Resetting circuits

The application requests the reset of a circuit by invoking ISUPStatusReq with the event type of CIRRESREQ.

When an acknowledgment (release complete message) is received from the far exchange, the ISUP layer delivers a release confirm (EVTSITRELCFM) event to the application. The application can consider the circuit reset upon receiving this indication.

The following illustration shows a circuit reset initiated by the far exchange:

If the far exchange initiates the reset of the circuit, the application receives a status indication (EVTSITSTAIND) with the event type of CIRRESREQ from the ISUP layer. The application can consider the circuit reset upon receiving this indication. The ISUP task acknowledges the reset request by sending a release complete message (RLC).

Note: If the application issued any request related to this circuit that was not processed by the ISUP layer before receipt of the circuit reset message, the application receives an error indication (EVTSITERRIND) with the cause code CCINVALCALLREF. The application can choose to ignore this indication.

The following illustration shows a circuit reset initiated by the far exchange:

The ISUP layer can decide to reset a particular circuit due to protocol errors. Under these circumstances, the ISUP layer issues a status indication (EVTSITSTAIND) with the event type of CIRRESREQLOC, and sends a circuit reset message to the far exchange.

When an acknowledgment (release complete message) is received from the far exchange, the ISUP layer delivers a release confirm (EVTSITRELCFM) event to the application. The application can consider the circuit reset upon receiving this indication.

The following illustration shows a circuit reset initiated by the ISUP layer: