Deco BE85 weird behavior/backhaul function clarification

Deco BE85 weird behavior/backhaul function clarification

Deco BE85 weird behavior/backhaul function clarification
Deco BE85 weird behavior/backhaul function clarification
2025-07-25 01:03:53
Model: Deco BE85  
Hardware Version: V1
Firmware Version: 1.1.1

Unfortunately, I have experienced recurring issues with my Deco BE85 setup since the beginning, and the more functions I rely on, the more problematic it becomes.

 

Setup overview:

 

  • 4× Deco BE85 units (all connected via 10G Ethernet)

  • 1× Deco XE75 (wireless only, in a remote corner of the house)

  • All units are running in bridge mode

  • Main Deco is a BE85

  • Switching infrastructure consists of:

    • 1× SKS7300-8GPY4XGS (10G managed switch, RSTP enabled)

    • 2× smaller managed XikeStor switches (one in front of a BE85, the other one behind another)

Wi-Fi setup:

  • 6 GHz / 5 GHz as the main network (~35 clients)

  • 2.4 GHz as a separate IoT network (~80 clients)

 

In the Deco app, everything looks fine:
All BE85 units show “Ethernet” as connection type. When checking the details, I see “Connected via Ethernet / 5 GHz / 6 GHz” – which I understand is expected, since there's no way to disable wireless backhaul on these devices.

 

From the switch side, everything also looks fine:
All Deco uplinks are stable 10G connections, no packet errors, no retransmits, and all ports remain in forwarding state all the time.

 

And yet, nearly all connections going through the Deco units are extremely unstable.

 

Example: If I ping my Hue Bridge from my desktop PC (both wired), I see ping times around 2 to 7 ms most of the time, but frequent spikes up to 500 ms or more. That’s typical wireless behavior, but this is a fully wired path: desktop → small switch → main switch → BE85 → small switch → Hue bridge.

Connections that don’t involve the Deco units at all are perfectly stable. For example: desktop → switch → router results in sub-1ms pings.

 

Interestingly, one specific BE85 unit performs fine – it’s the one connected to my gaming PC / VR setup. 

 

Just to get game streaming working, I had to insert an extra switch in front of my desktop – direct connection to Deco made streaming unusable, even though it was wired via 2.5G Ethernet.

 

I already tried factory resetting all Deco units, but it didn’t help. RSTP is enabled and properly configured on the switches, with no blocked ports or topology changes reported. Cabling has also been checked. There are no errors or collisions on any of the switch ports.

 

At this point, it looks like the Deco units either fall back to wireless backhaul dynamically, even when Ethernet is active – or they have some kind of instability or forwarding issue on the internal switching side.

 

Since Deco doesn’t expose internal path decisions or offer any option to disable wireless backhaul, it’s impossible to reliably work around this. Right now, I simply cannot use the BE85 units in a mixed Ethernet and wireless setup without running into these issues – which kind of defeats the whole point of a high-end tri-band mesh system.

Let me know if you need diagrams, logs, or test results – I’m happy to provide anything useful.

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#1
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Re:Deco BE85 weird behavior/backhaul function clarification
2025-07-25 06:47:06

  @ksh_osaka 

Hi, thank you very much for the feedback.

I would be glad if you could share a network topology of how the devices(ISP router/Deco/ Network switches/Hue Bridges, as well as the Gaming PC or other network devices that can't work well) are connected together.

 

And there happens to be a new firmware that could disable the WiFi Backhaul when Ethernet Backhaul is enabled.

I'll share this version via email, and it would be perfect if you could also reply to the email with some screenshots of the ping spike.

 

Thanks a lot.

Best regards.

 

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Re:Deco BE85 weird behavior/backhaul function clarification
2025-07-25 07:47:40

  @David-TP 

Hi David,

thanks for getting back to me! I have received your mail with the beta firmware and I will try it soon. Meanwhile, I hacked together a quick picture of my network topology. There are of course a lot more clients - this is just an example. 

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