My ISP has placed a bandwidth cap on my connection. What should I do?

The amount of data that is being pumped across the internet is enormous, and it's growth in recent years has been incredible.

At first, much of that growth was in the so-called "peer to peer file sharing networks". These tools are designed to make it easy to copy and share massive amounts of data. In recent years, sites like YouTube or Hulu are now bringing on-line video to the masses as a true alternative to things like TV. Add in sites like iTunes and Amazon and more are selling downloadable music and videos as an alternative to physical CDs and DVDs. You can quickly see that the demands for pushing data through the internet are growing at an incredible rate.

This has ISPs scared.

ISPs are scared because not all of them have the infrastructure - the hardware - to actually provide all that bandwidth to all their customers should they all start downloading more and more video. It's not practical to make sure that there's enough to cover it either; it would be exorbitantly expensive to do so. They may be building and adding capacity, but there's only so much they can add, and only so quickly. The result is a compromise.

And part of that compromise might be asking you, their customer, to slow down.

OK, so "ask" might not be the right word - in your case they're apparently telling you what you can, and cannot do.

The good news is that 5GB is a lot of data. You probably won't risk exceeding that with just email and normal web surfing. (In fact, if I understand your question correctly, these actually remain unlimited for you - they don't count against your cap.)

But as you point out, videos - like mine - probably count. And a lot of video watching can add up to a lot of data.

How much? That's hard to say. One recent video I posted is 3.5 megabytes in size - that means you could watch it 1,000 times and still not get reach your bandwidth cap. On the other hand, downloading a few 100 megabyte movies could get you close pretty quickly.

Unfortunately, while ISPs may implement these caps, rarely do they include the tools to monitor where you are with respect to the cap. My mobile broadband provider, Verizon, will show me how much I've used, but as I understand it they're the exception rather than the rule.

And as you say, even then it's all "after the fact". You don't know how much bandwidth you're using until after you've used it.

Measuring your bandwidth usage at home is difficult, particularly if you have more than one computer. There are some tools that will measure the usage of one computer, but when you connect multiple computers to a single internet connection things get difficult. Routers typically do not have the capability of measure usage.

So, what to do?

First, check with your ISP to see what kind of tools they may have to tell you where you are with respect to your bandwidth cap. If they have one, check in every day, or every few days as you use your internet connection, so you can get a sense for how quickly you're approaching the limit.

Second, to put it somewhat obliquely: download once, watch multiple times. By that I mean that it's common to watch a video multiple times, often by revisiting the site that hosts it. Depending on your system configuration and things like the size of your browser cache, each one of those visits could cause the video file to be downloaded again and again. Instead, see if there are explicit options to download the file to your computer's hard disk so that you can view it multiple times without needing to download. This isn't always available, and not always obvious, but when available can be a real bandwidth saver for videos that you expect to view multiple times. (I'm still experimenting with how best to provide video on my site, but I do know that there are tools that will allow you to download YouTube videos, for example.)

And of course, don't run peer-to-peer file sharing software if your ISP has a bandwidth cap. That'll get you to the limit fairly quickly.

But ultimately, if your ISP provides no tools to monitor your usage as they see it, then I'm not aware of any reasonable solution to actively monitor your usage from your end with the goal of avoiding that limit. Perhaps readers will comment with additional ideas on this.

Now, about your ISP.

The statement that has me most concerned is this: "Reading the fine print in the new contract I see that it expressly forbids streaming of videos, downloading of music, videos or games, hosting broadcasts or internet phone use."

If they actually prohibit you from streaming videos or downloading music, videos or games, then they might as well be prohibiting you from using the 21st century internet. That's when I say run away - find an ISP that "gets" the internet and how it's being used.

On the other hand, I'm hoping for one of two misunderstandings:

• You are actually prohibited from being a source of those types of things for others. What the wording really means is that you cannot set up a server on your internet connection and allow others to download from you.

• The wording doesn't prohibit you from downloading those types of things, but is just trying to be explicit about what counts. Since your question implies that your ISP can somehow identify "internet browsing, e-mail and intranet access" and leave all that as truly unlimited, they're probably trying to tell you about the other things that aren't unlimited and can count against your bandwidth cap.

Both of those are pretty reasonable, so I'm hoping that's what your ISP actually intends.

It might be worth contacting them to clarify.