AudioCodes Mediant 4000 SBC User Manual page 221

User's Manual
The device can record calls between two IP Groups. The type of calls to record can be
specified by source and/or destination prefix number or SIP Request-URI, as well as by call
initiator. The side ("leg") on which the recording is done must be specified. Specifying the
leg is important as it determines the various call media attributes of the recorded RTP (or
SRTP) such as coder type.
The device can also record SRTP calls and send it to the SRS in SRTP. In such scenarios,
the SRTP is used on one of the IP legs for SBC calls. For an SBC RTP-SRTP session, the
recorded IP Group in the SIP Recording table must be set to the RTP leg if recording is
required to be RTP, or set to the SRTP leg if recording is required to be SRTP.
For SBC calls, the device can also be located between an SRS and an SRC and act as an
RTP-SRTP translator. In such a setup, the device receives SIP recording sessions (as a
server) from the SRC and translates SRTP media to RTP, or vice versa, and then forwards
the recording to the SRS in the translated media format.
The device can send recorded SBC calls to multiple SRSs. To achieve this, you can
configure up to three groups of SRSs, where each group can contain one SRS
(standalone), or two SRSs operating in an active-standby (1+1) mode for SRS redundancy.
The device sends both SIP signaling and RTP to all standalone SRSs.
For SRS redundancy, the device sends SIP signaling to all SRSs (active and standby) in
the SRS redundancy groups, but sends RTP only to the active SRSs. If during a recorded
call session, the standby SRS detects that the active SRS has gone offline, the standby
SRS sends a re-INVITE to the device and the device then sends the recorded RTP to the
standby SRS instead (which now becomes the active SRS). For new calls, if the device
receives no response or a reject response from the active SRS to its' sent INVITE
message, the device sends the recorded call to the standby SRS.
Figure 15-7: Multiple SRSs (Standalone and Redundancy)
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Mediant 4000 SBC