Default VIM status as "Active" vs "Reachable"

Hi,

When devstack is deployed with tacker, i see that the default VIM status is "Active" in VIM Management. When sample NS is deployed it fails. However when the same VIM is added with a different name, the status becomes reachable. Could someone throw some light on the difference b/w VIM status as Active and reachable. Is there any knows issue that we cant deploy NS when vim status is active..

Thanks...