  Network virtualization offers flexibility by decoupling virtual network from
the underlying physical network. Software-Defined Network (SDN) could utilize
the virtual network. For example, in Software-Defined Networks, the entire
network can be run on commodity hardware and operating systems that use virtual
elements. However, this could present new challenges of data plane performance.
In this paper, we present an empirical model of the packet processing delay of
a widely used OpenFlow virtual switch, the Open vSwitch. In the empirical
model, we analyze the effect of varying Random Access Memory (RAM) and network
parameters on the performance of the Open vSwitch. Our empirical model captures
the non-network processing delays, which could be used in enhancing the network
modeling and simulation.
