LAN speed keeps dropping down to 100Mbps from 1000Mbps and requires re-plugging to be 1000Mbps again

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LAN speed keeps dropping down to 100Mbps from 1000Mbps and requires re-plugging to be 1000Mbps again

This thread has been locked for further replies. You can start a new thread to share your ideas or ask questions.
LAN speed keeps dropping down to 100Mbps from 1000Mbps and requires re-plugging to be 1000Mbps again
LAN speed keeps dropping down to 100Mbps from 1000Mbps and requires re-plugging to be 1000Mbps again
2023-05-02 00:20:29
Tags: #Firmware Update #LAN Speed
Model: Archer AX72  
Hardware Version: V1
Firmware Version: 1.1.2 Build 20220520 rel.75663(4555)

Hello,

 

I experience quite often that the speed of the wired connection between my router (AX72) and my unmanaged gigabit switch (TL-SG1008D) got limited in speed. If I check the speed of connection on the router's admin page, it says that the speed of the LAN port that the switch is connected to, is 100Mbps Full Duplex but if I physically disconnect one end of the connecting UTP cable from the switch or from the router and I plug it back, I get the 1000Mbps Full Duplex (gigabit) speed again. The decreased speed can also be measured with a speed test, as I have 1000/1000 Mbps fiber service.

 

The root cause of the problem can be that I sometimes step on the cable accidentally, however, no movement happens to the connectors.

 

I use PPPoE connection towards the ISP and I could set on my TP-Link router that the speed of my WAN port (connected to the GPON modem/router, received from the ISP) must be 1000Mbps Full Duplex all the time. But I couldn't find a similar setting on the router's admin page that could be used to do the same speed forcing, so the speed of my downstream LAN port towards the switch could be forced to be 1000Mbps. Thus, the port speed frequently stucks at 100Mbps Full Duplex. And, as I mentioned, my switch is unmanaged, so I cannot set the speed of the connection from the switch side manually, as I can on my easy smart switch.

 

Could I expect a firmware update that includes this setting? Or is it already implemented but I couldn't manage to find it?

 

 

Thank you in advance!

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Re:LAN speed keeps dropping down to 100Mbps from 1000Mbps and requires re-plugging to be 1000Mbps again
2023-05-05 11:16:24

@Simion 

 

You are not missing anything. It's not supported to modify or change the LAN Negotiation speed between the router and the client devices on the router web GUI. It is negotiated automatically.

 

Can I know how far is the SG1008D from the AX72? In other words, how long is the Ethernet cable between them? Try a shorter cable with good quality if possible.

 

You may also connect a computer that has a gigabit Ethernet adapter to the AX72's LAN port to test and monitor if it can negotiate at 1000Mbps properly.

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Re:LAN speed keeps dropping down to 100Mbps from 1000Mbps and requires re-plugging to be 1000Mbps again
2023-05-16 23:41:08

  @Kevin_Z 

 

Thanks for your reply! My Ethernet cable is about 15 meter long and cat.6, so it shouldn't cause the problem, I think. I didn't experience the issue in the last few weeks, but each time when I physically unplug and replug the cable the speed is negotiated properly, so as 1000 Mbps. I use sometimes one or two 100Mbps Ethernet devices (Raspberry Pis) connected to the SG1008D as well. They may request this speed at power-on if my gigabit Ethernet laptop is not running at that moment.

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Re:LAN speed keeps dropping down to 100Mbps from 1000Mbps and requires re-plugging to be 1000Mbps again
2023-05-17 02:14:12

@Simion 

 

15m with cat 6 cable should be not a problem I assume.

 

Are both the AX72 and the SG1008D purchased recently? Have you ever had a chance to test if the negotiation speed is good at 1000Mbps if you connect a computer with a gigabit Ethernet adapter to the AX72 directly bypassing the SG1008D? I would suggest trying different LAN ports on the AX72 as well as on the SG1008D.

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