The Measurement Mechanism Of Software Defined Network Based On Openflow

Faced with various problems in the process of SDN technological innovation,a fast and accurate SDN measurement against the underlying forwarding behavior of switches is still the most important demand of researchers.Current research of SDN network measurement mostly focus on the study of the mechanism for measuring traditional network status parameters,and lack research on mechanism for measuring the forwarding path of network traffic.In this paper,secondary development is made on OpenFlow1.0v protocol APIs and we propose a measurement mechanism aimed at measuring the real forwarding path of specific production traffic based on OpenFlow protocol.The main innovations in this paper are as following:1)Since forwarding based on "flow" is the core feature in SDN,this mechanism provides customization against "flow" features for different measurement objects.This mechanism makes full use of SDN's programmable feature and provides administrator measurement REST APIs,users can call REST APIs to specify the measurement object which satisfies specific "flow" characteristics.These APIs can customize the"flow" features range from layerl to layer4 of network and they also cover the whole 12-tuples of OpenFlow.All of above make this mechanism possible to measure forwarding path for different production traffics.2)This mechanism takes advantage of active measurement,the SDN controller measures forwarding path by sending probe packets to the forwarding plane.This mechanism makes full use of SDN's centralized control feature.After obtaining the measurement parameters delivered through REST APIs,the controller constructs probe packet according to the measurement parameters and sends the probe packet to the specific switch.Then the controller can get the feedback path info from switches because of the pre-installed flow tables in every switch along the forwarding path,finally the controller will get the whole forwarding path info.3)This mechnism can be deployed in different network scences such as SDN LAN and SDN WAN.It has the muli-scence applicability.And it can be used to measure WAN forwarding path after only a simple and small change on original LAN measurement design.In this paper,we propose a detailed WAN measurement design to prove this.