Hold-and-Resume Procedure

The hold-and-resume procedure has three states:

• Media Hold—Starts when the Oracle® Enterprise Session Border Controller sends the empty TCS to the called endpoint to put it on hold.

  When it detects media release, the Oracle® Enterprise Session Border Controller puts the called endpoint on hold. It can only do so if it has exchanged the TCS/TCSAck messages and completed master-slave determination with the calling endpoint.

  When theOracle® Enterprise Session Border Controller receives a TCSAck in response to the empty TCS that it sent to the called endpoint, it closes the logical channels it opened as part of the Fast Connect procedure; the called endpoint likewise closes its logical channels. The two then exchange CLC and CLCAck messages, which signals the start of the Media Resume state.

• Media Resume—Starts when the Oracle® Enterprise Session Border Controller sends a restricted TCS to resume the call.

  The restricted TCS the Oracle® Enterprise Session Border Controller sends contains only the receive/transmit capabilities of the codec types previously accepted by the called endpoint in the Fast Connect procedure. This forces the called endpoint to re-open logical channels of the same codec type that were previously accepted in the Fast Connect procedure.

  After sending this TCS, the Oracle® Enterprise Session Border Controller is ready (as specified in the ITU-T recommendations) to take part on the master-slave determination (MSD) process. However, the called party and not the Oracle® Enterprise Session Border Controller initiates the MSD if it is required. The MSD is completed if necessary. Alternately, the called endpoint can start to re-open its logical channels. When it receives the first OLC from the called endpoint, the Oracle® Enterprise Session Border Controller also starts to re-open its logical channels.

• Media Complete—Starts when all the logical channels that the Oracle® Enterprise Session Border Controller re-opens are acknowledged by the called endpoint.

  When it enters the Media Complete state, the Oracle® Enterprise Session Border Controller updates the called endpoint with the full capabilities of the calling endpoint by sending the full TCS.