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Re: Can P2P applications learn to play fair on networks?


From: Ron da Silva <don.rasilva () gmail com>
Date: Fri, 26 Oct 2007 23:30:44 -0400


On 10/22/07 2:01 AM, "Mikael Abrahamsson" <swmike () swm pp se> wrote:
Could someone who knows DOCSIS 3.0 (perhaps these are general
DOCSIS questions) enlighten me (and others?) by responding to a few things
I have been thinking about.

Let's say cable provider is worried about aggregate upstream capacity for
each HFC node that might have a few hundred users. Do the modems support
schemes such as "everybody is guaranteed 128 kilobit/s, if there is
anything to spare, people can use it but it's marked differently in IP
PRECEDENCE and treated accordingly to the HFC node", and then carry it
into the IP aggregation layer, where packets could also be treated
differently depending on IP PREC.

This is in my mind a much better scheme (guarantee subscribers a certain
percentage of their total upstream capacity, mark their packets
differently if they burst above this), as this is general and not protocol
specific. It could of course also differentiate on packet sizes and a lot
of other factors. Bad part is that it gives the user an incentive to
"hack" their CPE to allow them to send higher speed with high priority
traffic, thus hurting their neighbors.

Yes, as a part of the DOCSIS specification (waiting for D3.0 not required);
however, implementations vary on the CMTS end of the equation though.
Having this capability ubiquitously on the CMTS equipment simplifies the
problem space greatly (plus removes that hacked CPE risk).

-ron



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