BURLINGTON, MA, and ZURICH, SWITZERLAND, November 13, 2000—iBasis, Inc., (Nasdaq: IBAS), the leader in advanced Internet-based communications, and IPirion AG, the leading European VoIP carrier and a subsidiary of Red Cube – a worldwide provider of Internet Protocol (IP) and Web-based communications services – today announced an interconnection agreement that enables their networks to exchange voice and fax traffic. The agreement enables both companies to increase traffic on their respective networks, while also expanding the iBasis footprint in several European commercial centers, including Amsterdam, Brussels, London, Milan, Paris and Zurich, as well as other destinations served by IPirion's VoIP network.

"With our focus on service quality and building successful global partnerships, our choice of iBasis – the VoIP provider for many of the world's largest carriers – was clear," said Niklaus F. Zenger, CEO of Red Cube. "Together, we can both grow and maintain carrier-class service quality for our customers."

"Working with IPirion's fast-growing, high quality IP network expands our presence in Europe," said Ofer Gneezy, president and CEO of iBasis, Inc. "This interconnection provides additional capacity to important European markets for our carrier customers, enabling us to grow our traffic to and from major commercial hubs in the region."

The iBasis Network and Carrier-Class VoIP
Many of the world's largest carriers route international voice and fax traffic over The iBasis Network, including 10 of the top 20 global carriers and more than 14 European providers. The iBasis Network is the world's largest international Cisco Powered Network (CPN) for Internet telephony. The iBasis Network comprises large carrier-class switching facilities called Internet Central OfficesTM, strategically located in Amsterdam, Cambridge (Mass.), Frankfurt, Hong Kong, London, Los Angeles, Miami, New York, Sydney, Tokyo and Vancouver. The network also comprises numerous smaller points of presence called Internet Branch OfficesTM, which play an important role in both originating and terminating traffic. With this global infrastructure in more than 41 countries and through its telephony peering relationships with other communications providers, iBasis can terminate calls virtually anywhere in the world.

iBasis is the only provider that guarantees service quality by offering the industry's first Service Level Agreement (SLA) for VoIP (Voice-over-Internet-Protocol). The key to maintaining the high level of quality required by the world's largest carriers is the company's proven, proprietary Assured Quality Routing™ (AQR™) technology. At the company's 24 x 7 Network Operations Center (NOC), the nerve center 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 IPirion AG / Red Cube International AG
IPirion AG (www.ipirion.com) is a major VoIP telephony carrier, firmly established as the industry leader in Europe in terms of scope of coverage and quality. IPirion is a Cisco Powered Network partner that provides reliability and outstanding conversion quality thanks to its ownership of the PoPs (Points of Presence) and switches that make up its network. The company expects to expand its network offerings significantly later this year in terms of capacity and scope. Future plans include development as an efficient multimedia carrier, facilitating such tasks as video streaming and teleconferencing. IPirion is a subsidiary of Red Cube International AG, (www.redcube.com) a leading international provider of Internet Protocol (IP) and enhanced Web-based, next-generation communications services. Red Cube's strength lies in its global network, standard-setting technologies and enhanced value-added services. This includes its flagship product OneRedCube, an integrated communications portal that works like a virtual desktop with uniform access independent of time, place and platform.

About iBasis
Founded in 1996, iBasis (Nasdaq: IBAS) is the leader in advanced Internet-based communications. iBasis has built the world's first global IP network that delivers toll quality voice and fax service and other advanced hosted communications solutions, including VoCoreSM Unified Communications, to global tier one carriers and other service providers. The iBasis Network is the world's largest international Cisco Powered Network for Internet Telephony and the first to receive the Unified Communications-Cisco Powered Network (UC-CPN) designation. More than 100 international service providers are iBasis customers, including 11 of the top 12 U.S. international carriers. 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.net.

Except for historical information, all of the expectations, projections and assumptions contained in the foregoing press release 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, the considerations described as "Risk Factors" in iBasis' prospectus dated March 9, 2000, and the company's other SEC filings.

Assured Quality Routing and AQR are registered trademarks, VoCore is a service mark and iBasis, The iBasis Network, Internet Central Office and Internet Branch Office are trademarks of iBasis, Inc. Cisco and Cisco Powered Network are registered trademarks of Cisco Systems, Inc.