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List:       quagga-users
Subject:    [quagga-users 12568] Re: bgp - quagga-0.99.18
From:       Alexis Rosen <quagga-users () alexis ! users ! panix ! com>
Date:       2011-11-12 21:36:47
Message-ID: 2DF9F338-FE68-42E2-B5D2-6E61B22ED026 () alexis ! users ! panix ! com
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On Nov 11, 2011, at 10:35 AM, Ingo Flaschberger wrote:
> > There's rather more to the problem than what you do with small packets. And if \
> > you think that "the queue" is just 1mbit, you're mistaken - just at the level of \
> > one ethernet port's ring buffers, you could choose to configure 4096*9000 bytes \
> > of buffering. That alone could produce ~300ms of buffering on a gigabit \
> > interface. (Yes, that's generally unrealistic, but 4k*1500 bytes is not, and that \
> > still amounts to 50ms.) And that doesn't take into account the various other \
> > layers of buffering you may have in your system. Stick ten or twenty routers in \
> > between source and destination and you could have a real problem, if enough \
> > people make the wrong choices.
> 
> at freebsd:
> man ipfw
> man dummynet
> 
> and the queue has 1 mbit!

I quoted the words "the queue" for a reason - I was not talking specifically about \
any one particular queue- as I'd hoped the rest of the post, which was mostly talking \
about ethernet ring buffers, made clear. I was talking about all of the buffering \
that's done on the system.

> ethernet-queues only fill if the router has not enough time to handle packets - and \
> the you have other problems than only slow pings.

You've entirely missed the point. I was talking about maximum packet handling \
capability of quagga routers. In other words, the type of situation where your router \
may indeed not have enough time to handle all the packets, at least momentarily. It's \
exactly those types of situations that may encourage people to use too much \
buffering.

/a
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