ethtool available network interface ports

# ethtool eth0
Settings for eth0:
    Supported ports: [ TP MII ]
    Supported link modes:   10baseT/Half 10baseT/Full 
                            100baseT/Half 100baseT/Full 
    Supports auto-negotiation: Yes
    Advertised link modes:  10baseT/Half 10baseT/Full 
                            100baseT/Half 100baseT/Full 
    Advertised auto-negotiation: Yes
    Speed: 10Mb/s
    Duplex: Full
    Port: MII
    PHYAD: 4
    Transceiver: internal
    Auto-negotiation: on
    Current message level: 0x00000000 (0)
    Link detected: yes

The question is what does TP mean? I found out MII means media independent interface. Also I am wondering why can't I change the value of port:

# ethtool -s eth0 port tp
Cannot set new settings: Invalid argument
  not setting port

akostadinov

Posted 2013-09-07T19:23:35.723

Reputation: 1 140

Answers

It means Twisted Pair. The cable and port are named after the wire-twisting method which due to the chemical / mechanical properties of the metal reduces cross-talk and interference between several cables.

Ярослав Рахматуллин

Posted 2013-09-07T19:23:35.723

Reputation: 9 076

I thought about this. But how could an integrated single port eth card have both - mii and TP? Or is it the case that the TP phy is connected through card's mii port and it is just not possible to select the other one? I assume the card has two ports but only one is wired for use in the device. – akostadinov – 2013-09-09T11:39:50.107

Never payed attention to that bit, to be honest. Hopefully someone else will have a better (complete) answer. – Ярослав Рахматуллин – 2013-09-09T13:29:37.203