Verizon this week said it successfully completed its part of a four-nation, two week interoperability test of IP Multimedia Subsystem network equipment, which was orchestrated by the industry association MultiService Forum.
The two weeks of testing – called Global MSF Interoperability (GMI) 2006 – involved 500 test engineers and support staff at five locations. In addition to Verizon labs in Waltham, Mass., the other four locations were BT and Vodafone in England, Korea Telecom in South Korea, NTT in Japan and the University of New Hampshire Interoperability Labs in Durham, N.H.
IMS, currently being defined by several standards bodies, vendors and network operators, is intended to offer the ability to define and implement new multimedia services that interact with each other regardless of the network-access technology and location of the customer. The GMI 2006 tests adhered to MSF Release 3 Implementation Agreements, which combine elements of IMS specifications from the Third Generation Partnership Project (3GPP), 3GPP2 and the European Telecommunications Standards Institute’s TISPAN project.
The tests evaluated the interoperability of 197 IMS network devices manufactured by 26 companies. Eight scenarios were scrutinized, including roaming services across multiple types of networks; QoS through session border controllers and bandwidth managers; 3GPP IMS and mobile core network interoperability; IP carrier interconnect/internetworking; security interoperability; third-party applications and service brokering; network management and operations support systems; and IPv4 and IPv6 internetworking
The five test locations were connected real-time — via session border controllers and bandwidth-managed IP global networks — to perform the tests over two weeks.
Verizon officials said the tests were helpful in maturing IMS and winnowing it down to a set of implementable standards, but it did not conclude the specification’s evolution.
“It was important for moving (IMS) from a theoretical framework to implementation,” says Naseem Khan, principal member of technical staff in Verizon’s Technology organization and member of the MSF board. But Khan added that some IMS interfaces need further enhancement.
“It’s still not a complete picture,” he said.
And security is still a concern if operators’ IMS implementations include Session Initiation Protocol (SIP) elements, which most seem likely to, and especially at edge devices like session border gateways and bandwidth managers.
“Having VoIP or SIP enablement opens up security vulnerabilities,” says Stu Elby, vice president of network architecture and enterprise services at Verizon Laboratories. “There are security concerns and we are addressing those, but I’m not sure IMS brings anything new” to those vulnerabilities.
GMI 2006 participants will provide a full report of their test results on Dec. 1. They will also feed their results back into the industry standards bodies to refine IMS specifications.
Mark Wegleitner, Verizon senior vice president and CTO, says a “macro” IMS interoperability event involving network operators also might be forthcoming.
“We’re very likely to engage in peer wise testing,” he said. “That would be a valuable component in continuing to mature the technology.”
