bobpeers -> blog

The main train company in Denmark is called DSB and they have recently introduced wireless internet on many of their long distance trains.

In theory this is a great idea but in practice I can’t help but think they’re missed an opportunity. Remember when no so long ago you paid for your internet by the minute and so you connected, did what you had to do, and disconnected ASAP, well it’s the same for DSB.

If you don’t buy an access card then it costs 1 DKK per minute, even with a card it costs 299 DKK per month where I’m tied to using their WIFI hotspots.

Quite why I would do this when I can sign up for mobile broadband for between 200 and 300 DKK a month and have internet anywhere I go in Denmark (and abroad), even with unlimited use using the 3 network, is beyond my understanding.

Certainly last time I was on the train about a month ago the vast majority of people seemed to have their own USB dongles to access the internet. I don’t mind paying something (even though I really think it should be free) but this price is so uncompetitive as to be a joke. But then DSB was never known for good value or forward thinking.

On a related note the trains have their own computer that acts as a proxy server and gateway to the 3G network, users connect to this using an 802.11g connection. I didn’t pay for the internet but accessing the gateway I could see that it was running Ubuntu, the http headers are shown here.

Date: Thu, 13 Aug 2009 12:41:47 GMT
Server: Apache/2.2.8 (Ubuntu)
Accept-Ranges: bytes
Keep-Alive: timeout=15, max=100
Connection: Keep-Alive
Transfer-Encoding: chunked
Content-Type: text/html

Their on train solution I’ve translated from this DSB page and included below.

The chosen solution
DSB has chosen to offer wireless internet in the train, in cooperation with TDC. The solution is based on a combination of WiFi and 3G technology.

The train itself is thus a wireless WiFi solution. WiFi technology is the same as TDC for its Hotspot solutions, which are everywhere at home, at work, in hotels and elsewhere. The WiFi solution is based on a standard called IEEE 802.11g and has currently a capacity of 54 megabits per second.

Communication between the trains antenna and TDC terrestrial base stations / masts are using the latest 3G technology, called HSDPA (High Speed Downlink Package Access). Capacity as of early 2009 is up to 5.7 Mbits / sec. and will be expanded as the 3G technology is developed, and the need for higher capacity.

User’s PC communicate “WiFi” language to the trains Access Point. While the trains antenna communicates the “HSDPA” language with base stations / masts along the track and have a cable connection to the Internet.

The Train Access Point and the antenna are connected via cables to an Internet Controller. The Internet Controller is train solutions heart, and as such has 4 cardiac chambers. These are:

* An ethernet switch with firewall
* A mini-computer (which controls the particular capacity allocation among the users logged in)
* An HSDPA modem, and
* A power supply.