Does the router maintain a connection and can you access the routers web page if the router is disconnected from the Arris modem? Need to see if the router is stable with out the ISP modem connection. We've seen many issues with Arris modems.
FAQ LibraryI would also try and turn OFF the Wireless radio and see what happens.
Can you connect with a different PC and does it happen here as well? Make sure the PC Network Card drivers are updated?
You could reload FW load and use the following process: Do this with out the ISP modem connected. Just be sure to have the FW .bin file already on your desktop beforehand.
1. Factory Reset using the back button
2. Update using the .bin file. Let it process.
3. Factory Reset onces more using the back button or if you can access the routers web page, use the Restore Factory Settings under Tools/System.
4. Set up the router from scratch, set up WiFi and reservations and configure those options you listed. If the router seems to be stable at this point, connect to the ISP modem and test again.
One thing you can also try if you have a neighbor, friend or family near by, take this router to there house and see if the problem follows, if it does then you'll know. If it doesn't, then possible that the problem is upstream or down stream.
Let us know how it goes. Here to help.