Hi again

I did some more tests.

In my original setup the main Deco (running in AP mode) is connected to the same gigabit switch as the NAS. My router is also connected to that switch.

Now I tried to connect the NAS directly to the second network port on the main Deco instead of in the switch and now i can access the NAS with almost 100 Mbit/s.

But when it is connected to the gigabit switch performance drops as previously explained. The strange thing is that it is only from wifi that the performance issue occurs. If I connect my laptop either to the gigabit switch or the main Deco with cable I get the expected speed.

I don't understand why adding a switch causes the performance issue. The router is also connected to the switch and internet speed is performing as expected with almost full 100Mbit/s speed.

I hope someone can help with this as I don't really understand what is going on.

Thanks

@TP-Link 

Thank you for your reply.

I made a simple hand drawing of the network

The switch is a 3COM Gigabit Switch 5 - Model 3CGSU05

You ask whether I have tested the wireless speed from the Deco. I have done a test with Speedtest.net from my laptop wirelessly if that is what you mean. That gave me almost 100 Mbit/s so that is good.

I access the NAS local IP. I haven't opened for access externally.

I have also tried to remove the switch so both the main Deco and the NAS and wired computer is connected directly to the Linksys router, That makes no difference, still bad performance on the internal network. On the laptop I tried to copy a big file from the wired computer. It also performed bad so it is not only the NAS but seems to be internal traffic in general.

Last thing I tried was to attach the NAS directly to the second LAN port of the main Deco. Now I can copy from the NAS with full speed (almost 100 Mbit/s) from my wireless laptop. I find that very strange. As if the Deco doesn't like the switch. But it is also not working well when I use the Linksys router as a switch. On the other hand when connecting through the 3COM switch internet speed is fine and that also passes through the switch to get to the router. That makes no sense to me.

Both Deco's as well as the Linksys Router and NAS are on latest firmware. The switch is unmanaged so I don't think that can be firmware updated.

I found another forum topic from another user with a similar issue. He has a Deco M5 but besides that the issue is the same. https://community.tp-link.com/en/home/forum/topic/207514

Again thank you for your help, hope we can solve this.

Kenn

@TP-Link 

Thank you very much for taking my issue seriously

Yes I disabled wifi in the Linksys router

Kenn