Question Wireless & Ethernet Speed Dying at the Router (RT-AX92U)

Dec 19, 2021
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Hey all, long time lurker who's leveraged a lot of good advice from here in the past now with a problem I can't get by. I'm not a network expert but I know enough to get by and have fun.

For reference, my topology is straightforward: External MIMO antennas + 5G/LTE Modem --> Asus mesh network behind RT-AX92U with backhaul across MoCA 2.5

My network connection is dying at the router. Connections to the mesh network, wired or wireless, net about 0.5-1 mbps tops, verified by speed test and downloading. I get full speed (300mbps 5G / 30 mbps LTE) connecting directly to my modem or to any MoCA adapter. When I run the Asus speed test in the router console, I see full speed just as if I plugged to the modem directly.

Things I have tried to remediate with no improvement:
  • Factory firmware and most recent firmware
  • Device reset, every way to do it
  • Simplest configuration (no mesh, no MoCA, 1x router + modem only)
  • Tried with two different routers (RT-AX92Us)
  • Tested and swapped every cable involved
  • No QoS, jumbo frames, or any unusual settings
This system work flawlessly for a long time until a couple weeks ago. Anything else to test before I pull the trigger on a new router?
 
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So the ax92u connects it wan port to the modem via moca ? When you test this from the router itself all is good ?

How is the lan side of the ax92u connected. You say you have mesh nodes connected via moca. How do you keep the 2 moca networks from conflicting or is the WAN cable a dedicated coax between the 2 location with no other connections.

What happens if you plug a single pc into the ax92u via ethernet with no other wireless or wired connections.
 
Dec 19, 2021
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I made an error in the above, I'll fix that momentarily. The current setup is Modem --> 92U --[MoCA]--> mesh nodes

This has worked fantastic for a while and what's really odd, when I connect directly to the modem, I see full speed. When I connect to LAN on the 92U, <1mbps. I also see full speed across MoCA without the 92U in between and with the 92U downstream of MoCA (and no nodes) I again see <1mbps. This has lead me to believe the issue is at the router, but oddly multiple routers are showing the same behavior on all firmware I've tried and in every tested configuration.

What happens if you plug a single pc into the ax92u via ethernet with no other wireless or wired connections.

<1mbps speed for this config
 

kanewolf

Titan
Moderator
Those "gaming" routers always make me concerned. If they have too many "smarts" which just makes them work worse. I don't know if you can turn OFF things like AIMesh (which could cause loops), wtfast (a gaming enhancement) or other "features". Get back to a basic router.
I also wonder, if something like the MTU size on the WAN is incorrect on for your cellular link. Did you use the "Quick internet setup" ?
 
Dec 19, 2021
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They seem to have a lot going on prioritizing connections. I'm using these only because I had access to them for free; ideally I'd like to move towards a more dedicated ap system for our home.

In testing I did have AIMesh disabled and ran the router as a standalone on basic settings, but still encountering the problem.

Interesting call on MTU, something for me to look into. For the time being I've been able to get around the issue with an old (normally slow) router. I'll keep troubleshooting the 92U and update if I make progress.