On 1/9/16, 12:04 PM, "NANOG on behalf of Robert Webb" <nanog-boun...@nanog.org on behalf of rw...@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