1. ACLI Configuration Guide
  2. SIP Compatibility Options
  3. Ensuring Telephone Event Negotiation within Delayed Media and Conflicting Configurations

Ensuring Telephone Event Negotiation within Delayed Media and Conflicting Configurations

In some call flows, the Oracle® Enterprise Session Border Controller (ESBC) may stop including telephone events (101) in SIP responses sent to the calling UAC, including 180 and 200 OK messages. These cases typically include early or late media and additional configuration on the interface. You can configure the sip-interface with the add-sdp-baseBehavior option to ensure telephone event support for these cases without having to change other configuration.

A common, applicable call flow involves a delayed-offer INVITE, where the SDP is not present in the initial INVITE request from the calling UAC. In these cases, the configuration of the sip-interface facing the caller typically includes:

  • add-sdp-invite within a related profile,
  • rfc2833-mode set to transparent, and possibly
  • transcoding configuration.

The ESBC adds SDP based on the add-sdp-invite configuration. It begins call setup and subsequently receives 180 and 200 OK messages from the UAS that include a media offering, such as 0, 101. The conflicting configuration causes the ESBC to not forward the 101 to the caller.

To mitigate against this behavior, configure the caller's sip-interface with the add-sdp-baseBehavior option. 

ORACLE(sip-config)# options + add-sdp-baseBehavior

Note:

add-sdp-baseBehavior option is not compatible with SRTP.