Link Multiplexing in a Xen-based Network Emulation System

Network emulation has gained wide interest in the community of network researchers to evaluate the effectiveness of new protocols and applications in controllable and realistic network scenarios. To ensure scalability, modern emulation systems rely on the use of virtualization techniques to create complex networked systems by means of the computational resources available in a cluster of computers. In the context of network emulation systems, link multiplexing is the problem of emulating multiple point-to-point connections on top of a single Ethernet link. In this paper we present how link multiplexing is implemented in NEPTUNE, a Xen-based network emulation system developed at University of Napoli Federico II. We compare our technique with those adopted in other network emulation systems. We also present experimental results aimed at investigating the performance limits of our system and at providing researchers with useful insights into the faithfulness of emulated scenarios.