Significance of dividing subnets

Here, we must first understand the fact that what is the significance of dividing subnets?
One of the most incomprehensible questions for many readers. As we all know, using the re-division of subnets not only does not add new available
IP
Address,
It will also lose some
IP
Address. To solve this problem, we must first understand the concept of broadcast in the LAN.

We know that although the Switch replaces the hub, the number of broadcast packets sent in the LAN is obvious.
Because the vswitch has
Mac
Address learning function. data packets can be sent directly to the target node. However, at the beginning, it still needs to find the target node through broadcasting.
Some data packets must also be transmitted through broadcast. Therefore, packet Broadcast Transmission still exists in the LAN.

We all know that broadcast transmission sends the same message to all nodes in this section.
Packet, which requires a considerable amount of network resources (because each broadcast packet hardware device must analyze it), especially bandwidth resources. However, the most annoying thing is that in these broadcast transmissions
Only one of the users who receive the broadcast is really useful, because the purpose of the broadcast is to query the target user's
Mac
In this way, the vast majority of broadcast transmissions do not get any
It is a waste of resources. In addition, the larger the network scale, the more resources the broadcast data packet consumes (because the more data packets are transmitted in the broadcast), it is likely to form a broadcast storm. Normal network communication can
Can be interrupted, resulting in network paralysis. Currently, some hackers do not commonly use Denial-of-Service (DoS (
DoS
) Similar to this method, it is often used to attack some famous websites.
To send a large number of data packets to the website server, so that the server is tired of processing these data packets, occupying the entire system and bandwidth resources of the server, so that it finally crashes.

After understanding the above facts, we will know
Subnetworks are divided into the following aspects.

First, the most important thing is to reduce
The negative impact of broadcast to improve the overall performance. Because broadcast data packets can only be transmitted in the same network segment, the network size is small, the number of users in the network is fewer, of course, the resources occupied are fewer.

Second, it saves
IP
Address asset
Source. This seems to be in conflict with the number of connected hosts described earlier, but it depends on the specific object. The scale is large (
200
(More than one user) network, after dividing the subnet, available
IP
Address
The number is reduced, but for Small Enterprise Networks, dividing subnets can save a lot.
IP
Address resource. Because several small networks can share a large network address range, and
The sample can be isolated.
For example, if you are a student
School Network Management, now your school has four data centers in different locations, each of which
25
Machines, which need to be configured
IP
Address and subnet mask. You may think this is too simple to use.
4
Items
C
Class address
Segment, one for each data center, and one-to-one configuration won't be done. This is true in theory, but have you ever thought it would be a waste (
254-25
)
* 4 = 916
Items
IP
Address,
If you do the same on the internet
Internet
On
IP
Early address
It is exhausted. By dividing subnets, you can
C
The class network can accommodate this relatively independent subnet.

Another one, because different subnets cannot be straight
When the network security situation is not optimistic, the smaller the network, the higher the security, because the intrusion path is smaller. Especially for sensitive enterprise departments,
Such as finance and personnel. Moreover, small networks are easy to deploy special security policies, which may affect the work of other users in large networks.

The last one is easy to maintain. You know,
It is quite difficult for a large network to find the fault point. If the network scale is reduced, the search scope will be smaller and maintenance will be more convenient.