2020
2021
Let's use this topic to analyze the whole process of the application scenario where the host H1 accesses the Web server.
2022
Comprehensive topic
A collision domain refers to a group of devices sharing the same physical network, and when one of the devices sends data, the other devices must wait to avoid data collisions. In a collision domain, when two or more devices send data at the same time, the data collides, resulting in data corruption or loss. Therefore, reducing the size of the collision domain can improve the performance and reliability of the network.
A broadcast domain refers to a physical network where when a device sends a broadcast packet, the packet will be sent to all devices in the network . Within a broadcast domain, all devices are able to receive broadcast packets, which are typically used for purposes such as network discovery and advertising. Reducing the size of the broadcast domain can reduce unnecessary broadcast traffic in the network, thereby improving network performance.
Hubs work at the physical layer , switches work at the data link layer , and routers work at the network layer .
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Hub : A hub is a physical layer device that broadcasts data from one port to all other ports, thereby connecting multiple devices together to form a local area network. Hubs do not understand the logical structure of packets, and any device connected to a hub can see all packets on the network, which can lead to collisions and congestion. Hubs have gradually been replaced by switches.
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Switch : A switch is a data link layer device that can learn the MAC address of the device connected to each port and forward the data packet to the correct port according to the destination MAC address, thereby improving network performance and reliability. Switches can isolate conflict domains by segmenting networks , and different ports can be in different virtual networks, thereby improving network security.
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Router : A router is a network layer device that can identify data packets between different networks and forward the data packets to the correct network according to the destination IP address , thereby realizing communication between different networks. Routers can choose the best path to forward data packets according to network topology and routing protocols, thereby improving network efficiency and reliability. Routers can also implement functions such as network address translation (NAT) and port forwarding, thereby improving network security and scalability.
Since the broadcast mode of the hub will cause data packet conflicts and network congestion in the network, it is recommended to use a switch instead of a hub when the network is large in scale, with many data packets, high security requirements, and high bandwidth requirements . The switch uses the logical layer data exchange method, which can more accurately control the forwarding path of the data packet, and improve the network performance and reliability.
