Binge On! - get your umbrellas out, stuff's hitting the fan. [Comcast meter Q]

Sat Jan 9 20:40:23 UTC 2016

On 1/9/16, 12:04 PM, "NANOG on behalf of Robert Webb"
<nanog-bounces at nanog.org on behalf of rwebb at ropeguru.com> wrote:

>Unfortunately, providers like Comcast, yes, I know they aren't wireless,
>but their usage meter is a joke and a proprietary based joke at that. I
>do not think I have ever seen anyone from Comcast willing to describe
>exactly how their meter works and what is and is not counted towards
>usage. I am not a wireless expert, but my guess is that it would be even
>more difficult to accurately track usage on wireless given the portable
>nature.

Since my day job is at Comcast and part of that job is ensuring that the
usage meter is technically accurate I figured I would chime in. A few bits
of information that may be helpful follow below. **I am happy to answer
any questions you or others have.** And I have also copied our independent
auditor should there be questions for his firm.

1 - Comcast does byte counting via the IPDR standard (IP Detail Records).
I would think any other DOCSIS-based network that performs byte counting
would also use IPDR (and all the ones of which I am aware do so). You can
find some more information about the IPDR specification here:
https://en.wikipedia.org/wiki/Internet_Protocol_Detail_Record

https://www.incognito.com/tips-and-tutorials/faq-bandwidth-monitoring-with-
ipdr/

http://www.dslreports.com/r0/download/1603814~d44a19780841cdc79abf840b6066d
52d/ipdr-usage-counters.pdf

http://www.cablelabs.com/wp-content/uploads/specdocs/CM-SP-OSSIv3.0-I14-110
210.pdf

2 - Comcast first made mention of the use of IPDR in a 2008 FCC filing, as
part of a deployment of a protocol-agnostic congestion management system.
See these documents:
http://downloads.comcast.net/docs/Attachment_B_Future_Practices.pdf

https://tools.ietf.org/html/rfc6057

3 - Comcast engaged a 3rd party auditor called NetForecast
(http://www.netforecast.com/) to regularly, independently audit the
accuracy of our usage meter. We usually announce those audits on our
Network Management page (ex:
http://networkmanagement.xfinity.com/index.php/8-network-management-news/55
-2015-comcast-usage-meter-accuracy-report) and NetForecast publishes these
reports on their website. See the following documents:
- First accuracy report, 2009:
http://www.netforecast.com/wp-content/uploads/2012/06/NFR5101_Comcast_Usage
_Meter_Accuracy_Original.pdf
- Second accuracy report, 2010:
http://www.netforecast.com/wp-content/uploads/2012/06/NFR5101_Comcast_Usage
_Meter_Accuracy.pdf
- Third accuracy report, 2014:
http://www.netforecast.com/wp-content/uploads/2014/05/NFR5116_Comcast_Meter
_Accuracy_Report.pdf
- Fourth accuracy report, 2015:
http://www.netforecast.com/wp-content/uploads/2015/06/NFR5120_Fourth_Comcas
t_Meter_Accuracy_Validation_Report.pdf
- ISP best practice report:
http://www.netforecast.com/wp-content/uploads/2015/06/NFR5119_General_ISP_D
ata_Usage_Meter_Specification.pdf

4 - In terms of what is counted, all Internet traffic is counted (what is
now known as Title-II traffic). Title-VI video traffic and Xfinity Voice
traffic, which may use the IP protocol but are not Internet services, are
not counted.

Enjoy the rest of your weekend,
Jason