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Overview


Note

The SBC does not support Lync/Skype.


The SBC Core supports the late media scenarios for Interactive Connectivity Establishment (ICE) and Datagram Transport Layer Security (DTLS). The behavior of late media on the SBC is controlled by the flag lateMediaSupport. The possible values of this flag are passthru and convert.

  • For a late media pass-through call, the SBC supports:
    • Sending the ICE-Lite and DTLS related attributes in the Session Description Protocol (SDP) offer in 18x response or 200 Ok response to the ingress leg, when the INVITE is received without SDP.
    • Sending the ICE-Lite and DTLS related attributes in the SDP answer in PRACK or ACK to the egress leg, when the SDP offer is received in 18x or 200 from the egress leg.
  • For a late media convert call, the SBC supports:
    • Sending the ICE-Lite related attributes in the SDP offer in 18x response or 200 Ok response to the ingress leg, when the INVITE is received without SDP.
    • Sending the ICE-Lite related attributes in the SDP offer in INVITE request to the egress leg, when the ingress INVITE is received without SDP.
  • DTLS is not supported for late media convert calls.
  • Late media support for ICE and DTLS assumes that the SBC is configured appropriately for ICE and DTLS termination. For more details on configuration, refer to Configuring SBC for WRTC.

Call Flows

Non PRACK Late Media Pass-through

Non-PRACK Late Media Pass-through Call Flow

PRACK Late Media Pass-through

PRACK Late Media Pass-through Call Flow

Non-PRACK Late Media Convert

Figure 3: Non-PRACK Late Media Convert Call Flow

PRACK Late Media Convert

Figure 4: PRACK Late Media Convert Call Flow


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