Deco M9 Plus blinking red light (after upgrading from M5 at exact same location)

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Deco M9 Plus blinking red light (after upgrading from M5 at exact same location)

This thread has been locked for further replies. You can start a new thread to share your ideas or ask questions.
Deco M9 Plus blinking red light (after upgrading from M5 at exact same location)
Deco M9 Plus blinking red light (after upgrading from M5 at exact same location)
2021-06-02 10:15:52
Model: Deco M9 Plus  
Hardware Version: V2
Firmware Version: 1.5.3 Build 20210309 Rel. 36309

Hi all

 

I have a question which I hope you can help me with.

 

Recently I upgraded my Deco mesh network due to upgrading to Gigabit internet. 

 

Old situation:

main Deco: M9 Plus (connected to modem in bridge mode), location ground floor hallway

two wired Deco M9 Plus connected to a Gigabit switch (which is connected to the main Deco), locations ground floor living room and 1st floor master bed room

two Deco M5's connected via WiFi to the master bed room Deco, locations 1st floor study and 2nd floor bed room

 

New situation:

main Deco: X90 (connected to modem in bridge mode), location ground floor hallway

wired Deco X90 connected to a Gigabit switch (which is connected to the main Deco), location ground floor living room

wired Deco M9 Plus connected to a Gigabit switch (which is connected to the main Deco), location 1st floor master bed room

two Deco M9 Plus connected via WiFi to the master bed room Deco, locations 1st floor study and 2nd floor bed room

 

So no change in locations at all (all Deco's are in exactly the same location). Ground floor download speed has upgraded from an average 400 Mbps (through M9) to 700+ Mbps (X90). Since the M9's are supposed to have a better connection than the M5's (due to them being triband), I would have guessed that the Wifi connected M9's would have a better performance than the M5's had.

 

But, this is not the fact. The 2nd floor M9 keeps on losing its connection to the master bed room M9 and its red light keeps on blinking.

 

I have tried reconnecting, resetting, setting up the network again, network optimalisation etc. But this only helps for a very short while, after which the Deco enters into its blinking red state again. When it is active it does show a speed of 150 Mbps, which is 'decent' (even though I expected more, since the M5 showed roughly the same speed). 

 

Does anyone have a suggestion or solution for this?

 

Thanks!

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#1
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Re:Deco M9 Plus blinking red light (after upgrading from M5 at exact same location)
2021-06-02 13:29:25 - last edited 2021-06-02 13:30:36

@Ed72 

 

I can confirm that Satellite M9 Plus with wireless backhaul provides faster WiFi than Satellite M5. In my tests the best I can get from Satellite M5 was 225Mbps, for Satellite M9 Plus the peak was 490 Mbps, in the same location of my house and connected to same Main Deco.

 

These are almost ideal test conditions and best results, the usual speed from Satellite M9 in my house is around 350Mbps. My Internet connection is gigabit.

 

Tri-band M9 uses 5GHz for third, dedicated backhaul, band. If 5GHz connection between two M9s is weak, if there are obstacles or electronic noise, Satellite M9 might perform no better than Satellite M5, and might even do worse.

 

The first thing to check is quality of signal reported by your 2nd floor M9 when it is active (green LED). In Deco app, select that M9 and see what it shows, you should expect to see this:

 

 

This is my Satellite M9, shows all three bands and very good signal quality to "Living Room" Deco M9 it is connected to. If you see less than three bands, just 2.4GHz, weak signal with orange or yellow colors - that means your 2nd floor M9 is not optimally located. You should move it closer to the master bedroom M9.

 

Also, this will show you which Deco your 2nd floor M9 is connected to. Perhaps, it is trying to connect to Main Deco, that would be known issue TP-Link is working to address with firmware version 1.6.

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Re:Deco M9 Plus blinking red light (after upgrading from M5 at exact same location)
2021-06-02 13:37:42

@Alexandre. 
 

Thanks for that!

 

I did check that a couple of times and the 2nd floor M9 keeps being connected (when it works) to the master bedroom one (which is wired). 
 

