Circuit Blocking/Unblocking from a Network

Circuit Blocking from a Network - Normal Case

In this case, the circuit is put in the xxx_MN_REMOTELY_BLOCKED state.

Figure 20-1 Circuit Blocking from Network - Normal Case

Circuit Blocking from User - Normal Case

In this case, the circuit is put in the xxx_MN_LOCALLY_BLOCKED state.

Figure 20-2 Circuit Blocking from User - Normal Case

Circuit Unblocking from Network - Normal Case

In this case, the message only unblocks a maintenance-oriented blocked circuit.

Figure 20-3 Circuit Unblocking from Network - Normal Case

Circuit Unblocking from a Network on Reception of an IAM

A circuit which is remotely blocked (maintenance-oriented or hardware-oriented) is automatically unblocked on reception of an IAM, not being a test call.

The application is warned through a MAINTENANCE_SYSTEM_IND primitive indicating MN_UNBLOCKING or HW_UNBLOCKING, depending on the state of the circuit.

Figure 20-5 Circuit Unblocking on Reception of IAM

Circuit Blocking during Setup Procedure

The reception of a BLO during the setup procedure (wait_for_ACM state) triggers a release of the circuit. The application is informed through a START_RELEASE_IND primitive indicating BLOCKING. On reply with a START_RELEASE_IND_ACK, the REL message is sent to the network, and a RELEASE_CONF primitive is issued to the application by HP OpenCall SS7 ISUP on receipt of the RLC message.

Figure 20-6 Circuit Blocking during Call Setup