[onslauth]

The system in question is developed by a company called Byte Mobile, which was bought by Citrix.

Normally all port 80, and 8080 traffic are redirected to the system, and then rules are run to determine what happens to the traffic, and or code to be injected into the page.

[onslauth]

So let me add some more detail.

The system is used to help reduce bandwidth, as well as including a better TCP algorithm for use over the radio links, to help cut down lag and retransmissions, because the radio links are notoriously bad, and the standard algorithm doesn't quite cut it.

The system will actively try to down sample both images and video to help reduce bandwidth usage. In the case of video, it also tries to limit the buffered video to no more than X seconds ahead.

And finally, it is also big cache, and it tries to keep the most requested content locally. One of the new features is the ability to 'guess' what video is being viewed inside a HTTPS stream and try to cache it too.

As mentioned above with regards to the Canada telcos inserting iframes or content regarding their data usage and caps, the system can inject any content into the HTML page if it is provided over HTTP. They do this because normally they have no way to contact customers that have tablets, or 3G modems / dongles, to alert them of limits or just to be able to contact them.

[tempestn]

How could they not have any way to contact their customers? You need to provide contact information when you sign up for a data plan, don't you?

Even if you accept that the only way for them to contact their users is via their data connection (which, again, doesn't make sense,) there are far less intrusive methods than injecting content into existing pages. For instance, they could send the user to a separate notification page, perhaps with a helpful link to the resource that the user was intending to browse to. No need to mess with (or see) the contents of any pages.

[onslauth]

They very possibly can do all of the above.

However you have to understand how a lot of the cellular operators function. They don't build much of the systems in house, but buy from large companies like Ericsson, Huawei and so forth. Therefore all their functionality is controlled by those companies.

That being said, the cellular operators don't like to hand out contact information about their customers. All billing is normally done via a MSISDN to a single system that stores a customers credit, and records all billing information. It does not contain any customer details.

I have actually seen a different approach, wherein any messages going to a MSISDN that has been identified as a tablet or modem / dongle, will be redirected to another MSISDN as a SMS or an email address, depending on the customers preferences. All these details were stored in another database.