1. Configuration Guide
  2. SIP Signaling Services
  3. Early Media Support

Early Media Support

The Oracle Communications Session Border Controller (SBC) supports early media features, including SIP early media suppression, the Private Early Media (PEM) header, and multiple dialog management. This support complies with 3GPP TS 24.628, TS 24.182 and RFC 5009 behavior for sessions supporting early media.

Early media are the RTP/RTCP packets sent to or from the caller before a session is fully established by the receipt of a 200 OK. There are a variety of devices, including IVRs, that may generate this media. When the SBC receives an INVITE message with SDP, it can forward media packets conforming to that SDP to the calling endpoint as soon as it forwards the INVITE to the next hop. It can also forward media packets received from the calling side toward the called endpoint as soon as it receives SDP in a SIP response to the INVITE. These responses are usually provisional messages. This allows for any early media to be played, such as remote ringback or announcements.

Early media can be unidirectional or bidirectional, and can be generated by the caller, the callee, both, or by interim AS components. Important early media concepts for which the SBC provides feature support includes:

  • Private Early Media (PEM) Header Support
  • Early Media Suppression
  • Early Media Support for Multiple Early Dialog Scenarios
  • Selecting SDP within Multi-Dialog Call Scenarios