[CentOS] 3Com 3c940 moel only giving me 100 mb throughput to network switch
Gilbert Sebenste
sebenste at weather.admin.niu.edu
Mon Nov 23 18:59:59 UTC 2009
On Mon, 23 Nov 2009, Les Mikesell wrote:
> Gilbert Sebenste wrote:
>> Hello all,
>>
>> As the subject states, I have a 3Com 3c940 Ethernet card to a 1 gb network
>> switch. The switch detects it, but it only shows that it is giving me 100
>> mb/sec throughput. That card is rated for 1 GB...is there a way to force
>> it to try to use 1 GB/sec? System-config-network isn't helping me here.
>
> Does ethtool say it is running at 1Gb? What is the source of the data?
> Many things can't generate much more than 100Mb, especially going too
> or from a disk.
Nope, it says at 100 mb. I wonder why? Yep, I know I can only probably go
somewhat faster, but it would be nice. Here's ethtool's output before I
did something below...
ethtool eth0
Settings for eth0:
Supported ports: [ TP ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Advertised auto-negotiation: Yes
Speed: 100Mb/s
Duplex: Full
Port: Twisted Pair
PHYAD: 0
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: g
Wake-on: d
Current message level: 0x00000037 (55)
Link detected: yes
But then I tried this. Typing:
ethtool --change eth0 speed 1000 duplex full autoneg on
DID work! But I wonder why it didn't pick up on that automagically.
ethtool eth0
Settings for eth0:
Supported ports: [ TP ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Advertised auto-negotiation: Yes
Speed: 1000Mb/s
Duplex: Full
Port: Twisted Pair
PHYAD: 0
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: g
Wake-on: d
Current message level: 0x00000037 (55)
Link detected: yes
And thanks, Les, for the ethtool reminder/tip!
*******************************************************************************
Gilbert Sebenste ********
(My opinions only!) ******
Staff Meteorologist, Northern Illinois University ****
E-mail: sebenste at weather.admin.niu.edu ***
web: http://weather.admin.niu.edu **
*******************************************************************************
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