If you want to know the speed at which a system has connected to the LAN, e.g. the system can autonegotiate its speed and you need to know which speed it is using, you can use the mii-tool command to check the status of Ethernet devices in the system.
# mii-tool
eth0: no autonegotiation, 10baseT-HD, link okFrom the above output from the command on a Linux system, I can see that the Ethernet device, eth0, is not using autonegotiation to determine its speed and is set to 10 Mbs half duplex.
If you want more details for Ethernet devices in the system, you can
use -v or --verbose as a parameter to the command.
# mii-tool -v
eth0: no autonegotiation, 10baseT-HD, link ok
product info: vendor 00:10:18, model 23 rev 7
basic mode: autonegotiation enabled
basic status: autonegotiation complete, link ok
capabilities: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD
advertising: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD flow-control
From the above, I can see that eth0, though it is set for a 10baseT connection, i.e. 10 Mbs, can support a 100baseTx, i.e. 100 Mbs, connection.
The device is capable of the following port speeds:
| Port Speed | Description |
|---|---|
| 10baseT-HD | 10 megabits/s half duplex |
| 10baseT-FD | 10 megabits/s full duplex |
| 100baseTx-HD | 100 megabits/s half duplex |
| 100baseTx-FD | 100 megabits/s full duplex |
References:
