Spirent(R) Communications Unveils World's Most Comprehensive Test Suite to Ensure Successful IPTV Service Delivery; Spirent Test System Anticipates Subscriber's IPTV Quality of Experience Prior to Service Launch.

ROCKVILLE, Md. -- Responding to growing market demand, Spirent Communications (NYSE:SPM)(LSE:SPT), today unveiled the Spirent IPTV Quality of Experience (QoE) Test System, a comprehensive suite of test solutions that enables service providers to ensure the successful market launch of Internet Protocol-based television (IPTV) services. Spirent is a worldwide provider of integrated performance analysis and service management systems for testing ever evolving communications technology.

Increasing competition is driving telecom service providers to deploy bundled, Triple Play services. Data and voice services are table stakes however, the deciding factor will be IP-based video services delivered on the same network. Spirent's solution suite provides the most comprehensive test bed and diagnostic systems to guarantee subscriber Quality of Experience (QoE). The technology initiative comes as telcos enter the most critical phase of IPTV deployment, with service introductions expected to peak early next year.

"Ensuring that every element of the IPTV network meets subscriber's quality of service expectations is critical and Spirent's comprehensive suite of solutions enables us to analyze service delivery in the lab, during product development," said Desiree Lemons, product verification test engineer, Hitachi. "The Spirent test suite which can also be used in the field, during service trials ensures get-it-right-the-first-time IPTV deployment."

Spirent's test suite is able to emulate the triple play network environment and provide visibility into the subscriber's quality of experience. This capability is based on the company's embrace of V-Factor(TM) technology, a higher class of fidelity testing metrics that maximizes video quality as perceived by a subscriber and lets the service provider see how network performance issues impact this perceived quality. Older testing metrics merely attempted to infer subscriber QoE based on network performance indicators. V-Factor(TM), developed by QoSMetrics, is an implementation of the Moving Picture Quality Metric (MPQM) standard for network-delivered video assessment and displaces the older, inaccurate Media Delivery Index (MDI) diagnostic approach.

"Only Spirent enables equipment vendors and service providers to test the quality of experience end-to-end across the network and then continues monitoring QoS after deployment," said Bahaa Moukadam, vice president, IP Telephony, Spirent Communications. "Our integrated test and service management solutions enable our customers to thoroughly validate the readiness of converged networks to deliver high quality and reliable IP video services. They also assure Triple Play services with rapid identification and resolution of problems that occur."

Spirent's IPTV test initiative encompasses all three phases of network deployment: testing each network element for scalability and QoS in the lab; testing the system end-to-end in the field to introduce service quickly; assuring the deployed service; and the provisioning and diagnostics to fix problems fast and maintain QoE.

Spirent's latest individual IPTV test solution tool that implements V-Factor(TM) technology is the Abacus VTS video quality test system. Abacus VTS joins several other distinct test tools and capabilities in the Spirent IPTV testing suite. The Spirent TestCenter platform provides users a single device for testing IPTV infrastructure and video quality. The Spirent Converged Network Impairment Emulator assures that the testing process closely predicts true real-world conditions prior to the launch of live IP multimedia services. As IPTV operations scale in advance of subscriber growth, Spirent testing and diagnostic solution, SmartSight addresses and resolves service troubles rapidly and with minimum impact to operations or operational expenses.

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, Maryland, 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.

Spirent, Spirent Communications and the Spirent logo are trademarks or registered trademarks of Spirent plc. All other trademarks or registered trademarks mentioned herein are held by their respective companies. All rights reserved.

This press release may contain forward-looking statements that are based on current expectations or beliefs, as well as assumptions about future events. By their nature, forward-looking statements are inherently predictive, speculative and involve risk and uncertainty because they relate to events and depend on circumstances that will occur in the future. You should not place undue reliance on these forward-looking statements, which are not a guarantee of future performance and are subject to factors that could cause our actual results to differ materially from those expressed or implied by these statements. These risks include the risks described from time to time in Spirent plc's Securities and Exchange Commission periodic reports and filings. We undertake no obligation to update any forward-looking statements contained in this press release, whether as a result of new information, future events or otherwise.