Why wouldn't an ethernet interface advertise gigabit speed if it's capable?
Solution 1
In my case the reason was obvious but still I searched quite some time before figuring it out. The cable was not gigabit-capable (i.e. only 4 out of 8 wires actually exist in the cable). Replacing the cable fixed the issue.
Definitely something to check before investigating complicated software parameters :)
Solution 2
Well, I'm experiencing the same thing on one of my interfaces. The output of ethtool
and mii-tool
are a bit different, which is shown below.
mii-tool -v
tells us:
eth0: negotiated 100baseTx-FD flow-control, link ok
product info: vendor 00:07:32, model 17 rev 2
basic mode: autonegotiation enabled
basic status: autonegotiation complete, link ok
capabilities: 1000baseT-HD 1000baseT-FD 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD
advertising: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD flow-control
link partner: 1000baseT-HD 1000baseT-FD 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD flow-control
Which seems to be that we're not advertising 1000BaseT-HD/FD.
However if you look at the output from ethtool
you'll get the following:
Settings for eth0:
Supported ports: [ TP MII ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Advertised pause frame use: No
Advertised auto-negotiation: Yes
Link partner advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Link partner advertised pause frame use: No
Link partner advertised auto-negotiation: Yes
Speed: 100Mb/s
Duplex: Full
Port: MII
PHYAD: 0
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: pumbg
Wake-on: g
Current message level: 0x00000033 (51)
Link detected: yes
This actually tells us that it is the link partner which is not advertising the 1000BaseT-HD/FD modes. Which it is I have not figured out yet, but it might explain what you're seeing as well.
bpaterni
Updated on September 18, 2022Comments
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bpaterni almost 2 years
I have a laptop with a gigabit capable ethernet interface:
# lspci -vvnn -s 08:02.0 08:02.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL-8110SC/8169SC Gigabit Ethernet [10ec:8167] (rev 10) Subsystem: Realtek Semiconductor Co., Ltd. RTL-8110SC/8169SC Gigabit Ethernet [10ec:8167] Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV+ VGASnoop- ParErr- Stepping- SERR+ FastB2B- DisINTx- Status: Cap+ 66MHz+ UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 64 (8000ns min, 16000ns max), Cache Line Size: 32 bytes Interrupt: pin A routed to IRQ 20 Region 0: I/O ports at b800 [size=256] Region 1: Memory at feafe400 (32-bit, non-prefetchable) [size=256] Expansion ROM at feac0000 [disabled] [size=128K] Capabilities: [dc] Power Management version 2 Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=375mA PME(D0-,D1+,D2+,D3hot+,D3cold+) Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME- Kernel driver in use: r8169
which I'm trying to connect to a gigabit capable router with Cat 6 (gigabit) cable for gigabit communication within the LAN. The problem is that the interface on my laptop is not advertising gigabit link speed that it used to:
# mii-tool -v eth0: negotiated 100baseTx-FD flow-control, link ok product info: vendor 00:07:32, model 17 rev 2 basic mode: autonegotiation enabled basic status: autonegotiation complete, link ok capabilities: 1000baseT-HD 1000baseT-FD 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD advertising: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD flow-control link partner: 1000baseT-HD 1000baseT-FD 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD flow-control
What would be the cause of this?
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bpaterni over 11 yearsThis doesn't seem to work.
mii-tool -A 1000baseT-FD,100baseTx-FD eth0
brings down the link but doesn't add 1000baseT-FD to 'advertising' list. If it was disabled manually, I'm not sure how that would've happened. I've only used mii-tool to investigate this problem. -
Mike Redrobe about 6 yearsHaha, always check the simple solution first ! I just had similar with what turned out to be a faulty cable