There is the added complication of VM life cycles moving from months/years to weeks/days. So basically, port management is increasingly difficult. Have a look at the following diagram for more details:

The following are some major problems with role issues:

• VMs can result in bridging loops on the network
• VMs could be on the wrong VLANs
• No insight into VM to VM communication is available
• The network admin has no visibility or policy/VLAN control