QoS not working on Deco M9
Setting total bandwidth under QoS doesn't do anything and doesn't limit the bandwidth as it should. On a previous router, I could set the max download and upload speed to a bit less than my max speed. This greatly helped mitigate latency issues (aka Bufferbloat) due to my cable provider's supplied cable modem (uses Puma 6 chipset).
Unfortunately, the same setting does nothing in the M9 which results in 200-300ms latency results when testing with http://www.dslreports.com/speedtest. This extra latency negatively impacts any latency sensitive traffic (gaming, voip, video chat)
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Hello, below is the instruction to setup QoS on the Deco M9 plus.
https://www.tp-link.com/support/faq/1601/
For the latency sensitive traffic, you can priortize the corresponding application under more-QoS-application priority.
Best regards.
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@Kevin_Z I did as instructed and there were no changes. The traffic used was still higher than the limit set.
Additionally, on every other brand of router I've had, when you set a QoS limit, it affected ALL the traffic leaving the router and not just for specified internal hosts. That setting was separate from prioritizing the internal hosts' traffic.
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Thanks for your reply.
Regarding to the high latency issue, we can do further analysis.
Please tell us the current network diagram, how do you connect these devices together.
Please show us a screenshot of the ping results.
Meanwhile, please verify which Deco the device has connected and get its IP address from the Deco app. Then try to ping the IP of the connected Deco first, then ping the IP of the main Deco. Please show us the ping results also.
Good day.
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The network topology is as follows:
- Cable Modem connects to Router via ethernet
- Router connects to gigabit switch via eithernet
- Computers and second Deco unit connect to gigabit switch via ethernet.
This is the same topology I have been using for years, the only recent change is the router (and its second unit).
Below is a link to the result I mentioned in the original post. You'll notice that I am getting 301 Mb down /17 Mb up. This is despite having set a limit of 140 down / 18 up (my plan is 150/20 and 140/18 in the past was shown to reduce bufferbloat). As a result, the bufferbloat result is a C (look under the Grades heading) since the ping went as high as 245ms with an average of 163ms.
http://www.dslreports.com/speedtest/55265913
Today for some reason, as I was about to try and get the results for this post, I ran another test and got completely different results. I haven't changed anything in my config since the previous results either. This is the result I got today: http://www.dslreports.com/speedtest/55556190. Here we now see the average is 35ms with a high of 39ms. This is inline with results I used to have. On a test with my old router just before switching to the deco, I had an average of 39ms with a peak of 52ms.
I'm not sure what changed to get such a variance in results.
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I re-ran a speed test later in the day just to eliminate time of day as a factor for the varying results. I am still getting the latest results where the bandwidth limiter is working and bufferbloat is mitigated.
As best as I can tell, it looks like when i did the first round of tests, the QoS were in the app UI and were applied there but not in effect at the router. Is it possible that it took time for them to go into effect (or after a reboot)?
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Thanks for your updates, glad to hear that it works as expected now.
Generally speaking, once you enabled QoS and set it up, it will take effect within seconds. For the latency issue, cause there are serveral network nodes existed on the total sysem, we need verify which unit is the root cause.
Anyway, cause it works well now, you can take more time to test its performance.
If it happens again, please verify which Deco unit your device has connected to, and ping the Deco first, and then ping the switch/main Deco/modem one by one.
Good day.
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