Call Release

A call can be released by either party, calling or called.

Abnormal Call Release - Case 1

This scenario depicts a a situation where the peer node fails to acknowledge the REL message sent out by HP OpenCall SS7 ISUP. As a result, HP OpenCall SS7 ISUP:

First retransmits the REL message every T1, until T5 pops
After T5, HP OpenCall SS7 ISUP A issues a MAINTENANCE_SYSTEM_IND indicating T5_TIMEOUT to application A and initiate the “Circuit Reset after T5” procedure by sending a START_RESET_IND primitive to the application. The procedure is controlled by one timer: T17. A reset message (RSC) is sent out upon receipt of the START_RESET_IND_ACK from application.
On each occurrence of T17, an RSC message is sent out
The procedure goes on until a STOP_REQ primitive is received from application A. The STOP primitive stops the reset procedure and brings the circuit back to idle state.

The abnormal call release procedure described in this scenario is applicable to both inbound and outbound circuits.




	NOTE: RSC Message generation upon time-out is suspended if MTP3 is not available or congested.

Figure 19-6 Abnormal Release - Reset Failed

Abnormal Call Release - Case 2

In this case, an RLC message is eventually received during the reset procedure. As a result, HP OpenCall SS7 ISUP completes the reset sequence and issues a RESET_CONF() primitive. A MAINTENANCE_SYSTEM_IND indicating RLC_AFTER_T17 is issued to the application before RESET_CONF.

Figure 19-7 Abnormal Release - RLC Received at Least

Call Release

Technical documentation

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Abnormal Call Release - Case 1

Abnormal Call Release - Case 2