LAN drops to 100Mbps/Full

I notice one of my AP suddenly downgraded connection from 1Gbps/Full to 100Mbps/Full, I saw some strange kernel logs as follows,

[1152623.612533] Rekeying PTK for STA a2:82:f9:3f:9e:30 but driver can't safely do that.
[1152915.684709] Rekeying PTK for STA a2:82:f9:3f:9e:30 but driver can't safely do that.
[1152942.545239] Rekeying PTK for STA a2:82:f9:3f:9e:30 but driver can't safely do that.
[1152967.304892] Rekeying PTK for STA a2:82:f9:3f:9e:30 but driver can't safely do that.
[1152973.523733] Rekeying PTK for STA a2:82:f9:3f:9e:30 but driver can't safely do that.
[1153405.140270] Rekeying PTK for STA a2:82:f9:3f:9e:30 but driver can't safely do that.
[1153506.079497] Rekeying PTK for STA a2:82:f9:3f:9e:30 but driver can't safely do that.
[1153534.695141] Rekeying PTK for STA a2:82:f9:3f:9e:30 but driver can't safely do that.
[1164854.255854] Rekeying PTK for STA 22:2b:d1:9a:74:86 but driver can't safely do that.
[1177345.863650] Rekeying PTK for STA a2:82:f9:3f:9e:30 but driver can't safely do that.
[1177364.861583] Rekeying PTK for STA 22:2b:d1:9a:74:86 but driver can't safely do that.
[1178946.852161] mt7530 mdio-bus:1f lan1: Link is Down
[1178946.865289] br-lan: port 1(lan1) entered disabled state
[1178948.900273] mt7530 mdio-bus:1f lan1: Link is Up - 1Gbps/Full - flow control rx/tx
[1178948.908022] br-lan: port 1(lan1) entered blocking state
[1178948.913445] br-lan: port 1(lan1) entered forwarding state
[1179013.411736] mt7530 mdio-bus:1f lan1: Link is Down
[1179013.416783] br-lan: port 1(lan1) entered disabled state
[1179015.459877] mt7530 mdio-bus:1f lan1: Link is Up - 1Gbps/Full - flow control rx/tx
[1179015.467623] br-lan: port 1(lan1) entered blocking state
[1179015.473047] br-lan: port 1(lan1) entered forwarding state
[1179016.483717] mt7530 mdio-bus:1f lan1: Link is Down
[1179016.488763] br-lan: port 1(lan1) entered disabled state
[1179022.627868] mt7530 mdio-bus:1f lan1: Link is Up - 1Gbps/Full - flow control rx/tx
[1179022.635611] br-lan: port 1(lan1) entered blocking state
[1179022.641033] br-lan: port 1(lan1) entered forwarding state
[1179023.651662] mt7530 mdio-bus:1f lan1: Link is Down
[1179023.656695] br-lan: port 1(lan1) entered disabled state
[1179025.699884] mt7530 mdio-bus:1f lan1: Link is Up - 1Gbps/Full - flow control rx/tx
[1179025.707628] br-lan: port 1(lan1) entered blocking state
[1179025.713054] br-lan: port 1(lan1) entered forwarding state
[1179026.723650] mt7530 mdio-bus:1f lan1: Link is Down
[1179026.728683] br-lan: port 1(lan1) entered disabled state
[1179028.771797] mt7530 mdio-bus:1f lan1: Link is Up - 1Gbps/Full - flow control rx/tx
[1179028.779547] br-lan: port 1(lan1) entered blocking state
[1179028.784978] br-lan: port 1(lan1) entered forwarding state
[1179029.795640] mt7530 mdio-bus:1f lan1: Link is Down
[1179029.800677] br-lan: port 1(lan1) entered disabled state
[1179031.843873] mt7530 mdio-bus:1f lan1: Link is Up - 100Mbps/Full - flow control rx/tx
[1179031.851800] br-lan: port 1(lan1) entered blocking state
[1179031.857223] br-lan: port 1(lan1) entered forwarding state
[1194627.579318] Rekeying PTK for STA a2:82:f9:3f:9e:30 but driver can't safely do that.
[1196521.768190] Rekeying PTK for STA b4:4b:d2:ed:ba:5b but driver can't safely do that.
[1198264.626795] Rekeying PTK for STA 22:2b:d1:9a:74:86 but driver can't safely do that.
[1209172.775406] Rekeying PTK for STA a2:82:f9:3f:9e:30 but driver can't safely do that.

