基于控制信息集约的SDN流表更新策略

在控制器带内模式下，为减小流表更新时间，简化流表下发过程，提出了基于控制信息集约的流表更新策略。从路径创建和路径切换2种场景讨论流表更新过程，引入源路由机制和跟踪包机制，集约化流表更新报文形式，统筹规划下发方式，旨在保证流表更新的一致性的同时，降低控制器端的收发信息量和更新时间。仿真实验表明：在不同链路时延和传输速率的条件下，更新策略相较于基于分类的更新策略(C-FUS)和基于路径及反馈的更新策略(PF-FUS)，流表更新时间大大降低，更新过程不会造成较大的网络传输波动；更新策略下的控制器端收发信息量与PF-FUS相近，都远低于C-FUS。

A Control Message Intensive Strategy Based Flow Table Update for SDN

In the controller in-band connection mode, a control message intensive based flow update strategy is proposed to reduce the flow table update time and simplify the process of pushing flows. The flow table update is discussed from two aspects, i.e. path creation and path switching. The source routing and tracking packet are used to intensify the form of flow table update message and plan the way to send it. This strategy is aimed at guaranteeing the consistency of the flow table update and simultaneously reducing the amount of information of controllers receiving and sending and updating time. The simulation results show that rather than classification based flow update strategy and path and feedback based policy update strategy, by this strategy the flow table update time is reduced severely and no great fluctuation is caused in data transmission under different link delay and transmission rate conditions. In addition, the amount of information that controllers receive and send by this strategy is similar to PF-FUS, and both the amounts of information are lower than that of C-FUS.