Performance Analysis of SDN Switches with Hardware and Software Flow Tables

Nowadays data centers are increasingly becoming larger and dynamic due to virtualization. Software-Defined Network- ing is the leading approach to network virtualization and flexible management. The wide variety of hardware imple- mentations have brought strong heterogeneity to the market of networking devices which are different in terms of Open- Flow features and performance. In this paper we address the issue of heterogeneity of four hardware OpenFlow switches by characterizing selected performance relevant parameters for the hardware and software flow tables. We characterize maximum size of hardware flow tables for each switch in- cluding the behavior of a rule promotion engine that moves the rules between tables. We show that in the worst case for- warding packets using software table decreases the through- put by two orders of magnitude (from 940 to 14 Mbit/s). Our results can help the developers of SDN applications to account performance limitations of hardware and software processing as well as limited hardware support for a specific rule types.