I plugged my cable modem into a dumb switch. It had a link, but there was nothing else attached; there was no router to act as a DHCP client, no frames being sent to the cable modem at all. In six days, my usage meter incremented by 0.5 GB. Plugging in a protocol analyzer revealed a constant stream of ARP requests for other subscribers' IPs. These were apparently counted against my cap, and presumably they were counted against everyone's caps, making 250 GB/month 1% smaller than advertised.
Comcast sent me to a document describing their metering methodology:
http://www.netforecast.com/documents/NFR5101_Comcast_Usage_M...
Their reps defended the practice of counting Comcast-generated broadcast traffic against everyone, even though there's no way for subscribers to prevent it.
Our ISP has recently enacted data caps. The first time they threatened to disable our account for going over, I pointed out to them that:
- My firewall has logged tens of gigabytes of dropped/rejected traffic.
- That if I ran a TCPDump on our WAN interface, could see management and broadcast traffic for neighboring CPEs (modem).
- That I know for a fact (I used to work for them in a previous iteration) that their network isn't built in a way that would allow them differentiate their management and monitoring traffic from individual customer traffic.
- And finally, that the Layer 2 & 3 statistics of that WAN interface were nowhere close to their own statistics for the account.
They have yet to respond to that complaint, despite going to the FCC. I really wonder what would happen if one were to take their ISP to court with the proper documentation.
Am I understanding correctly that you want Comcast examining the content you are downloading and deciding whether it counts towards your usage or not? This sounds like the complete opposite of net neutrality.
The point of my comment is partially tongue-in-cheek, because this is a problem Comcast can't solve, and they're setting themselves up for a rampage of angry people, as the amount of bandwidth being used for advertising increases every year.
But, since you brought it up, Comcast already examines your content. You are mistaken that net neutrality is broken if they filter advertising from your meter. Net neutrality is about not prioritizing or throttling responses to your request, not how Comcast bills you. And, for that matter, auto-play advertising is already worse for net neutrality than it would be for Comcast to categorize your surfing for billing purposes. Your internets are already being jammed and throttled by advertising video that in many cases is much larger than what you asked for.
If they are injecting ads (which I have seen through other providers, but I believe it wasn't related to Comcast) then your point is valid. At that point you are being delivered packets (large video-laden amounts) were not requested, and being charged for them. As a side note, I believe Verizon was doing this to mobile customers, not sure how it ended though.
So if Comcast bills you at double the rate for going to Facebook instead of Google+, that's consistent with net neutrality?
For instance, grocery store scales, gas pumps, power meter manufacturers, etc.
If we're going to lose the fight with Comcast over metered bandwidth, then perhaps we need to push for laws regarding inspection and validation of their metering systems themselves.
If they're limiting consumers to a certain amount of traffic, I want the definition of traffic to be clearly delineated and for the measurement systems to be properly inspected and regulated.
For instance, do they measure at the modem? At the local node? At the edge of the network?
Does local traffic within Comcast's city-wide network count?
If someone sends an IP traffic that their computer never requested and is filtered out, does it add to the traffic usage?
Does a UDP broadcast in a subnet count towards everyone's bandwidth, even if the cable modem filters it out?
Does this cover ICMP and UDP?
Does Comcast's own "Are you there?" packets to cable modems count towards traffic allotments? Does Comcast's cable modem traffic to the registration and DHCP servers count?
If they're going to screw-over customers, then there needs to be clear rules they have to follow so they can't just make up numbers. There also needs to be a way to make sure that DDOS attacks can't attack the bills of customers.