Re: READ Marketplace story on FCC and Comcast

[David Farber <dave () farber net>]

________________________________________
From: jon.strayer () gmail com [jon.strayer () gmail com] On Behalf Of Jon Strayer [jon () strayer org]
Sent: Wednesday, July 16, 2008 3:43 PM
To: David Farber
Subject: Re: [IP] READ Marketplace story on FCC and Comcast

For IP if you wish/

On Sun, Jul 13, 2008 at 8:51 PM, David Farber <dave () farber net<mailto:dave () farber net>> wrote:

________________________________________
From: Dr. Lawrence Roberts [lroberts () anagran com<mailto:lroberts () anagran com>]
Sent: Sunday, July 13, 2008 8:38 PM
To: DV Henkel-Wallace; lroberts () anagran com<mailto:lroberts () anagran com>
Cc: David Farber
Subject: Re: [IP] Marketplace story on FCC and Comcast

DV,
Re "all it can get":
Today TCP/IP networks use as the basic fairness, "all flows get equal capacity". This is a result of our thinking in 
the early days where each person had one flow in each direction like a voice call. But today, an application can start 
up 100 or 1000 flows. Each flow gets "all it can", perhaps 100 Kbps. So do other users on the same cable or DSLAM. But 
the P2P application started 100 flows so it gets 10 Mbps and the other users still get 100 Kbps. That is fairness as 
the network works today. If you wished your FTP to operate at 10 Mbps, you also could start 100 flows and send a part 
of the file in each one. Then others would do this and soon all your flows would be operating at 10 Kbps since the 
cable is overloaded and must slow them all down. This is the problem we face today with P2P. It is better at getting 
capacity than any normal application. So a few users get most of the capacity.

Which means that the problem is that users can't use all the bandwidth they paid for.  If I pay for a 10Mbps connection 
and use 10Mbps where is the problem?  Apparently the problem is that the cable company only provisioned 10Kpbs per 
customer.



Re modeling:
The problem is simple to model after observing the behavior of P2P programs. It is at layers 3 & 4 not 7. The P2P 
application finds a list of other users with a movie the user wants.

Movie?  Let's just say "file".  My major use of BitTorrent is to download Eclipse.


It opens a flow to get part of the movie from the first other site. There is no concern about closeness in the net, in 
fact a majority of these flows go overseas.

That's a problem, but it's also fixable<http://crypto.stanford.edu/%7Ecao/biased-bt.pdf>.




--
Esse Quam Videre
To Be, rather than to Seem


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