I unplugged my modem last week before I went to Dortmund for some days and plugged it back in last Sunday when I came back. Since then my DSL broadband access is pretty slow. Like 1 Mbit/s downstream, should be around 16 Mbit/s. Therefore I messed a little bit around with my configuration and found out that my DSL Modem – Siemens C2-010-I, is actually Viking II Plus and not a modem but a moden/router/bridge. My provider configured the Viking as a bridge, therefore it looked like a usual DSL modem.