Design And Research Of Campus Network Interconnection Based On IPv4 Tunnel

China has always attached great importance to the upgrade of the campus network.It hopes that the next generation campus network supports IPv6 multifunction.But the overall migration of the IPv4 network to the IPv6 network is a gradual process and the coexistence of the two networks in the transition process will last for a long time.Therefore,the interchange of IPv6 interworking must cross the IPv4 public network.Reasonable exchange program can be conducive to promoting the upgrade of the campus network and ensure the coexistence of stable and orderly manner.In the widely used transition mechanism,the tunnel technology because of its simple principle and without the need for large-scale equipment upgrades was highly concerned.However,according to the study,it is found that the past tunnel scheme was limited to the purpose of realizing isolated communication and had no synchronization security policy.More importantly,it did not consider the impact of MTU differences on tunneling packets.This is a potential threat to the campus network communication and has become the biggest obstacle to the application of tunneling solutions.This paper fully considers the interdisciplinary demand and the shortcomings of the tunnel transition scheme,then designs and implements the IPv6 over IPv4 manual tunnel interconnection scheme.The main contents and innovations of this paper are as follows:1)Because of the ability of the chip,it does not support the secondary search of the tunnel routing.This article uses the way to create a business loopback.At the same time,the principle of MTU discovery mechanism is studied,and two different MTU configuration schemes are proposed.With reference to the three-layer forwarding process of tunnel packets,the MTU is set up in the service loopback port,which reduces the unnecessary fragmentation.2)The campus network carries a large number of data exchange,so the bandwidth has a higher demand.In order to improve the export bandwidth utilization of the campus network,this paper proposes ECMP load balancing and support for querying ECMP configuration on board.Unlike the traditional ECMP,the two-layer IP header of the packet in the tunnel mode can be selected to participate in the operation.3)The tunnel interchange scheme with security strategy proposed in this paper.Firstly,this program gives full play to technology of VPN for its security isolation networking advantages.Besides,it is proposed to create VPN instances and bind it with the tunnel,so that the tunnel channel is intended for users.Secondly,it is proposed to turn on u RPF globally based on the tunnel mode,which effectively prevented source address spoofing attacks.This paper first analyzes the three common transition mechanisms and compares IPv6 over IPv4 manual tunnels and automatic tunnels.Then,the related technology in the system is reviewed,and the overall architecture of the system is summarized based on the analysis of the demand of campus network interconnection.This paper focuses on the design and implementation of the tunnel module,the tunnel-based ECMP load sharing module and the u RPF module in the driver layer.Finally,in this paper it simulates the campus network communication scene to build a test environment.Then the system has a connectivity test and comprehensive functional module unit test to ensure the feasibility and reliability of the program.