Research On Key Technology Of Rules Management In Software-Defined Networking

The ossified architecture of traditional network bring the challenge to net-work management and innovation. Thus, The industrial and academic commu-nity proposed many network innovations. The active networking was proposed by DARPA in 1990. The basic idea of the active networking is that some codes was added into packet. After receiving the packet, the node process it flexibly based the code. At the same time, OpenSig suggests that the programming in-terface should be provided so that the service provider can control the network through the middleware(e.g. COBAR). ForCES, PCEP and RCP proposed so-lutions separating the control and data plane of routing protocol. 4D proposed a solution that the control plane are separated from data plane and centralized.Referring to the solution mentioned above, Software-Defined Networking(SDN) become a result that the "white box" design is introduced into network,attract lots of attentions from the industrial and academic community. The func-tion of switch is only to forward the packet. The control functions of all switch are centralized logically into the controller. For dynamic network, the operator only need to configure the controller with high level policy that can response to the network change, not to configure the network device individually. SDN has great power to network innovation. Through programming, researcher can deploy new network function fast.OpenFlow consider both the object that SDN enables anything to be pro-grammed and the difficult in the deployment of SDN, enable the theory of SDN to be realised. The OpenFlow protocol has become the actually standard of communication between switch and controller, original view to network man-ager and researcher. However, many new problems have been brought with OpenFlow. For instance, how to design the programming language, how to de-cide the grain of the flow controlled, how to measure the flow, how to virtualize the network, even how to combine SDN and traditional network. The essence of these problem is how to manage the rules. For example, how to measure flow is to find a solution of rule placement under the constraint of network resource.This paper give first introduce the background and challenge of rules man-agement in SDN, then study how to place rules under the space constraint of flow table. The details are as following:1) Analyzing the upper bound of delay of combined SDN forwarding el-ement constituted by software and hardware SDN switch. The combined SDN forwarding element is an important method that resolve the problem of limit flow table . In combined SDN forwarding element, the character of the software and hardware switch and the cooperation between them decide that the packet delay which match rules in hardware switch is faster than the other packets. For analyzing the upper bound of delay of combined SDN forwarding element, the author propose a model of the combined SDN forwarding element first. Then,based on the arrival process of all flows entering the combined SDN forwarding element, the theorem related with network calculus are utilized , for example,Output Characterization, Leftover Service, Delay Bound, to analyze the delay of flow across the combined SDN forwarding element in the worst case. The simulation in NS-3 show that the error between the theory value based on net-work calculus and the experiment value of delay bound is very small, and show the effect of the number of software switch and the rule placement on the delay bound.2) Proposing a genetic-based rules placement algorithm for combined SDN forwarding element. In combined SDN forwarding element, there are only a part of flows that are allowed to be forwarded through fast channel because of limit flow table in hardware switch, and the choice about channel of any flow will affect the delay bounds of all flows. For guaranteeing the delay require-ment of the flow at combined SDN forwarding element, the author defines the Delay Satisfaction Degree for evaluating the delay guarantee level of the rule placement algorithm, formalizes the problem of rules placement in combined SDN forwarding element, proves that this problem is NP-hard, resolves this problem by the genetic based rules placement algorithm. The simulation shows that the algorithm proposed can get higher Delay Satisfaction Degree than the three other algorithm.3) proposing a time and space based rules placement algorithm. In addi-tion to the combined SDN forwarding element, the increase of utilization rate of flow table is also important method to solve the problem of the limit space of flow table. The timeout and wildcard match of OpenFlow can adjuster the flow table occupation of a rule at time and space respectively. Thus, they provide an chance to resolve the problem of limit space of flow table. Utilizing the time-out and wildcard match, many rules placement algorithms are proposed to im-prove the match rate of flow table. However, only one of timeout and wildcard schemes is exploited in existing algorithms so that the match rate of flow table can not be increased enough, and the ranges of application of the existing algo-rithms are limited. Thus, the author formalize the problem of rules placement utilizing timeout and wildcard match, propose the time and space based rules placement algorithm in which an rules placement solution are decided through considering together the sojourn time of rules in flow table and the match space of rules. The result shows that the algorithm proposed can improve the match rate of flow table and decrease the rate of packet refused.4) Proposing a SDN based network virtualization.Network virtualization can enable each tenant to have own network topology and to control it. In addi-tion, each virtual network can be adjust flexibly. Software-defined networking,especially OpenFlow, provide an open abstract interface of network device, im-prove the programmability. SDN based network virtualiztion architecture can integrated the advantages of SDN and virtualization, can promote the develop-ment of network. Although network virtualization in SDN has attract a popular attention, how to design SDN based network virtualization architecture is still an open problem. The author analyzes the design requirement of SDN based network virtualization architecture first, and then propose and SDN based net-work virtualization architecture, SDNVA. In SDNVA, the virtualization com-ponent are realized through the extent of OpenDayLight controller; exploring the support of OpenFlow for multiple flow table, the virtual pipeline is proposed and extended to combined SDN forwarding element; autonomic management schemes for physical network and virtual network are proposed. At last, it is verified in prototype that the resource isolation function of the virtualization component and the perception of virtual network for the change of physical network.