CPE510 - Multiple Problems

CPE510 - Multiple Problems
CPE510 - Multiple Problems
2020-09-12 18:50:28 - last edited 2020-09-13 05:23:39
Model: CPE510
Hardware Version: V3
Firmware Version:

My plan was to use a CPE510 to extend my existing wifi network to my workshop, which is a large metal building about 200 feet away from my main house.  I also planned to use a second CPE510 to accomplish the same thing for yet a 3rd building, slightly further away from the house, in a different direction. My existing WiFi network at the house is served by a Ubiquiti AP, mounted outdoors with an omni-directional antenna, which has been working reasonably well for years.  I also use a TP-RE650 extender to improve coverage from the Ubiquiti AP to the inside of the house, but that's not a critical bit of information for what follows.

 

Before going to the trouble of installing the new CPE510 "in the air" outside my shop and on the other building, I wanted to test to make sure everything worked.  Good thing I did.

 

I configured the first CPE510 to run in client mode and connect to my existing client network.  DHCP services are provided by redundant/failover servers on my main network, so none of my various network appliances (routers, switches, AP's, etc.) are configured as DHCP servers.

 

The CPE510 established a WiFi connection to my main AP just fine, no problem.  However when I attached a laptop to its LAN port, the laptop failed to acquire an IP address from my DHCP servers.   It made no difference whether I allowed the CPE to choose its own connection point, or whether I locked it to either the Ubiquiti AP or the TP-RE650. 

I tried lots of different tweaks, nothing worked, so I opened a ticket with support.  I also spent some time looking through here for other posts on the subject, but only found a few that seemed to confirm that "it should work" and that I had things configured correctly.

 

After spending several days trying (unsuccessfully) their various suggestions, they suggested I configure the second CPE510 as an AP with a different SSID on my network and connecting the client CPE that way.  That worked  ----  for the devices attached to the client mode CPE's LAN port.

 

However, neither an Android phone nor a different Windows laptop was able to connect directly to the new AP/SSID provided by the CPE510 running as an AP - at all.

 

I'm disappointed.  I liked the idea of using the CPE510's to extend my network to other buildings on the property and I liked their price point, but it appears that unless I'm willing to replace all my exiting WiFi gear with TP-Link products (and hope that they all will play nice with each other), it's just not going to work. 

 

Unless support is able to crack this nut and help me solve the problem within the next couple of days, I'll be boxing them up and returning them to "that big online retailer in the sky" for a refund.

 

 

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Re:CPE510 - Multiple Problems
2020-09-13 11:09:32 - last edited 2020-09-13 11:16:47

 

BearGFR wrote

My existing WiFi network at the house is served by a Ubiquiti AP, mounted outdoors with an omni-directional antenna, which has been working reasonably well for years.  I also use a TP-RE650 extender to improve coverage from the Ubiquiti AP to the inside of the house, but that's not a critical bit of information for what follows.

 

This can indeed be critical. Read on.

 

I configured the first CPE510 to run in client mode and connect to my existing client network.

 

That's not what CPEs are designed for. CPEs are designed for directional wireless links over large distances what means that CPEs are always used pair-wise in PtP or with three and more CPEs in PtMP scenarios:

 

 

The distance over which a CPE can exchange data reliably with any other AP depends on the AP with the smallest coverage, that's in this case the UniFi AP.

 

If you cannot receive the signal of your UniFi outdoor AP at the workshop with standard clients, you can't either with a CPE510. The typical symptom is that the remote CPE can receive the SSID of the UniFi AP (which is sent at 1 Mbps WiFi rate and covers 4-5 times the area covered by higher WiFi rates), but you can't exchange data. That's why your laptop doesn't get an IP via DHCP.

 

You should use the CPEs pair-wise and mount it (far enough) away from the UniFi outdoor AP and the repeater.

 

You also need a fresnel zone clearance of at least 40% on the PtP link, that's especially important if one of the two CPE is mounted above a metal which can generate reflections of the signal sent from the local CPE at the house to the remote CPE at the workshop. The remote CPE receives two delayed waves of the same signal if such reflections occur. To mitigate against such interferneces, compute the fresnel zone and you get as result the height at which the CPEs need to be mounted on the antenna poles at the workshop and at the house.

