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Re: Extreme congestion (was Re: inter-domain link recovery)

  • From: Fred Baker
  • Date: Thu Aug 16 00:50:54 2007
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On Aug 15, 2007, at 8:39 PM, Sean Donelan wrote:

Or would it be better to let the datagram protocols fight it out with the session oriented protocols, just like normal Internet operations

Session protocol start packets (TCP SYN/SYN-ACK, SCTP INIT, etc) 1% queue
Everything else (UDP, ICMP, GRE, TCP ACK/FIN, etc) normal queue

And finally why only do this during extreme congestion? Why not always
do it?

I think I would always do it, and expect it to take effect only under extreme congestion.


On Aug 15, 2007, at 8:39 PM, Sean Donelan wrote:
On Wed, 15 Aug 2007, Fred Baker wrote:
So I would suggest that a third thing that can be done, after the other two avenues have been exhausted, is to decide to not start new sessions unless there is some reasonable chance that they will be able to accomplish their work.

I view this as part of the flash crowd family of congestion problems, a combination of a rapid increase in demand and a rapid decrease in capacity.

In many cases, yes. I know of a certain network that ran with 30% loss for a matter of years because the option didn't exist to increase the bandwidth. When it became reality, guess what they did.

That's when I got to thinking about this.