Dynamic topology adaptation of virtual networks of virtual machines

Virtual machine grid computing greatly simplifies the use of widespread computing resources by lowering the level of abstraction, benefiting both resource providers and users. For the user, the Virtuoso middleware that we are developing closely emulates the existing process of buying, configuring and using machines. VNET, a component of Virtuoso, is a simple and efficient layer two virtual network tool that makes these virtual machines appear to be connected to the home network of the user, simplifying network management. Overlays like VNET have great potential as the mechanism for adaptation. Here, we describe our second generation VNET implementation, which includes support for arbitrary topologies and routing, application topology inference, and adaptive control of the overlay. We demonstrate that the performance of unmodified applications, in particular bulk synchronous parallel applications running inside the virtual machines and serviced by VNET, can be significantly (up to a factor of two) enhanced by adapting the VNET topology and forwarding rules on the fly based on intelligent application traffic inference methods. The adaptation scheme requires no knowledge or participation from the user or application developer.