A new ARRIS device connected to my wifi yesterday

I noticed when I checked my wifi network on my.Xfinity.com this evening the following "Notification" under the heading YESTERDAY:

"New Device Connected7:21pm

A device called ARRIS AX061AEI just connected to your home network for the first time."

I have no idea what this device is.  Is this a Comcast action or an intruder?