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lcrhea25
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Low recieve speeds please help!!

Thu Nov 19, 2009 10:02 pm

I have a problem on a few AP's that have been driving me crazy!! When I do recieve tests from customers some have great speeds....others are around 400k and at times much lower. When this is happening all ccq's drop on all customers. I feel like I have tried so many things but not sure what to do next. I have a few small AP repeaters pointing at the ap and have the hardware retries set to 15 or they don't work decent at all. Some customers who are set at 4 work fine though. I believe once I tried setting all client radios to 15 but I think that just made things worse. What is the best setting for hardware retries and does anybody have any ideas what could be going on here? I have tried different frequencies so don't think that is it but I could be wrong. Let me know if any other info is needed.

Thanks

Larry
 
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nest
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Re: Low recieve speeds please help!!

Sat Nov 21, 2009 2:50 am

Leave hardware retries at 4, I have never found it makes that large a difference. If the link association is failing (usually due to interference), let it fail. Leaving it at 4 means it will try to re-associate sooner. Increasing the retry value means it keeps retrying and retrying and even after 15 retries still fails.

You are effectively only delaying the inevitable loss of the link. There are some arguments for increasing it slightly, say to 6 or 7, in noisy environments, but I've not seen a value of 15 provide any benefit. All very much trial and error however!

Sudden falling CCQ values does sound like you have interference or a fault. Either another user on the same frequency (look with a freq scan to see if this is true), someone using a (non-)linear amplifier nearby causing a high level of side products on adjacent channels(test by freq scan and finding identical ssid and mac address on multiple channels - but this is not 100% guaranteed as the products generated may be too distorted to be decodeable), local interference (your own cards in same routerboard), test this by turning off cards temporarily.

Faults to look for are pigtail connections, especially uFL types, water ingress in antennae and coax. But if all links at one site are failing at the same time, I suspect interference.

AP repeaters? Please explain how this has been arranged and where you are measuring the 400k speed.
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lcrhea25
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Re: Low recieve speeds please help!!

Mon Nov 23, 2009 11:29 pm

I have 2 APs up on this tower. 1 has 2 XR2 cards in it and 1 has 1 XR2 card. They all go to 120degree sectors. The AP with the 2 cards does not appear to be as bad as the AP with 1. I have disabled both the cards in the other AP to see if that is the cause but it still happens. What gets me is I have some customers whose speeds are find and some that aren't and there signals are about the same. I will get into the AP and do a receive test from my customer and that is where I see the problem on some. CCQ's start falling an throughputs decrease. But there is no issue when I do a speed test to the customers. Let me know if you need to know anything else.

Thanks

Larry
 
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nest
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Re: Low recieve speeds please help!!

Tue Nov 24, 2009 2:25 am

post the export of the wireless settings of the AP with the two XR2's and a client that has problems and a client that does not.

Falling throughput and a matching falling CCQ is logical. CCQ is a measure of the number of retries, the more noise/interference/distortion/errors the lower the throughput as it has to keep resending the packets and this is then seen as a low CCQ. If you do a high speed bandwidth test, the link is stressed and works hard to maximise the packet throughput, any errors will immediately been seen as a poor CCQ.
Ron Touw - Mikrotik Certified Trainer
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lcrhea25
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Re: Low recieve speeds please help!!

