Unusually High Data Usage / False Overage Charges - Solved! (Bridge Mode Only)

NOTE:This applies only if you are experiencing this while your appliance is in Bridge Mode.

TLDR: Bridge Mode on your appliance measures all traffic whether or not you requested it leading to false readings.

So I've been dealing with Comcast Customer Service for the past 3 months after I've been registering 1.5-1.7 TB of data per month with multiple 100 GB days happening when no one was home and everything is turned off.

I have a home network setup so I have placed the Comcast appliance in  Bridge Mode so that I can handle all of my own traffic. After investigating my actual usage of all my devices on my internal network, I came to an average of 250 GB per month. Now where is the remaining ~1.5 Terrabytes?

I check the logging for the past 30 days on my perimeter device (router) and lo and behold, I found the culprit. It was registering approximately 40-50 GB inbound traffic daily, which makes sense because the internet is a noisy place thats being constantly scanned and attacked. The most obvious answer here is that Comcast is measuring all traffic that crosses the device while in Bridge mode regardless of whether or not you requested this traffic.

This makes sense because when their appliance is in routing mode, they can drop all of the unsolicited traffic prior to the traffic hitting their data monitoring application in the device. In Bridge Mode, the data usage monitoring software likely does not have enough insight to properly measure and categorize traffic.

Solutions:
1. I'm going to cancel my Xfinity service due to the grief I just went through and unfulfilled promises by customer service reps
2. (Not confirmed) You can switch into router mode and restructure your network and see if this works. However, be warned, if you have your own router, it still may mess with the data monitoring software on the device.