CHELMSFORD, Mass. and ORLANDO, Fla., May 11, 2004 - Sonus Networks (Nasdaq: SONSE), a leading provider of voice over IP (VoIP) infrastructure solutions, and Volo Communications, Inc., a leading next-generation wholesale service provider and technology company, today announced that Volo has added packet voice solutions from Sonus Networks to its IP backbone network, further enhancing Volo’s already unsurpassed technology solutions and service offerings to carriers, service providers and cable operators.  Volo’s nationwide IP backbone network is fully optimized for the highest quality business applications, offering MPLS services between switches, over one national backbone network rather than 1,000s of Internet subnetworks.  Volo has now added Sonus’ Open Services ArchitectureTM (OSA) featuring the GSX9000TM Open Services Switch into its technology solution.

“We chose Sonus Networks because the company is recognized as a pioneer in the VoIP market and because their products integrate very well with our own industry-leading Caerus Networks Inc. (CNI) network technology,” said president and CEO Shawn Lewis of Caerus, Inc., Volo’s parent company.  “Many of our carrier, cable company and service provider customers already have Sonus infrastructure in their networks, and we view Sonus as a valued partner as we continue to build out our truly open, next-generation packet communications network across the U.S.”

“With its next-generation network, Volo Communications is taking a leading role in driving the adoption of packet voice communications and enabling a full suite of hosted VoIP services for other carriers, cable operators, CLECs, and ISPs,” said Hassan Ahmed, CEO and chairman, Sonus Networks.  “We are very pleased to be working with Volo.”

Volo’s voice services are offered over Volo Communications’ private IP backbone network, which is fully optimized for the highest quality business applications.  Volo’s network is Multiprotocol Label Switching (MPLS), SIP, and H.323-enabled, and incorporates both packet and TDM technology.
The Sonus voice infrastructure solutions offer proven reliability and carrier-class scalability, and enable Volo to significantly increase the capacity of its VoIP network.  

About Volo Communications and Caerus, Inc.

A certified CLEC and IXC, Volo Communications is revolutionizing the communications industry by pioneering VoiceOne – a next generation network and wholesale packet voice communications and termination services offering that enables carriers, CLECs, IXCs, cable operators, ISPs, and resellers to provide carrier-quality voice services to consumers. The VoiceOne MPLS network supports most standard protocols including SS7, PRI, H323, SIP, MGCP, AAL/1, etc. and utilizes both TDM and Packet technology.

Volo is wholly owned by Caerus, Inc., the parent company of Caerus Networks, Inc., and Caerus Billing, Inc.  The three companies together provide a customized end-to-end solution that is unmatched in the industry today with its ‘free softswitch’ and ‘free service creation environment’. Caerus, Inc.’s founder holds patents for the first softswitch and the first SS7 Media Gateway.
Caerus Networks, Inc. is the technology development arm of the company, and Caerus Billing is a billing and mediation software company.  Both companies provide in-house services for third party service providers and carriers.  More information is available at: http://www.volocommunications.com.

About Sonus Networks

Sonus Networks, Inc. is a leading provider of voice over IP (VoIP) infrastructure solutions for wireline and wireless service providers.  With its Open Services ArchitectureÔ (OSA), Sonus delivers end-to-end solutions addressing a full range of carrier applications, including trunking and tandem switching, residential and business access, network border switching and enhanced services. Sonus’ voice infrastructure solutions, including media gateways, softswitches and network management systems, are deployed in service provider networks worldwide.  Sonus, founded in 1997, is headquartered in Chelmsford, Massachusetts.  Additional information on Sonus is available at http://www.sonusnet.com.

This release may contain projections or other forward-looking statements regarding future events or the future financial performance of Sonus that involve risks and uncertainties.  Readers are cautioned that these forward-looking statements are only predictions and may differ materially from actual future events or results.  Readers are referred to the “Cautionary Statements” section of Sonus’ Quarterly Report on Form 10-Q, dated November 10, 2003 and filed with the SEC, which identifies important risk factors that could cause actual results to differ from those contained in the forward-looking statements.  Risk factors include, among others, uncertainties regarding the timing of the Company’s completion of the audit and filing of its Annual Report on Form 10-K/A for 2003 and future periodic reports, risks as to the SEC’s investigation of these or other matters, unforeseen issues encountered in the completion of the audit, uncertainties regarding the extent to which prior period financial statements will be restated, the continued adverse effect of developments in the telecommunications industry, Sonus’ ability to grow its customer base, dependence on new product offerings, market acceptance of its products, competition from large incumbent vendors, rapid technological and market change and manufacturing and sourcing risks.  In addition, any forward-looking statements represent Sonus’ views only as of today and should not be relied upon as representing Sonus’ views as of any subsequent date.  While Sonus may elect to update forward-looking statements at some point, Sonus specifically disclaims any obligation to do so.

Sonus is a registered trademark of Sonus Networks.  Open Services Architecture, GSX9000, Insignus and Sonus Insight are trademarks of Sonus Networks.  All other trademarks, service marks, registered trademarks, or registered service marks are the property of their respective owners.