Tue Nov 24, 2009 10:38 pm

Export of the AP

/interface wireless
set 0 ack-timeout=dynamic adaptive-noise-immunity=ap-and-client-mode \
allow-sharedkey=no antenna-gain=0 antenna-mode=ant-a area="" arp=enabled \
band=2.4ghz-b basic-rates-a/g=6Mbps basic-rates-b=1Mbps burst-time=\
disabled comment="" compression=no country="united states" \
default-ap-tx-limit=0 default-authentication=no default-client-tx-limit=0 \
default-forwarding=yes dfs-mode=none disable-running-check=no disabled=no \
disconnect-timeout=3s frame-lifetime=0 frequency=2422 frequency-mode=\
manual-txpower hide-ssid=no hw-retries=4 mac-address=00:15:6D:65:6E:23 \
max-station-count=2007 mode=ap-bridge mtu=1500 name=wlan1 \
noise-floor-threshold=default on-fail-retry-time=100ms \
periodic-calibration=default periodic-calibration-interval=60 \
preamble-mode=both proprietary-extensions=post-2.9.25 radio-name=\
"Faught NE" rate-set=default scan-list=default security-profile=\
"128bit WEP" ssid=XXXXX station-bridge-clone-mac=00:00:00:00:00:00 \
supported-rates-a/g=6Mbps,9Mbps,12Mbps,18Mbps,24Mbps,36Mbps,48Mbps,54Mbps \
supported-rates-b=1Mbps,2Mbps,5.5Mbps,11Mbps tx-power-mode=default \
update-stats-interval=disabled wds-cost-range=50-150 wds-default-bridge=\
none wds-default-cost=100 wds-ignore-ssid=no wds-mode=disabled \
wmm-support=disabled
set 1 ack-timeout=dynamic adaptive-noise-immunity=ap-and-client-mode \
allow-sharedkey=no antenna-gain=0 antenna-mode=ant-a area="" arp=enabled \
band=2.4ghz-b basic-rates-a/g=6Mbps basic-rates-b=1Mbps burst-time=\
disabled comment="" compression=no country="united states" \
default-ap-tx-limit=0 default-authentication=no default-client-tx-limit=0 \
default-forwarding=yes dfs-mode=none disable-running-check=no disabled=no \
disconnect-timeout=3s frame-lifetime=0 frequency=2447 frequency-mode=\
manual-txpower hide-ssid=no hw-retries=4 mac-address=00:15:6D:64:78:12 \
max-station-count=2007 mode=ap-bridge mtu=1500 name=wlan2 \
noise-floor-threshold=default on-fail-retry-time=100ms \
periodic-calibration=default periodic-calibration-interval=60 \
preamble-mode=both proprietary-extensions=post-2.9.25 radio-name=\
"Faught S" rate-set=default scan-list=default security-profile=default \
ssid=XXXXX station-bridge-clone-mac=00:00:00:00:00:00 \
supported-rates-a/g=6Mbps,9Mbps,12Mbps,18Mbps,24Mbps,36Mbps,48Mbps,54Mbps \
supported-rates-b=1Mbps,2Mbps,5.5Mbps,11Mbps tx-power=28 tx-power-mode=\
card-rates update-stats-interval=disabled wds-cost-range=50-150 \
wds-default-bridge=none wds-default-cost=100 wds-ignore-ssid=no wds-mode=\
disabled wmm-support=disabled


Customer with slow recieve speeds signal is -69 and speed avg about 400k

/interface wireless
set 0 ack-timeout=dynamic adaptive-noise-immunity=client-mode \
allow-sharedkey=no antenna-gain=0 antenna-mode=ant-a area="" arp=enabled \
band=2.4ghz-b basic-rates-a/g=6Mbps basic-rates-b=1Mbps,2Mbps burst-time=\
disabled comment="" compression=no country="united states" \
default-ap-tx-limit=0 default-authentication=yes default-client-tx-limit=\
0 default-forwarding=yes dfs-mode=none disable-running-check=no disabled=\
no disconnect-timeout=3s frame-lifetime=0 frequency=2412 frequency-mode=\
manual-txpower hide-ssid=no hw-retries=4 mac-address=00:0C:42:39:17:55 \
max-station-count=2007 mode=station mtu=1500 name=wlan1 \
noise-floor-threshold=default on-fail-retry-time=100ms \
periodic-calibration=default periodic-calibration-interval=60 \
preamble-mode=short proprietary-extensions=post-2.9.25 radio-name=\
starnet-12096 rate-set=configured scan-list=default security-profile=\
"WEP 128" ssid=XXXXX station-bridge-clone-mac=00:00:00:00:00:00 \
supported-rates-a/g=6Mbps,9Mbps,12Mbps,18Mbps supported-rates-b=\
1Mbps,2Mbps,5.5Mbps,11Mbps tx-power-mode=default update-stats-interval=\
disabled wds-cost-range=50-150 wds-default-bridge=none wds-default-cost=\
100 wds-ignore-ssid=no wds-mode=disabled wmm-support=disabled

