When a subscriber using the conditional redirection (e.g. voice mail) is logging on to a foreign network abroad, but is momentarily unavailable, incoming calls would typically have two calls built up: one of them is caller à GMSC à VMSC, the other is VMSC à GMSC à VM. This solution is disadvantageous for the service provider and expensive for the subscriber. Building two international calls can be avoided using AITIA International's new product, the Free Divert To Voice Mail (FDTVM). FDTVM is an IN-based service that monitors calls and intervenes when necessary to stop international legs and redirect callers to service provider's voice mail service or another number.
Regarding traffic distribution, signals may run on two parallel links (their way regulated by the STP), and if one link would discontinue, the whole signal traffic would divert to the other link.
Regarding redundancy, the two devices are configured prioritized: when both devices operate, the service is running through FDTVM1 device, but if the FDTVM1 does not answer, or neither of its links is available, FDTVM2 automatically takes over.
The system without the FDTVM service
In a system without the FDTVM, two call legs are built: one between the subscriber and the VMSC, the other between the VMSC and the voice mail service.
The events are:
1. A subscriber places a call towards another (roaming) subscriber;
2. The GMSC notices that the called party is located in another network abroad and directs the call towards the VMSC;
3. The VMSC notices that the called party is not available and activated conditional redirection (e.g. to his Voice Mail);
4. The VMSC forwards the call to the number set in the conditional redirection and builds a call leg towards the GMSC;
The GMSC forwards the call to the Voice Mail.
The system with the FDTVM service
The FDTVM service collects information about the status of roaming calls and the conditional redirection. The FDTVM intervenes the call process after collecting the necessary information and as a result the redirection would be completed through the national GMSC and not through the foreign VMSC.
The events are:
1. A subscriber places a call towards another (roaming) subscriber;
2. The GMSC notices that the called party is located in another network abroad of which it notifies the FDTVM-device. The FDTVM-device stores the call's parameters;
3. The GMSC continues the call procedure and forwards the call leg towards the foreign VMSC;
4. The VMSC notices that the called party is not available and activated conditional redirection (e.g. to his Voice Mail);
5. The VMSC forwards the call to the number set in the conditional redirection and starts to build a call leg towards the GMSC. The GMSC notifies the FDTVM-device about the start of the new call. In case the call has been authorized for the second FTN, the device stores it and terminates the call;
6. The FDTVM notices the unsuccessful redirection and starts the connection of the first call leg towards the Voice Mail;
7. The GMSC redirects the first call leg to the Voice Mail.
AITIA International, Inc. Czetz János u. 48-50., Budapest 1039, Hungary Ph: +36 1 453 8080 F: +36 1 453 8081
