[100280] in North American Network Operators' Group
Re: Comcast blocking p2p uploads
daemon@ATHENA.MIT.EDU (Eric Spaeth)
Sat Oct 20 20:50:54 2007
Date: Sat, 20 Oct 2007 19:46:34 -0500
From: Eric Spaeth <eric@spaethco.com>
Reply-To: eric@spaethco.com
To: nanog@merit.edu
In-Reply-To: <20071020232137.GB44916@ussenterprise.ufp.org>
X-SpaethCo-MailScanner-From: eric@spaethco.com
Errors-To: owner-nanog@merit.edu
Leo Bicknell wrote:
> I'm a bit confused by your statement. Are you saying it's more
> cost effective for ISP's to carry downloads thousands of miles
> across the US before giving them to the end user than it is to allow
> a local end user to "upload" them to other local end users?
>
Not to speak on Joe's behalf, but whether the content comes from
elsewhere on the Internet or within the ISP's own network the issue is
the same: limitations on the transmission medium between the cable modem
and the CMTS/head-end. The issue that cable companies are having with
P2P is that compared to doing a HTTP or FTP fetch of the same content
you will use more network resources, particularly in the upstream
direction where contention is a much bigger issue. On DOCSIS 1.x
systems like Comcast's plant, there's a limitation of ~10mbps of
capacity per upstream channel. You get enough 384 - 768k connected
users all running P2P apps and you're going to start having problems in
a big hurry. It's to remove some of the strain on the upstream channels
that Comcast has started to deploy Sandvine to start closing *outbound*
connections from P2P apps.
-Eric
