random disconnects from live

What Country/State/Province do you live in? Netherlands
Modem brand & model number: **** VoIP(?)
Router brand & model number: TP-Link 1403
Network Connection Type: Wired If Wireless,
what type of encryption are you using? xx
Things you have tried: Is UPnP Enabled? Yes (and dhcp is standard-on)
Is NAT Type Open? Yes - also tried direct connection to modem and dmz.. but it still fails to connect to xboxlive, also changed the mtu value(read something about that) and then I also increades the lease time from 2 hours to 24 hours...
Any Error Codes you encounter: the xbox can connect to the internet but not to xboxlive
What type of internet do you have? Cable
Who is your ISP(Internet Service Provider)? ziggo
When you run "Test Xbox LIVE connection" what is the exact message shown on screen? - when I run the test immediatly it tells me that the xbox can connect to the internet but not to xboxlive, If I wait a few seconds, no message it just says I'm connected and all seems to go well. After a few minutes I get again disconnected and sometimes I can be online for a max of 30 minutes... this are the code's when I can connect to xboxlive W: 0000 000B X: 0000 F001 Y: 20A8 4840 Z: 0000 0000 ID: ffff ffff these are the code's when I get disconnected(plus the message that he cannot connect to xboxlive. w 0000 000B x 0000 F001 y 20A8 4840 z 0000 0000 id 0006 0000 When waiting only a few seconds I get the first code again and I can connect to live again! then only to get disconnected again and then I receive the below code, with the message to check if the correct port is open, or that my isp might be blocking the xboxlive service, but I called them and they're not. w 0000 000B x 0000 f001 y 00a8 4820 z 0000 0000 id 0006 0001 and then it starts all over again, saying the connection is good... it's driving me crazy!! It all went bad when I bought the La Noire Pass saturday and started downloading the dlc which didn;t go very smoothly(random disconnects started then!)or that might just be a coincidence.