E-Businesses Select Spirent Communications' Upgraded Security Test Systems to Protect Against Debilitating Attacks.

Business Editors/High-Tech Writers

NetWorld+Interop 2003 Las Vegas

LAS VEGAS--(BUSINESS WIRE)--April 28, 2003

Spirent's New Distributed Denial of Service Solution Provides First Industry Test for Simulating Attacks with Multi-Protocol Traffic

Spirent Communications(TM) (NYSE:SPM), a worldwide provider of integrated performance analysis and service assurance systems for next-generation network technologies, today announced comprehensive software upgrades for its Avalanche 2200 product. The new software advances Spirent's portfolio of security test systems by including the industry's first product to test for distributed denial of service (DDoS) attacks inline with real multi-protocol traffic.

"As the Web's second most popular search engine, it is essential that Ask Jeeves is always available to help our users find the information they need when they need it," said Dayne Sampson, Vice President of IT for Ask Jeeves. "Not only has Spirent's Avalanche product made our lives easier by allowing us to realistically test a variety of features that before now have been difficult and expensive to simulate, their inline DDoS capability helps us improve our security and ensure that our networks remain up and running."

Ask Jeeves joins a list of other well-known e-businesses using Spirent's Avalanche product family including BEA, Cisco Systems, CNET, Deutsche Bank, eBay, Forbes.com, Intuit, and MSNBC. Avalanche provides companies with comprehensive Internet security test solutions for Layers 4-7 traffic that simulate today's complex network conditions to ensure that the network, as well as its products and services will excel in a real-world network environment. The new capabilities added to Avalanche 2200 allow network equipment manufacturers, service providers and Web site managers to more fully stress test and validate their web infrastructure, including security and streaming media applications under high-volume multi-protocol traffic loads. The new software includes:

-- Inline DDoS: integrating a high-performance DDoS traffic

generator with real-world multi-protocol traffic, Avalanche

helps users proactively validate that their security

infrastructure can resist large-scale attacks while allowing

valid user traffic through.

-- Realistic IP fragmentation: Avalanche is the only load

generating product that can introduce fragmented packets

on-demand (in-order and out-of-order) to closely mimic

real-world environments and evaluate the significant

performance impact fragmentation has on infrastructure.

-- Significantly increased Secure Sockets Layer (SSL)

performance: providing users with a doubling of SSL rate

performance (in excess of 4,000 new sessions per second on the

flagship Avalanche 2200) and a nine-fold increase in the

capacity of simultaneous SSL sessions (up to 90,000

simultaneous sessions), enabling users to test SSL Web Sites

and SSL VPNs at industry-leading levels.

-- Increase in streaming capacity: allowing users to test at

capacities three times the previous limit (over 30,000

simultaneous video/audio streams), exercising even the largest

streaming infrastructures.

"There are many dubious claims by network security vendors about their scalability and throughput handling capabilities," said Dan Keldsen, senior analyst and director of information systems for the Delphi Group. "Spirent's Avalanche with 5.2 provides a benchmarking tool to develop real numbers relating to security related issues in specific IDS equipment and in networks, with direct application to real customers. Hard numbers, not 'highly scalable.'"

In addition to the major feature additions, this release broadens Avalanche's protocol breadth with support for DNS, Telnet and 802.1Q VLANs, providing increased test coverage that ultimately translates into greater assurance that the customers' web infrastructure can stand up to the vagaries of real-world multi-protocol traffic. The 5.2 software release encompasses these new testing features, and will be available to customers in 30 days.

About Avalanche

Avalanche is designed for network equipment manufacturers, service providers and Web site managers that demand absolute realism and control under all conditions. Avalanche challenges any computing infrastructure's ability to stand up to the load and complexity of the real world. Avalanche can generate in excess of 30,000 HTTP requests per second, and supports HTTP/1.0, HTTP/1.1, HTTPS, RTSP/RTP (Apple QuickTime(R)), RealSystem(R) streaming, Microsoft(R)Windows Media(R) 8 and 9 Series, SMTP, POP3, DNS, Telnet and FTP. In addition, Avalanche can generate Distributed Denial of Service attack traffic inline with any mix of multi-protocol traffic. Through clustering, Avalanche can scale to the needs of even the world's largest infrastructures. Many leading corporations use Avalanche to ensure that their products and services excel in real-world conditions. Real-world conditions are accurately replicated by simulating error conditions, realistic user behavior, and maintaining over one million open connections from distinct IP addresses. Current customers include AT&T, BEA, Cable & Wireless, Cisco Systems, CNET, Deutsche Bank, eBay, Extreme Networks, F5 Networks, Forbes.com, Foundry Networks, Intuit, MSNBC, Network Appliance, NetScreen, Nortel Networks, NTT DATA, SBC Communications, and WatchGuard. http://www.spirentcom.com/L4-7

About Spirent Communications

Spirent Communications is a worldwide provider of integrated performance analysis and service assurance systems for next-generation network technologies. Spirent's solutions accelerate the profitable development and deployment of network equipment and services by emulating real-world conditions in the lab and assuring end-to-end performance of large-scale networks. www.spirentcom.com

Spirent Communications is a wholly owned group of Spirent plc, an international network technology company. Spirent plc is listed on the London Stock Exchange (LSE:SPT). The company is also listed on the New York Stock Exchange (ticker: SPM; CUSIP number: 84856M209). www.spirent.com

Spirent, Spirent Communications and the Spirent logo are trademarks of Spirent plc. All other trademarks or registered trademarks 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 Spirent's 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's SEC periodic reports and filings. We undertake no obligation to update our forward-looking statements, whether as a result of new information, future events or otherwise.

Note: Ask Jeeves is a registered trademark of Ask Jeeves, Inc.