Virtual Networks Link-Layer Topologies Discovery through Host-based Tracing

The network link-layer topology, also known as the physical topology, describes the networking hardware devices, their corresponding placement, and the interconnection between them. Discovering and maintaining updated information about the network topology is of utmost importance for many protocols and monitoring tools. For instance, the algorithms of most routing protocols include modules in charge of the automatic discovery of the link-layer topology. On the other hand, network virtualization is one of the technologies that enable Virtual Machines (VMs) in a cloud platform to share the same physical network infrastructure. This technology has been one of the most important key players in the Cloud Computing industry. Unfortunately, research communities have put a modest effort into developing efficient algorithms capable of discovering the topology of Virtual Networks (VNs).In this paper, we address this issue and propose an approach to recover the link-layer topology of a VN from an execution trace. Our approach uses tracing techniques to collect data from the kernels of host machines. Since we limit the data collection only to the host machine, this approach is completely transparent to VMs. Furthermore, we propose a prototype framework that implements our approach.