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cpina
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CCQ decreasing if traffic is increasing

Tue Mar 10, 2009 1:38 pm

Hello,

We are using a RB600 with a dish antenna, connecting to a RB411 and RB493 (multiport LAN). RB600 is about 10 or 13 Km. far from RB411 and RB493. Everybody has nstream enabled. Connected to 9 Mbps (we don't need more).

The clients are connected with a very good CCQ (90 or 100, etc.).

When I'm doing a bandwidth test (from the antennas itself or from computers) I can transmit without problems about 6 or 7 Mbps. The interesting part is that CCQ of that antenna and the other antenna drops to 50 or 60.

Why is the other antenna connection affected? I mean, I transmit from RB411 to RB600, and the connection from RB493 to RB600 gets very bad. And only transmitting at 7 Mbps.

Are there too much collisions because the distance? For only 9 Mbps? I was expecting to have some problems on 70 or 80 Mbps, not only 7...
I haven't played with ACK Timeouts.
It's using Ubuquity network cards.
The CPU Load is not high.

If you need any other information ask me.

Carles
 
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nest
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Re: CCQ decreasing if traffic is increasing

Wed Mar 11, 2009 3:00 am

What are the frequencies of the two links? On one of the routerboards, what happens to the noise floor measurement on the one (up and running) wlan1 link, when you turn wlan2 on and off - on the same routerboard of course, not opposite ends of the link? What happens to the noise floor and signal levels on this routerboard when you do this?

Ron
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cpina
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Re: CCQ decreasing if traffic is increasing

Wed Mar 11, 2009 2:23 pm

Hello nest and others,

Two clients are connecting to the same antenna (so same radio, wlan). There isn't wlan1 and wlan2 involved, as everything is happening in the same one.
I'm using a dish antenna in the RB600, but the two clients are inside the same zone.

Status:
Client A and B are connected to the same radio antenna, 5 GHz band.

Client B has this status (RB493):
Tx/Rx: -73/-68 dBm
Signal to Noise: 33 dB
CCQ: 98/100%

Client A (RB411) starts receiving or transmitting about 8 Mbps, then client B suffers:
Tx/Rx: the same
Signal to Noise: the same
CCQ: 60/80 (sometimes worse, sometimes better, not regular at all).

CPU of RB600 is 3-5%.

Distance from RB600 to Client A or B: about 10 or 15 km.

Nstream is enabled in this tests, but I have some other links with the same problem without nstream. Same central installation (tower with a lot of Wifi connections).

I don't know why CCQ is affected but not the other parameters. I only can think about CSMA problems, but I tried enabling and disabling and polling.

Any ideas? suggestions? Experiences?

Thank you very much,

Carles
 
popcorrin
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Re: CCQ decreasing if traffic is increasing

Wed Mar 11, 2009 2:57 pm

Are the RB493 and the RB411 in close proximity to each other or are they in line with each other in relation to your access point?
 
cpina
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Re: CCQ decreasing if traffic is increasing

Wed Mar 11, 2009 4:52 pm

Hello popcorrin,

RB493 and RB411 are not exactly in the line. They are about 12 or 15 Km far from RB600 (where they are connecting to), RB493 and RB411 they are some kilometres far.

Thanks,
 
rmichael
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Re: CCQ decreasing if traffic is increasing

Wed Mar 11, 2009 7:42 pm

Hello,

The clients are connected with a very good CCQ (90 or 100, etc.).

When I'm doing a bandwidth test (from the antennas itself or from computers) I can transmit without problems about 6 or 7 Mbps. The interesting part is that CCQ of that antenna and the other antenna drops to 50 or 60.

Why is the other antenna connection affected? I mean, I transmit from RB411 to RB600, and the connection from RB493 to RB600 gets very bad. And only transmitting at 7 Mbps.
Carles
(edited)
I read that nstream for ptm links did not work well until latest release so you might want to check what release you are running.
 
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nest
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Re: CCQ decreasing if traffic is increasing

Wed Mar 11, 2009 11:53 pm

If you want to operate nstream to multiple clients, you will need the latest test package. What wireless package are you using?

If you are, have you enabled polling?

If you perform a bandwidth test between an AP and one of the two clients, then of course the other client will see a degraded perform for their connection. Becuase the link is working so hard for the first client connection, there is little time available for the second client. therefore there are more retries, so the CCQ falls. But with polling this should be much better controlled than without polling.

Also suggest you look at adjusting hw-retries. (play with different values until you find the one that is best for your link - there is no 'golden number')

Ron.
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LinITX.com - MultiThread Consultants
Get your MikroTik RBs and Training: http://linitx.com/category/166
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