网络环境与实现翻译的

E-Learning environment network With the rapid development of network technology, especially digital campus and the construction of educational information needs of the campus network have become increasingly demanding. In terms of speed, campus network backbone speed increase from the first 100 Mbps to 10,000 Mbps (10 Gbps). In the agreement, from past to upgrade to the IPv4 IPv6. In the segment has also been a qualitative breakthrough: from the early development of the shared medium local area network to the current switched LAN. Switched LAN technology enables bandwidth of dedicated users as opposed to greatly improve the efficiency of local area network transmission. In addition, such as the broadband intelligent network, intelligent optical networking, optical fiber communication network and softswitch technology, new network technologies are emerging. Were given the following set

1 Multi-layer switching technology park network network. Convergence layer generally far away from the network center, the need for dozens of buildings a few blocks or access switch convergence, for a regional networking. Access layer generally located within a building, or the floor for Gailou computer terminal network. As the more complex the structure of the campus network, the management be more number of computers, in order to better manage the network, improve network efficiency, the layered switching technology involved. Among them, the third layer switching technology is operational in the third layer network protocol is a routing device and can be played to understand the role of the routing decision; fast, almost to the second tier exchange rate. Here, we discuss an example of a park should be considered in network design and network switching elements. The current network architecture with layered structure are: core layer, convergence layer and access layer. From the network protocol level can be divided into the first layer, second layer, third layer .... The structure of the network system, the core layer in the network engine room, responsible for the management of the entire campus network. Convergence layer generally far away from the network center, the need for dozens of buildings a few blocks or access switch convergence, for a regional networking. Access layer generally located within a building, or the floor for Gailou computer terminal network. As the more complex the structure of the campus network, the management be more number of computers, in order to better manage the network, improve network efficiency, the layered switching technology involved. Among them, the third layer switching technology is operational in the third layer network protocol is a routing device and can be played to understand the role of the routing decision; fast, almost to the second tier exchange rate.

1.1 Flat Bridge Network The first park is considered the single LAN in the number of new users added to the formation. This LAN is a network device connected through the physical or logical lines with a network. In such a network, all network devices to share the 10 Mbps half-duplex Ethernet bandwidth available. At this time, the whole network is a conflict domain, because all network devices can listen to the network to transmit data packets will have conflicts, and therefore the introduction of CSMA / CD collision detection mechanism to plan the network data transmission. When a conflict domain data transfer has become very crowded, usually we should add a bridge. Bridge is a store-forward type of data packet switches, which the whole network into several collision domains, to reduce packet collisions, increase the transmission efficiency. Bridge will not end the isolation network broadcast, multicast, and multicast data, that is, all bridge networks throughout the campus network is a single broadcast domain. This poses a problem of data circuits, application of the application of STP Spanning Tree Protocol can successfully prevent the loop.

In theory, the size of the data broadcast by the broadcast domain size limit, in fact, management of a bridge structure of the campus network will be expanded as the network becomes more and more difficult, a workstation may cause failure of the entire network paralysis.

When the design of the bridge net, each bridge segment is equivalent to a working group, work group server and client as being in the same segment, the majority of data transmission in the local segment, which is follow the 80/20 principle。