This paper dedicated to SDN modeling and analysis. We analyze the packet delivery time and propose the method to redu?e it. We consider delay of packets in SDN switch caused by the processing time. The proposed model represents a packet delay as time which is necessary for the searching in the routing table. Processing time depends on the routing table size and its structure. In this paper, we propose a method for configuring the OpenFlow switch buffer, which allows to reduse processing delay and improve the switch throughput. © 2017 Association for Computing Machinery.