Ethernet Backbone dropping from Gbps connection to 100Mbps

  • Hi there,
    Here is my setup: One AmpliFi Gamer's Edition, 3 AmpliFi HD Mesh Routers. The Gamer's Edition is my main router. Actually running 3.4.0 rc0 but I had the following problem even on previous non beta firmware.

    I use backbone ethernet for one of the AmpliFi HD. I have read how to set it up and the set up is working. However the ethernet connection is randomly dropping from Gbps to 100 Mbps between the 2 AmpliFis. There is a 50 feet Cat5e between those 2. When I hook up this long ethernet cable directly into the iMac, there's no problem keeping the connection to Gbps with the Gamer's router.

    Any idea of what could be causing this problem?


  • @Xuan-Vien-Do said in Ethernet Backbone dropping from Gbps connection to 100Mbps:

    There is a 50 feet Cat5e between those 2

    Are these direct connections, or is there a switch being used?

    My guess (if you are using the same cable) Is that either the LAN port on the primary router is negotiating down to 100Mbps, or the WAN port on the RAMP is negotiating down to 100Mbps. If no switch is being used, and your iMac is maintaining gig speeds over an extended period of time using the same connection, that would make me believe its the Router as a mesh point.

    When your speed drops again, if you could generate support files from the primary router using the app, we can review the logs and see what we believe to be causing the issue.

  • Thanks for the quick follow-up.

    There was no switch involved.
    I finally installed a second long Cat5e cable. One is dedicated to the mesh router and the other connected to a switch to hook up the iMac and a Macbook air. System has been stable since then with great performance.

    I did read on AMPLIFI website that every mesh router with backbone ethernet must be directly hook up to the main router but switch is allowed. I would like to connect a 2nd mesh router with backbone ethernet to enhance the wifi network. Is it allowed to connect a switch to the main router and 2 mesh routers to that switch?

    Many thanks!

  • @Xuan-Vien-Do said in Ethernet Backbone dropping from Gbps connection to 100Mbps:

    Is it allowed to connect a switch to the main router and 2 mesh routers to that switch?

    Yes, theoretically this can be done with no issues. In some instances a switch does not allow the mesh point to connect but in most cases it works properly.

  • Hello again @UI-Brett,

    Still have the same dropping to 100Mbps connection problems. Between the Gamer’s Edition main router and a backbone ethernet mesh AMPLIFI HD router. I just sent the log file to AmpliFi support. They told me they would forward the file to you to see if you’re able to find the cause of this dropping performance.


    Xuan Vien Do

  • @UI-Brett I'm experiencing exactly the same issue. Randomly the ethernet backbone falls back to 100Mbps. Unplugging the wan-cable and plugging it back in resolves it.

  • @Toon-Willems Is your RaMP connected via a switch or directly to a LAN port on the primary router?

    If you can generate support files for our development team to review, we can see if we can identify what may be causing this in your environment.

  • @UI-AmpliFi it's directly connect to the primary router, over a cat6a cable (The one thing that in my mind could be the cause is that on the primary router also a LG tv is connected which only supports 100mbps). I've sent the support files via mail.

  • @Toon-Willems That could be the cause, but the support files will help us identify if the WAN port is negotiating down to 100 on the RaMP, or if for some reason the LAN ports on the primary router are all negotiating down to 100. Are there any switches in use on your home network?

  • @UI-AmpliFi There are no switches in my home network.

  • @Toon-Willems Can you get another device to connect at 1 gig using the same ethernet cable?

  • @UI-AmpliFi yes, after a simple unplug and plug back in, it is back to gigabit. I’ve also done iperf3 measurements & nothing appears off with the cable.

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