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Operator Pays for Leaving Voice Mail to Roamers

Leaving voice mail messages to roaming subscribers usually means building up two international calls – both on the operator’s cost. This is due to the new regulations that inhibit operators to charge subscribers for the extra costs of voice mails left to a roaming subscriber with conditional call forwarding. This usually means the charges of two international calls explained below:

• a subscriber having an active conditional call divert (e.g., to the voice mail system) attaches to a foreign network abroad;
• the subscriber becomes temporarily unavailable;
• the incoming call builds up two calls: the first on the “caller – GwMSC – visited MSC” and the second on the “visited MSC – GwMSC – VoiceMail” route.

This solution is obviously disadvantageous and expensive for the service provider.

Solution for Cutting Unnecessary Roaming Costs: FDTVM

Building up two international calls can be avoided by using AITIA's product, the Free Divert To Voice Mail (FDTVM) equipment. It is an IN-based service, which monitors calls and intervenes when necessary to release international legs and to redirect the caller to the operator’s voice mail service locally (or optionally to any other number). This IN-based solution includes standalone SSF and SCF functions, and fits well into regular IN systems.

 

The signaling traffic is handled on two parallel signaling links. If either of them fails, the whole traffic is rerouted to the other link automatically.

Meet Regulations

There are new EU regulations that forbid the charging of “tromboning” calls when leaving voice mail. Tromboning refers to the two unnecessary calls set up when a call (initiated towards a roaming subscriber) is forwarded back home due to conditional call divert or late call forwarding. Prior to July 1st 2010, it was common practice to charge these extra call legs to the roaming subscriber, but it is no longer permitted. After this date mobile operators in the E.C. either pay for these extra call-legs by themselves, or implement a technical workaround such as SGA-FDTVM.

Operation/Compatibility

The SGA-FDTVM equipment can handle three different operation modes according to the capabilities of the VPLMN.

• Dealing with postpaid cases in a CAMEL-supported network – FDTVM1
• Dealing with subscribers in a non-CAMEL-supported network – FDTVM2
• Dealing with prepaid cases in a CAMEL-supported network – FDTVM3

System Architecture

SGA-FDTVM is a standalone equipment with standard SS7 or SIGTRAN interfaces. For SS7 we provide our own, proprietary E1 interface cards (SGA-47) that can be inserted into an ISA extension slot of the host machine. For SIGTRAN connections we suggest using commercially available Ethernet cards. The host machine is an industrial grade PC. The software of SGAFDTVM is also well optimized, hence not computationally intensive.

 

These hardware and software requirements allow the operators to use various other SGA programs to run on the same PC. Application availability can be increased by system duplication, which is highly cost-effective for SGA-FDTVM, due to its minimal hardware requirements.