This logs also can be seen from system logs,

Wed Dec 15 16:10:12 2021 daemon.info hostapd: wlan1: STA a2:82:f9:3f:9e:30 IEEE 802.11: disassociated due to inactivity
Wed Dec 15 16:10:13 2021 daemon.info hostapd: wlan1: STA a2:82:f9:3f:9e:30 IEEE 802.11: deauthenticated due to inactivity (timer DEAUTH/REMOVE)
Wed Dec 15 16:10:19 2021 daemon.info dnsmasq-dhcp[7490]: DHCPREQUEST(br-guest) 192.168.10.224 34:ce:00:b2:7f:e5
Wed Dec 15 16:10:19 2021 daemon.info dnsmasq-dhcp[7490]: DHCPACK(br-guest) 192.168.10.224 34:ce:00:b2:7f:e5
Wed Dec 15 16:29:50 2021 kern.warn kernel: [1177364.861583] Rekeying PTK for STA 22:2b:d1:9a:74:86 but driver can't safely do that.
Wed Dec 15 16:29:50 2021 kern.info kernel: [1178946.852161] mt7530 mdio-bus:1f lan1: Link is Down
Wed Dec 15 16:29:50 2021 kern.info kernel: [1178946.865289] br-lan: port 1(lan1) entered disabled state
Wed Dec 15 16:29:50 2021 daemon.notice netifd: Network device 'lan1' link is down
Wed Dec 15 16:29:52 2021 kern.info kernel: [1178948.900273] mt7530 mdio-bus:1f lan1: Link is Up - 1Gbps/Full - flow control rx/tx
Wed Dec 15 16:29:52 2021 kern.info kernel: [1178948.908022] br-lan: port 1(lan1) entered blocking state
Wed Dec 15 16:29:52 2021 kern.info kernel: [1178948.913445] br-lan: port 1(lan1) entered forwarding state
Wed Dec 15 16:29:52 2021 daemon.notice netifd: Network device 'lan1' link is up
Wed Dec 15 16:30:57 2021 kern.info kernel: [1179013.411736] mt7530 mdio-bus:1f lan1: Link is Down
Wed Dec 15 16:30:57 2021 kern.info kernel: [1179013.416783] br-lan: port 1(lan1) entered disabled state
Wed Dec 15 16:30:57 2021 daemon.notice netifd: Network device 'lan1' link is down
Wed Dec 15 16:30:59 2021 kern.info kernel: [1179015.459877] mt7530 mdio-bus:1f lan1: Link is Up - 1Gbps/Full - flow control rx/tx
Wed Dec 15 16:30:59 2021 kern.info kernel: [1179015.467623] br-lan: port 1(lan1) entered blocking state
Wed Dec 15 16:30:59 2021 kern.info kernel: [1179015.473047] br-lan: port 1(lan1) entered forwarding state
Wed Dec 15 16:30:59 2021 daemon.notice netifd: Network device 'lan1' link is up
Wed Dec 15 16:31:00 2021 kern.info kernel: [1179016.483717] mt7530 mdio-bus:1f lan1: Link is Down
Wed Dec 15 16:31:00 2021 kern.info kernel: [1179016.488763] br-lan: port 1(lan1) entered disabled state
Wed Dec 15 16:31:00 2021 daemon.notice netifd: Network device 'lan1' link is down
Wed Dec 15 16:31:06 2021 kern.info kernel: [1179022.627868] mt7530 mdio-bus:1f lan1: Link is Up - 1Gbps/Full - flow control rx/tx
Wed Dec 15 16:31:06 2021 kern.info kernel: [1179022.635611] br-lan: port 1(lan1) entered blocking state
