MikroTik

AP: RB411A, SR2, Nstreme (best fit 3200) overall CCQ 95+, 90deg sector,
Clients RB411, R52H.
All software is 3.30 with wireless test on all CPE's and AP.
AP RF modulation is default. Clients are limited to 24-36mbps depending on ccq qaulity

29 clients all with -70 or better signal, 80+ CCQ, ap overall ccq is around 95+
Clients limited to 1.3mb down and 300k up, limited by Radius or access list (tested with both)

If any single client is down loading their max 1.3mbps then the latencies goes up to 1-2 seconds and no other through put is available to any other client. Ap's total traffic is maxed at about 1.5mbps

If clients are not maxed out (down loading at 1 or 1.2 mbps) latency is typically under 30ms until the AP hits about 5-6mbps when the latency jumps to 200ms +. AP appears to max out at 6-7mps.

We have tried all possible combination to fine tune the AP and clients. Same Results with out Nstreme. we have other similarly loaded aps that function fine(ap's are all 3.3 with test, clients are 3.10 and up). I have another behaving the same way.

Any one else have/had the same issue any ideas as to a fix? I'll likely send in

What does your CPU utilization look like?

absolutely lovely! 411A are under 30% most of the time and 411AH's are hardly of of idle.

Up Date:

I have now confirmed the issue appears to be with the down load only and seems to be related to the bandwidth control at the AP as the results are the same across many different sites with software revs going back to 3.23. I did a few ping test on an ap with live traffic and saw the high latency. I have not confirmed it on all AP's yet but so far all affected. I have even tested on an AP with only 4 customers.

On a side note I also noticed that my bandwidth only about 25-33% of a P2P link with the same setting. While I expect to loose some through put as the client count goes up I should not be taking a 50-75% hit. Oddly I'm taking a bigger hit on downloads

only client on ap: send 5-6mbps ccq drops some 82/64ccq. Receive 9.2mpbs (as expected) 95/100ccq
With 7 Clients on ap: send 5.2mbps 90/90ccq. Receive 7.5mbps 99/96 ccq.
With all 16 Clients on AP: send 3mbps 90/100ccq. 3mbps 83/75 ccq.