RFC 2833 Payload Type Mapping

The Oracle® Enterprise Session Border Controller does not require that call legs use the same media type for telephone-event. If each call leg uses a different media type value, the Oracle® Enterprise Session Border Controller facilitates payload type mapping to ensure the telephone-event media stream be reliably transported across the call.

• On the SDP offer side, when the Oracle® Enterprise Session Border Controller returns its SDP answer, it uses the same media type that the SDP offerer offered.
• The Oracle® Enterprise Session Border Controller forwards the originally offered telephone-event media type to the SDP answerer. If telephone-event was added by RFC 2833 mode, the Oracle® Enterprise Session Border Controller adds telephone-event with the media type value configured in the RFC 2833 payload parameter. If telephone-event was added by a codec policy, the Oracle® Enterprise Session Border Controller adds telephone-event with the media type value configured in the media profile.
• If the SDP answerer returns a new value for telephone-event, the Oracle® Enterprise Session Border Controller still supports RFC 2833 on that side of the call and uses the media type that the answerer sent.