Friends who are engaged in network management must know the hub, which is a very important infrastructure in the local area network, but there should still be many friends who don't know what a hub is and what kind of function it has. Here is an introduction to the hub.
What is a hub?
The English name of the hub is "HUB". HUB means the center. The important function of the hub is to regenerate, reshape, and amplify the received signal to expand the transmission distance of the network and at the same time concentrate all nodes on the node centered on it.
A hub is a basic device in a data communication system. Like a transmission medium such as a twisted pair cable, it is a hardware device that does not require any software support or requires little management software management. It is widely used in various occasions. The hub works in a local area network (LAN) environment, like a network card, applied to the first layer of the OSI reference model, so it is also called a physical layer device. The hub uses electrical interconnection. When the LAN maintenance environment is a logical bus or ring structure, the hub can be used to establish a physical star or tree network structure. In this respect, the hub functions as a multi-port repeater. A hub is actually a kind of repeater. The difference is only that the hub can provide more port services, so the hub is also called a multi-port repeater.
The working characteristics of the hub:
According to the IEEE 802.3 protocol, the hub function is to randomly select a port of equipment and let it monopolize the entire bandwidth to communicate with the hub's uplink devices (switches, routers, or servers, etc.). The hub has the following two characteristics at work.
The first is that the Hub is just a multi-port signal amplifying device. When a data signal is received by one port during work, the signal has been attenuated during the transmission from the source port to the Hub, so the Hub will shape and amplify the signal. The attenuated signal is regenerated (recovered) to the state when it was sent, and then forwarded to all other ports in the working state.
The second is that Hub only communicates with its uplink devices (such as upper-level Hub, switch, or server). The ports on the same layer will not communicate directly, but broadcast information to all ports through the uplink device.
However, with the development of technology and changes in demand, many current Hubs have expanded their functions and are no longer affected by this working mechanism. The network composed of Hub is a shared network, and Hub can only work in half-duplex.
The above is an introduction to the hub, I hope it can be helpful to friends who don’t know much about it.
