IDS mailing list archives

Re: port bonding and taps


From: "Sam f. Stover" <sstover () iwc sytexinc com>
Date: Fri, 3 Oct 2003 14:04:12 -0400

I did captive-net testing, using a pair of generator machines direct
patched (xover cables for 100BaseT) to the snorter's NICs, using
tcpreplay to inject traffic. I was using completely untuned snort
1.9 on Compaq DL-320 low-end boxes, as I recall PIII-1.25GHz and
640MB RAM. Packet losses started getting noticeable somewhere around
70-80Mbps aggregate, and it made absolutely no difference whether
the aggregate was coming in over two bonded interfaces, or over a
single NIC with no bonding loaded. Bonding didn't seem to enter into
the performance picture at all.

I can see how that would be the case on lower end boxes. However, had they been extremely beefy, it's possible that the application wouldn't be the weak link, but the bonding. That's where I'm driving with this - I'd like to know where the overhead imposed by the bonding causes packet drops.

If I'd needed to hit higher performance, there were certainly easy
measures to take; but as it turned out, I didn't:-).

Also, is there a way to know if you are dropping frames on the
bonded interface?  Or do you have to query the individual card
statistics, just like anything else?

In my case, I could compare sent to received packet counts
end-to-end.

My question here was more directed at an environment where the bonded interface was dropping packets - which didn't appear to be the case in your situation... Still cool though.

____
S.f.Stover
sstover () iwc sytexinc com

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