iBasis Agreement with China's Third Largest Carrier, JITONG Communications, Significantly Expands Presence in China

Chinese Provider to Route Voice and Fax Traffic over the iBasis Global Network; iBasis Now Able to Deliver International Traffic to Every Province in China

URLINGTON, Mass., June 21, 2000-iBasis, Inc., (Nasdaq: IBAS), the leader in advanced Internet-based communications, today announced that China's third largest carrier, JITONG Communications Co., Ltd. (JITONG), has chosen the iBasis Network™ for global Internet Telephony. Under the terms of the agreement, JITONG will be able to send international voice and fax traffic over the iBasis Network, the world's largest Cisco Powered Network for Internet Telephony. In addition, JITONG will complete international calls from the iBasis Network to destinations in China.

The JITONG Communications IP network spans 45 cities within China, including Beijing, Shanghai, Guangzhou, Shenzhen, Wuhan, Dalian, Qingdao, Shenyang, Chongqing and Changchun, and provides telecommunications services to each of the country's provinces. JITONG is one of only five carriers within China that has received a telecommunications license from the Chinese Ministry of the Information Industry.

"The iBasis Network allows us to cost effectively expand our reach across the world and continue to provide our customers with superior, toll quality Voice over IP connections regardless of the call destination," said Ming Qiu Qi, CEO of JITONG Communications. "iBasis' proven, well-established track record in delivering the highest quality of telecommunications service made our choice of iBasis an easy one."

"With more than 1.2 billion people, China represents a very large market opportunity for delivering IP-based communication services," said Ofer Gneezy, president and CEO of iBasis. "With our connection into JITONG's extensive country-wide network, iBasis can look forward to servicing a greater percentage of the rapidly growing Chinese market with our world-class communications capabilities."

This announcement with JITONG expands iBasis’ already significant presence in the Asian telecommunications market. iBasis has previously announced interconnection agreements with some of Asia’s largest carriers, including China Unicom and China Mobile (China’s second largest carrier and the world’s largest wireless carrier, respectively), as well as Japan’s NTT, The Communications Authority of Thailand, Korea’s Dacom and Australia’s Telstra.

The iBasis Network 
The iBasis Network is the world's largest international Cisco Powered Network (CPN) for Internet telephony. iBasis is the only Internet telephony carrier 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, located at iBasis' global headquarters in Burlington, Massachusetts, USA, engineers continuously monitor the global circuit-switched (PSTN) and packet-switched (IP) networks to ensure the highest quality of service to customers worldwide.

iBasis has a long-standing strategic relationship with Cisco, as an alliance partner, an ecosystem partner, and one of only 21 Cisco service provider global accounts.

About JITONG Communications Co., Ltd
 JITONG Communications Co. , Ltd. (JITONG) is a joint stock company sanctioned by the State Economic and Trade Commission and registered at the Administration Bureau of Industry and Commerce on Jan.12th, 1994. The shareholders consist of some state-owned, large-scale electronic enterprises such as the Rainbow (Caihong) Group and China Electronic Information Industry Group. JITONG is administered by the Ministry of Information Industry, and is a high technology enterprise with the purpose of developing modern communication technology and electronic information technology, serving the national economy and promoting the people's living standard. Aiming at both the domestic and the international markets, JITONG tries to realize the integration of science, industry and trade, and combine manufacturing with utilization. JITONG is the owner of the Golden Bridge Project.

Since 1997, JITONG has established ten branches in cities of Beijing, Shanghai, Guangzhou, Shenzhen, Wuhan, Dalian, Qingdao, Shenyang, Chongqing and Changchun. JITONG has adopted modern enterprise operation systems that provide services such as satellite communications, Internet access, Intranet/Extranet implementation, domain name and IP address application, and training, etc.

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 VoCore, to global tier one carriers and other service providers. The iBasis Network™ is the world's largest international Cisco Powered Network for Internet telephony. More than 70 international carriers are iBasis customers, including 11 of the top 12 US international carriers. 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 is a registered trademark and iBasis and The iBasis Network are trademarks of iBasis, Inc. Cisco and Cisco Powered Network are registered trademarks of Cisco Systems, Inc.