One key requirement for achieving network virtualization is resource isolation among slices (virtual networks), that is, to avoid interferences between slices of resources. This paper proposes two methods, per-slice shaping and per-link policing for network-resource isolation (NRI) in terms of bandwidth and delay. These methods use traffic shaping and traffic policing, which are widely-used traffic control methods for guaranteeing QoS. Per-slice shaping utilizes weighted fair queuing (WFQ) usually applied to a fine-grained flow such as a flow from a specific server application to a user. Since the WFQ for fine-grained flows requires many queues, it may not scale to a large number of slices with a large number of virtual nodes. Considering that the purpose of NRI is not thoroughly guaranteeing QoS but avoiding interferences between slices, we believe per-slice (not per virtual link) shaping satisfies our objective. In contrast, per-link policing uses traffic policing per virtual link. It requires less resource and achieves less-strict but more-scalable isolation between hundreds of slices (500 to 700 slices in estimation). Our results show that both methods perform NRI well but the performance of the former is better in terms of delay. Accordingly, per-slice shaping (with/without policing) is effective for delay-sensitive services while per-link policing may be sufficiently used for the other types of services.
2013 The Institute of Electronics, Information and Communication Engineers