Telecoms carriers’ next-generation networks (NGNs) currently under construction cannot guarantee either interoperability or quality of voice-over-IP (VoIP) calls across national boundaries, according to a report from analyst Ovum.

Differences in the definition of NGNs and national regulations from one country to the next, coupled with squabbles about interconnect charges, could lead to significant problems between telecoms carriers, Dan Bieler of Ovum Germany warned last week.

“Outside a private network, it remains basically impossible to control VoIP quality of service and it is difficult to make calls between various soft-client VoIP providers,” Bieler said. “This will slow the spread of VoIP technology.”

Angus Flett, director of product management at BT Wholesale, agreed that end-to-end IP networks increase complexity. But he pointed out that bodies such as the Institute of Electrical and Electronics Engineers and the European Telecoms Standards Institute have worked to implement pan-European standards, such as Session Initiation Protocol (SIP), across networks.

“The [telecoms] industry globally has got on very well for years and there are very well established technical forums outside the regulatory framework to agree standards to allow interoperability,” Flett said.

Bieler expected most NGNs to be operational by 2012, and mobile operators are scheduled to complete all-IP networks by 2020. However, BT’s 21st Century Network is due to be fully IP-based by 2008.

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