Re: Clarifying Misconceptions of the New Comcast Congestion Mgmt System

[David Farber <dave () farber net>]

Begin forwarded message:

From: "Livingood, Jason" <Jason_Livingood () cable comcast com>
Date: September 24, 2008 2:19:50 PM EDT
To: "Hasan Diwan" <hasan.diwan () gmail com>, <dave () farber net>
Subject: RE: [IP] Clarifying Misconceptions of the New Comcast  
Congestion Mgmt System

Not deep at all.  We have a count of bytes, by cable modem, in the
upstream and the downstream direction.  We have no visibility into the
apps being used, the source/destination of the packets, or the content
of the packets.

Jason

> -----Original Message-----
> From: Hasan Diwan [mailto:hasan.diwan () gmail com]
> Sent: Wednesday, September 24, 2008 2:11 PM
> To: dave () farber net
> Cc: Livingood, Jason
> Subject: Re: [IP] Clarifying Misconceptions of the New
> Comcast Congestion Mgmt System
>
> 2008/9/24 David Farber <dave () farber net>:
> > When one of these threshold conditions has been met, we
> consider that
> > individual port (not all ports on the CMTS) to be in a
> so-called Near
> > Congestion State.  This simply means that the pattern of usage is
> > predictive of that network port approaching a point of high
> > utilization, where congestion could soon occur.  Then, and
> only then,
> > do we search the most recent 15 minutes of user traffic on that
> > specific port, in order to determine if a user has consumed
> more that
> > 70% of their provisioned speed for greater than 15 minutes.  By
> > provisioned speed, we mean the "up to" or "burst to" speed of their
> > service tier.  This is typically something like
> > (1) 8Mbps downstream / 2Mbps upstream or (2) 6Mbps
> downstream / 1Mbps
> > upstream.
>
> I would like to know how deep this "search" is. Does it
> reveal, eg, whether the traffic was P2P or not? Does it show
> whether I was downloading a Linux ISO using Bittorrent or
> conducting a video conference with family? I'm cc'ing mr
> Livingood on this email because he ends his note with "You
> can others can feel free to contact me directly if you have
> any questions." When he responds, I'll also be forwarding
> that note to the list.
> --
> Cheers,
> Hasan Diwan <hasan.diwan () gmail com>




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