Versatel Interconnected with iBasis
Global VoIP Network

Leading Benelux & German Communications
Service Provider Selects iBasis To
Expand International Service

BURLINGTON, MA-November 27, 2001-iBasis, Inc., (Nasdaq: IBAS), the leader in Internet-based voice communications, today announced that Versatel Telecom International N.V. (Nasdaq & AEX: VRSA), a leading competitive broadband communications service provider based in Amsterdam, has interconnected its regional European network with The iBasis NetworkTM. The interconnection enables Versatel to route international voice traffic over The iBasis Network - the Tier 1 quality VoIP infrastructure for the world's largest carriers. In addition, the interconnection agreement allows iBasis to terminate international calls on Versatel's high quality regional network, deepening iBasis' presence in the Benelux region and Germany.

Versatel operates a high bandwidth fiber optic network and provides over 72,000 business customers in The Netherlands, Belgium and Germany with direct and indirect access to broadband voice, data and Internet services. Versatel is the second largest operator covering these markets.

"VoIP services continue to penetrate the European telecommunications markets, due, in large part, to the compelling value propositions of efficient, high quality carriers like iBasis and Versatel," said Ofer Gneezy, president and CEO of iBasis. "Through our relationship with Versatel, we gain expanded access to many of the most important commercial centers of Western Europe."

"Connecting to The iBasis Network instantly gives us high quality, efficient service to more than 80 countries and will help Versatel continue to strengthen its position as one of the most important competitive providers in the region," said Aad Beekhuis, Chief Operations Officer of Versatel.

iBasis in Europe
Today's announcement adds another major European carrier interconnection to The iBasis Network. iBasis currently provides service to more than 15 major European carriers. The company has seen tremendous growth in the region over the past year as revenues from European voice traffic nearly quadrupled from Q3 2000 to Q3 2001. According to industry analyst firm TeleGeography, Europe has experienced the strongest international traffic growth of any region outside North America, and represented about 43% of all international traffic in 2000.

More than 50 percent of the voice traffic on The iBasis Network is generated by Tier 1 carriers, the world's largest and most demanding service providers.

iBasis and the Move to VoIP
While the international voice services market is expected to be worth more than $70 billion, for most large carriers, international service is not core, and generally represents about 5% of revenues. At the same time, the cost of maintaining global service operations is disproportionately high. Outsourcing international traffic to iBasis offers service providers a powerful competitive advantage by lowering the cost of transport and reducing overall global infrastructure and service support requirements.

According to TeleGeography, VoIP transport is expected to account for approximately 6% of all international voice traffic in 2001, doubling the 3% rate for 2000. As international voice traffic continues to grow, decreasing sales of traditional circuit-switching equipment and a predicted tripling of VoIP gateway equipment sales¹ over the next five years offers further evidence that the fundamental shift to VoIP is well underway.

About Versatel
Versatel Telecom International N.V. (Nasdaq & AEX: VRSA) based in Amsterdam, is a competitive communications network operator and a leading alternative to the former monopoly telecommunications carriers in our target market of the Benelux and northwest Germany. Founded in October 1995, the Company holds full telecommunications licenses in The Netherlands, Belgium and Germany and has over 72,000 business customers and 1,565 employees. Versatel operates a facilities-based local access broadband network that uses the latest network technologies to provide business customers with high bandwidth voice, data and Internet services. Versatel is a publicly traded company on the Amsterdam Stock Exchanges and Nasdaq National Market under the symbol "VRSA". News and information are available at www.versatel.com .

About iBasis
Founded in 1996, iBasis (Nasdaq: IBAS) is the leader in advanced Internet-based voice communications. iBasis delivers toll quality international voice services and provides the infrastructure for hosted communications solutions, including messaging and speech-enabled content, e-commerce and customer service applications. The company's customers include many of the largest enterprises and carriers in the world, including AT&T, Cable & Wireless, China Mobile, China Unicom, Concert, ExxonMobil, Gannett, H&R Block, Home Shopping Network, Morgan Stanley, NTT, Telefonica, Telstra, Sabre Group, Sprint, Western Union, WorldCom, and Verizon. iBasis' hosted, enhanced service solutions include SpeechPortTM, a scalable, customizable ASP environment for speech-enabled business solutions, VoCore^SM messaging and the IP CallCardTM pre- and post-paid calling card platform. The iBasis Network is the world's largest international Cisco Powered Network for Internet Telephony. iBasis is listed in both the Russell 2000® and Russell 3000® Indexes. The company can be reached at its worldwide headquarters in Burlington, Massachusetts, USA at 781-505-7500 or on the Internet at www.ibasis.net .

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Assured Quality Routing and iBasis are registered marks, VoCore is a service mark, The iBasis Network, Internet Central Office, Internet Branch Office, IP CallCard, SpeechPort, IPort, and PriceInteractive are trademarks of iBasis, Inc. or its subsidiaries. Cisco and Cisco Powered Network are registered trademarks of Cisco Systems, Inc. All other trademarks are the property of their respective owners.

Except for historical information, all of the expectations, projections and assumptions contained in the foregoing press release, including those relating to the company's current expectations regarding revenue growth, sources of revenue, margin improvement and future capital expenditures constitute forward-looking statements under the Private Securities Litigation Reform Act of 1995 and involve risks and uncertainties. Important factors that could cause actual results to differ materially from such forward-looking statements include, but are not limited to, (i) the extent of adoption of the company's voice-based Internet services and the timing and amount of revenue generated by these services; (ii) fluctuations in the market for and pricing of VoIP services; and (iii) the other considerations described as "Risk Factors" in iBasis' Annual Report on Form 10-K for its fiscal year ended December 31, 2000, and the company's other SEC filings.