[CentOS] link speed

Craig White craigwhite at azapple.com
Thu Sep 18 19:37:39 UTC 2008


On Thu, 2008-09-18 at 15:05 -0400, John Kordash wrote:
> > Craig White írta:
> > > Is there a command line way to tell me whether a ethernet
> > connection is
> > > 100 BaseT or Gigabit Ethernet?
> >
> > mii-tool
> 
> 
> My experience with mii-tool on CentOS4 and 5 is that it won't show link speed above 100 even if it is.  If the OP is trying to differentiate 100 vs. 1000, then I would suggest using ethtool instead.
----
yup...mii-tool didn't report what I wanted...

# mii-tool
eth0: negotiated 100baseTx-FD flow-control, link ok
eth1: negotiated 100baseTx-FD flow-control, link ok

but ethtool did...
# ethtool eth0
Settings for eth0:
        Supported ports: [ 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 auto-negotiation: Yes
        Speed: 100Mb/s
        Duplex: Full
        Port: Twisted Pair
        PHYAD: 1
        Transceiver: internal
        Auto-negotiation: on
        Supports Wake-on: g
        Wake-on: d
        Current message level: 0x000000ff (255)
        Link detected: yes
[root at srv kbenedetto]# ethtool eth1
Settings for eth1:
        Supported ports: [ 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 auto-negotiation: Yes
        Speed: 1000Mb/s
        Duplex: Full
        Port: Twisted Pair
        PHYAD: 1
        Transceiver: internal
        Auto-negotiation: on
        Supports Wake-on: g
        Wake-on: d
        Current message level: 0x000000ff (255)
        Link detected: yes

Thanks

Craig



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