iBasis and Golden Telecom Complete VoIP Interconnection for Russian Telecommunications Services

Relationship Leverages iBasis DirectVoIP Service and Interoperability with MERA Networks Softswitch

BURLINGTON, MA April 20, 2004 —iBasis, Inc. (OTCBB: IBAS), the leader in Internet-based voice communications, today announced the completion of a direct VoIP interconnection with Golden Telecom, a leading alternative provider of integrated telecommunications and Internet services in major cities of Russia and other countries of the Commonwealth of Independent States (CIS). Through the iBasis DirectVoIP™ service, the interconnection takes advantage of interoperability between iBasis' Cisco Powered Network and Golden Telecom's softswitch from MERA Networks, a rapidly growing Russian provider of creative IP solutions for carriers and service providers.

Interoperability with MERA Networks' VoIP Transit SoftSwitch (MVTS) expands iBasis' access to carriers that originate international telephone traffic, like Golden Telecom, and to prospective terminating partners who can provide new destinations or supplement existing points of presence to provide greater capacity and geographic coverage. Carriers that implement DirectVoIP interconnections benefit from the lower capital and operational costs of VoIP and immediate access to iBasis' global VoIP network, which comprises more than 90 on-net countries and carries billions of minutes of international traffic.

"With more than 230 carriers connected to the iBasis Network, we have clearly demonstrated our ability to deliver the benefits of high quality international VoIP," said Ofer Gneezy, president and CEO of iBasis. "As more and more carriers, like Golden Telecom, expand VoIP services, we are providing easy interoperability with a variety of proven VoIP platforms. MERA has achieved a strong position in Russia & the CIS countries with eight of the top ten Russian carriers among MERA's customers. Interoperability with MERA Networks allows more carriers to establish direct VoIP interconnections to the iBasis Network for high quality, cost-effective completion of their international calls. It also enables iBasis to expand our footprint and network capacity in desirable destinations without capital expense."

"As one of the 10 largest carriers of international traffic in the world, iBasis provides MERA customers with a proven international VoIP network that will deliver high quality call completion as well as revenue opportunities through termination of calls from the iBasis Network," said Natalya Korobkova, Marketing Director, MERA Networks, Inc. MERA. "By collaborating with major VoIP carriers like iBasis MERA Networks is helping to establish a more seamless multi-vendor VoIP infrastructure, which will drive global telecommunications growth through greater efficiency."

About DirectVoIP Certification

VoIP equipment undergoes testing in the iBasis interoperability lab and in the field before being deployed as a part of the iBasis network. As of March 2004, gateways, gatekeepers, session controllers, softswitches, and SIP proxies from more than 20 different equipment vendors including Cisco Systems, Sonus Networks, NexTone, MERA Networks, MediaRing, Quintum, and VocalTec have been tested and connected to the iBasis network.

About Golden Telecom

Golden Telecom, Inc. (NASDAQ: "GLDN")— is a leading facilities-based alternative provider of integrated telecommunications and Internet services in major cities of Russia and other countries of the Commonwealth of Independent States (CIS). The Company offers voice, data and internet services to corporations, operators and individual customers using its overlay networks in Moscow, Kiev, St. Petersburg, Nizhny Novgorod, and Krasnoyarsk and via inter-city fiber-optic and satellite-based networks, including 150 combined access points in Russia and other CIS countries. The Company provides mobile services in Kiev and Odessa. www.goldentelecom.com.

About MERA Networks

MERA Networks, Inc. is the forefront supplier of VoIP technologies delivering the functionality and features needed for successful operation of service providers. The MERA solutions offer a powerful combination of efficiency, scalability and affordable price, bringing added value and revenue-generating opportunities to carriers globally. MERA is a privately owned corporation with offices in Canada and Russia. It has 12 years of experience in international software development and employs over 400 qualified engineers. MERA Networks pioneered the industry of session border controllers by launching a VoIP division in 2001. To date the company is a key provider of highly reliable and cost-effective SBC's, has over 200 customer deployments in 21 countries of the world, and controls 80% of the SBC market in Russia.

About iBasis

Founded in 1996, iBasis (OTCBB: IBAS) is a leading provider of wholesale international telecommunications services. For the past two years the company has been named by service providers as the best international wholesale carrier in Atlantic-ACM's annual International Wholesale Carrier Report Card¹. iBasis is a preferred provider for many of the largest carriers in the world, including AT&T, Cable & Wireless, China Mobile, China Unicom, MCI, Sprint, Telefonica, Telenor, and Telstra. iBasis has carried more than six billion minutes of international voice traffic over its global Cisco Powered Network™, and is one of the ten largest carriers of international voice traffic in the world². In addition to its wholesale international telecommunications services, iBasis provides retail prepaid calling cards to major distributors, utilizing the international iBasis Network. Based on its revenue growth from 1997 through 2001, iBasis was ranked the #8 fastest-growing technology company in North America and the #1 fastest-growing technology company in New England in the Technology Fast 500 national program sponsored by Deloitte & Touche. The company can be reached at its worldwide headquarters in Burlington, Massachusetts, USA at 781-505-7500 or on the Internet at www.ibasis.com.