Wed Dec 15 16:31:06 2021 kern.info kernel: [1179022.641033] br-lan: port 1(lan1) entered forwarding state
Wed Dec 15 16:31:06 2021 daemon.notice netifd: Network device 'lan1' link is up
Wed Dec 15 16:31:07 2021 kern.info kernel: [1179023.651662] mt7530 mdio-bus:1f lan1: Link is Down
Wed Dec 15 16:31:07 2021 kern.info kernel: [1179023.656695] br-lan: port 1(lan1) entered disabled state
Wed Dec 15 16:31:07 2021 daemon.notice netifd: Network device 'lan1' link is down
Wed Dec 15 16:31:09 2021 kern.info kernel: [1179025.699884] mt7530 mdio-bus:1f lan1: Link is Up - 1Gbps/Full - flow control rx/tx
Wed Dec 15 16:31:09 2021 kern.info kernel: [1179025.707628] br-lan: port 1(lan1) entered blocking state
Wed Dec 15 16:31:09 2021 kern.info kernel: [1179025.713054] br-lan: port 1(lan1) entered forwarding state
Wed Dec 15 16:31:09 2021 daemon.notice netifd: Network device 'lan1' link is up
Wed Dec 15 16:31:10 2021 kern.info kernel: [1179026.723650] mt7530 mdio-bus:1f lan1: Link is Down
Wed Dec 15 16:31:10 2021 kern.info kernel: [1179026.728683] br-lan: port 1(lan1) entered disabled state
Wed Dec 15 16:31:10 2021 daemon.notice netifd: Network device 'lan1' link is down
Wed Dec 15 16:31:12 2021 kern.info kernel: [1179028.771797] mt7530 mdio-bus:1f lan1: Link is Up - 1Gbps/Full - flow control rx/tx
Wed Dec 15 16:31:12 2021 kern.info kernel: [1179028.779547] br-lan: port 1(lan1) entered blocking state
Wed Dec 15 16:31:12 2021 kern.info kernel: [1179028.784978] br-lan: port 1(lan1) entered forwarding state
Wed Dec 15 16:31:12 2021 daemon.notice netifd: Network device 'lan1' link is up
Wed Dec 15 16:31:13 2021 kern.info kernel: [1179029.795640] mt7530 mdio-bus:1f lan1: Link is Down
Wed Dec 15 16:31:13 2021 kern.info kernel: [1179029.800677] br-lan: port 1(lan1) entered disabled state
Wed Dec 15 16:31:13 2021 daemon.notice netifd: Network device 'lan1' link is down
Wed Dec 15 16:31:15 2021 kern.info kernel: [1179031.843873] mt7530 mdio-bus:1f lan1: Link is Up - 100Mbps/Full - flow control rx/tx
Wed Dec 15 16:31:15 2021 kern.info kernel: [1179031.851800] br-lan: port 1(lan1) entered blocking state
Wed Dec 15 16:31:15 2021 kern.info kernel: [1179031.857223] br-lan: port 1(lan1) entered forwarding state
Wed Dec 15 16:31:15 2021 daemon.notice netifd: Network device 'lan1' link is up
Wed Dec 15 17:05:23 2021 daemon.info hostapd: wlan1: STA b4:4b:d2:ed:ba:5b WPA: group key handshake completed (RSN)
Wed Dec 15 17:05:23 2021 daemon.info hostapd: wlan1: STA dc:56:e7:4f:80:4a WPA: group key handshake completed (RSN)

