On Table Resource Virtualization and Network Slicing in Programmable Data Plane

摘要

Recently, the advances on programmable data plane (PDP) promote the studies on the network virtualization in a PDP-based substrate network (SNT). In this paper, we address the table resource virtualization and network slicing in PDP-based SNTs. We first leverage the idea of "Big-Switch" to design an effective table resource virtualization scheme in which the flow tables of a virtual switch (V-SW) can be installed in multiple adjacent substrate switches (S-SWs) according to their table sizes, while the feasible table size(s) on each S-SW are determined based on the global information of the SNT. By doing so, we can regulate the flow tables in the S-SWs in a more organized way to minimize memory fragmentation. Next, we address the network slicing based on the virtualization scheme, and come up with a three-layer VNE problem. To the best of our knowledge, such a VNE problem has not been studied before and the existing algorithms designed for traditional two-layer VNE problems can hardly solve it. We formulate an integer linear programming (ILP) model to solve the VNE problem exactly, and also design a time-efficient heuristic that can provide near-optimal solutions. Finally, we implement the heuristic in TPVX, which is a network hypervisor based on protocol-oblivious forwarding (POF), and also improve its performance by introducing source routing. The new TPVX is experimentally demonstrated in a real network testbed, and the results verify that our proposal maintains the additional latency caused by the three-layer VNE well and would not degrade the network services in virtual networks (VNTs).