suffering from poor network performance...

[Eli Dart]

In reply to Alex (ander Sendzimir) <xela at battleface.com> :

> First, I know very little about networking, especially performance 
> turning. I would really like to learn more but don't know where/how to 
> start effectively.

Take a look at the tools ttcp, netperf and iperf.  They build 
straight out of ports.

Also, there are several good network tuning sites out there -- this 
one has most of them listed (take a look at the links page):

http://www-didc.lbl.gov/TCP-tuning/TCP-tuning.html

Note that most of the techniques covered here are for high-bandwidth, 
high-latency links (long fat pipes).  Bumping up your tcp buffers a 
bit might help a bit, but for the most part the machines you have 
should saturate a 100Mbps link with no trouble at all.  If you see a 
bit less than that, realize that you're connected to a hub, and so 
you're doing collision detection.  Fast Ethernet performance falls 
off pretty quickly in the face of competing traffic on a hub.  Note 
also that if you just crank up your tcp buffers to something large 
without thinking about what you're doing, you can actually decrease 
performance.

As someone else pointed out, using ping as a measure of network 
performance often doesn't give reliable results, since most operating 
systems (including FreeBSD) rate limit ICMP in various ways to 
protect against DoS attacks.

Hope this helps,

		--eli


> 
> Thanks for the help.
> Alex

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