@TP-Link Deco 

I´m attempting to troubleshoot an issue with my ethernet backhaul. Everything was working fine for 6 months or so, and then suddenly a couple of evenings ago all Decos (we have 6 in service, 5 (mix of Deco M4 and M5) connected via a star network over a TP Link TL-SG116 to the main (Deco M4 which is then connected to the modem (Archer VR600) suddenly lost internet connectivity. We have 4 stories in our house and with very thick reinforced concrete floors, the backhaul is important for stability. As a work-around I´ve had to shift the units around to allow the wifi signal to flow up the stairwell.

The next morning after some power cycling (no impact), a couple of hard resets and re-adding into the network, still no success, I started some troubleshooting:

• The decos have connectivity when connected via wifi/mesh. After plugging the LAN cable in the connectivity is immediately lost
• Connecting via a LAN cable directly to the main (bypassing the switch) was successful - no issues
• Other devices connected directly via LAN to the switch (TV, Hue bridge etc) continued to work. Laptop plugged directly to the switch was also fine when tested.
• Tried all troubleshooting suggested via the TP Link page. Only thing I noticed is that when power cycling the switch, the decos appeared to connect successfully for maybe 30 seconds when monitored in the app, and then immediately cut out again.
• SO....the modem is working, the decos are working, the switch is working, but the decos will not longer work with the Switch it seems

The problem appears to be specific to the Decos when communicating via the Switch. I hadn´t changed any settings, and it´s an unmanaged switch so nothing will have changed there. Have tried to see a similar issue amongst the replies here but I´m at a loss.

Any ideas?

Thanks!

A few thoughts

-- are you sure the Deco's are in AP (Access-Point) mode? The Archer should be providing the DHCP service to the network

-- is there a physical reason you can't configure as in the 3rd diagram on the 1st note of this thread? (That would eliminate any physical port failure issue of the Master Deco, as you could designate another LAN-wired Deco as the Master as needed.)

-- check the DHCP service configuration; had you added more devices? If so, the DHCP default settings might not be appropriate any more.

-- I would recommend considering assigning fixed IP address mappings (in the DHCP service) for the DECO's ... as well as other "permanent" devices on the network. That alone can prevent a lot of issues, particularly if there are brief power outages or 'glitches' which cause some devices to restart but not all of them.

-- As you are trouble-shooting, keep in mind that the MAC address is different for the physical cable connection vs. a WiFi connection.

-- Oh!! .... are you using the Archer's WiFi?? If there is no need for it in providing coverage, turn it off. It's not a mesh device like the Deco!

  @Dan_C. 

Many thanks for your reply. I checked some of the ideas you gave me:

 - Wifi on the Archer was always turned off from the start, and I checked on the settings and the only wired/connected device was the main deco.

- I tried reshuffling the setup to an AP only star, with all units directly attached to the Archer via the Switch and no main between. All decos failed to connect via the switch in this setup.

- I then went back to the previous setup to at least recover an internet signal. I then noticed all other devices connected via the switch had failed, and would only get signal via the wifi network. I then power cycled the switch about 10 times in a row out of frustration. No change. This morning I woke up, and they were working again. I plugged one of the decos back in via LAN.....it continued working, and in the app after some seconds registered as being connected via LAN to the main.

So in the end it is working again, with the same setup as before, and no change to the settings. I have a feeling maybe there is an issue with the switch, but cannnot understand what...! Main thing, it's working.

  @Matt1979 

The fact that the Deco's did not work initially when restored to the original configuration (after trying other alternatives) – but then worked as expected the next morning – indicates to me that the most likely causes of the problem are either the switch itself, or (more likely) the DHCP service in the Archer (a likely explanation is the DHCP leases were conflicting until after they expired and new leases were re-issued).  Which leads to the question: I'm not clear if you are running the Deco's in AP mode or not.  If the DHCP service in the Archer is active AND the Deco's are NOT in AP mode ... that will cause problems.  There should only be one DHCP service on a (sub-)network.

If you do only have one DHCP service active (i.e. in the Archer), then is may have performance/reliability issues.

The 3rd source of "flakiness" can be due to power line problems.  As much as possible I put all my network devices on small UPS units (inexpensive 350-550w units) ... partly for power stability and partly so the network will not "reset" due to short power fluctuations.

Personally, I prefer to separate the routing (with DHCP service) from the modem/gateway device simply so I can replace one without replacing both.  I've learned that the performance of the router/DHCP service device can be crucial to overall network performance & reliability ... particularly for Internet speeds over ~500Mb.  It's nice to have a spare switch, too.

Just some more thoughts...

  @Dan_C. 

To be honest it´s so long since I did the setup during a move-in to a new house I honestly cannot remember whether they were in AP mode or not. I did check what would be the best setup at the start but what that resulted in I can´t remember.

Anyway, I have now checked the DHCP settings and I think you may be correct - this was enabled on the Archer, and currently as the Decos are not in AP mode it would of course also be active there. I´ve now disabled it on the Archer...let´s see if this fixes it for good!

Speed/Performance for us isn´t such an issue....in the German countryside we have max 30MB speeds for the time being...albeit stable. But in any case it seems to be working again now and thanks for your tips, much appreciated!

  @TP-Link Deco 

Can I use one Ethernet port on the Deco for Ethernet backhaul and the other to connect a computer THEN use its wifi function simultaneously?

  @MCLoki - Yes, you can use your computer directly attached to a Deco unit while the other DECO port is used for the backhaul; that's not an issue at all.

You can also have your computer use both the hardwired Ethernet port and have the computer's WiFi receiver enabled; that will give your computer parallel connections into the network (and generally it will prefer the hardwired connection as the faster one, with the WiFi as a backup / alternate pathway).

You should not attempt to use the computer as an alternative "WiFi host" or "access point".   (There's probably not an easy way to configure that, anyway ... the computer is just another 'client' on the network.)

  @TP-Link Deco 

Hi Hi, need advice. Currently, I am using a D-link Wifi Router (850L) with TP-Link Powerline Wifi Extender (TL-WPA4220). This is a simple setup. Router (Living)+Extender (Room) with the same SSID. I am connecting with my phone. When I am in the room, Wifi drop to 1 bar or lost the signal. It will reconnect with a 1 bar Wifi signal which means it reconnects back to the Wifi Router in the Living Room. Sometimes it reconnects with Wifi Full bar which means it connects to the Extender. (I think those time the Mesh Technology still new and expensive).

I am going to move to another bigger place hence need to plan the wiring and connection.

My intention of the Mesh setup is very simple. To allow my portable device to connect seamlessly.

Question

1. Ideally I would prefer the Diagram 1 setup. I presume it will be in AP mode. Will the Mesh still work as intended which my portable device will auto-switch when detect weak signal?

2. Or for Mesh to work it has to be in chain connection as Diagram 2?

  @David-TP 

Thanks David. 

Agreed. Diagram 1 would be the preferred method.

Just want to clarify that under Access Point mode, will the connecting device do the Auto-Switching?

(Will the Mesh still work as intended which my portable device will auto-switch when detect weak signal?)