US Patent 9397943 Configuring virtual media access control addresses for virtual machines

A network management apparatus according to an example may configure virtual Media Access Control (MAC) addresses for virtual machines (VMs). A virtual MAC addresses may include a Uniqueness identifier (ID), a DC ID, a Device ID and a Host ID. A number of bytes of the virtual MAC address may be equal to a number of bytes of an actual MAC address of the VM. VMs accessing the same access layer device in the same data center may have the same Uniqueness ID, DC ID, and Device ID and have different Host IDs. VMs accessing different access layer devices and in the same data center may have the same Uniqueness ID and DC ID and have different Device IDs.