Selecting SDP within Multi-Dialog Call Scenarios

By default, the Oracle® Enterprise Session Border Controller saves SDP presented in a series of early dialogs using To tags to differentiate between dialogs. If the session continues with a 200OK that does not include SDP, the Oracle® Enterprise Session Border Controller refers to the To tag to identify the dialog from which the Oracle® Enterprise Session Border Controller selects the SDP for the media flow. This complies with 3GPP TS 24.628, TS 24.182 and RFC 5009 behavior for sessions supporting early media.

Consider a SIP dialog with early media that proceeds by establishing call scenarios in which the final 200 OK does not include any SDP. This messaging may include multiple 183 (Session Progress) messages with SDP that differ from each other and include different To tags, establishing multiple early dialogs. In these scenarios, the Oracle® Enterprise Session Border Controller uses the saved SDP from the dialog that matches the dialog indicated in the 200 OK's To tag to anchor the media. If the 200 OK includes SDP, the Oracle® Enterprise Session Border Controller uses that SDP to anchor the media.

Note:

The user can disable this behavior, for example, to use the functional behavior in Oracle® Enterprise Session Border Controller version S-CZ7.2.0 and below, which is to use the last SDP seen as the source for SDP. Deployments that rely on this behavior must revert to it using the sip-config's dont-save-early-dialog-sdp option parameter.

ORACLE(sip-config)# options +dont-save-early-dialog-sdp