nanog mailing list archives

Re: Network end users to pull down 2 gigabytes a day, continuously?


From: Michael.Dillon () btradianz com
Date: Mon, 8 Jan 2007 10:25:54 +0000


But what happens when 5% of the paying subscribers use 95% of the 
existing 
capacity, and then the other 95% of the subscribers complain about poor 
performance?

"Capacity" is too vague of a word here. If we assume that the P2P 
software can be made to recognize the ISP's architecture and prefer
peers that are topologically nearby, then the issue focuses on the 
ISP's own internal capacity. It should not have a major impact on
the ISP's upstream capacity which involves stuff that is rented 
from others (transit, peering). Also, because P2P traffic has its
sources evenly distributed, it makes a case for cheap local
BGP peering connections, again, to offload traffic from more
expensive upstream transit/peering.

 What is the real cost to the ISP needing to upgrade the
network to handle the additional traffic being generated by 5% of the
subscribers when there isn't "spare" capacity?

In the case of DSL/Cable providers, I suspect it is mostly in
the Ethernet switches that tie the subscriber lines into the
network.

The reason why many universities buy rate-shaping devices is dorm users 
don't restrain their application usage to only off-peak hours, which may 

or may not be related to sleeping hours.  If peer-to-peer applications 
restrained their network usage during periods of peak network usage so 
it didn't result in complaints from other users, it would probably 
have a better reputation.

I am suggesting that ISP folks should be cooperating with
P2P software developers. Typically, the developers have a very
vague understanding of how the network is structured and are
essentially trying to reverse engineer network capabilities. 
It should not be too difficult to develop P2P clients that
receive topology hints from their local ISPs. If this results
in faster or more reliable/predictable downloads, then users
will choose to use such a client. 

The Internet is good for narrowcasting, but its
still working on mass audience events.

Then, perhaps we should not even try to use the Internet
for mass audience events. Is there something wrong with
the current broadcast model? Did TV replace radio? Did
radio replace newspapers?

--Michael Dillon


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