This topic shows are events are generated and how cleanup occurs when TUPConnectReq connection requests fail in the following situations:
If the called number is busy, TUPConnectReq can fail. The following illustration shows how events are generated and how cleanup occurs (before a reconnection is attempted) when a connection fails because the subscriber is busy:
If the far exchange blocked the circuit, TUPConnectReq can fail. The following illustration shows how events are generated and how cleanup occurs (before a reconnection is attempted) when a connection fails because the circuit is blocked:
If the far end exchange resets the circuit, TUPConnectReq can fail. The following illustration shows how events are generated and how cleanup occurs (before a reconnection is attempted) when a connection fails because the circuit has been reset:
If an intelligible answer to the initial address message (IAM) is not received, TUPConnectReq can fail. The following illustration shows how events are generated and how cleanup occurs (before a reconnection is attempted) when a connection fails because there is an unknown or missing response: