《计算机双语论文-Setting Up A VPN Through LAN.doc》由会员分享，可在线阅读，更多相关《计算机双语论文-Setting Up A VPN Through LAN.doc（32页珍藏版）》请在三一文库上搜索。
1、ContentsAbstract2Chapter 1 LAN Technology31.1 LAN Overview31.1.1 The local area network transmission medium31.2 Interconnection Technology41.3 The Expansion of LAN Technology41.3.1 repeater51.3.2 Bridge51.3.3 The Difference Between LAN And WAN6Chapter2 Switch72.1 Definition of Switch72.2. Packet Swi
2、tches82.3 the principle of Packet Switch92.4 Switch features and benefits9Chapter3 Router123.1 Router Disposition123.1.1 Concept And Function123.2 the role of Router163.3 Routing Table Computation163.4 A Corporation router disposition17Chapter 4 Design a LAN184.1Design ideas184.2 Hub194.3 Modem204.4
3、 IP Address214.5 Safety Work214.5.1 Authentication technology214.5.2 Encryption technology214.5.3 Key exchange and management224.6 The LAN Configuration Software224.6.1 VPN Gateway Type Configuration224.7 Servers254.7.1 FTP Server254.7.2 Web Server274.7.3 DNS Server294.8 The steps of these projects2
4、9Chapter 5 Conclusion30References:31Setting Up A VPN Through LANAbstractInternet is develop at full speed, Internet becomes people and obtains, releases and transmits the important channel of information fast,it is playing an important role on such all respects as peoples politics, economy, living,e
5、tc.summed up the design of the local area network technologies, in particular, illustrates the local area network routers in the application, with a focus on wide-area network LAN design, including system design principles technology network of choice, premises distribution systems, network topology
6、 and equipment Selection of this design can achieve the basic functions of the various modules to meet the internal needs of various departments and ultimately designed as a simple, inexpensive and effective practical local area network within the company.Key words： Local Area Network (LAN)； router；
7、 vpn； Internet Protocol AddressChapter 1 LAN Technology1.1 LAN OverviewLAN is a small geographical area of data communications equipment linked to that of the communications network. From the hardware point of view, A local area network is aggregates made up from computers, network adapter and trans
8、mission medium; from the software point of view, LAN service a lot of resource sharing, such as the provision of documents, printing, communications; from the architecture point of the view, LAN is definite by a series of hierarchical network protocols. LAN network with limited geographical scope of
9、 coverage, high transfer rate, a small delay, low error rate, network management into a single organization for all and so on. LAN is one of the most widely used type of network.1.1.1 The local area network transmission mediumCoaxial CableCoaxial cable is BNC cable,It is a copper core, the outer lay
10、er of insulating material set, which was outside the insulator layer of aluminum or copper mesh to do around the conductor can be shielded from outside interference. Twisted-pairTwisted pair from each other throughout the winding two pairs or four pairs of wires pose, as each wire conductors are eac
11、h other winding radio frequency noise can be shielded. There are two types of twisted-pair: STP and UTP. The type of line can be divided into five categories:(1) most of the old-fashioned telephone line.(2) Such lines actual transfer rate up 4m4Mbps(3)This type of cable is a local area network can b
12、e used in most of the low-grade twisted pair, and its transfer rate of up to 10Mbps.(4)For the 16Mbps token ring network.(5)Such twisted-pair is dedicated to Fiber Distributed Data Interface it can provide the maximum 100Mbps.FiberAs the optical fiber transmission medium, and thus has nothing to do
13、with the radio-frequency noise: The light from the point of noise. Light along the slender plastic or glass fiber conduction, the slender plastic or glass fiber was wrapped with a thin layer of sets of outer layer of plastic coat was wrapped in order to protect the valuables of the fiber. Cable has
14、a huge data transfer rate, which for video, voice and image transmission very useful. As the optical signal transmission cable is not the signal that it does not electromagnetic transmission, radio signals, which often signals can be transmitted a few miles without attenuation. There are single-mode
15、 fiber and multi-mode.1.2 Interconnection TechnologyInterconnection is the use of certain technologies and methods, network interconnection facilities will be two or more networks. Off the Internet network technology is usually composed of two aspects, one will be a small number of network connectio
16、ns into a large network, has achieved a wider range of resource sharing, which is the main purpose of the Internet network. By the Internet is the worlds thousands of computer networks, interconnection network equipment - routers, the Internet, a worldwide network of large, resource-sharing. The sec