 

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Re:CPE510 - Multiple Problems
2020-09-13 12:24:07 - last edited 2020-09-13 12:25:43

Signal strength or quality was not a problem,  not according to the SNR Db readings or other metrics on the CPE itself, either when connected to my existing AP or paired with the other CPE configured as an AP.  Nothing in the doc explicitly specifies that they must be used in pairs, and that was never mentioned at any time during any of my interactions with tech support.  They definitely understood rhe detals of my specific configuration, that it was mixed vendors,  and what I was trying to accomplish.   

 

Even if a paired configuration is required, that does not explain why my other devices were unable to connect directly to the CPE configured as an AP, which is clearly documented as a supported configuration under scenario 3, figure 1-3 in this document:

https://www.tp-link.com/us/configuration-guides/introduction_to_operation_modes_cpe_and_wbs_/?configurationId=18702#_idTextAnchor000

 

This same document, scenario 6, shows using the CPE in client router mode to establish a connect to an ISP (WISP).  Certainly it wouild not be reasonable to assume that any WISP would also use TPLink equipment of any kind, so the surely intention must be for the CPE to be able to "run" with any standard 802xx signal/protocol that it's documented to support.

 

I'm not knocking the product.  It seemed like a great solution for me and I really wanted it to work.  It just didn't.

 

My intention was to replace all my existing WiFi gear in stages, this being the first step, because I didn't want to be tied to a specific vendor and there are things about my current WiFi vendor's gear that I don't like.  It might work fine if I was running 100% TPLink gear, I already have quite a few of their switches and routers, but I'm not willing to be tied like that.

 

Bear

 

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Re:CPE510 - Multiple Problems
2020-09-13 12:36:08

 

BearGFR wrote

This same document, scenario 6, shows using the CPE in client router mode to establish a connect to an ISP (WISP). 

 

You cannot compare your application scenario with that of a WISP. A WISP uses high-gain sector antennas which are designed especially for directional links. To realize a WSIP scenario you would have to use a WBS510 with TL-ANT5819MS sector antenna or similar, mounted on a high antenna mast.

 

If you think CPEs can reliably exchange data with standard omnidirectional APs, I won't argue with you about that. Our CPE setups work very well on all installations my company deployed such as on camping grounds or as simple network bridges.

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Re:CPE510 - Multiple Problems
2020-09-13 14:00:07

@R1D2  You seem determined to 'make' this a signal quality problem.  Again, signal strength and quality was NOT the problem!  I hadn't permanently installed things yet and had just mocked it all up for testing.  When trying to run the CPE with my main AP, it was less than 50 feet from it and oriented so that it's radiation pattern was aimed directly at the AP.  When using the other CPE as an AP, the two were "looking at" each other and maybe 20-30 feet apart.    No matter which configuration I was working with, there was never any problem with accessing the management interface inside the "remote" CPE over the wireless link to it.  If signal itself was a problem, I would not have been able to do that.  However, I could only get "beyond" the client-mode CPE to the devices attached to its LAN port when it was connected to the TPLink CPE configured as an AP.   They were not accessible when it was paired either directly with my main AP, or the TPLink RE650 extender.  I tried both. 

 

However when running via my main AP, if I logged into the main AP itself via SSH and tried to ping a client device via the AP's command shell, it wasn't successful.  At that point, the only physical devices along the physical path involved in the ping attempt were:

 

  main AP --(wireless)--> CPE 510 --(LAN port)--> client device.

 

I could ping the CPE's IP address just fine, but not anyhing beyond it.

I discerned that the client device (a laptop PC) was not able to acquire a DHCP assigned address in this configuration.  Something I discovered by first releasing its lease and then attempting to renew it.  However, using the 'tools' drop down on the CPE itself I could ping anything anywhere in my network, including my DHCP server(s).  Furthermore, if I 'hard assigned' an IP to the laptop in this scenario, it would run and be accessible.  So the problem, whatever it was, had to do with 'something' in the physical path not correctly handling/forwarding/etc DHCP traffic.  Perhaps the problem is something in my main AP, I can't say for sure - I just know the CPE's don't work here.

 

When engaged in an interactive session with support, they too checked and double-checked my CPE configuration settings and verified they were correct.

 

None of that explains why the CPE would not even function as a basic simple AP by itself.  When using a CPE as an AP, the client devices I was trying to connect to it with were maybe 20 feet away from it, if that.  They were able to see the unique SSID I had assigned to it, but connections failed during the association phase.  I don't have problems like that with my existing AP.

 

I'm glad your setup works for you.

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