Customer working at about 2 to 3 meg on recieve speed signal -75

0 R name="wlan1" mtu=1500 mac-address=00:0C:42:18:FC:BC arp=enabled
disable-running-check=no interface-type=Atheros AR5413
radio-name="starnet-11885" mode=station ssid="XXXXXX" area=""
frequency-mode=manual-txpower country=united states antenna-gain=0
frequency=2412 band=2.4ghz-b scan-list=default rate-set=configured
supported-rates-b=1Mbps,2Mbps,5.5Mbps,11Mbps
supported-rates-a/g=6Mbps,9Mbps,12Mbps,18Mbps basic-rates-b=1Mbps,2Mbps
basic-rates-a/g=6Mbps max-station-count=2007 ack-timeout=dynamic
tx-power=25 tx-power-mode=card-rates noise-floor-threshold=default
periodic-calibration=default periodic-calibration-interval=60
burst-time=disabled dfs-mode=none antenna-mode=ant-a wds-mode=disabled
wds-default-bridge=none wds-default-cost=100 wds-cost-range=50-150
wds-ignore-ssid=no update-stats-interval=disabled
default-authentication=yes default-forwarding=yes default-ap-tx-limit=0
default-client-tx-limit=0 proprietary-extensions=post-2.9.25
hide-ssid=no security-profile=default disconnect-timeout=3s
on-fail-retry-time=100ms hw-retries=15 preamble-mode=long
compression=no allow-sharedkey=no

Also noticed that it appears that customers on software version before 3.10 have the good recieve speeds and customers on 3.10 or later are having the recieve speed problems.

Thanks

Larry
 
lcrhea25
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Re: Low recieve speeds please help!!

Tue Nov 24, 2009 11:50 pm

After doing some testing I have discoverd something. It appears that every customer I have that is on version 3.x they are having the receive speed issue with the ccq dropping when I do the test. If they are on version 2.9.x they don't have the issue. I do have 3 small repeater pointing that this issue that are running 3.30 that don't have the problem but I have to put their hardware retries to 15. I tried upgrading a client to 3.30 and set the hw retries to 15 but it didn't work for him so I'm not sure why it is fine on those AP's. But it is clear that all clients before 3.x are working fine.

Larry
 
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nest
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Re: Low recieve speeds please help!!

Wed Nov 25, 2009 12:41 am

Cannot see too much wrong in your setup, but I have some suggestions,

Security - I would disable "default forwarding". At the moment users can connect to each other and see each other. Did you mean to allow this?

Security - you have default-authentication enabled and no connect or access lists. So anyone can connect to your AP and cause trouble. Did you mean to do that as well?

Note you have limited the wireless data rate on the client. Better to keep the client open to any speed the AP will support, but then speed limit the AP by disabling the higher rates if that is what you want to do. (This is a good idea as it reduces drop outs while the link is re-establishing different speed for different clients all the time. Especially a problem for VOIP.

You have also set preamble-mode to long on one of the clients and short on the other. Change it to 'both' on both of them and let the wireless chipset determine the best preamble burst length not you. :-) (This might be the first thing to try.)

Versions - not a good idea to run mixed versions. A few minor versions different is usually fine (say 3.30 and 3.17) as the radio interface has not gone through many changes so minor versions are very happy working to each other, but running whole major versions apart (2.9x at one end and 3.x at the other) is asking for trouble. Chose your version with testing on a less important client or in your own lab "on the bench", then stick with it. Keep all the units at the same version if you can. That way it gives you more stability.

If changing all the above makes no difference, I would put your troubles down to some external influence. (Noise/interference/distortion/fresnel zone interference/reflections/faulty equipment - 'stuff' like that) In which it starts to get even more interesting. :-)
Ron Touw - Mikrotik Certified Trainer
LinITX.com - MultiThread Consultants
Get your MikroTik RBs and Training: http://linitx.com/category/166
Largest Official UK MikroTik Distributor
IRC channel: #routerboard on irc.z.je (IPv4), 6.irc.z.je (IPv6)
 
lcrhea25
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Re: Low recieve speeds please help!!

Wed Nov 25, 2009 9:13 pm

Thanks...I will try some of that after the Holiday. The only thing I worry about is some of my clients are on a RB133c and have noticed that winbox sometimes won't load on those boards when they are upgraded to version 3. Looks like it starts running out of memory when I try to load winbox.
 
lcrhea25
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Re: Low recieve speeds please help!!

Tue Dec 01, 2009 10:19 pm

I ended up putting 3.30 on all clients but that didn't help. I put the wireless test package on all the clients and the AP and set rts cts on all the clients and that has seemed to help. I have been seeing conflicting advice on the forum as to turn that on the AP or not. Do you know what would be best?

Thanks

Larry
 
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Re: Low recieve speeds please help!!

Tue Dec 01, 2009 11:41 pm

Sounds like local interference do they have a wireless ap that is on the same channel as the tower or on an overlapping channel
 
lcrhea25
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Re: Low recieve speeds please help!!

Wed Dec 02, 2009 9:27 pm

Not sure but this was happening to many of my clients. But I bet you are right that it was some kind of interference. Apparently the RTS CTS is supposed to help out with hidden nodes.

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