Implementation Of GRE Tunnel On Distributed Switches

GRE tunneling technology is a three-layer packaging technology, it is a networkprotocol used to transmit data to another network protocol, a virtual point to pointconnection technology. On switches and routers, tunnel technique performs as a tunnelinterface; a virtual tunnel interface is working at the network layer as the globalinterface. A complete tunnel packet forwarding process, including closing the switchhardware package, delivery to driver, and the packet will be sent to the tunnel kernelmode packet processing parts.Paper first analyzes the tunnel with the GRE protocol itself and the tunnel scenario.Analysis of the switch software platform interface management, FIB, ADJ and otherfunctions associated with the tunnel module, ensure the interface message to create thetunnel interface and make tunnel link state up, make sure of encapsulation andde-encapsulation packet processing requirements.Use the interface control module andmessage mechanism to design and implementation of the tunnel creation and tunnel linklayer up function,use the ADJ function to design the tunnel encapsulation function,usethe protocol stack to design the de-encapsulation function. The next simulationenvironment for distributed packet forwarding, construct and execute test cases to verifythe correctness of the tunnel module. Finally, make a summary of the content of thepaper.