Routing optimization for live VM migration between datacenters

Virtual Machines (VMs) and network virtualization technologies have been widely used for cloud computing. Active VMs can move to other execution environments, an action called "live migration." VMs must have the same IP address before and after migration. Therefore, live migration must be in the same segment. For this reason, network virtualization technologies are used to make a wide area L2 network between data centers (DC). Such L2 networks have a redundant route problem resulting from the distance between a particular VM and the default gateway. To solve this problem, each DC has a default gateway and VMs use the nearest default gateway. However, if live migration is used, the VMs' nearest default gateway changes. In this paper, we explain these problems, and propose solutions to change to the proper default gateway.