Telenor Selects iBasis to Expand International Service

Relationship with Global Carrier Expands iBasis Footprint in Europe, South Asia; iBasis European Revenues Nearly Quadruple in Past Year

BURLINGTON, MA - December 10, 2001 - iBasis, Inc., (Nasdaq: IBAS), the leader in advanced Internet-based voice communications, today announced that Telenor AS has interconnected with The iBasis NetworkTM to expand international service. With this service agreement, Telenor, a global carrier based in Norway, is able to route international voice traffic over The iBasis Network. In addition, iBasis is able to expand the volume of traffic it carries to and from the markets served by Telenor and its more than 70 wholly or partially-owned subsidiaries throughout Europe and Southeast Asia.

Founded in 1855 as the Norwegian Telegraph Administration, Telenor has rapidly expanded its services and reach and customer base, which in 2000 included more than two million mobile subscribers. Telenor was the first service provider worldwide to introduce SmartPhones, which provide mobile Internet services to ordinary phone subscribers.

"Telenor is an important global carrier who joins a growing community of Tier 1 carriers that has chosen to connect to iBasis for international service," said Ofer Gneezy, president and CEO of iBasis. "This interconnection to Telenor's global network complements our already extensive presence in Europe and South Asia and will help us grow the volume of Tier 1 traffic we carry to and from these important regions."

"Carriers like iBasis are proving that Internet telephony has truly come of age. Routing international traffic over The iBasis Network, a global VoIP infrastructure for many of the world's largest carriers, helps to continually improve the efficiency and focus of our business by lowering the cost of providing international service," said Terje Haufmann, Director Products, Telenor Global Services. "Our decision to connect to iBasis reflects our confidence in the quality and reliability of their global Tier 1 VoIP service."

The iBasis Network in Europe
Today's announcement continues iBasis' impressive growth with Tier 1 carriers in Europe. With more than 16 major European carrier customers, iBasis revenues from European voice traffic nearly quadrupled from Q3 2000 to Q3 2001. Much of the growing demand for iBasis international VoIP services in Europe, as in other regions, has come from Tier 1 carriers, the world's largest and most demanding service providers. More than 50% of all voice traffic carried by The iBasis Network is generated by Tier 1 carriers. iBasis' growth in traffic from Tier 1 carriers, who collectively control the vast majority of the world's voice traffic, reflects the larger telecommunications technology shift identified by industry consultants Frost & Sullivan, who recently predicted that 75% of global voice traffic will be Voice-over-Internet-Protocol (VoIP) by 2007.

While the international voice services market is expected to be worth more than $70 billion, for most large carriers, international service is not a core business, and generally represents about 5% of revenues. At the same time, the cost of maintaining global service operations is disproportionately high. This is why large carriers continue to outsource increasing amounts of international traffic to efficient, Tier 1 quality VoIP carriers like iBasis.

iBasis and the Move to VoIP
iBasis handles millions of minutes of traditional carriers' international voice traffic every day on its global VoIP network. Outsourcing international traffic to iBasis offers service providers a powerful competitive advantage by lowering the cost of transport and reducing overall global infrastructure requirements. According to industry analyst firm TeleGeography, VoIP transport is expected to account for approximately 6% of all international voice traffic in 2001, double the approximately 3% it represented in 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.

iBasis VoIP Service Quality
iBasis guarantees its service quality, offering the industry's first Service Level Agreement (SLA) for VoIP. The key to maintaining the high level of quality required by the world's largest carriers is the company's proven, proprietary Assured Quality RoutingTM (AQRTM) technology. At the company's 24 x 7 Network Operations Centers (NOC) in Burlington, Mass., USA and Hong Kong, the nerve centers of The iBasis Network, engineers continuously monitor the global circuit-switched (PSTN) and packet-switched (IP) networks to ensure the highest quality of service to customers worldwide.

About Telenor
Telenor is a Norwegian telecommunications group with extensive and fast growing business operations in a number of countries in Europe and Southeast Asia. The company is Norway's leading distributor of voice, information, knowledge and entertainment through a broad range of modern communications services. On December 4, 2000, Telenor took the plunge into the world of publicly-listed companies. The company was listed on the Oslo and NASDAQ Stock Exchanges at a final price of NOK 42 per share, raising a total of NOK 15.6 billion (USD $1.7 billion). An initial global offering of 372,151,899 ordinary shares arising solely from a capital increase was tendered, representing 21 per cent of Telenor's share capital.

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, Telecom Argentina, Telstra, Sabre Group, Sprint, Western Union, WorldCom, and Verizon. iBasis' hosted, enhanced service solutions include SpeechPort^TM, 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, Mass., USA at 781-505-7500 or on the Internet at www.ibasis.com .

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Assured Quality Routing and AQR are registered trademarks, VoCore is a service mark and iBasis, 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.