ipfw bandwidth shaping problems (intermittent latency)

[Luigi Rizzo]

you must have some huge traffic source somewhere else which perhaps
fires every 3 seconds ?
The default queue is 50 slots so the fact that reducing the
queue to 15 brings the latency down to 70ms probably means
that for some reason the queue is almost full

	cheers
	luigi

On Wed, Jun 25, 2003 at 10:48:02AM +0100, Andy Coates wrote:
> Hi,
> 
> Up until now I've been fairly happy with just using a simple pipe with:
> 
>   pipe 1 config bw 2400Kbit/s
> 
> However recently under a more utilised link we start to see every third
> packet or so have a higher latency than the rest.  For example, an icmp
> ping to the host would show 10ms, 10ms, and then 190ms, then back to 10ms
> for another 2 pings and upto 190ms again.
> 
> I decided to play with the queue settings, and tried:
> 
>   pipe 1 config bw 2400Kbit/s queue 15
> 
> This then brought that third ping down to 70ms, so an improvement.  This
> still isn't acceptable however, since the amount of bandwidth being used
> is only 1000Kbit/s so I can't see where the problem is.
> 
> Is there anything else I can change to improve the response/latency? Or
> is this some type of bug?
> 
> Thanks in advance.
> 
> Andy.
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