17、ond is a large and complicated network is divided into a number of small subnet, a network equipment to interconnect the various sub-linking in order to improve network management and network performance.The purpose of the interconnection network: multiple networks, in order to achieve a wider scope
18、 of information exchange and sharing of resources and work together.LAN interconnection: first, LAN interconnection can be divided into local and remote local area network interconnection LAN interconnection. Second, LAN interconnection can use different media: Unshielded Twisted pair, shielded twis
19、ted pair, optical fiber and so work interconnection requirements: to provide a link between the network, at least one physical link and control link; in the process of the different networks which provide routing and data transmission; provide network users to record and Maintain the status informat
20、ion; in the provision of these services do not need to modify the existing network of networks.Interconnection of functional categories: basic functions, referring to the interconnection of the need to function, even for those of the same type of interconnection should have functions, which include
21、the transmission between the different network routing and addressing, and so on. Extensions, when referring to the interconnection network to provide a variety of different levels of service required functions, including the conversion agreement, the sub-group and re-combination and sequencing erro
22、r detection. 3, connection-oriented mode of operation: even to the same subnet between the two DTE can establish a logical network connection. 4, connectionless mode of operation: corresponding to the packet-switched data network reported that the mechanism, and the connection-oriented operation cor
23、responding to the virtual circuit mechanism.1.3 The Expansion of LAN Technology1.3.1 repeaterRepeater network is a line of devices used in two network nodes between the physical signals of the work of the two-way forward. Repeater is the simplest Internet network equipment, responsible for the two n
24、odes on the physical layer according to the transmission of digital information. Repeater is the simplest Internet network equipment , it is in charge of the two nodes on the physical layer according to the transmission of digital information, signaling the completion of the copy and adjustment in o
25、rder to extend the length of the network.Because of wear and tear, on-line transmission of the signal power will gradually decay, the decay to a certain extent, will cause signal distortion, it will lead to the wrong receiving. Repeater is to solve this problem and design. it completed the physical
26、line connection, the attenuation of the signal amplification to maintain the same as the original data. under normal circumstances, the repeater to connect the two ends of the same media, but some repeaters can complete the work in different media adapter. in theory, the use of repeaters is unlimite
27、d, so the network can be extended indefinitely. in fact this is impossible because the standard network signal in all of the specific scope of the delay, the repeater can only be provided for within the framework of the effective work, or give rise to a network failure.1.3.2 Bridge As the same to tr
28、ansponders, Bridge will be two (or more) segment connected with can increase the diameter of the network, but the bridge differences also help to control network traffic. Bridge work in the data link layer, the two together, LAN, according to the MAC address to forward frames, can be seen as a low-l
29、evel router (routers in the network layer, according to the network such as IP address of the address Forwarding)Remote bridge is usually through a slow link (such as telephone lines) to connect the two long-range LAN, speaking of the local bridge, performance is more important, but the bridge on th
30、e long-range, in the long-distance running can be more important.There are two bridges, transparent bridge and spanning tree bridge.Transparent bridge:Transparent bridge to work in mixed mode, which receive all the LAN connection with the transfer of each frame. When a arrived, the bridge must be de
31、cided to discard or forward. If you want to forward, the decision must be made to any LAN. Need to bridge this query in a large-scale, scattered and the purpose of the address list and make a decision. The forms are available for each possible destination, where it belongs, as well as a line output
32、(LAN). Insert at the beginning of the bridge, all of the hash table were empty. Since the bridge did not know of any place of destination, thus the proliferation of the use algorithm. Over time, the bridge will be the location of each destination. Once aware of the destination locations, sent to the
