By PURPLELEC | 25 December 2023 | 0 Comments
What are the functions of a hub?
A hub is an important tool for centralized management of the network. Like the trunk of a tree, it is the gathering point of all branches. Its essence is a repeater, and the main function of a repeater is to regenerate and amplify the received information. , to expand the transmission distance of the network. To put it simply, it means that multiple computers can use one incoming interface to access the Internet or form a local area network at the same time.
Hub function
1. Each twisted pair interface is only connected to one workstation (network card), and signals are transmitted point-to-point.
Each station is connected to the hub using its own dedicated transmission medium. There is no longer only one transmission channel between nodes. The signals sent back by each node are concentrated through the hub. The hub then shapes and amplifies the signal and sends it to all nodes. In this way, collisions no longer occur on the upward channel.
2. When a certain port receives a signal, HUB reshapes it and broadcasts it to each other port, sending the data packet instead of data to the destination node.
The hub does not have the MAC address table that the switch has, so when it sends data, it is not targeted, but uses broadcast mode to send it. That is to say, when it wants to send data to a certain node, it does not send the data directly to the destination node, but sends the data packet to all nodes connected to the hub.
3. The HUB itself can automatically detect signal collisions and immediately send out a jam signal to notify other ports when a collision occurs.
When the hub detects a collision from its internal port, it generates a collision enhancement signal (jam) and transmits it to the target port to which the hub is connected. At this time, all data cannot be sent successfully, resulting in a "big traffic jam" on the network. Automatic signal detection is so powerful and willful!
4. When the transmission line or network card of a certain port fails, the HUB automatically isolates the port so that it does not affect the normal operation of other ports.
When a "big traffic jam" occurs on the network, affecting the normal use of the network card, the hub will automatically isolate the failed port to ensure that other target ports can operate normally.
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