Study On Protocol Independent Network Programming And Its Environment Implementation

The programming environment of SDN provides users with a programming lan-guage to write network policies firstly,and then interprets these policies into SDN mes-sages which can be understood by the underlying forwarding elements(FEs).Finally,FEs create flow tables and deploy flow entries based on the interpreted messages to process the coming packets in the network.It is the programming environment that directly affects the control results of the entire network.A full-featured,easy-to-use programming environment will simplify the programming complexity,and improve the management efficiency.Most models of the existing programming environment are based on OpenFlow.However,users cannot write network policies to control arbitrary protocols because of the inflexibility of supporting new protocols of OpenFlow.Thus not only limiting the capability of SDN network to support specific protocols but also restricting the abil-ity of users to program deeply.Correspondingly,Huawei proposes Protocol-Oblivious Forwarding(POF)to solve the above problems exited in OpenFlow.POF evolves the concept of tuples to express protocol fields and provides a concise set of protocol obliv-ious instructions for better protocol expansion future networks.This paper presents PNPL:an efficient and dynamic programming environment which is based on POF technology.PNPL automatically generates forwarding pipeline for data plane according to the protocol specification and network policy written by users.PNPL uses parse graph instance to process every packet and maps the pro-tocol specification to framework of forwarding pipeline.Moreover.PNPL generates trace and extended trace tree to record the operations on metadata and Packet-In trig-gered network policy.In summary,we make the following two specific contributions:Firstly,we propose a protocol independent network programming mechanism,includ-ing designed prototype of forwarding plane and model of metadata/multi-table program-ming.This provides a wealth of programming abilities and solves the complexity issues that brought by POF.Secondly,we realize this mechanism and develop PNPL in real SDN network.We finally take some experiments to show the feasibility of the scheme through firewall policies,source routing,throughput and so on.