Spirent® Communications Enables Service Providers to Accelerate Implementation of IPTV Networks; Integration of New Technology with Spirent IPTV Quality of Experience Test System Facilitates Accurate Anticipation of Subscriber Experience

Business Wire, March 20, 2006

ROCKVILLE, Md. -- Spirent Communications (NYSE:SPM)(LSE:SPT), a provider of integrated performance analysis and service assurance systems for next-generation network technologies, today announced that it has integrated V-Factor(TM) into the Spirent IPTV Quality of Experience (QoE) Test System. V-Factor, developed by QoSmetrics, is an implementation of the Moving Picture Quality Metric (MPQM) standard for network-delivered video assessment and displaces the older, primitive Media Delivery Index (MDI) approach.

By employing the Spirent IPTV QoE Test System with V-Factor, network equipment manufacturers and service providers can rapidly deliver the highest quality IPTV service. By accurately anticipating subscriber's IPTV service experience, V-Factor is critical to the successful launch of IPTV networks and services. This drives service adoption, increases subscriber loyalty and reduces churn. Hitachi is one of the first IPTV network equipment manufacturers to employ Spirent's V-Factor enabled test system.

The Spirent IPTV QoE Test System along with V-Factor technology provides a higher class of fidelity testing metrics. It determines video quality as perceived by a subscriber and offers the highest correlation with user's actual quality of experience. V-Factor, which also includes audio performance assurance, takes into account network impairments such as delay variation and packet loss episodes that impact the video buffer used to restitute a video image as well as image complexity and the type of codec used. The technology enables the service provider to understand how network performance issues impact this perceived quality, in advance of the service being launched. Obsolescent testing metrics such as MDI merely attempt to infer subscriber QoE based on network performance indicators.

"MDI only looks at two network parameters and is blind to video stream content making it unsuitable for video quality assessment," said Bahaa Moukadam, vice president, IP Telephony, Spirent Communication. "The Spirent test system combined with V-Factor looks at both network impairments and video stream content to report a video MOS score and a wide range of relevant statistics for comprehensive diagnostics of network and coding problems enabling service providers to successfully rollout IPTV services."

V-Factor is an objective measurement system that reproduces the subjective experience of the human observer. Network-based metrics are only capable of suggesting a coarse grade of subscriber QoE and are not sufficient for performance evaluation of video services like IPTV, especially in the context of a highly competitive broadband video market. MPQM, by comparison, is based on an objective evaluation method that is capable of filtering network-induced quality of degradation by properties of human vision.

"We're delighted at the opportunity to work with Spirent Communications to deliver such strong IPTV testing solutions for service providers and network equipment manufacturers," said Yves Cognet, chairman, QoSmetrics. "Our V-Factor technology has proven itself to be adaptable and deployable in everything from the core to the set top. Integrating this technology into the Spirent IPTV QoS Test System is certainly a key milestone for the IPTV test market."

About QoSmetrics

QoSmetrics is a leading provider of integrated network performance assurance solutions for carriers, service providers and enterprises who seek network performance assurance for high availability mission-critical service offerings tied to their revenues and/or productivity. Products sold and deployed worldwide through a network of channel partners are ideal for a variety of applications, including triple play, voice, video, data and other converged network applications and services, such as IPTV. QoSmetrics' software agents, web-based agents and hardware probes combine to provide comprehensive real time multi-protocol, end-to-end and scalable testing, monitoring and diagnostics to troubleshoot network problems prohibiting or hindering access to applications or the delivery of promised levels of services. QoSmetrics products feature advanced patented capabilities that go beyond traditional ping-based solutions to fully pinpoint, dissect and resolve any network problems during planning or deployment, such as jitter, packet loss, latency or equipment failures and inabilities. Founded in 1999, QoSmetrics maintains corporate and R&D facilities in Camarillo, Calif., just west of Los Angeles, and in Massy, France, near Paris. A privately held company, QoSmetrics has secured funding from leading investors and has been generating revenues since 2003 with four generations of products. More information about the company can be found online at www.qosmetrics.com.

About Spirent Communications

Spirent Communications (www.spirentcom.com) is a global provider of integrated performance analysis and service assurance systems that enable the development and deployment of next-generation networking technology such as Internet Telephony, broadband services, 3G wireless, global navigation satellite systems and network security equipment. Spirent's solutions are used by more than 1,500 customers in 30 countries, including the world's largest equipment manufacturers, service providers, enterprises and governments. Based in Rockville, Md., Spirent Communications reported 2005 revenue of $403.3 million and has 1,700 employees worldwide. The company is the largest business group of Spirent plc, traded on the London and New York Stock Exchanges (LSE:SPT)(NYSE:SPM)(CUSIP number:84856M209). www.spirent.com. Spirent Communications' sales to the United States government are made through Spirent Federal Systems. www.spirentfederal.com.