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Re: Ethernet suddenly limited to 100 Mbps



On 2013-08-18 15:55:20 -0600, Bob Proulx wrote:
> I think it would be useful to double check the settings using ethtool
> to dump the current values.  Maybe there will be a clue in your
> output.  Here is an example from my machine.

I get the following:

xvii:~> ethtool eth0
Settings for eth0:
        Supported ports: [ TP ]
        Supported link modes:   10baseT/Half 10baseT/Full 
                                100baseT/Half 100baseT/Full 
                                1000baseT/Full 
        Supported pause frame use: No
        Supports auto-negotiation: Yes
        Advertised link modes:  10baseT/Half 10baseT/Full 
                                100baseT/Half 100baseT/Full 
                                1000baseT/Full 
        Advertised pause frame use: No
        Advertised auto-negotiation: Yes
        Speed: 100Mb/s
        Duplex: Full
        Port: Twisted Pair
        PHYAD: 2
        Transceiver: internal
        Auto-negotiation: on
        MDI-X: on (auto)
Cannot get wake-on-lan settings: Operation not permitted
        Current message level: 0x00000007 (7)
                               drv probe link
        Link detected: yes

> I have been using 'iperf' lately for bandwidth testing.  Just getting
> a GigE connection does not mean that I get full wire speeds out of it
> end to end.  So it is good to have an objective tool to test.
> 
>   $ iperf -s
>   ...
>   [  3]  0.0-10.0 sec   904 MBytes   758 Mbits/sec

If I understand correctly, I need a second machine to test with iperf.
But I no longer have one here locally. I had done a speedtest.net test
and got something around 93 Mbps for d/l, while I had got 260 Mbps
back in June. Of course, this isn't necessarily meaningful as not
completely local, but this seems to match the 100 Mbps limit.

-- 
Vincent Lefèvre <vincent@vinc17.net> - Web: <http://www.vinc17.net/>
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Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)


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