33、 frame only on the appropriate LAN, and is no longer distributed. Frame arrived in the routing process of sending depends on the LAN (Source LAN) and the destinations LAN (purpose LAN).In order to improve the reliability of the LAN was set up in parallel between two or more of the bridge, however, t
34、his configuration has caused some problems because of topology have had a loop, may lead to infinite loop.Spanning tree bridge:Address the above mentioned infinite loop problem is to bridge communications with each other, the use of spanning tree can be appointed to ensure that the LAN between the t
35、wo, only one path only, once the bridge spanning tree well agreed, LAN among all have to comply with this transmission spanning tree. From each source to each destination is only the only path, it will never again have a cycle.In order to build spanning tree, first of all to be elected as a bridge s
36、panning tree root. To achieve is to bridge each of its radio serial number (the serial number set by the manufacturers and to ensure that the worlds only), the election of the smallest serial number as the root bridge.1.3.3 The Difference Between LAN And WANTo appreciate the distinction,it is inport
37、ant to understand how the size of a network is measured.We have seen that although LAB thchnologies are designed to be used at a single site,techniques exist that can extend the distance spanned.In particular,a satellite bridge can connect two segments of a LAN over an arbitrary distance.However,a b
38、ridged LAN is not considered a Wide Area techonlogy because bandwidth limitations prevent a bridged LAN from serving arbitrarily many computers at arbitrarily many sites.The key issue that separates WAN technologies from LAN technologies is scalabilitya WAN must be able to grow as needed to connect
39、many sites spread across large geographic distances,with many conputers at each site. For example,a WAN should be able to connect al the computers in a large corporation that has offices or factories at dozens of locations spread across thousands of square miles.Furthermore,a technology is not class
40、ified as a WAN unless it can deliber reasonable performance for large size networks.That is ,a WAN does not merely connect to many computers at many sitesit must provide sufficient capacity to permit the conputers to communicate simultaneouly.Chapter2 Switch2.1 Definition of SwitchSwitch is technolo
41、gy that Communications is in accordance with the needs of both ends of the transmission of information, and use of artificial devices or auto-complete approach to the transmission of information to meet the requirements on the routing. Switches have a very high bandwidth backplane bus matrix and in-
42、house exchange. The switch ports are all articulated in the back on the bus. Control circuit received packets, port handling memory to find the MAC address table to determine the purpose of the network card to connect the port which, through the exchange of in-house matrix directly to the rapid tran
43、smission of data packets to the destination node, if the purpose of the MAC did not exist before Broadcast to all ports. In this way the high efficiency of the transmission will not be a waste of network resources, Because the only purpose of the address to send data, so difficult to have a network
44、plug. The main functions of switches, including addressing the physical, network topology, error checking, as well as the frame sequence flow control.each port of the switches have independent bandwidth. The use of the network switch into the net, through the IP address of the control table, you can
45、 limit the data flow through the switch. Switches through the filter and forwarding functions can be effectively isolated broadcast storm, reducing errors and packets of the wrong package, to avoid sharing the conflict. In this way, switches at the same time be able to carry out a number of data tra
46、nsmission between nodes, each node can be seen as an independent network, do not need to compete with other equipment to increase the transmission rate. When the node A to D node to send data, the Node B to Node C at the same time can send data transmission and the two enjoy the full network bandwid
47、th, have their own virtual connection. If here is the use of the 10Mbps Ethernet switch, the switch at this time, the total circulation is equivalent to 2 10Mbps = 20Mbps, and 10Mbps using the shared-HUB, HUB a total circulation will not exceed 10Mbps .Switches through straight-through processing, d
48、ebris and store-and-forward three ways to carry out the exchange. Store-and-forward manner in which the computer is the most widely used network in the area. It input port to store data packets, followed by a CRC (cyclical redundancy check) checks in the wrong package deal after the packet out the destination address, look-up table into the output port to send packets. For this reason, store-and-forward mode when the delay in data processing, which is less than it, but it can switch into packets for error detection to improve the network performance. It