Time Capsule conflict with Internet

[nancyh1990]

Please excuse my ignorance with Mac.
I am trying to hook up my brother's iMac i5.
With cisco E3200, I get internet just fine via Cablevision.
When the time capsule is hookup to the Cisco, sooner or later, no internet service.
When I remove the ethernet connection, internet connection is restored.
Also, with the Cisco E3200, my wireless network is HOME1.
I also see another wireless SSID - THE HOFFMAN'S NETWORK.
We live in the country and there is not another neighbor within 100 yards.
Since our last name is Hoffman, I am confused.
Questions:
Reason why Time Capsule conflicts with internet connection.
It is apparent that THE HOFFMAN'S NETWORK is create by our computer, but where from?
Thanks so much for your help.

 

[osxx]

If you are going to keep the Cisco as your router then you need to set the Time Capsule in the bridge mode with config IPv4 using DHCP and encryption using WPA2.
Probably it was trying to double NAT with both routers running.