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FrantzCollini08
Contributor
Contributor

Ethernet Speed problem with single VM

Hi to all,

I have a vmware 3.5 infrastructure installed and i've created 5 VMs.... The ethernet in vmware negotiated at 1000Mbps or 100Mbps, so my VMs virtual ethernet controls negotiated at 100Mbps o r 1000, but only in one VM is verifing a problem with speed: this one negotiated at 10Mbps :S

For me it's a big problem because this VM is the principal production server and it has a lot of data traffic...

my question is: why this VM negotiated at 10Mbps?? I checked all possible network configurations and everything is ok...

How can i manually change the speed link of my virtual ethernet control? is it dangerous do it?

each response will be much appreciated...

Thanks in advanced

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2 Replies
FranckRookie
Leadership
Leadership

Hi Frantz,

For the physical cards on the ESXs, you must:

- configure the speed to 100Mbps/full for cards connected to 100Mbps/full port on physical switches

- configure the speed to Autoneg for cards connected to 1000Mbps

For the VMs, they should always be set as autoneg. You can not change the speed of the vNic from the VM configuration. You can have a look inside your VM in case there is an old hidden network card. You can also try to reinstall VMware tools.

Regards

Franck

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AWo
Immortal
Immortal

my question is: why this VM negotiated at 10Mbps?? I checked all possible network configurations and everything is ok...

What the virtual guest thinks about network speed is not important. If you use any virtual network card adapter type other than "vlance" (which emulates the AMD PCnet32 adapter), you're find. Install the VMware Tools in the guest to have the correct driver in place.

The guest doesn't negotiate with the physical components of your network. It runs always at maximum speed which is limited by the CPU power of your host.

As soon as the packets from the guest hit the physical network adapter assigned to the virtual switch, the physical network speed enters the game. The physical adapter in your host should be configured accordingly. For 100 MBit/s I suggest to set both, the NIC and the swicth port to 100 MBit/s FDX.

How can i manually change the speed link of my virtual ethernet control?

You can't as it is not necessary, doesn't make sense and is not possible.


AWo

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