I didn't do anything in between and I confirm the cable is good and meets cat6.e category stander, I have three APs are enabled FT and all wired up to the primary router. I'm confused, why is this happening? I never saw this but today, coz I saw the lan light became to amber which indicates speed capped to 100Mbps only. The other two APs work at 1Gbps/F with no this issue.

Any comment would be welcome, thanks.

Model Linksys EA7500 v2
Architecture MediaTek MT7621 ver:1 eco:3
Firmware Version OpenWrt 21.02.1 r16325-88151b8303 / LuCI openwrt-21.02 branch git-21.295.67054-13df80d
Kernel Version 5.4.154
Local Time 2021-12-16 22:37:55

Hi,

  1. check if the other end using some kind of energy saving feature and disable,
  2. check with ethtool if your device using energy saving and disable (ethtool --set-eee $iface eee off).

check if disabling energy saving improves situation.

1 Like

Are you certain that the device on the other end isn't responsible for the drop to 100Mbps? For example, I have a Mac mini that drops to 100Mbps when it is in low power/sleep mode. This is normal behavior.

Have you swapped the cable for another known good one. Just because it is a cat6 cable doesn't mean it isn't defective or damaged in some way.

Also, do you have anything physically between the two devices other than a single cable? Things like a wall termination, patch panel, coupler or switch, etc? Sometimes there can be an issue with those intermediate connections.

Have you moved the cable to another port on the router (swapping ports with something that maintains a consistent gigabit connection)? This will tell you if the problem is with the port or with something downstream (cable, terminations, an issue on a switch port or device port, etc.)

1 Like

Hi thank you for the comments, when I run the commands it always complains,

ethtool --show-eee br-lan
ethtool --show-eee eth0

Cannot get EEE settings: Not supported

Seems my router does not support EEE relevant settings.

And I couldn't find any energy saving feature here and there, seems it's not related to this.

Hi thank you first for the comments.

Because I use it as AP for wireless only, and a lot of devices connected to this AP wirelessly, I mainly use Apple devices like Mackbook Pro, iPhone, iPad etc, if it drops to 100Mbps, it needs all devices drop to 100Mbps at the same time to make the amber light right?

I confirm that there is no other device between this AP and primary router except a single cable, this AP just is placed next to the primary router in living room, so no wall termination, panel etc.

And the cable I don't think it is broken or damaged, because it was working like a charm for quite few weeks, it's a brand new cable, because I was very busy since I noticed the speed dropping problem, so I didn't touch that AP on that day, never reboot and just left it there, and today I saw it ran back to 1Gbps already, but I saw some similar information from the log too, seems this up and down stuff happen periodically every few hours (note the ethernet cable wired to lan1, and other lans are empty).

Sat Dec 18 17:05:19 2021 daemon.notice hostapd: wlan0: AP-STA-CONNECTED 06:4c:0c:31:7d:17
Sat Dec 18 17:05:19 2021 daemon.info hostapd: wlan0: STA 06:4c:0c:31:7d:17 WPA: pairwise key handshake completed (RSN)
Sat Dec 18 17:05:23 2021 daemon.info hostapd: wlan1: STA 48:a5:e7:fb:5f:41 WPA: group key handshake completed (RSN)
Sat Dec 18 17:05:23 2021 daemon.info hostapd: wlan1: STA dc:56:e7:4f:80:4a WPA: group key handshake completed (RSN)
Sat Dec 18 17:05:23 2021 daemon.info hostapd: wlan1: STA 3c:22:fb:17:3a:3d WPA: group key handshake completed (RSN)
Sat Dec 18 17:05:23 2021 daemon.info hostapd: wlan1: STA b4:4b:d2:ed:ba:5b WPA: group key handshake completed (RSN)
Sat Dec 18 17:10:19 2021 kern.warn kernel: [1429129.439152] Rekeying PTK for STA b4:4b:d2:ed:ba:5b but driver can't safely do that.
Sat Dec 18 17:10:19 2021 kern.info kernel: [1440574.214276] mt7530 mdio-bus:1f lan1: Link is Down
Sat Dec 18 17:10:19 2021 kern.info kernel: [1440574.227380] br-lan: port 1(lan1) entered disabled state
Sat Dec 18 17:10:19 2021 daemon.notice netifd: Network device 'lan1' link is down
Sat Dec 18 17:10:22 2021 kern.info kernel: [1440577.286509] mt7530 mdio-bus:1f lan1: Link is Up - 1Gbps/Full - flow control rx/tx
Sat Dec 18 17:10:22 2021 kern.info kernel: [1440577.294247] br-lan: port 1(lan1) entered blocking state
Sat Dec 18 17:10:22 2021 kern.info kernel: [1440577.299674] br-lan: port 1(lan1) entered forwarding state
Sat Dec 18 17:10:22 2021 daemon.notice netifd: Network device 'lan1' link is up
Sat Dec 18 17:10:34 2021 kern.info kernel: [1440588.550193] mt7530 mdio-bus:1f lan1: Link is Down
Sat Dec 18 17:10:34 2021 kern.info kernel: [1440588.555232] br-lan: port 1(lan1) entered disabled state
Sat Dec 18 17:10:34 2021 daemon.notice netifd: Network device 'lan1' link is down
Sat Dec 18 17:10:37 2021 kern.info kernel: [1440591.622326] mt7530 mdio-bus:1f lan1: Link is Up - 1Gbps/Full - flow control rx/tx
Sat Dec 18 17:10:37 2021 kern.info kernel: [1440591.630067] br-lan: port 1(lan1) entered blocking state
Sat Dec 18 17:10:37 2021 kern.info kernel: [1440591.635493] br-lan: port 1(lan1) entered forwarding state
Sat Dec 18 17:10:37 2021 daemon.notice netifd: Network device 'lan1' link is up
Sat Dec 18 17:10:56 2021 daemon.notice hostapd: wlan1: AP-STA-DISCONNECTED 48:a5:e7:fb:5f:41

