[57930] in North American Network Operators' Group
Re: Selfish routing
daemon@ATHENA.MIT.EDU (alex@yuriev.com)
Sun Apr 27 18:18:51 2003
Date: Sun, 27 Apr 2003 18:22:49 -0400 (EDT)
From: alex@yuriev.com
To: "David G. Andersen" <dga@lcs.mit.edu>
Cc: Mike Lloyd <drmike@routescience.com>, nanog@merit.edu
In-Reply-To: <20030427220406.GA43386@lcs.mit.edu>
Errors-To: owner-nanog-outgoing@merit.edu
> > alex@yuriev.com wrote:
> > >>But curiously, adding some
> > >>incremental capacity to a network can, under some conditions, actually
> > >>make it worse!
> > >
> > >Oh, rubbish.
>
> To alex: It's not necessary to add a tiny link to the network
> to make things worse. In fact, the actual Braess Paradox example
> that roughgarden uses arises from the addition of a high-capacity,
> low-latency link in the wrong place. It presumes the existence of
> a smaller capacity path through the network somewhere, but are you
> arguing that those paths don't exist? I can show you a lot of them,
> since it's what my software (the aforementioned MIT RON project) is
> designed to exploit. The Internet is full of weird, unexpected paths
> when you start routing in ways that the network designers didn't intend.
> And that's what selfish routing _does_.
To those who really dont get what I am saying:
If you do not have enough capacity, the selfish or non-selfish routing does
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
not matter.
^^^^^^^^^^
99.99999% of network problems are caused by CAPACITY issues be that packet
loss, or routers incapable of dealing with the traffic.
Addressing 0.00001% of problems caused by selfish routing is not going to
make it better. Address the issues that cause 99.99999% of the problems
before addressing 0.00001%
Alex
