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This article mainly introduces how to realize the interconnection between local area network and wide area net. the article is very detailed and has a certain reference value. Interested friends must finish reading it!

The main equipment to realize the interconnection between local area network and wide area network is "router". A router is a hardware device that connects two or more networks and acts as a gateway between networks. it is a dedicated intelligent network device that reads the address in each packet and then decides how to transmit it.

The operating environment of this tutorial: windows7 system, Dell G3 computer.

Routers are used to interconnect the local area network and the wide area network.

A router (Router) is a hardware device that connects two or more networks and acts as a gateway between networks. It is a dedicated intelligent network device that reads the address in each packet and then decides how to transmit it. It can understand different protocols, such as the Ethernet protocol used by a local area network and the TCP/IP protocol used by the Internet. In this way, the router can analyze the destination addresses of packets from different types of networks, convert the addresses of non-TCP/IP networks into TCP/IP addresses, or vice versa, and then send each packet to the designated location according to the selected routing algorithm. So routers can connect non-TCP/ IP networks to the Internet.

Function

The main function of the router can be understood as the transfer of information. Therefore, we call this process the addressing process. Because the router is between different networks, but it is not necessarily the final receiving address of the message. So in a router, there is usually a routing table. According to the final address of the information sent by the transmitting website, find out which network the next forwarding address should be. In fact, in a nutshell, it's like a courier company to send mail. The mail does not arrive at the final destination instantly, but through the sorting of different sub-stations, constantly approaching the final address, so as to achieve the mail delivery process. The router addressing process has a similar principle. Through the final address, match in the routing table, through the algorithm to determine the next forwarding address. This address may be the intermediate address or the final arrival address. [4]

The function of a router is to transfer data between different subnets. The specific functions are as follows:

(1) realize the interconnection of IP, TCP, UDP, ICMP and other networks.

(2) deal with the data. Sending and receiving data packets has the functions of packet filtering, multiplexing, encryption, compression and protective wall.

(3) the next transmission destination of the packet is selected according to the information of the routing table.

(4) exchanging topology information between external gateway protocols and other autonomous domains.

(5) realize the functions of network management and system support.

Connect different networks

From the point of view of filtering network traffic, the role of routers is very similar to switches and bridges. However, unlike the switch that works in the network data link layer and physically divides the network segment, the router uses special software protocols to logically divide the whole network. For example, a router that supports the IP protocol can divide a network into multiple subnet segments, and only network traffic directed to a special IP address can pass through the router. For each packet received, the router recalculates its check value and writes a new physical address. As a result, routers tend to forward and filter data more slowly than switches that only look at the physical address of the packet. However, for those networks with complex structures, the use of routers can improve the overall efficiency of the network. Another obvious advantage of routers is that they can filter webcasts automatically. Overall, the entire installation process of adding a router to a network is much more complex than a plug-and-play switch.

Information transmission

Some routers only support a single protocol, but most routers can support the transmission of multiple protocols, that is, multi-protocol routers. Because each protocol has its own rules, to complete the algorithm of multiple protocols in a router is bound to reduce the performance of the router. The main job of a router is to find an optimal transmission path for each data frame passing through the router and effectively transmit the data to the destination site. Thus it can be seen that the strategy of choosing the best path, that is, the routing algorithm, is the key to the router. In order to complete this work, the route table (Routing Table), which is related to various transmission paths, is stored in the router for routing. The path table stores the logo information of the subnet, the number of routers on the network and the name of the next router. The path table can be fixed by the system administrator.

The above is all the contents of the article "how to interconnect the local area network and the wide area network". Thank you for reading! Hope to share the content to help you, more related knowledge, welcome to follow the industry information channel!

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