A small group of AT&T Broadband cable-modem customers will soon be finding out that there is no such thing as a free link to the high-speed pipe.
As part of a network-housecleaning effort, the Englewood, Colo.-based MSO has started sending out letters to customers who have linked more than one computer to their cable modem but are not paying for the extra Internet-protocol address.
From the beginning, AT&T has charged users $4.95 for each extra Internet-protocol address — or effectively for each extra computer they connect. But some users slipped through the cracks when AT&T Broadband moved its customers off the network of now-defunct Excite@Home Corp. late last year, according to spokeswoman Sarah Eder.
The MSO estimates that these customers constitute less than 5 percent of AT&T's 1.8 million data households.
Letters were sent out in July and August, telling affected customers in Oregon and Washington that they'd have to pay for their multiple IP addresses. If not, the primary address would be kept active, but the secondary IP addresses would be disabled.
The MSO plans to notify subscribers in other systems, but that may take a back seat to an accelerating merger process, as AT&T Broadband expects to combine with Comcast Corp. by year-end. There is a schedule for notifying customers in other markets, but so far it has been delayed twice, Eder said.
"Frankly, it has slowed a bit with everything happening with the merger as well, and to make sure we are doing this in line with what perhaps we might want to do in the future," she said.
This effort might not eliminate all of the IP-address freeloaders. Another common strategy for broadband-modem sharing is use of a network address translator (NAT). That device allows multiple computers to share the same IP address, so to AT&T Broadband's network, it looks like a single PC. And NATs are illegal unless AT&T authorizes them, according to its cable-modem acceptable-use policies.
Although it can help users duck the extra IP address charge, Eder said. The policy is based on quality-of-service.
"If we can't see behind it, we can't troubleshoot it," she said. "It is purely about serving customers and providing them care. If someone puts up a NAT box, they should know that they can't get care for their additional computers."
AT&T Broadband also is looking at cleaning up other operational issues related to network performance, but that won't necessarily involve such customer-facing issues as IP addresses, Eder added.