The thing I do see is that the signal strength drops: after just having installed it, it shows all blue bars (so full strength), but this drops to two bars and sometimes even one bar. Without an excessive load on either two of the M9s or moving them of course. 
 

The M9s I now moved upstairs have always worked perfectly when they were located downstairs. So I also know they should work fine, but right now I do not feel like that at all and am even thinking about returning the X90s and reverting back to my M9/5 setup. Which is of course not what I want, because that way I won't reach the high wireless speeds. 

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#3
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Re:Deco M9 Plus blinking red light (after upgrading from M5 at exact same location)
2021-06-02 13:45:58

this was my situation a minute ago (after resetting it and adding it to my network again). 
 

But now it has lost connection again and is in its annoying red blinking state again. 

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#4
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Re:Deco M9 Plus blinking red light (after upgrading from M5 at exact same location)
2021-06-02 14:33:51

@Ed72 

 

I wonder if you have some sort of wireless noise or interference in your house. 

 

It makes sense to return to original working configuration. Still, I would suggest you try, as a test, moving 2nd floor M9 closer to the master bedroom M9. It is somewhat common misconception that one must put Satellite Deco unit with WiFi backhaul same place where wireless devices are that will connect to it. In fact, the better place for Satellite Deco using WiFi backhaul is somewhere in the middle between wireless devices and Deco it is connected to.

 

Only when Satellite Deco is wired, you should place it as close to wireless devices as possible.

 

In your case, place Satellite M9 servicing 2nd floor bedroom in the middle between master bedroom M9 and 2nd floor bedroom. It does not have to be exact "in the middle" - for example, you can place that Satellite M9 on the first floor but under the 2nd floor bedroom.

Run this as a test, all you need is electric outlet(s), try different ones in a few places, see if you could find a better location for that Satellite M9.

 

By the way, that does not apply just to M9. It is applicable to any Deco model and to any WiFi mesh in general: Satellite units that are wired should go as close to wireless devices as possible, Satellite units with wireless backhaul must be placed in the middle between mesh unit they connect to and wireless devices.

 

Finally, if you really have time on your hands, you can run one more test after you rollback to original configuration but before you returned X90s. Replace 2nd floor M9 and master bedroom M9 with X90s you have available now, and see if X90 to X90 connectivity has same problem. 

In the future, you may decide to upgrade your house WiFi mesh to WiFi6, it would make sense to know in advance if X90s do or do not suffer like M9s in your house.

 

 

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#5
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Re:Deco M9 Plus blinking red light (after upgrading from M5 at exact same location)
2021-06-02 15:55:34

@Alexandre.

 

Thanks for your tips Alexandre! I will try the roll back during the weekend (easier than during the work week when we have two people working from home in constant need of a signal). 
 

I will for sure test the X90 upstairs and was even thinking about using a M9 as my main Deco and have the two X90's connected to it wired. I know TP advises to make the X90 the main Deco, but in my case this just works as a router for the rest. I do not actually use its wireless signal (since it is tucked away in the meter box) and only use the WiFi signals of the living room and master bed room as main WiFi. 
 

So I don't know if that is a possibility for now, but I thought it would be worth a try. 

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#6
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Re:Deco M9 Plus blinking red light (after upgrading from M5 at exact same location)
2021-06-03 03:29:41

@Ed72 

Thank you very much for the detailed information.

Since there are two wireless connected Deco M9 plus, could you please try to swap their location to see if it is always the same unit that was disconnected from the mesh?

As for the network map, is it quite like the following picture:

(the full line means wired connection; the dotted link mean wireless)

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#7
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Re:Deco M9 Plus blinking red light (after upgrading from M5 at exact same location)
2021-06-03 23:11:22

@TP-Link 

Thanks for your reply. 
 

The network structure is indeed as pictured in the diagram you made. 
 

As for swapping the M9s: I will give this a try during the weekend as well. 
 

Could you also confirm whether the idea to make an M9 the main Deco and the two X90s the wired ones in the ground floor living room and the first floor bed room would or could work?
 

For now I have changed to 2nd floor M9 back to an M5 and this one does, as always was the case, keep its connection.

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#8
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