Shulou(Shulou.com)06/01 Report--

I. the emergence and development of switches

In the early days of the emergence of the network, the purpose of network interconnection is also limited to scientific computing and academic research, so the scope of application of the network is extremely limited, which in turn limits the development of network technology. At that time, the purpose of people using the network was very simple, as long as they could connect computers together, they could transmit data.

With the development of the times, just connecting computers together has been far from being able to meet the requirements of technological development. And because of the limited transmission distance, it is particularly common to generate signal attenuation and data loss, at this time, the repeater arises at the historic moment, and has the function of amplifying and regenerating the signal on the line in the process of signal transmission. used to expand the transmission distance of the network.

Although the repeater solves the problem of signal transmission distance, the interface of the repeater is too few to cope with more and more transmission requirements, so there is a multi-port repeater-hub.

The hub can connect multiple devices for communication, but in the process of communication, signal conflicts often occur among the connected devices, which affect the transmission efficiency. At this time, in order to avoid signal collision, CSMA/AD (Carrier sense multiple access Mechanism with collision Detection) is introduced. Listen before the signal is transmitted, and transmit the data by yourself if there is no other device for data transmission. The transmission efficiency is still very low.

In order to solve the problem of signal conflict, there is a new device-bridge, which can divide the conflict domain, and each port belongs to a different conflict domain. But the bridge also has its drawbacks-there are only two ports, so there is a bridge with multiple ports, that is, we now have a switch. The essence of a switch is a multi-port bridge.

Below, I would like to use a picture to give you a more simple and clear understanding of the development process:

The Development of switch

2. Basic configuration of the switch

1. Switch: indicates the name of the device, which is the default name for all Cisco switches.

2, >, and # represent a pattern prompt to inform the operator of the current mode

(1) "switch >": user mode, in which there are few commands and permissions, so you can only view some statistical information.

(2) "switch#": privileged mode. Enter enable to enter privileged mode in user mode. Commands in this mode are much more abundant than those in user mode, and can be used to view and modify device information of Cisco devices.

(3) "switch (config) #": global configuration mode. Enter config terminal in privileged mode to enter global configuration mode. In this mode, the original information of the device can be changed.

3. Exit to the previous mode: switch (config) # exit

4. Exit from privileged mode to user mode: switch (config) # disable

5. Exit directly to privileged mode: switch (config-if) # end

Liu Pengfei QQ905058582

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