Alonet Selects Clarent for World's First LatinAmerican-Headquartered IP Telephony...

Business Editors/High-Tech Writers

REDWOOD CITY, Calif.--(BUSINESS WIRE)--March 13, 2000

Alonet is Also Expanding Clarent-Based IP

Telephony Network to Eight Cities in Brazil

Clarent(tm) Corporation (Nasdaq:CLRN), a worldwide leader in providing carrier-grade,

phone-to-phone Internet Protocol (IP) telephony solutions, and Alonet, a Brazil-based telecommunications Service Provider, announced today that Alonet is building the world's first Latin American-headquartered global IP telephony clearinghouse. The clearinghouse is based on Clarent products.

Alonet further announced that it is expanding its Clarent-based IP telephony network to include five more Brazilian cities, bringing the total number of Alonet points of presence in Brazil to eight locations. The cities already in operation are Sao Paulo, Rio de Janeiro, Curitiba and New York. The five additional cities are Salvador (Bahia), Recife (Pernambuco), Manaus (Amazonas), Belo Horizonte (Minas Gerais) and Porto Alegre (Rio Grande do Sul).

"IP telephony clearinghouses play a very important role in the fast growing IP telephony industry by serving as a one stop shop for regional telecommunications service providers," said Heidi Bersin, senior vice president, Corporate Marketing, Clarent Corporation. "Alonet is a showcase IP telephony service provider in Brazil and, as a clearinghouse provider, should be able to provide Latin American coverage and contacts to IP telephony service providers from around the world."

"In our first few months of operation, we have experienced tremendous growth in our IP telephony traffic," said Alexandre Flit, senior vice president and chief technology officer, Alonet. "Based on this, we are excited about the potential for the IP telephony market. We are quickly expanding our network in Brazil and are looking forward to becoming an IP telephony global clearinghouse provider in addition to running our own Internet telephony network. Clarent has provided an excellent foundation and product mix to support us in our network expansion and our implementation of Alonet's global IP telephony clearinghouse."

Alonet's clearinghouse and network expansion are expected to be completed by the end of this month. Internet telephony service providers who are interested in talking to Alonet about their global clearinghouse should contact Alexandre Flit (flit@alonetsa.com.br) or Sergio Skarbnik (sergiosk@alonetsa.com.br).

About Alonet

Alonet believes it is the first company to transport voice over Internet targeted to enterprise customers, domestically and internationally, in observance of the Brazilian laws. The company's focus is to design, deploy, manage and service corporate IP telephony networks.

Alonet's headquarters are based in Sao Paulo, Brazil. The company also has offices in other major Brazilian cities and in the United States.

Alexandre Flit is the senior vice president and chief technology officer, Daniel E. Goldshmidt is the senior vice president and chief operating officer, and chief technical officer and Sergio Skarbnik is the senior vice president, Worldwide Sales.

About Clarent Corporation

Clarent Corporation is a premier provider of scalable, IP telephony products to carriers and Internet service providers around the world. Clarent's intelligent architecture and the Clarent Command Center enable Clarent products to route, manage, inter-connect and terminate high volumes of calls for service provider customers including the world's largest long distance telecommunication companies.

According to an iLocus report published in 1999, more minutes travel across Clarent-enabled networks worldwide than those of any other equipment supplier.(a)

Founded in July 1996, Clarent is headquartered in Redwood City and has offices in major cities in Asia, Europe, Latin America and North America. Additional information about Clarent is available at www.clarent.com.

Forward-Looking Statements

This release may contain forward-looking statements regarding Clarent's products, business, customers or other factors that may affect future earnings or financial results. Such statements involve risks and uncertainties, including but not limited to potential issues relating to interoperability, inability to introduce new products, ability to retain key customers, changes in market conditions, government regulations, the international communications industry, technological changes and other factors, which could cause actual results to vary materially from those expressed in or indicated by the forward-looking statements. These risks and uncertainties are described further in the risk factors discussed in Clarent's recent Prospectus, filed with the Securities and Exchange Commission on November 23, 1999.

Note to Editors: Clarent is a registered trademark of Clarent Corporation in the United States and other jurisdictions. All other company or product names mentioned may be trademarks or registered trademarks of the respective companies with which they are associated.

(a) "IP Telephony Clearinghouses -- A New Business Model." Published November 1999 by iLocus. iLocus, a division of Cape Saffron Ltd., is a UK-based research group focused on the IP telephony industry. http://www.ilocus.com