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ASK: how to maximize R52HN

Posted: Tue Feb 22, 2011 12:36 pm
by tsmalam
Hi all,

i have a problem, maybe any one knows about it
i have install Mikrotik RB433AH+ R52HN with software version 5.orc9, the distance about 1 km
the problem is i never get maximize troughput for 802.11N my troughput only get 40Mbps in one way.
before i use R52HN i use R52H and the troughput i can get 100Mbps in one way, any one can explain why?

Re: ASK: how to maximize R52HN

Posted: Tue Feb 22, 2011 2:23 pm
by uldis
tell us your configuration.
What antennas you are using?
Are try dual polarized?
How you test the speed?

Re: ASK: how to maximize R52HN

Posted: Wed Feb 23, 2011 9:53 am
by tsmalam
this is my config

name="wlan1" mtu=1500 mac-address=00:0C:42:xx:xx:xx arp=enabled
disable-running-check=no interface-type=Atheros 11N
radio-name="xxx" mode=ap-bridge ssid="Dxxk" area=""
frequency-mode=manual-txpower country=no_country_set antenna-gain=0
frequency=5300 band=5ghz-a/n channel-width=20mhz scan-list=default
wireless-protocol=802.11 rate-set=configured
supported-rates-b=1Mbps,2Mbps,5.5Mbps,11Mbps
supported-rates-a/g=6Mbps,9Mbps,12Mbps,18Mbps,24Mbps,36Mbps,48Mbps,54Mbps
basic-rates-b=1Mbps
basic-rates-a/g=6Mbps,9Mbps,12Mbps,18Mbps,24Mbps,36Mbps,48Mbps,54Mbps
max-station-count=2007 distance=dynamic tx-power-mode=default
noise-floor-threshold=default nv2-noise-floor-offset=default
periodic-calibration=default periodic-calibration-interval=60
dfs-mode=none wds-mode=disabled wds-default-bridge=none
wds-default-cost=100 wds-cost-range=50-150 wds-ignore-ssid=no
update-stats-interval=disabled bridge-mode=enabled
default-authentication=yes default-forwarding=yes default-ap-tx-limit=0
default-client-tx-limit=0 proprietary-extensions=post-2.9.25
wmm-support=enabled hide-ssid=no security-profile=default
disconnect-timeout=3s on-fail-retry-time=100ms preamble-mode=both
compression=no allow-sharedkey=no
station-bridge-clone-mac=00:00:00:00:00:00
ht-ampdu-priorities=0,1,2,3,4,5,6,7 ht-guard-interval=any
ht-extension-channel=above-control
ht-supported-mcs=mcs-0,mcs-1,mcs-2,mcs-3,mcs-4,mcs-5,mcs-6,mcs-7,mcs-8,mcs-
9,mcs-10,mcs-11,mcs-12,mcs-13,mcs-14,mcs-15
ht-basic-mcs=mcs-0,mcs-1,mcs-2,mcs-3,mcs-4,mcs-5,mcs-6,mcs-7,mcs-8,mcs-9,
mcs-10,mcs-11,mcs-12,mcs-13,mcs-14,mcs-15
ht-txchains=0,1 ht-rxchains=0,1 ht-amsdu-limit=8192
ht-amsdu-threshold=8192 tdma-debug=0 tdma-override-rate=disabled
tdma-override-size=0 tdma-period-size=2 nv2-queue-count=2
nv2-qos=frame-priority nv2-cell-radius=30 nv2-security=disabled
nv2-preshared-key="" hw-retries=4 frame-lifetime=0
adaptive-noise-immunity=none hw-fragmentation-threshold=disabled
hw-protection-mode=none hw-protection-threshold=0 frequency-offset=0

i'm using antenna grid single polarisation

i'm using bandwidht test form the routerboard, bwtest wireless to wireless

Re: ASK: how to maximize R52HN

Posted: Wed Feb 23, 2011 11:14 am
by stealth
Hello, maybe I have the very same problem. Here is my story.

I'm looking for solution how to upgrade one old 600m long ptp lint with mikrotik+802.11n bridge.
Current hardware is old RB532A with .11a turbo. The real throughput is 32Mbps+.
I always use bridge ptp links as there are routers at the nodes running ospf.

About year ago I tried mikrotik with .11n, but the support was terrible, slowdowns, blackouts. So year later I tried again since mikrotik is advertising it's TDMA solution everywhere.

Configuration
2x RB433AH + R52N-M
setted on the desk, .11n, two streams, signal lowered. link quality 99-100%. channel bonding.

I configured the link as (AP-bridge) <-> (Client-pseudobridge). The wifi is bridged with the ether1 port and the link acts as transparent bridge.

When I do bandwidth test directly on both 433AHs the UDP speed is 200Mbps+ and tcp 70Mbps+ with 100% cpu utilization.

When I add two Linux boxes on each end and tests throughput on them through the bridge the speed is roughly 40Mbps at maximum.
I tried many simultaneous links but the speed increased only by few Mbps.
I tried direct connection of the Linux boxes, the speed is 99.5Mbps, also same in full-duplex.
I tried to reconfigure the bridge into routing link, so the interfaces on routerboards was routed. Even slower than bridged.
I replaced mikrotik with two ubnt rocket M bridge. the speed is 95Mbps.


What is the correct configuration and real life performance of mikrotik .11n bridge ?
I tried both v4 and v5. Maybe v5 has more blackouts.

Re: ASK: how to maximize R52HN

Posted: Wed Feb 23, 2011 1:26 pm
by uldis
tsmalam, if you are using single antenna and using only one antenna connector (J4 which is the main) then you need to set the ht-txchains=0 ht-rxchains=0 as you enabled other chain which causes you the problem getting higher speed. also you can damage the power amp of the chain1 is you haven't connected anything there.

Re: ASK: how to maximize R52HN

Posted: Wed Feb 23, 2011 1:30 pm
by uldis
stealth, what configuration you had in your setup?
If you used the Ubnt, then most likely their Airmax protocol was used.
You need to use Nv2 wireless-protocol.
Please upgrade to RouterOS v5.0rc10 and use ap-bridge on the AP and station-bridge on the client side and bridge them together.