Australia's explosive demand for mobile communications and the tremendous growth of the Internet - IDC predicts 5.76 million Australian users by 2002 - is presenting an exciting opportunity for Cable & Wireless Optus to capture new markets by offering a dynamic range of new and differentiating data applications on its nationwide GSM mobile network.

In today's competitive marketplace, GSM operators like Cable & Wireless Optus are keen to offer low-cost, profitable and innovative services to increase revenues and expand its subscriber base. Nortel Network's GPRS (General Packet Radio Service) provides unlimited opportunities for GSM operators to offer advanced mobile data services for individuals, businesses and corporate users alike.

Of particular appeal is wireless Internet - putting The Net In Your Pocket' - with the upsurge in GSM growth rates paralleling Internet demand, and worldwide mobile Internet penetration, according to IDC and Ovum, to reach 20 percent by 2003.

For mobile operators, Nortel Networks - GPRS solution is the first step towards Unified Networks, bringing together the world of IP (Internet Protocol) and GSM: global, scalable, high-capacity public and private networks built on innovation, IP technology, and application-focused thinking. Unified Networks delivers the benefit of voice and data over one single IP backbone, allowing service transparency across multiple networks and management by one core system.

GPRS is often referred to as generation 2+ technology as it is viewed as a precursor for the move toward third generation mobile technology. Second generation digital mobile technology was primarily designed to deliver voice services. The system uses circuit switched connections which occupy the line for the length of the call. GPRS is a packet switched technology which breaks information into discreet packets for transmission. Unlike circuit switched technology, a packet switched system uses available bandwidth more efficiently by sending packets from multiple users across one line.

The advantage of GPRS is that it takes into account the 'bursty' nature of data traffic and effectively optimises spectrum use by dynamically sharing time slots between different users. GPRS supports direct end-to-end IP connectivity, transparent and non-transparent data, and standard data protocols such as TCP/IP and X.25. Applications can be based on point-to-point and point-to-multipoint services.

The Nortel Networks GPRS solution, designed to minimise the hardware impact on the network, involves a simply overlay to the core Cable & Wireless Optus GSM network. With the simple addition of a few key modules, Cable & Wireless Optus will be able to provide value-added data services to subscribers quickly, whenever and wherever the need arises.

The three core modules are the PCU (Packet Control Unit), SGSN (Serving GPRS Support Node) and GGSN (Gateway GPRS Support Node).

The PCU manages channel and radio link control and provides the standard interface to the SGSN. Based on Nortel Networks' Passport' product - ranked number one in global WAN, ATM, frame relay and frame relay access device markets by IDC, The DellOro Group, In-Sat, Dataquest and Vertical Systems Group - the PCU converts frames from the radio part into packets and vice versa. Additionally, it features a Quality of Service functionality, load sharing and flow control.

The SGSN, also based on Passport, is primarily responsible for mobility management. In addition, it detects mobile stations in the local area for the transmission and receipt of packets; locates and identifies mobile station status; gathers crucial call information, essential for billing; and controls ciphering, compression and interaction with GSM circuit-switched services for mobile paging and Short Message Services (SMS).

The GGSN acts as a gateway between the GSM network and public data networks. Based on Nortel Networks 'feature-rich Connectivity' Extranet switch, the GGSN connects directly to the Internet using IP over a variety of physical and tunnelling protocols. The GGSN also functions as a security firewall, ensuring authorisation of all incoming and outgoing data.

Due to the unique and open platforms of Passport and the Contivity Extranet switch, the GPRS network components support all wireless functions, from the Inter-Working Function (IWF) for today's circuit-switched functionality, to future protocols such as Enhanced Data rates for GSM Evolution (EDGE) and Universal Mobile Telecommunication System (UMTS).