CPE210 Daisy Chain Link - slow internet

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CPE210 Daisy Chain Link - slow internet

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CPE210 Daisy Chain Link - slow internet
CPE210 Daisy Chain Link - slow internet
2020-09-22 12:18:14
Model: CPE210  
Hardware Version: V3
Firmware Version: 2.2.1 Build 20200423 Rel. 71454 (4555)

Hi there,

We have a few CPE210 in use. One pair has been running a AP/Client setup to provide a connection over a 50-75m distance for some time. I have recently purchased four more to extend access from the main building to a lakeside campsite we have. My setup is as below:

 

  1. Internet/network at main building.
  2. CPE210 in AP on roof of main buidling pointing to intermediate point 180m away.

Wireless gap 180m

  1. CPE210 in client mode on interneidat building. Wired to:
  2. CPE210 in AP mnode pointing away from original to final destination

Wireless gap 120m

  1. CPE210 in client at final destination. Wired to:
  2. EAP110-Outdoor 

 

There is no line of sight directly from soruce to destination, hence to two steps.

 

Devides are connected and working fine. I can manage all of the devices from my office at source and go to the remote area and manage all via wifi. At the remote location there is an interent connection of sorts, but it is very very slow. Multiple seconds to resolve an address etc.

 

DHCP is being delat with in the office, with all clients being served from there.

 

When doing a speed test between AP/Cleints I often get errors (Date note found or similar). When i can get a response it has been aroiund 61Mb. Signal for the clinets are both -101dB Noise strength,  32 to 37dB SNR. 

 

What am. i doing worng? Is there a fundamental problem with daisy chaining the CPE210 in this way? Are the signal strengths not ideal (It;'s a short distance compared to what the product is capable of). Is there a problem with the DHCP/IP setup?

 

Thanks in advance.

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#1
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7 Reply
Re:CPE210 Daisy Chain Link - slow internet
2020-09-22 13:29:56 - last edited 2020-09-22 13:39:18

 

Jasonpandre wrote

When doing a speed test between AP/Cleints I often get errors (Date note found or similar).

 

 It's »No data found«. The AJAX call of the web UI didn't succeed. You get this error when starting the speed test client over a wireless connection on the remote CPE.

 

Solution is to start the speed test server on the remote CPE and then run the test client on the local (or on the »most local«) CPE. You can even log out from the remote's web UI, the speed test in server mode will continue to run.

 

When i can get a response it has been aroiund 61Mb. Signal for the clinets are both -101dB Noise strength,  32 to 37dB SNR.

 

IMO that's a pretty bad signal strength (64 to 69 dBm) for such short distances. SNR should be ~50 to 60dB, signal strength ~50 to 40dBm. Try to align the CPE's antennas more precisely to each other.

 

Set WiFi mode to 802.11n-only, not to mixed mode, MAXtream disabled, distance setting to »Auto«. I guess you use 20 MHz channel width? You could try 40 MHz, but note that 40 MHz allocates 8 channels (out of 11 or 13 in the 2.4 GHz band) at once, so interferences with nearby APs are most likely to occur if the 2.4 GHz band is overcrowded. That's why I prefer CPE510 for directional links.

 

But even with 20 MHz channel width you should be able to reach ~100Mbps half-duplex wireless throughput in 802.11n-only mode (max. possible WiFi rate - 30% overhead).

 

Is there a fundamental problem with daisy chaining the CPE210 in this way?

 

No, that's not a problem; it's a typical topology using a relay (the CPEs in the midst of the whole link form the relay), sometimes also called »hopple-hopple-hopple route« (each wireless link is a hop and the whole route can go around corners). This is the preferred topology if there is no free line of sight between the endpoints. But I would use static IP addresses for all CPEs and the EAP, not DHCP. DHCP is not suitable for stationary devices.

 

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#2
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Re:CPE210 Daisy Chain Link - slow internet
2020-09-22 13:32:53
Thanks for the prompt reply. I think the alignment is good. Will try amending other settings. I should have said - the CPE and EAP devices are fixed IP, it's the clients that connect to the WiFi that are running via DHCP from the main office. Thanks Jason
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Re:CPE210 Daisy Chain Link - slow internet
2020-09-22 14:09:01 - last edited 2020-09-22 14:09:47

@Jasonpandre, of course that's fine to have DHCP for the mobile clients.

 

One aspect if you have the midst two CPEs on the same antenna pole is that they can slightly interfere with each other. I would mount them distant from each other, probably at different heights on the same pole, but preferably on their own poles if possible.

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Re:CPE210 Daisy Chain Link - slow internet
2020-09-22 15:52:33

@R1D2 Thanks again for the reply. The mid point CPEs are now quite high up on a single pole. They are mounted at slightly different heights, though i see interference may still be an issue. I will try powering one down to see if this make a difference to the reminaing unit.

 

For refence status pages of the four units are posted below.

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#5
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Re:CPE210 Daisy Chain Link - slow internet
2020-09-23 13:27:44

@Jasonpandre, there is something weird: CPE #1 uses channel 1, CPE #2 uses channel 11 to connect to CPE #1? Can't work this way.

 

Why do you use 10 MHz channel width? Any reason for this? 10 MHz limits max WiFi rate to 72 Mbps, so you cannot achieve more than 50 Mbps goodput (= throughput - WiFi protocol overhead).

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#6
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Re:CPE210 Daisy Chain Link - slow internet
2020-09-23 19:59:30

@R1D2 thanks for your help on this.

 

R1D2 wrote

@Jasonpandre, there is something weird: CPE #1 uses channel 1, CPE #2 uses channel 11 to connect to CPE #1? Can't work this way.

 

Turns out I annotated the images incorrectly. Sorry!

 

R1D2 wrote

Why do you use 10 MHz channel width? Any reason for this? 10 MHz limits max WiFi rate to 72 Mbps, so you cannot achieve more than 50 Mbps goodput (= throughput - WiFi protocol overhead).

 

This was an extension of your idea re the 20Mhz. 

 

I spent a few hours playing again today (including and infuriating moment when I amended some settings in the wrong order and had to visit the mid units to connect directly.) one of the clients bizarrely stopped reporting any signal strength, so i ended up doing a factory reset.

 

eventually I solved the problem with a small movement of the final CPE unit. It was mounted on a low building with some small

young trees in front, but not directly in line. Move it forward about 10m to the fence line seemed sensible and completely solved the problem. Connection is now blistering and as good there as at my desk!

 

Again thanks for the help!

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Re:CPE210 Daisy Chain Link - slow internet
2020-09-24 10:09:35

 

Jasonpandre wrote

This was an extension of your idea re the 20Mhz.

 

I see. In the standards, channels are numbered at 5 MHz spacing within a band (except in the 60 GHz band), but transmitters usually occupy at least 20 MHz channel width.

 

eventually I solved the problem with a small movement of the final CPE unit. It was mounted on a low building with some small young trees in front, but not directly in line.

 

Ah, ok. Trees in between CPEs is not a free line of sight (or more precisely a required fresnel zone clearance). Trees will cause distortions of the WiFi signal in directional links.

 

Glad that it works now. Have fun with your CPEs!

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