Research And Implementation Of Forwarding Technology In Routing Cooperation Network

With the increasing complexity of network and commercialization of its application, demands of new businesses on QoS,multicast,mobility,and security in IP network are becoming stronger and more specialized.Easy routing architecture of the IP packet has been proved its inability to carry these strictly demanding business.In the gradual evolution process of Internet,we have found more and more weaknesses and shortcomings,which is the result of its rigid organization.To solve this problem,self-organizing network and overlay network became the focus of researching.Overlay network uses the existing Internet as the a virtual network for its transport layer and builds a self-organizing network on it,which means that we treat existing Internet as a bottom and make new business-oriented features of network deployment and support on top layers.In current solutions for overlay network implementation,taking RON(Resilient Overlay Network,flexibility in coverage) as an example,full-mesh of virtual connections are established between each node with adopting link state routing algorithm,which gets and publishes link performance information by sending frequent flooding link detections. This solution inevitably will lead to the cost of network bandwidth and cause expansibility questions,which limits Overlay Network's scale.In order to solve above problems,we seek to build a foundation for self-organized network on existing Internet which can expand flexibly.And we also study the corresponding mechanism of ad-hoc networks,distributed self-healing routing protocols with traffic adaptive dynamic resource management and distribution technology in the large-scale network management to reduce network maintenance costs.Our implementation proves that the surviving nodes can be automatically formed new topology quickly in order to protect the reliability of communications,real-time and manageability when some nodes are ineffectiveWe propose a direct-to-end business performance optimization overlay network architecture named RCN(Routing Cooperation Network) system.The characteristic of it is: the application of user terminals can select transmission path actively so as to enhance the transmission quality,which aims at resolving the different QoS requirements from various businesses,and enhance network robustness.The methods of RCN optimizing routing and improving business transmission are: conforming the path with better performance among the pre-selected ones through path detecting and once the transmission path being used is not meet QoS requirement any longer,the backup one is chosen at once.Moreover,in RCN,we have adopted a one-hop forward strategy.No matter for the pre-selected paths or the substitute ones,suitable mid nodes(ie.neighbor node ) to forward packets must be found.RCN system divides all nodes into three layers based on end-host processing performance and the export bandwidth:top overlay is responsible for deploying high-performance server in each ISP's AS for RCN and providing system maintenance and forward information services;Second class overlay nodes are the high-performance user ones using RCN system such as servers and workstations.They not only use RCN system to optimize network performance,but also assist RCN servers in business forwarding;First class overlay nodes are the normal user ones using RCN system such as personal computer terminals.The ones which do not meet the forward part of the system performance requirements only receive the services provided by RCN.RCN system includes RCN client and RCN server.Server is mainly responsible for RCN neighbor distribution and node management,which is corresponding to the top Overlay nodes;RCN client is used for controlling the system in selecting path and forwarding messages during carrying out the path of survivability and routing optimization. RCN client is corresponding to first and second class Overlay Node Overlay.The research focus of this paper is RCN client network layer(RCN-CN).Its main function is when a user wants to optimize transmission for a application,if the current network performance dose not meet the needs of user,RCN-CN will automatically re-route the data packets to transmit them through better performance path.RCN-CN is comprised of routing forwarding module,performance monitoring module, data encapsulation/un-encapsulation module,internal communication module and QoS controlling and management module.Route forwarding module sends the optimized packets to original destination through the forwarding nodes.For sending nodes,it is necessary to redirect the packets to forwarding nodes;For forwarding nodes,it is necessary to know the original destination of the packets;For the receiving node,it is necessary to know the original source of the packets.Data encapsulation / un-encapsulation module provides services for routing forwarding module and performance monitoring module.It will add the necessary information in transmission to IP options,implementing data encapsulation at sending node and data un--encapsulation at the receiving node.Internal communication module provides interface between RCN application-layer application and network-layer application for communication between user space and kernel.QoS controlling and management module is mainly used to optimize the transmission quality of the traffic control and shaping;when the network load or congestion,ensure that essential business data will not be delayed or discarded;guarantee the performance of forward nodes. We implement RCN client prototype under Linux.Netlink is used for internal communications,which is between kernel module and user space modules.Netfilter is used for packet capture and modify when network performance is decreasing.The use of tc and iptables achieve QoS control and management,implementing network optimization through priority classification,queue scheduling,traffic shaping and congestion control.However,our system has some shortcomings such as the RCN client is developed on Linux platform,but Linux is not like Windows for the vast majority of ordinary users, Therefore,in order to popularize RCN client system,first of all we must transplant RCN client to Windows.If the subject-oriented network performance optimization of terminal RCN system can successfully transit to industrialization,in the product market we will have many potential users,such as end-users,all types of ICP Internet service providers,ISP providers, value-added services platform and so on,not only can protect the reliability of network communication with help of our system,but also save the cost of server deployment, expanding profit margins for businesses and means significantly for the advancement of Internet in China.