ipfw bandwidth shaping problems (intermittent latency)

[clemens fischer]

* Andy Coates:

> 64 bytes from x.x.x.x: icmp_seq=0 ttl=248 time=70.803 ms
> 64 bytes from x.x.x.x: icmp_seq=1 ttl=248 time=3.850 ms
> 64 bytes from x.x.x.x: icmp_seq=2 ttl=248 time=3.551 ms
> 64 bytes from x.x.x.x: icmp_seq=3 ttl=248 time=123.844 ms

what type of network-card do you have installed?  some people claim
that this can be an issue with the card, although i don't believe this
having tried a couple.

PING (some external host): 56 data bytes
64 bytes from x1.x2.x3.x4: icmp_seq=0 ttl=246 time=74.959 ms
64 bytes from x1.x2.x3.x4: icmp_seq=1 ttl=246 time=69.179 ms
64 bytes from x1.x2.x3.x4: icmp_seq=2 ttl=246 time=68.582 ms
64 bytes from x1.x2.x3.x4: icmp_seq=3 ttl=246 time=70.825 ms
64 bytes from x1.x2.x3.x4: icmp_seq=4 ttl=246 time=69.149 ms
64 bytes from x1.x2.x3.x4: icmp_seq=5 ttl=246 time=68.967 ms
64 bytes from x1.x2.x3.x4: icmp_seq=6 ttl=246 time=67.849 ms
64 bytes from x1.x2.x3.x4: icmp_seq=7 ttl=246 time=69.080 ms
64 bytes from x1.x2.x3.x4: icmp_seq=8 ttl=246 time=68.407 ms
64 bytes from x1.x2.x3.x4: icmp_seq=9 ttl=246 time=67.727 ms
64 bytes from x1.x2.x3.x4: icmp_seq=10 ttl=246 time=69.813 ms
64 bytes from x1.x2.x3.x4: icmp_seq=11 ttl=246 time=70.237 ms
64 bytes from x1.x2.x3.x4: icmp_seq=12 ttl=246 time=70.484 ms
64 bytes from x1.x2.x3.x4: icmp_seq=13 ttl=246 time=68.549 ms
64 bytes from x1.x2.x3.x4: icmp_seq=14 ttl=246 time=70.120 ms
64 bytes from x1.x2.x3.x4: icmp_seq=15 ttl=246 time=69.537 ms
64 bytes from x1.x2.x3.x4: icmp_seq=16 ttl=246 time=1075.376 ms
64 bytes from x1.x2.x3.x4: icmp_seq=17 ttl=246 time=75.057 ms
64 bytes from x1.x2.x3.x4: icmp_seq=18 ttl=246 time=1076.529 ms
64 bytes from x1.x2.x3.x4: icmp_seq=19 ttl=246 time=74.996 ms
64 bytes from x1.x2.x3.x4: icmp_seq=20 ttl=246 time=69.312 ms
64 bytes from x1.x2.x3.x4: icmp_seq=21 ttl=246 time=70.170 ms
64 bytes from x1.x2.x3.x4: icmp_seq=22 ttl=246 time=71.475 ms
64 bytes from x1.x2.x3.x4: icmp_seq=23 ttl=246 time=69.761 ms
64 bytes from x1.x2.x3.x4: icmp_seq=24 ttl=246 time=67.868 ms

i don't use any type of pipes/queues, and have been noticing this
"phenomenon" for years without any god explanation.  there's not much
traffic into or out of this workstation, no bursts correlating with
these delays.  this is on A-DSL line.

my firewall rules changed considerably over time, but not these
numbers.

the quoted delays appear on every tenth packet on average.

  clemens