Design and Implementation of Virtual TAP for SDN-based OpenStack Networking

Currently, virtualization technology that enables a data center to efficiently use server resources is promising as cloud services are being prevalent with increasing traffic volumes and requirements for service quality. vTAP (Virtual Test Access Port), we propose in this work, can overcome the problem that existing hardware TAP devices cannot be used in duplicating inter-VM (Virtual Machine) packets being transmitted over virtual links. vTAP can be implemented using a virtual switch that provides network connectivity to VMs by switching packets over the virtual links. Port mirroring, or SPAN (Switched Port Analyzer), that is available in some software switches can be a naive solution but using it in a system that needs to treat a large volume of network traffic implies performance degradation in packet switching and error-prone manual configuration. In this work, we describe the design and detailed considerations on our OpenFlow-based vTAP implementation. It is based on Open vSwitch and ONOS (Open Network Operating System) SDN (Software-Defined Networking) controller to enable packet-level traffic monitoring in OpenStack environment. We also present the performance evaluation on our vTAP used in some network monitoring cases, with packet processing acceleration by DPDK (Data Plane Development Kit).