Ethernet switch speeds connected to OpenWrt router

Hey all, I have a TP-Link ethernet switch (LS1008G) connected to a port on my WRT3200ACM router running openwrt 22.03.2. Speeds on wifi from the router are around 450mbps usually, but anything connected to the switch is 100mpbs or less.

I am using brand new Cat6 ethernet cables, that have all been tested with an ethernet tester, so I'm 99% sure it's not cable related, and wondering if there is something on the router I need to do?

The devices connected to the switch are working well, just limited to 100mbps or less.

I have the ethernet plugged into LAN 2 on router and port 1 on switch, then other devices from port 3 onwards of switch.

Wondering what else I can try, or if I need a better switch? Thanks in advance !

You need to figure out where the bottleneck is... some methodical troubleshooting can get some answers. It could be the physical link on one end or the other, or it could be something else... but internet speed tests don't always tell the whole story, so you may want to run iPef3 tests locally on your network.

Start with physical links: Does the switch have colors to indicate link speed (sometimes 100Mbps is amber, 1Gbps is green, for example). Look at what each physical link is reporting.

Also, what are the downstream devices? Not all devices actually have 1Gbps ethernet (although any modern full fledged computer with built-in ethernet should, in theory). Check to see what the ethernet adapters support in each of your downstream devices, and where possible, look at the OS to determine the physical link speed it believes has been established.

You could connect devices directly to the router to see if they achieve 1G link speeds.

Also, look for physical debris or bent pins in the connectors on the switch, the router, and the end devices.

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I had a similar issue with some cables that I built myself (6e), the issue was the switch that, I have no idea why, was connecting at 100mbps instead of 1000mbps when I was connecting first one cable instead the other.

Try to unplug all the cable and plug in only one… just an idea.

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So I tried just now plugging my iMac straight into the router, and it is still only getting less than 100mbps, so I'm wondering would this indicate a cable issue or something on openwrt that needs to be set? The weird thing is that my access point is providing 450 mbps from an ethernet cable connected to LAN 3 on this router, so I'm assuming if one LAN port is doing that all should be providing full speed?

You could have one or more damaged ports... what does the iMac report as the physical connection speed? What happens if you plug your iMac into the LAN 3 port?

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So after all that, I have changed cables and plugged back into the iMac with a new cable, and this one is now reporting 509mbps and this is through the switch! apologies for wasting time, I will be investing in some different ethernet cables, I had wrongly assumed if these cables were new and reporting 100mbps they couldn't be the issue but they were

Glad you found the issue.

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