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This article mainly introduces the exchange how to update the exchange table, the article is very detailed, has a certain reference value, interested friends must read it!

We know that switches are not as stupid as hubs, where every byte received on one port is transmitted to all other ports. The switch can recognize the host connected to each of its ports through autonomous learning. Therefore, when the switch receives a mac frame, it knows the destination host to which the packet is to be sent by looking at the destination address of the frame, and then sends the packet to the destination host through another connected destination host port.

So how does the switch know the host to which it is connected? This is an intelligent place of the switch, it is through autonomous learning ability to store the information of each host in the exchange table, to know each host.

Let's use a simple example to illustrate how the switch conducts autonomous learning. As shown in the figure, there are four hosts with MAC addresses of ABCD, connected through interfaces 1, 2, 3, 4 and the switch.

First, when host A sends data to host B. When the switch receives data from host A, the exchange table is empty at first, so this data is broadcast to all ports except port 1. With the exception of host B, all hosts will discard received packets. In addition, record the host An information in the exchange table, which is as follows

When host B sends data to host A, the switch looks up the exchange table and knows that host An is on its own port 1 and is sent directly to host A through port 1 instead of broadcasting. Then, the information of host B is also recorded, and the exchange table is as follows

As long as hosts C and D also send data to other hosts, their information is also recorded in the exchange table, so eventually the switch knows all the hosts.

The above is all the contents of the article "how to update the switch table". 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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