VMs loose network after Vmotion

Hi,

This is frequent in my virtual environment, VMs loose network after vmotion.and Once I disconnect and reconnect the vNIC, it fixes the issue.Details below : -

VM H\W version = 7

Host = ESXi 4.1

VMtool = Updated

I have VDS and standard switches both in question . Checked some basic settings such as "Notify switch" is set to YES on Standard switches.

Any other suggestions ?

Thanks in advance !