Research And Realization Of VLAN Switch Mode On EPON

The development of access network technology has always been the most active network technology, The fact that the access network located closest to the user make access network need continually meet customers'demand of a variety of services, bandwidth capacity, speed and so on. At present, EPON is the most mainstream optical access technology in our country, which takes on the characteristics of low cost, high flexibility, good expansibility. OLT, with access and aggregation ability itself, is the most important optical access network equipment. Taking optical fiber as transmission medium, OLT has considerable competence on the transmission distance and bandwidth capacity. Therefore, taking OLT replace the traditional DSLAM device, is not simple supersession on the two aspects of function and network location. Nowadays, the coverage capacity of OLT has gone beyond the scope of optical access network, and extended toward the layer 2 aggregation network. Thus, OLT breaks the boundary between optical access network and layer 2 aggregation network, makes the two networks present the tendency of network amalgamation. To a certain degree, OLT urges the network's level turn much flater, clearer, and simpler.The first chapter of this paper firstly introduced the application status and development trend of optical access network at home and abroad, as well as the domestic mainstream optical access technology EPON, analyzed the key technologies of layer 2 aggregation network, pointed out the superiority of optical access technology compared to the traditional DSL copper technology, as well as the integration direction of optical access network and layer 2 aggregation network; The second chapter focus on the network location of OLT equipment, and analyzed the practical significance and specific practice of OLT replacing the aggregation switch from the aspects of device capabilities, network model and the cost; The third chapter described virtual LAN technology and a few data frame format, which was inserted tag information, illustrated the application methods and feasibility of these VLAN technologies in Ethernet of carrying the traditional layer 2 special line business; The fourth chapter described the Ethernet-based converged network architecture of TR-101, along with the realization method of VLAN switching technology on OLT, stressed the tag adding approach for OLT to achive the transmission of different business; The fifth chapter described the FPGA implementation of VLAN exchanging on OLT from the aspects the FPGA model and RAM selection, pipeline design, and gave the results of circuit synthesis and timing analysis finally; The sixth chapter is the summary and prospect of the whole paper.