Hardware platform required for networking
Source: Shangpin China |
Type: website encyclopedia |
Time: July 7, 2014
structure Website construction First of all, you should understand the principle of network connection devices. The following describes common network hardware devices. The hub acts as a network intermediary device. Its function is just to distribute and broaden, and it does not have the function of translating official documents 1、 Hub
(1) Passive hub: it does not process any signal by itself. Only the signals of different network segments are gathered together. All devices connected to the hub can see the data packets of all signals passing through the hub ARCnet often uses passive hubs (2) Active hub: This hub itself contains electronic components that amplify signals, which is called "signal regeneration: signal regeneration has two advantages: one is to make the network more robust and fault tolerant, and the other is to increase the distance between devices. Active hub also has the function of" middle dimension ", so it is also called" multi port middle dimension ". (3) Intelligent hub: The intelligent hub is the strong point of the active hub, adding many functions. It has network management functions, supports network management protocols, and can send data packets to the network console. The network console can also control the hub (4) Switched hub: It contains a circuit that can quickly transmit signals between ports. The line interactive hub only concentrates on the port of the destination computer, rather than repeatedly sending to all ports. Some switching hubs also have the ability to switch to the path that can transmit packets to the destination at the fastest speed, which can replace bridges and routers in some aspects 2、 Bridge
A bridge is a network hardware or software device that can connect different network segments together. You can use a bridge to connect different network segments. As long as the two network segments use the same high-level network protocol, they can be connected successfully When the bridge transmits information, it can find information, filter information, and forward information (correct address forwarding). The working principle of the bridge: when the computers in the same network segment communicate, the bridge will not forward to other network segments, thereby eliminating the network Congestion and congestion of network information. Only when computers in different network segments communicate can they be forwarded to another network segment through the bridge. Most bridges connect only two network segments. Multiple bridges will form a "bridge circulation" in the network. Therefore, it must be ensured that there is only one path between connecting one network segment and another network segment. If there are two paths, the destination PC will receive two pieces of information. It is not recognized when grouping. If two or more network segments are connected. The bridge will send packets to all network segments, causing network congestion 3、 Router
A router is a network device that forwards information from one network to another. When working, if it is connected to a network or network segment with the same protocol. It will send the information directly to the destination port. In short, the router only processes the packets that need to be routed, while the bridge must check all the transmission packet clips on the network to determine whether translation is required. The bridge is connected to a network segment with the same transmission protocol. The router is different, and it needs to have the same routing protocol. If you want to connect two networks with different transmission protocols. Routers are the best choice. Routes can manage and control multiple tasks between nodes. They can help manage data transmission on the network and handle packets that need to be routed. Different protocols are involved in connecting routers to different networks 4、 Switch
Switch is a popular term at present. Anyone who is new to the network will hear it. Traditional network technology has become the bottle of network development, so it is necessary to establish a switch based network structure that is easy to configure. The switch works in the data link layer of the seven layer network protocol. It is a kind of network equipment with MP address identification and can complete the function of encapsulating and forwarding data packets, which can effectively isolate the wide swing wind, Avoid sharing conflicts. Compared with the traditional hub, the switch has a high bandwidth back bus and internal switching matrix. All ports of the switch are attached to this back bus. After the control circuit receives the data packet, the processing port will look up the address comparison table 'MAC Port Number] in the memory to determine which port the NIC of the destination MAC is attached to, and quickly transmit the data packet to the destination port through the internal switch matrix. If the destination MAC does not exist, it will broadcast to all ports, and each port can be regarded as an independent network segment, The network devices connected to it enjoy full bandwidth alone, without competing with other devices The switching network provides higher transmission bandwidth. Layer 2 switching technology has basically developed and improved. In addition to the usual functions, it also includes Tninking (link aggregation) and VLAN (considering LAN technology). Link aggregation can not change the existing network equipment wiring. Multiple switch to server or switch to switch teaching channels are bundled together, A high bandwidth link is formed. The so-called new technology of virtual LAN refers to the establishment of multiple virtual workgroups through switches, which truly realizes that users are independent of their physical locations The switch is a high-end product in the network. When purchasing, consider: throughput: the maximum rate that can be reached without losing frames. Delay time: the time to process Ethernet packets, from receiving the last bit to sending the earliest bit. Loss rate The rate at which a switch loses packets under load. Although packets have the characteristics of loss and retransmission, the loss of the largest packet also reduces the utilization of the network. Illegal frame side test: The switch uses store and forward technology. Therefore, when the port receives a frame, it will automatically process it. If there is an error, it will automatically discard it and not send it. You can input the wrong packet from the port, It is impossible to see these blocking side checks from other Swiss ports: if the switch sends data packets to both ends at the same time, one port is blocked and the other port is not blocked, then the data packets should be received on the other port 5、 Repeater
The purpose of repeater is to solve the problem of cable length. It can amplify the transmission signal, so that it can go farther on the network. Advanced repeaters can expand the transmission distance of media by amplifying and regenerating signals, but because of "transmission delay" (the longest time of signal transmission), the scale of the network is limited
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