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ivanoff

Member

Registered: 2012-03-18

Posts: 73

Ethernet 2.5Gbps falling back to 1Gbps. Cable or software issue ?

Hello
NetworkManager can't seem to connect to my internet box in 2.5GBps. The link comes up, then down.
I am connected to an ethernet wall plug with a cat8 cable, then an unknown cable goes to my internet box cabinet where another cat8 connects it to the box.
Here is the journal of the event. After some tries, it falls back to 1Gbps.

mars 30 17:36:07 nordi NetworkManager[653]: <info>  [1743348967.8082] device (eno1): carrier: link connected
mars 30 17:36:07 nordi kernel: r8169 0000:07:00.0 eno1: Link is Up - 2.5Gbps/Full - flow control rx/tx
mars 30 17:36:07 nordi NetworkManager[653]: <info>  [1743348967.8084] device (eno1): state change: unavailable -> disconnected (reason 'carrier-changed', managed-type: 'full')
mars 30 17:36:07 nordi NetworkManager[653]: <info>  [1743348967.8086] policy: auto-activating connection 'Connexion filaire 1' (6f392085-d724-387b-8001-65e66d4bce81)
mars 30 17:36:07 nordi NetworkManager[653]: <info>  [1743348967.8088] device (eno1): Activation: starting connection 'Connexion filaire 1' (6f392085-d724-387b-8001-65e66d4bce81)
mars 30 17:36:07 nordi NetworkManager[653]: <info>  [1743348967.8088] device (eno1): state change: disconnected -> prepare (reason 'none', managed-type: 'full')
mars 30 17:36:07 nordi NetworkManager[653]: <info>  [1743348967.8089] manager: NetworkManager state is now CONNECTING
mars 30 17:36:07 nordi NetworkManager[653]: <info>  [1743348967.8089] device (eno1): state change: prepare -> config (reason 'none', managed-type: 'full')
mars 30 17:36:07 nordi NetworkManager[653]: <info>  [1743348967.8091] device (eno1): state change: config -> ip-config (reason 'none', managed-type: 'full')
mars 30 17:36:07 nordi NetworkManager[653]: <info>  [1743348967.8093] dhcp4 (eno1): activation: beginning transaction (timeout in 45 seconds)
mars 30 17:36:09 nordi wpa_supplicant[699]: wlp8s0: CTRL-EVENT-REGDOM-CHANGE init=BEACON_HINT type=UNKNOWN
mars 30 17:36:09 nordi wpa_supplicant[699]: wlp8s0: CTRL-EVENT-REGDOM-BEACON-HINT before freq=5180 max_tx_power=2000 no_ir=1
mars 30 17:36:09 nordi wpa_supplicant[699]: wlp8s0: CTRL-EVENT-REGDOM-BEACON-HINT after freq=5180 max_tx_power=2000
mars 30 17:36:10 nordi kernel: r8169 0000:07:00.0 eno1: Link is Down

What can I try to check whether this is due to the cables or some software configuration issue?
Note: Controller is: "Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8125 2.5GbE Controller (rev 0c)"
My internet box is 10Gbps capable

Thanks

Last edited by ivanoff (2025-03-30 17:29:37)

-thc

Member

Registered: 2017-03-15

Posts: 998

Re: Ethernet 2.5Gbps falling back to 1Gbps. Cable or software issue ?

As you may already fear - the in-between-cable and both sockets need to be multi-GB capable too.

You may try using a very long cable (Cat 5E and above) and plug your PC directly into the box or get a 2.5 GB capable small switch and test your connection with it.

ivanoff

Member

Registered: 2012-03-18

Posts: 73

Re: Ethernet 2.5Gbps falling back to 1Gbps. Cable or software issue ?

Well, I just did the test, and believe it or not, it doesn't work better with a direct connection with a cat 8 cable. So it really look like a hardware incompatibility, or a software issue in the PC drives, or the box itself

-thc

Member

Registered: 2017-03-15

Posts: 998

Re: Ethernet 2.5Gbps falling back to 1Gbps. Cable or software issue ?

O.K. - both sides normally try to find their link speed via auto-negotiation. You can try to set the link speed manually on either side (maybe it's not possible on the box' side) or if that fails, "insert" a small 2.5 GBIt capable switch that circumvents the direct link negotiation.

ivanoff

Member

Registered: 2012-03-18

Posts: 73

Re: Ethernet 2.5Gbps falling back to 1Gbps. Cable or software issue ?

Thank you for the ideas