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Re: Clarifying Misconceptions of the New Comcast Congestion Mgmt System
From: David Farber <dave () farber net>
Date: Wed, 24 Sep 2008 14:31:53 -0400

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.


-----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

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.
Hasan Diwan <hasan.diwan () gmail com>

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