Here is the diagram:
My PC(192.168.1.10) --> Hub --> DSL Modem(192.168.1.1) --(via TM Net Streamyx)-> The Internet
I have one caremo DSL modem, which I bought myself and one ZTE 831 DSL modem, which I got for free when subscribe to TMNet Streamyx service.
To use bittorrent client, we have to enable the port forwarding in this modem.
1. If your PC is connected to the Internet like mine, open the Internet Explorer, and type 192.168.1.1, where it is the usual configuration page for any ADSL modem like Caremo and ZTE 831.
2. Type in your username and password. The default username is admin and the default password is also admin.
3. When you press enter key, you will be forward to the modem's wizard page. Click 'Advance Setting', and you will arrive at the advance configuration page.
4. Clik 'Advance Setting' on the left menu. Check 'Enable UPNP', select your connection and click apply button.
5. Click 'Port Forwarding' from the left menu.
6. Choose the connection name, select your computer IP (mine is 192.168.10).
7. Click 'User' under the category (because only under this category you could insert a custome category).
8. Click 'Add' button.
9. Create a rule name, example torrent. Select TCP, Port Start 6889, Port End 6889, Port Map 6889, click 'Apply'. The port number is just an example. You have to put the same port number which you are using in the torrent client. Use only one port is enough for Utorrent or Azureous.
10. Now you have create a rule named torrent. Select it from the available rule, click add button, and apply.