Broadband Internet access providers’ support (or lack thereof) of Network Address Translation (NAT) has been in the tech news a lot lately. Some companies support it, some allow it but don’t specifically help users with it, and according to some reports, some are even taking steps to stop it all together. MacCentral talked with one such provider today — AT&T Broadband — to find out more about what’s happening.
Network Address Translation explained
NAT makes it possible for users of home networks to share their Internet access through a single point of origin — an AirPort Base Station, for example. Many broadband ISPs put limits on the specific numbers of computers that they’ll allow to be used on a single access point, or will charge additional money for each extra connection. Through the use of DHCP servers and monitoring of the hard-wired Ethernet interface address a computer uses, service providers can limit Internet access only to systems that have been registered.
NAT makes it possible for all local network traffic to be routed through a single address. The NAT router distributes a range of local IP addresses used by computers needing Internet access. All Internet traffic goes through the router, so only one Ethernet interface is visible to the service provider. Once the user registers the router’s Ethernet interface with the service provider, the provider’s DHCP allocates a TCP/IP address for the router. Voila, all local machines can then access the Internet.
It’s this ability to shield how many systems are actually working from a specific broadband access point that worries Internet service providers. This paves the way to abuse, suggest some, and taxes their existing infrastructure. It’s also an area of questionable legality, under certain circumstances.
Specifically, with the advent of wireless networking, it’s become possible for one broadband Internet access customer to share his connection with neighbors, especially in apartment buildings and condominium dwellings where the 802.11b wireless networking standard’s limited range is not an issue. Is this wrong? Yes, said AT&T Broadband.
“We consider this cable theft,” said AT&T Broadband spokesman Andrew Johnson during an interview with MacCentral. Johnson said that sharing cable modem access between domiciles is the same as sharing cable television access between domiciles — not only is it against the company’s terms of service, but it’s a violation of federal law.
NAT use allowed, but not supported
Johnson said that AT&T Broadband isn’t actively restricting NAT access on its networks, but all the same, don’t expect the company’s tech support staff to assist you. If you’re using NAT and your Internet connection goes down, you’ll likely need to disconnect it and hook your Mac up straight to the cable modem before AT&T Broadband’s tech support crew will be willing to help you troubleshoot.
How much of a problem is that? It depends on your own self-sufficiency. Many folks using AirPort Base Stations and other similar technology are sophisticated enough to do many basic troubleshooting steps themselves, and Mac OS X comes with built-in diagnostic tools like Network Utility which can help users establish where the most likely problems are coming from when their Internet access goes down. Lots of other third-party software is available, as well.
How much usage is too much?
“At the moment these are isolated incidents we’re talking about,” said Johnson, but AT&T Broadband recognizes excessive bandwidth usage as a growing issue. Johnson also said that home users who want to extend wireless Internet access to multiple computers used by family members aren’t the core problem — AT&T Broadband is willing to accommodate them, for a fee.
Johnson said that AT&T Broadband is more concerned about their customers using their residential cable modem access to run a business, serve files or Web sites, or do things that are outside the specific dictates of their terms of service.
“One percent of our customers use 16 percent of the bandwidth,” noted Johnson. He indicated that following the collapse of Excite@Home, AT&T Broadband put bandwidth restrictions in place both upstream and downstream to cap the maximum transfer speed its Internet customers can use.
Ultimately, however, AT&T Broadband plans a different approach. It’s not anxious to chase away customers who need that speed, but it does want to be compensated for what it sees as extra service.
“Tiered services, tiered speed, tiered prices,” is how Johnson refers to the company’s future Internet access plans. Johnson said AT&T Broadband will put those efforts in place sometime this year.