Bandwidth caps are coming to Japan, but not in the way to which North Americans are accustomed. OCN, operated by NTT Communications, has decided to impose a daily upload limit beginning on August 1. The limit? 30GB per day. Upstream.

According to the company, the limit is being implemented to address a "small number" of users who apparently upload far more than that on a day-to-day basis by running servers for file-sharing. Customers will get a warning upon first violation, NTT spokesperson Tei Gordon told IDG News Service today, but could be disconnected for repeat offenses.

Of course, NTT's 100Mbps fiber-optic connections make it easy to use and abuse the service. And—let's be realistic—a 30GB-per-day upload limit is plenty for even heavy P2P use. That's almost a terabyte per month of data, and those concerned over download caps shouldn't worry, though, as those will remain unlimited. Download all the terabytes upon terabytes of data you want!

This kind of extremely generous usage cap is made possible because of Japan's fiber-centric broadband infrastructure. Here in the US, fiber installations are few and far between, leaving most of us with subpar speeds and service. It's a large reason why users who use even moderate levels of bandwidth will face very low usage caps. For example, Time Warner recently announced that it would begin capping customers' downloads in Beaumont, Texas at 40GB per month for $55. Users will be billed $1 for each additional gigabyte downloaded.

At first glance, such usage caps might seem reasonable, but they're not so attractive after you consider the growing number of important services we use that soak up lots of bandwidth. The Internet is now used to distribute software, digital high-definition video, and music. It also facilitates online gaming, video conferencing, real-time collaboration, interactive remote desktop access, file backups, and many other bandwidth-intensive activities.

Other companies are tossing around slightly more generous caps, like Comcast's possible 250GB per month limit. As we noted in his analysis of Time Warner's decision, however, ISPs who have ample bandwidth will be happy to take in customers who aren't interested in being metered. And there are some intriguing wireless broadband options on the horizon that could draw customers away from bandwidth-constrained cable companies.