An Inter-Domain Data Transferring System Based On Para-virtualizing Device Model

Recently, virtual machine technology has experienced a rebirth of popularity due to its many excellent features such as performance isolation, server consolidation and so on. However, the natural isolation property of VMs makes it excruciatingly difficult for the virtual machine to communicate with each other. TCP/IP approach is a feasible way to solve the problem, but this method cannot ensure high reliability and low latency for data transferring, the quality of which is still badly affected by the network situation. Moreover, under the virtual network environment, data is transferred by the virtual network device not by the original network device, which makes the quality of data transferring much harder to guarantee. At last, the network itself can be easily attacked under virtual environments.Therefore, a para-virtualizing device model based inter-domain data transferring system (IDTS) which supports bidirectional communications is developed. The most prominent feature of this system is that it is fully network-bypass, and explores the facility of memory sharing mechanism to realize bidirectional inter-domain data transfer instead of using traditional TCP/IP approach. What's more, it not only supports domain-to-domain communication, but also supports domain-to-domains communication, which makes IDTS much more popular among applications. From the view of system architecture, it is comprised of three layers, including transmission layer, device driver layer and tunnel management layer. Transmission layer plays a very important role to bridge the gap between applications and device driver layer. It is responsible for providing data information and control information for applications which communicate with each other in different domains on the same physical machine. Device driver layer is the core of whole system, because it provides interfaces for transmission layer to access the two shared memory regions which functions as data tunnel and control tunnel in our system. At the same time, task management and schedule part is developed to help backend VM to manage connected frontend VMs, organize read/write requests sent by frontend VMs and schedule these requests with proper policy. Tunnel management layer is also very important to support the communication of device driver layer. It is responsible to setup tunnels for domains which want to communicate with each other, and destroy tunnels when communication is finished. Shared memory regions and event channels are created when tunnels are set up, and freed when tunnels are destroyed.Compared with traditional TCP/IP approach, IDTS is much more secure and efficient. Our evaluation demonstrates that IDTS can reduce inter-domain round trip latency by nearly a factor of four, and throughput has been increased by 6.2 times and 1.2 times respectively when the data is transferred from the backend domain to the frontend domain and from the frontend domain to the backend domain, compared with traditional TCP/IP approach. In the final analysis, we can easily come to the conclusion that the overall performance of the system is much superior to that of TCP/IP network.