North American Network Operators Group

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Re: Selfish routing

  • From: alex
  • Date: Sun Apr 27 18:14:10 2003

> 
> [email protected] wrote:
> >>But curiously, adding some 
> >>incremental capacity to a network can, under some conditions, actually 
> >>make it worse!
> > 
> > Oh, rubbish.
> 
> Hmm?  You dispute the result in Roughgarden's paper - that Braess' 
> paradox can occur?  Or are you just saying that if the Internet is run 
> solely by people at your intelligence level, it'll never come up as an 
> issue?  (I've not said Braess' paradox is common; only that it's an 
> interesting result.)

No, I simply read the paper without a need to mold it into my "product
vision".

The paper describes a perfect mathematical system with unlimited resources
available in it. Since we have neither the perfect system nor the resources,
it really does not apply to the real world apart from a nice theoretical 
background (similiar to a nice background papers published around 1995 that
said there is no way CPUs of the size of P4 would be able to run at speeds
over 1 Ghz).

> Glad to be accused of offering a technology that can only do what smart 
> people can do (whether I agree or not).  Since the supply of clue in 
> this world is limited ...

The problem is that the technology offered really does not do anything more
than what already exist. It is similiar to going to Wawa and buying 18 rolls
of TP for $99c each, rather than driving to Wallmart 4 minutes away and
buying the same 18 rolls for $4.50.

> >>If you want an optimal network, you can:
> >>   1/ sit in the middle and play at being the God of TE
> >>   2/ have the various actors optimize "selfishly"
> >>   3/ count hops and assume that's close enough
> >>(Oh, and if you're into that sort of thing, I suppose you can try 
> >>dropping some packets to speed things up.)
> > 
> > Oh how about "fire those who are ordering wrong size of interconnects, order
> > right sized interconnects, count the moneys that you did not waste".
> 
> Certainly a reasonable addition to the list - I'd prefer it to those who 
> believe smart packet loss will solve all our problems. 

Actually, I said that using this magical technology that somehow eliminates
the need of having clueful staff as the solution is equivalent of using
claiming that since one uses QoS on packets he/she does not need to address
the problems of packet loss.

> Trouble is, 
> firing staff and buying big cross connects does rather assume that all 
> the people you hand packets to are as smart as you are (or can be 
> stopped from misbehavhing promptly).

Rubbish.

SM fiber for OC-3, OC-12, OC-48, OC-192 costs the same.
It is the OC-3, OC-12, OC-48, OC-192 service that you are ordering from one
cage to the one next to you that is killing you.

Even accounting for the costs of cards to support those OC-x connections,
you will be much better of. Why are you using OC-12 and above anyway? Did
someone forget to tell you that gige actually works rather well for
interconnect applications?

> In your own parallel posts, you acknowledge all the murky reasons why 
> other people don't build their networks in the way you'd like.  OK; so I 
> can make my own network and interconnects Yuriev-compliant, but that 
> still doesn't solve all the issues as long as I want to talk to people 
> across fabric that is not Y-c.  It's a network of networks we live in.

And no amount of technology on YOUR end is going to make the other side
Yuriev-compliant, because the moment the packet leaves your network, you
have exactly the same problem as the one have described. 

Did not you notice that people really do not care if they get problems as
they see in traceroute on 2nd, 3rd, 4th or more hops inside the other
network. It is the same to them. They care about the presence of a problem
no matter where it is.

Alex