Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top
# 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
share|improve this question

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.

share|improve this answer
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 Sep 9 '13 at 11:39
Never payed attention to that bit, to be honest. Hopefully someone else will have a better (complete) answer. – Ярослав Рахматуллин Sep 9 '13 at 13:29

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.