, where encryption is the preferred setting.
• When set to YES (default), Undefined participants must connect encrypted, otherwise
they are disconnected.
For defined participants, connection to the conference is decided according to the encryption
settings in the conference Profile, the Defined Participant’s encryption settings.
For undefined participants, connection to the conference is decided according to the
encryption settings in the conference Profile, the System Flag setting and the connecting
endpoint’s Media Encryption capabilities.