Distributed Cloud Computing Environment Enhanced with Capabilities for   Wide-Area Migration and Replication of Virtual Machines
  When a network application is implmented as a virtual machine on a cloud and is used by a large number of users, the location of the virtual machine should be selected carefully so that the response time experienced by users is minimized. As the user population moves and/or increases, the virtual machine may need to be migrated to a new location or replicated on many locations over a wide-area network. Virtual machine migration and replication have been studied extensively but in most cases are limited within a subnetwork to be able to maintain service continuity. In this paper we introduce a distributed cloud computing environment which facilitates the migration and replication of a virtual machine over a wide area network. The mechanism is provided by an overlay network of smart routers, each of which connects a cooperating data center to the Internet. The proposed approach is analyzed and compared with related works 
Young-Chul Shim
cs.DC