Research And Implementation Of Spanning Tree Protocol On EOC Switch

At present, the two-way transformation of cable TV network is imperative. In the two-way transformation of cable TV network, a scheme based on EPON + EOC has been widely applied, a coaxial Ethernet access device is required in this scheme. As a coaxial Ethernet access device, EOC Switch consists of data switching module, CATV module and data/TV signal hybrid multiplex module. Data switching module is similar to a network switching equipment in Layer Two, and Spanning Tree Protocol is needed to eliminate data loops in the LAN networks. Spanning Tree Protocol is the basic protocol of network equipment in Layer Two, distributed computing is used to make the structure of network active topology like a tree. So it can ensure the active topology is loop free and avoid broadcast storm brought by loops and repeated receiving of frame. In this paper, Spanning Tree Protocol is studied and realized on the data switching module.Firstly, this thesis introduces the hardware platform of data switching module, based on S3C4510B processor, using IP1717 and IP108A as core switching chips, depicts the software system architecture of data switching module and the configuration and transplantation of uClinux OS, the implementation of MII management interface which is related to STP is described. Secondly, the theory of STP is expatiated based on IEEE 802.1D, and the implementation of STP on specifically hardware and software platform of data switching module is elaborated detailed. The implementation of STP is divided into STP initialization, protocol information configuration update, BPDU transmitting and receiving, port status setting, protocol parameter configuration and timer expired sub-modules functionally, sub-modules are organized by internal function calls, and the communication with other external modules are realized by message queue.The implementation of STP has been tested from protocol initialization, Topology Change Notification BPDU received and protocol parameter configuration three respects. The test results show that the function of STP has been achieved basically.