Hello,

I have found what I suspect may be a FW issue in the Deco M9 Plus.

When I run the Main Deco in Firewall mode, upload and download speeds on the Ethernet WAN port are both unrestricted to 1000Mbit.

When I run the Main Deco in Bridge mode, upload speed is unrestricted, but download speed on the Ethernet port is capped at 500Mbit.

This is clearly visible from testing by running the speed test from the Main Deco itself from its Ethernet port out over the ISP router.

The Internet connection is a symmetrical 1000/1000Gb fiber connection.

Topology:

[Main Deco] <------- 1Gb Ethernet -------> [ISP Router] <------- 1Gb Ethernet -------> [Fiber Transceiver] <------- Fiber ------->  (Internet)

The ISP router is a VOIP, TV, Internet access and Firewall device and needs to be the very first device behind the transceiver.

The Deco needs to run in bridge mode since I have other devices on the inside of the ISP router that needs direct access to devices on the Deco MESH network.

If anything, I would expect that the firewall mode would be slightly slower than than the bridge mode due to the packet processing overhead.

The fact that it's only download speed that is affected, but upload speed is not, makes me think it's something in the Deco Bridge mode that is at fault.

Here is an example test just run from the Main Deco in Bridge mode (Running in FW mode gives full 900+/990+):

The problem is consistent and 100% repeatable and has been there since I installed the Decos some two years ago.

I have tried switching out the Main Deco and switching ports but found no solution so far.

I have been waiting and hoping that the fix would come in any of the new FW updates, but it hasn't so far, and I have tried all new FW updates provided so far AFAIK.

I just checked that I am on the latest version before I wrote this.

Is there a known solution to this?

Can any TP-Link associate assist with input or support?

Regards,

/Ricky-T