AT&T and Global Crossing are the first carriers in the United States to establish dedicated interconnections for sharing IPv6 traffic, company officials say.

The interconnections – known as peering – will allow efficient and seamless sharing of IPv6 traffic across the two carriers’ networks, which span 30 countries.

IPv6 is a long-anticipated upgrade to the Internet’s main communications protocol, which is known as IPv4. IPv6 uses a new addressing scheme that supports trillions of additional devices connected directly to the Internet. IPv6 also offers built-in security and mobility as well as easier administration.

AT&T and Global Crossing developed their IPv6 peering service as part of a joint bid on a U.S. federal government telecommunications procurement called Networx. However, the IPv6 peering service is available free of charge to commercial customers of either carriers’ IPv6 services.

"What we have done that’s unique is that we have now interconnected two separate major IP backbone networks to allow exchange of IPv6 traffic, so sites that are on Global Crossing’s network can communicate with sites on AT&T’s IP backbone," explains Bob Bernstein, director of product marketing for Networx at AT&T. "Before, each provider might have had an IPv6 offering but the networks were separate."

AT&T and Global Crossing completed the IPv6 interconnection earlier this fall. The two carriers previously had an IPv4 peering arrangement.

"Now an agency can continue to exchange IPv4 traffic and add IPv6 traffic and go transparently between our separate networks," Bernstein says.

Bernstein says government agencies are interested in IPv6 peering because they want to connect to multiple IP backbones for disaster recovery.

"Customers are seeking dual homing – or connection to more than one IP backbone – for diverse routing and to ensure continuity of operations if there is a problem on one network," Bernstein says.

AT&T has a handful of U.S. federal agency customers for its IPv6 service, which allows customers to support both IPv6 and IPv4 traffic with edge routers running in what is known as dual-stack mode.

Global Crossing has supported IPv6 in its backbone network since 2002 and has 40-plus IPv6 customers, most of whom are carriers.