This is a very good hints, ok, because previously I connected to random lan ports of all AP, and I noticed this up and down thing happened a lot with 2 of the APs and the speed always dropped from 1Gbps to 100Mbps after a while, had to reboot to bring 1Gbps back, then another loop, after the investigation I realised that the silent AP got cable wired to lan1, so I changed all to lan1 and this issue magically gone from the other 2 APs, after that the up and down never happen again ( or maybe I never noticed, I just glance at the lights of the primary router when passing through, didn't check the logs..) until days ago I saw the flashing amber light.

So it sounds like your problem is solved, right?

Just to address some of the questions and observations:

The ethernet (wired) connection speed is independent of the wifi link speeds (at a physical level). So, no, the wireless devices don't also necessarily drop down to 100Mbps link speeds.
Obviously a 100Mbps connection from the AP to the upstream infrastructure limits the speed of actual data transfers from the (clients of the) AP to upstream devices, but the wifi link itself could still be established at a faster rate. You can think of it the same way as your home network functions -- you can have a gigabit copper link between all of your devices but only a 100Mbps or slower link to your ISP and things still work just fine (just a limit of 100Mpbs to the internet).

This seems not to be the issue in this case, but don't automatically assume that brand new cables are always good. They can be faulty -- including intermittent issues. For example, if one of the ends isn't crimped quite right, you could have an intermittent connection between one or more of the pins and the wires. This could be affected by movement or even just temperature (which might fluctuate due to time of day, heat/AC, surrounding equipment, sunlight hitting it, etc.). When in doubt, cables are a simple thing to swap out as basic troubleshooting, especially if you're getting a lot of port-flapping or drops in negotiated speed.

I'm a little confused about this, but it sounds like things are working properly now? This could indicate an issue with the physical port (i.e. debris in the connector or some other mechanical issue; an electrical issue with the circuitry, or an issue with the software driver in some circumstances).

Another thing to keep in mind is that the colors for the indicators are not always standardized, nor are the meanings of a given LED. For example, a flashing amber LED on the front of an Apple Airport/Time Capsule device actually means that there is something that needs attention (such as a firmware update, or an issue with the upstream connection), while solid green means everything is okay -- it doesn't represent the connection speed, though. Some devices have 2 LEDs to indicate port status (10/100 = left, 1000 = both), some use different colors, etc. So just make sure that you're correctly interpreting what it is trying to tell you. But, it does sound like everything is fine now.

If your problem is solved, please consider marking this topic as [Solved]. See How to mark a topic as [Solved] for a short how-to.

Thank you for the explanations, it seems that the problem is gone since yesterday, I didn't do anything meanwhile, but I still don't figure out why the up and down things happen, I believe this is the thing that caused the drop.

Sorry about this confusion, that was a separated story, in the very beginning when I set up my network, I have 3 APs in total, 2 of them got cable wried to non-lan1 port had similar problem, and problem gone when I changed all wired to lan1 at that time, until days ago I saw one of the AP with lan1 connected went into this problem again.

Never mind, since it's turned to normal itself, I have also changed the cable, will keep an eye on that AP if it happens again and might be able to capture more clues that caused this problem.

Thank you all again.

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