AT&T today said it has expanded to 40 Gb/s capacity on more than 50,000 miles of its IP/MPLS national network, as part of the latest push to meet growing demand for online video and other IP-based traffic.

The announcement comes a few weeks after Verizon announced turned up 40 Gb/s links but only along some East Coast routes. One other major difference – Verizon is working with Juniper Networks, while AT&T’s upgrade is based on Cisco Systems CRS-1 technology, the two companies said today.

Both service providers are already tipping their hands at the next step – 100 Gb/s transport. AT&T said its next-generation network includes 18,000 miles of optical ultra-long haul routes that will eventually be able to carry traffic at 100 Gb/s, adding that more than 40% of its IP traffic will ride over its next-gen network by the end of 2007. Verizon has said it will start using 100 Gb/s in either 2008 or 2009.

“As the demand for Internet and IP-based applications continues to explode, IP traffic on the AT&T network has doubled throughout the past two years, and we fully expect this substantial growth to continue in the future,” said John Stankey, group president of Telecom Operations at AT&T, in a prepared statement. “Our industry-leading deployment of 40-Gigabit technology enables us to stay ahead of our customers’ growing need for bandwidth and to continually deliver the fast, reliable connectivity our customers need to connect with their world.”