Observations of an Internet Middleman (Level3)

Livingood, Jason Jason_Livingood at cable.comcast.com
Thu May 15 21:19:22 UTC 2014


On 5/15/14, 4:16 PM, "Scott Berkman" <scott at sberkman.net<mailto:scott at sberkman.net>> wrote:
Everyone knows Comcast uses (or used) Sandvine for shaping (unless
they've finished building a new probably internal solution, I'm sure
this is another secret we'll only have rumors to work with, ).

Comcast turned off Sandvine’s active traffic management system at the end of 2008; I know because it was my job to do it (and I had nothing to do with the decision to turn on the Sandvine system). ;-) FCC Chairman Kevin Martin required the turn down of that system by EOY 2008. Here is the letter to the FCC confirming that transition was completed on January 9, 2009: http://downloads.comcast.net/docs/comcast-nm-transition-notification.pdf.

It was replaced with a protocol-agnosting congestion management system (active only in the DOCSIS network). That system was disclosed here:
http://downloads.comcast.net/docs/Attachment_B_Future_Practices.pdf
http://tools.ietf.org/html/rfc6057
http://downloads.comcast.net/docs/IETF%2072%20-%20TANA%20BoF%20-%20ISP%20Requirements%20-%20Comcast.pdf
http://downloads.comcast.net/docs/Comcast-IETF-P2Pi-20080528.pdf
http://downloads.comcast.net/docs/ietf-p2pi-comcast-20080509.pdf

There is no other active traffic management system (other than what any ISP has for DDoS protection/mitigation), period.

I'm no longer in a position to test this for reporting to the FCC as
suggested, but in a previous life we were able to prove it enough for the Comcast customer getting the short end of the stick to stop yelling at us and get a new provider, which of course made everyone involved happier.

We used to have a “positive” traffic shaping system called PowerBoost. That enabled customers to boost above their advertised or provisioned rates for brief periods. That system seemed to cause more customer confusion than it was worth and PowerBoost was eliminated across all of our tiers of service. Sometimes tools to notice traffic shaping noticed PowerBoost and it was sometimes hard to explain that we were shaping traffic *up* in capacity rather than down, but I digress.

I'd love to see a case study published by
Comcast on how that project went and what the impacts to the network and bottom line were.

We documented every step of the way on our Network Management page at http://networkmanagement.comcast.net/. You may also be interested to read Alissa Cooper’s September 2013 PhD thesis, which touches on this system on some level at http://www.alissacooper.com/files/Thesis.pdf.

There is also a good paper by the Broadband Internet Technical Advisory Group (BITAG) on this topic at http://www.bitag.org/documents/BITAG_-_Congestion_Management_Report.pdf. We at Comcast comply with all of the BITAG recommendations in that paper.

Jason



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