ERCIM News No.37 - April 1999

Internet Telephony merges with the GSM Network

by Jori Paananen

VTT Information Technology has played a significant role in the development of the Nokia GSM Intranet Office product, which was launched at the CeBIT’98 exhibition. This product is the first in the world to combine Internet Protocol (IP) telephone systems and the worldwide GSM standard using normal GSM phones as terminal devices. By merging the corporate intranet and the GSM network, the Nokia product makes internal company calls extremely cheap or even totally free of charge.

The Nokia GSM Intranet Office product uses standard GSM phones as terminal devices and GSM base stations connected to the corporate intranet. The system utilises the corporate intranet to route internal calls to other GSM phones or workstations (H.323 terminals) equipped with software for IP telephony. Outside the office the calls are routed normally through the public GSM network. The integration of the corporate intranet and the GSM network represents a quantum leap towards total mobility and reachability of company employees at a reasonable cost. On the other hand, new cost-effective services will enable telecom operators to improve customer loyalty and increase the use of mobile phones.

The GSM Intranet Office prototype system demonstrated at CeBIT’98 was equipped with a Gatekeeper and an Intranet Location Register (ILR) developed by VTT. For the GSM phones registered to the system, the Gatekeeper is equivalent to a Mobile Switching Centre (MSC). The other system network elements are connected to the Gatekeeper over an IP-based intranet. The Gatekeeper checks the ILR to determine whether the phones involved in the call are authorised to use the system and whether they are located in the GSM Intranet Office area. If they are, it routes the GSM signalling and traffic inside the system. If either one is located outside the area, or is not registered as a user, it routes the call through the A-interface Gateway to the public GSM network.

The development of the GSM Intranet Office system towards the final product has continued throughout 1998. VTT Information Technology has participated in the development of various parts of the system.

Fore more information, see:

Please contact:

Jori Paananen - VTT Information Technology
Tel: +358 9 456 5646

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