Spirent(R) Communications Solution Now Rated ''Avaya Compliant''; Spirent Abacus 5000 IP Telephony Test System is compatible with key Avaya IP Telephony and SIP solutions.

SUNNYVALE, Calif. -- Spirent Communications (NYSE:SPM) (LSE:SPT), today announced that its Abacus 5000 IP Telephony Test System is now compliant with industry leading solutions from Avaya (NYSE:AV), a leading global provider of business communications applications, systems and services. Spirent's Abacus 5000 IP Telephony Test System helps businesses test, verify and ensure voice over IP (VoIP) network interoperability for enterprise infrastructure and applications.

Spirent's Abacus 5000 IP Telephony Test System is now compliance-tested by Avaya for compatibility with the Avaya Communication Manager, the company's industry leading IP telephony software; the Avaya Converged Communication Server, which supports flexible communication via SIP; and Avaya IP Office, an easy-to-use converged voice and data system designed especially for small and medium businesses.

Spirent's compatibility with key Avaya IP Telephony solutions enables enterprises to verify the interoperability of their IP Telephony infrastructure. It also helps enterprise customers add new and enhanced IP Telephony services cost effectively.

"We are pleased to have our best-in-class Abacus 5000 IP Telephony Test System compliance tested by Avaya," said Bahaa Moukadam, vice president next-generation networks, Spirent Communications. "Our enterprise customers can now deploy and upgrade IP Telephony service with the knowledge that their network will continue to operate flawlessly."

Spirent is a member of the Avaya DeveloperConnection Program--an initiative to develop, market and sell innovative third-party products that interoperate with Avaya technology and extend the value of a company's investment in its network. As a member of the program, Spirent is eligible to submit products for compatibility testing by the Avaya Solution Interoperability and Test Lab. Doing so ensures businesses can confidently add best-in-breed capabilities to their network without having to replace their existing infrastructure--speeding deployment of new applications and reducing both network complexity and implementation costs.

"By offering compliance testing to innovative companies like Spirent Communications, Avaya promotes interoperable solutions that help businesses unleash powerful new possibilities," said Eric Rossman, vice president, developer relations and technical alliances, Avaya. "They are able to use Intelligent Communications to connect employees and customers to information from wherever they are, over whatever device they have available to get more out of their multivendor network and to deliver new value to their bottom line."

About Avaya Inc.

Avaya Inc. designs, builds and manages communications networks for more than 1 million businesses worldwide, including over 90 percent of the FORTUNE 500(R). Focused on businesses large to small, Avaya is a world leader in secure and reliable Internet protocol (IP) telephony systems and communications software applications and services.

Driving the convergence of voice and data communications with business applications - and distinguished by comprehensive worldwide services - Avaya helps customers leverage existing and new networks to achieve superior business results. For more information visit the Avaya website: www.avaya.com. For more information on the Avaya DeveloperConnection Program, visit www.devconnectprogram.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, 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.

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