North American Network Operators Group

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Re: Comcast blocking p2p uploads

  • From: Eric Spaeth
  • Date: Sat Oct 20 20:52:03 2007


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