Duplex Mode???

[MrVmware9423]

Dear Team,

one of my vmnic shows me 100 half duplex if i set the same to Auto Negotiate, for 100 FUL i have to  forcefully harcode to 100FULL then it shows vmnic 100 FULL duplex. Can u please help me what will be the problem

Regards

MrVMware

[Troy_Clavell]

what is the physical switch setup as?

[jjkrueger]

General practice, when you hard set speed and duplex on a NIC, is to also hard set the same value on the physical switch port.

Link speed and duplex autonegotiation has given folks fits for ages.

[rickardnobel · Accepted solution]

A possible reason is that the switch port is set to hard full duplex, this will make your esxi to enter half mode when using auto.

[MauroBonder]

When using fast ethernet the recomended is set: (vmnic and port of switch core)

Fast Ethernet – 100 MB /Full Duplex <-> 100 MB /Full Duplex

reference: http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=100408...

[abirhasan]

Please make sure that you have configure full duplex in the both side of your connection. If you configure one side half duplex and other side full duplex it won't work full duplex.

abirhasan   

[rickardnobel]

abirhasan wrote:

Please make sure that you have configure full duplex in the both side of your connection. If you configure one side half duplex and other side full duplex it won't work full duplex.

It will be even worse than that: the feared duplex mismatch - which will create very very bad throughput.