CM700 dropping internet connection #2

You have a lot of MDD timeout messages. Usually those are when the modem sends a signal to the cmts and its not received. 

You can check all the cables and ends again. But you might have to have xfinity check the line. I recommend moving the modem to right where the coax comes into the home to prevent it from being the wiring in the home being the issue because xfinity charges if the issue is inside the home.