Shulou(Shulou.com)06/03 Report--

one。 Why do we need VLAN?

In the network, all users are in the same broadcast domain. When the network scale is relatively large, our hosts need APR broadcasts to find MAC addresses. At this time, the number of broadcast packets increases sharply. When the number of broadcast packets accounts for 30% of the total, the network transmission speed will decrease significantly, especially after a network equipment failure, it will continue to send broadcasts to the network, resulting in a broadcast storm and complete network paralysis. At this time, we need VLAN to separate broadcasts and control broadcasts.

II. Functions and advantages of VLANs

Let's take a look at this picture to see what physical segmentation is. The three hosts on the left are connected to the switch through three ports, and we set up a VLAN for each port. The two on the right are connected to the other switch. Hosts connected to the same switch can only be divided into the same network.

Or look at this picture what is logical segmentation, we can divide according to the location, function, and department of network users, our VLAN can be divided across switches, for example, the two hosts on the left above can be connected to one host on the right through VLAN. At this time, we can name the Finance Department, and the next two of us can teach the Network Department, which is called logical division.

III. Types of VLAN

Our switch generally has 8.16.24.48 interfaces, so if we set up a VLAN, we need to configure it on the port.

IV. Range of VLANs

We only have 2-1001 and 1025-4094 can use, usually we 2-1001 is enough, every family in our family has a VLAN, operators usually use double-layer VLAN to assign to us, for example, 100 VLAN has a layer of 20.

five。 Let's configure it through GNS3.

1. Let's open GNS3 and add three hosts and a router first.

two。 Add a veneer with a capacity of 68m to make it a switch

3. We changed all the names and pictures.

4. Let's turn on the switch.

5. Let's format the memory and check to see if there is any space

6. Let's practice the line and write down the address and VLAN to mark it.

7. We turn off the routing function, and then assign addresses to each host.

8. Let's try to see if we can connect (if not, just restart the router and turn off the routing function)

9. Let's start configuring VLAN

10. We put the port in the VLAN.

11. Let's check whether our 1 host can connect with 2 hosts and 2 hosts can connect with 3 hosts.

That's all of our VLAN content.

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