@spcolyvas:
Thanks Nullity,
ICMP packets do go through the same limiter. Eventually I'll be pumping video through these limiters to see how the video client and server adapts to the bandwidth constraints, latency, packet loss etc. the client/server should do stuff like adjust the framerate, resolution etc. The problem is that the behavior that pfsense is showing starting with 40ms latency and counting down to 6ms latency will really mix it up. it may be a good test but I'd like to run other tests as well.
For testing, use limiters, sure. Limiters, AFAIK, make no worst-case latency guarantees.
but for actual deployment of video/audio services use HFSC, optionally with "CoDel Active Queue" enabled. I'd at least test your scenerio with HFSC to see your latency fluctuation is being caused by limiters or something else.
I dunno. Without more details it's hard to even know where to begin. Maybe iperf is queueing packets in bursts… maybe... ? More tests are in order. :)