Wednesday, July 16, 2008

GSM Tests Voice Calls based on the SIP-I Protocol

The GSM Association (GSMA), which represents the world's 750 GSM mobile phone operators across 218 countries, has completed trials of voice calls based on the SIP-I protocol between core networks supplied by Ericsson and Nokia Siemens Networks.

SIP-I, or the Session Initiation Protocol with encapsulated ISUP, is a protocol used to create, modify, and terminate communication sessions based on ISUP using SIP and IP networks. Services using SIP-I include voice, video telephony, fax and data. In this trial, SIP-I was used to control the transmission of voice calls from a conventional circuit-switched mobile network on to a IP-based backbone network and then back onto a conventional circuit-switched mobile network.

The SIP-I trials, which were hosted by TeliaSonera in their Finnish and Swedish laboratories, form part of the GSMA's IPX initiative to develop a private global Internet Protocol (IP) backbone designed specifically to provide guaranteed levels of quality of service and security to customers of mobile operators and other service providers.

The GSMA recommends that mobile operators adopt SIP-I, which is widely used by fixed network operators and transit networks, to control the transmission of packet-based voice between mobile networks. Using SIP-I will typically involve less transcoding and provide a higher-quality of service than other protocols, while making it easier for mobile operators to achieve end-to-end call control and upgrade their networks in future.

"SIP-I is the protocol of choice for mobile and fixed operators alike and is an important element of the GSMA's strategy to help mobile operators migrate their networks to IP," said Alex Sinclair, Chief Technology Officer of the GSMA. "With the help of Ericsson, Nokia Siemens Networks and TeliaSonera, we have demonstrated that SIP-I can work well across networks supplied by different vendors."

The GSMA trials were the first to test the SIP-I interoperability of Nokia Siemens Networks and Ericsson mobile softswitches, which connect calls from one device to another. The GSMA plans to conduct further trials to advance the level of inter-operability of SIP-I.

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