I have seven M9 plus Deco units and am experiencing constant packet losses for UDP in the mesh network. The main effect of this is that DNS resolution is extremely patchy. I've tried using the default DNS setting, setting the DNS servers in the master Deco to 8.8.8.8,1.1.1.1 and setting DNS servers on the individual connected computers.

I have tried using the setup in both Router and AP mode, and I have swapped out each Deco in turn to be the master. I have tested with both a ZTE mf286 4g router and a Huawei B315 4g router. Note that this has involved 7*2*2=28 test configurations. I have been thorough.

The losses seem to vary over time between 5% and 50% of UDP packets, getting worse and then better over a period of an hour or two. I wrote the following Python script to perform multiple nslookups to determine this:

import sys
import string
import os
import time
import timeit

with open("results.txt","w") as f:
    for a in range(97,123):
        for b in range(97,123):
            cmd = "nslookup " + (chr(a) + chr(b) + ".com")
            exec_time = timeit.timeit('os.system(cmd)', globals=globals(), number=1)
            f.write(cmd + "\t" + str(exec_time) + "\n")
            time.sleep(1)

TP Link - feel free to use this to reproduce the problem.

When the UDP loss is very high, sometimes TCP starts dropping too (verified by running ping 172.217.22.174 - that's google.com - in a second command terminal).

All the problems are immediately resolved if I switch my computer connection from the Deco mesh to, for example, my phone running as a hotspot.

Is this a known issue, and does anyone know how to resolve it?