said by eekthecat:
Has anyone else noticed a difference in the data usage meter's accuracy between different routers? I haven't had the time to put this observation to any testing, but it seems like the meter was wildly inaccurate (in a good way) when I was using my Motorola SBG6580 (e.g. 50GB days would register as 10GB), but ever since I put the SBG6580 into bridge mode and switched to a D-Link router, it's a lot closer to accurate (e.g. 50GB days as 40-50GB)... I'm not sure if something changed in their system or if there's just something different between the two routers?
It's hard to say whether any metric will match what Cox's own accounting systems report.
The reason why is because there aren't any industry defined rules for determining how you count the data. Are they counting just layer 3 data, or layer 2 data as well? If layer 2, then in which network segment and what encapsulation type does that segment use? Do they include DOCSIS overhead? Are they counting packets that are dropped somewhere between your demarc and their first border router? (Your equipment and/or any remote equipment is completely unable to measure this, especially if interleaving is involved.)
These and a bunch of other variables come into play, and unless somebody inside of Cox answers how the data rates are measured, you'll never know; the best you can do is make an educated guess.
If I were to set a standard, I would say since you are offering "internet" service, then only internetwork traffic should be measured. In other words, all layer 3 (internet protocol) data that successfully traverses the space between your demarc and their border routers. Any data lost between there doesn't count, nor does any layer 2 traffic.