Architecture and algorithms for virtual routers as a service

The deployment of virtualized network resources has the potential to spur new business models and increase flexibility for network customers as well as infrastructure operators. It is worthwhile to re-evaluate how to effectively express traditional network elements in the virtualization domain. In this paper we consider network routers and argue that the representation of routing functionality as a service, rather than an isolated virtual resource is better suited in the virtualization context. We present an architecture enabling physical infrastructure operators to provide routing as a service. To this end, distributed forwarding elements are combined to appear a single virtual router instance which routes traffic between a set of customer points of presence. We provide embedding algorithms for virtual router topologies with minimum allocation cost. We consider the customer´s geographical attachment to the network, bandwidth demands as well as capacity constraints in the core substrate. Moreover, we present a live-migration approach for the virtual router data plane which allows network operators to quickly adapt resources to changing network demands.