Problem with switch connected to Xiaomi Redmi AC2100

Installing and Using OpenWrt Network and Wireless Configuration
1

Hello everyone,

I have a Xiaomi Redmi AC2100 running OpenWrt 21.02.1 r16325-88151b8303 version in bridge mode without DHCP using WLAN. Connected to it via LAN ports are the main router and a TP-link TL-SG1008D switch. When the router starts everything seems to work fine, but suddently Switch Lan port changes to "Connected, 100 MBit/s, full-duplex" instead of 1000 MBit/s and connection of all devices connected via this port starts to fail (devices connected via WLAN continue working perfectly).

I have tried with lots of different cables and still happens and I have changed also the connection ports and the same. It only works if computer is connected to the OpenWrt device without the switch, but I have replaced the switch for a new one and the problem is still present. So, I guess that there could be a configuration problem. Do you know what could be happening?

Thank you so much in advance.

2

try ethtool, force the port to 1gbit.

3

Than you for your response. I tried forcing it with the following command:

ethtool -s lan2 speed 1000 duplex full autoneg on

It was working fine for a while. However, now it stopped working and Bridge VLAN filtering shows "no link" for lan2 port. This is the ethtool lan2 output:

Settings for lan2:
	Supported ports: [ TP MII ]
	Supported link modes:   10baseT/Half 10baseT/Full 
	                        100baseT/Half 100baseT/Full 
	                        1000baseT/Full 
	Supported pause frame use: Symmetric Receive-only
	Supports auto-negotiation: Yes
	Supported FEC modes: Not reported
	Advertised link modes:  1000baseT/Full 
	Advertised pause frame use: Symmetric Receive-only
	Advertised auto-negotiation: Yes
	Advertised FEC modes: Not reported
	Speed: Unknown!
	Duplex: Unknown! (255)
	Port: MII
	PHYAD: 3
	Transceiver: external
	Auto-negotiation: on
	Supports Wake-on: d
	Wake-on: d
	Link detected: no
4

try disabling autoneg....

5

I have done it with following command:

ethtool -s lan2 speed 1000 duplex full autoneg off

Now, there is always no link:

root@OpenWrt:~# ethtool lan2
Settings for lan2:
	Supported ports: [ TP MII ]
	Supported link modes:   10baseT/Half 10baseT/Full 
	                        100baseT/Half 100baseT/Full 
	                        1000baseT/Full 
	Supported pause frame use: Symmetric Receive-only
	Supports auto-negotiation: Yes
	Supported FEC modes: Not reported
	Advertised link modes:  1000baseT/Full 
	Advertised pause frame use: Symmetric Receive-only
	Advertised auto-negotiation: No
	Advertised FEC modes: Not reported
	Speed: 1000Mb/s
	Duplex: Full
	Port: MII
	PHYAD: 3
	Transceiver: external
	Auto-negotiation: off
	Supports Wake-on: d
	Wake-on: d
	Link detected: no