Key Points of concept differentiation between bridges and switches

Does the bridge need software assistance?

To answer this question, we should first look at the original bridge. Traditionally, the bridge usually contains a CPU and "forwarding-storage" is implemented by software. In the past, the bridge was like this. However, due to the improvement of the hardware level, bridges and switches all contain special integrated circuit parts for forwarding, the current bridges and switches do not require software assistance! By the way, software that simulates the bridge function is now available.

Is a bridge used to connect different network segments?

First of all, we need to understand what a CIDR block is. This concept is an article! It involves a series of topics such as subnet masks ....

Here I think it should be clear that bridges are not used to connect different network segments! At the beginning, I was miserable by this problem. I had more than N pieces of data, but it was a bit rewarding:>, communication between different network segments requires help from the gateway, it is generally a network-layer device such as a router. A bridge or switch is a link layer device. The network segment is an IP-related concept and belongs to the network layer.

Bridges and switches are incapable of handling network-layer things! If you have to say that using a bridge and a switch to connect two networks in different CIDR blocks does not work, but it does not work, because machines in different CIDR blocks cannot access each other and bridges cannot act as gateways!

I have already mentioned the origin of the bridge. It aims to reduce the broadcast of the HUB and improve the lan network performance. The bridge connects only two sub-LAN networks, and the sub-lan mentioned here must be homogeneous (homogeneous means: If it is Ethernet, the two subnets connected by the bridge must be Ethernet, one cannot be Ethernet or the other is a token network. I always think that the Ethernet feature leads to the emergence of bridges. Because broadcast is an important feature of Ethernet, other constructed networks do not necessarily have one ~ Here I guess, I can't help but say-_-! On the networks of other structures -_-!).

To optimize the performance of the Ethernet, the bridge appears ~ Therefore, other network structures do not need to use bridges! In fact, later I continued to look at wireless networks with this idea and found that this idea should be wrong. The nature of the bridge should be: connecting two homogeneous networks, while on Ethernet, the HUB can be used as a device to connect to two networks. However, due to the disadvantages of the HUB, people have developed bridges working on the Link Layer. This article introduces the following ), in addition to the ability to connect two networks, it also has the ability to optimize network performance. In other constructed networks, there is also a bridge device, but its function may be to connect only two networks without the function of optimizing network performance or according to network characteristics, it has new features ).

Summary of bridges and switches

The bridge and switch users divide the conflict domain, that is, the bridge and the switch can be less forced to broadcast (caused by hub), but cannot divide the broadcast domain. Not strictly speaking, a switch can be regarded as a bridge highly integrated.

Conflict domain: In general, a conflict domain is a collection of All workstations connected to the same wire, or a collection of all nodes on the same physical network segment, or a set of nodes that compete for the same bandwidth over Ethernet. HUB devices cannot be separated into conflicting domains.

Broadcast domain: a collection of all devices in the network that receive broadcast frames from any device.

All the ports of the HUB are in the same broadcast domain and conflict with each other.

All the ports of the Switch are in the same broadcast domain, and each port is a conflict domain.

Each port of the Router belongs to a different broadcast domain.

The distinction between the concept of a bridge and a switch is over. I hope you can clearly understand the two concepts of a bridge and a switch. If you still understand their concepts, please refer to the following articles:

Basic network knowledge: hubs, bridges, and switches

Working principles and differences between bridges and Switches Based on Network