Quality-of-Service Signaling for Virtual Networks

Network virtualization is a promising abstraction technique, not only to optimize the utilization of network resources, but also to design and actually bring out completely novel network architectures and protocols [1]. Such a virtual network consists of virtual nodes that are interconnected by virtual links. Thus the virtual network builds its own logical overlay structure on top of the physical “substrate”, i.e. the underlying real physical network. Virtual links are, however, mostly configured statically, or do not provide Quality-of-Service (QoS) guarantees along the entire substrate path or are limited to a specific administrative domain. While there are lots of different link virtualization technologies in the substrate available (from Virtual LANs to MPLS LSPs), we consider in this paper an IP-based substrate as well as also inter-provider, inter-domain virtual links. In order to setup and configure virtual links dynamically and on-demand between providers, signaling protocols are needed. The Internet Engineering Task Force’s (IETF) Next Steps in Signaling (NSIS) framework already provides an up-to-date signaling protocol suite that can be used for various different signaling applications [2], e.g., for QoS resource reservations. In our approach we combine the signaling for QoS guarantees (i.e., resource reservation) in the substrate with the virtual link setup signaling to reduce the time required for virtual link set up. In this paper, we examine how the NSIS QoS NSLP protocol can be extended in order to be used for virtual link signaling. We discuss the advantages of using a path-coupled signaling model as it is used by the QoS NSLP protocol. We then describe potential challenges and problems that arise in the context of virtual networks and provide a set of possible solutions.