Research And Implemention Of VLAN Technology

The future of the "last-mile" belongs to Ethernet because of its low cost,high-speed and powerful functions, while switch plays a very important role in constructing high performance networks. It makes the workstations attached to the network need not to share the bandwidth with one another. It can also eliminate the pointless collision detection and retransmission in the network to improve the efficiency of data transmission.However the traditional switch also has its weak points: inability to restrain broadcasting storm,internetworking of different networks and security control. VLAN technology is put forward to devide broadcast domain,which can alleviate the broadcasting storm, facilitate the network management and improve the security. How to assign vlan and how to exchange VLAN information between switches are the two key problems in VLAN implementation.I participated in a Layer-3 switch project,designed and implemented VLAN technology and a layer-2 multicast module in a layer-3 switch with 24 100M Ethernet ports and 2 1000M Ethernet ports. I also put forward my solution in VLAN assignment and multicast VLAN. The following are the main contributions of this dissertation.1 .Implemented the port-based VLAN and GVRP in the layer-3 switch. I have finished the VLAN operation and solved two problems in GVRP implementation:state machine design and timer design.2.Designed and implemented multicast VLAN in switches with IGMP Snooping technology, Multicast VLAN maps a group of hosts in an IP multicast group to a group of ports in a VLAN, and makes the distribution of multicast data by VLAN. This dissertation also brings forward a solution to manage multicast VLAN.3.Put forward a mechanism named DVMM (Dot1x-based VLAN Management Mechanism) to assign VLAN dynamically on switch ports based on user identity.4.A protocol named AVMP (ARP-based VLAN Management Protocol) is proposed to assign and learn VLAN dynamically on switch ports. This protocol can assign VLAN according to users' IP address automatically.