I need more time to look at it. Perhaps also a network guru might pass through soon.

From my own experience your ISP gives you a modem.

Most ISP require certain modems.

In my case I configured my modem as a bridge and connected it to a router that I bought myself. Through this router I can set up my network.

Well that is all my ISP gave me.

Who is your ISP?

This site has many ISP particular setups:

http://www.dslreports.com/faq/faq

http://whirlpool.net.au/index.cfm?a=h_view&model_id=279

http://www.siemens.com/Daten/siecom/...01_1274277.pdf

This device should work for your network. Here is the manual section:

http://www.siemens.com/Daten/siecom/...01_1274277.pdf

I will look further for details.

I don't know why it says Electric Lightwave, but we use a local telephone compay for DSL called Frontier.
http://www.frontieronline.com/ I believe that is their site.

Chapter 3 here has the setup instructions:

http://www.siemens.com/Daten/siecom/...01_1274277.pdf