I had to guess this is on WiFi. Remember that WiFi is open to interference so the usual is to drop the distance to the router by half and then change the routers SSID so you create a new setup on the client.
I also have the client forget all prior WiFi connections and set up the new connection.
Since 802.11n has one non-overlapping channel, the first setup is done with 802.11g WPA2 and personal security.
For about 2 years or so my internet connection has been disconnecting about every 5-20 minutes. Sometimes It gets really bad and disconnects multiple times under 5 minutes. I always end up having to reset the modem. I have Xfinity and a Arris TG862 gateway with a Netgear R6250 router. I've tried resetting the modem and router. What else is there to try other than calling Comcast?