Power over Ethernet, Ethernet Switch and Crossover Cables , Ethernet Hub
What is Power over Ethernet
Power over Ethernet (PoE) is a system that provides a constant supply of DC power to a computer network using the same Ethernet cables used for connectivity. Devices such as network cameras and IP telephones can hence be powered without the need for extra wiring. PoE is easy to maintain and requires little or no human intervention. Another name for PoE is Power over LAN (PoL).
In order for Power over Ethernet to work effectively, the electrical current must flow through the data cable at the main supply entrance and out through the device end to avoid any interference between data and power supply. In case the device at the end of the cable is not PoE synced, then another hardware called a picker needs to be put in place.
What is an Ethernet Switch and Crossover Cables
A switch is something that is used to turn on or off various electronic devices. However, in computer networking, a switch is used to connect multiple computers with each other. Since it is an external device it becomes part of the hardware peripherals used in the operation of a computer system. This connection is done within an existing Local Area network (LAN) only and is identical to an Ethernet hub in terms of appearance except with more intelligence. These switches not only receive data packets, but also have the ability to inspect them before passing them on to the next computer. That is, they can figure out the source, the contents of the data, and identify the destination as well. Because of this uniqueness; it sends the data to the relevant connected system only, thereby using less bandwidth at high performance rates.
Ethernet Switches and Crossover Cables
The wires in a crossover cable are "crossed" so that output signals from the transmitting device are properly sent as input signals to the receiving end. An Ethernet switch can be thought of as a device that makes temporary crossover cable connections between computers that want to communicate. Just like crossover cables, switches do not suffer from the problem of collisions.
However, it should be noted that the actual cables used are "straight through". The crossover function is done inside of the switch.
Since separate wires are used for sending and receiving, switches support operation in full duplex mode. This mode allows devices to send and receive data at the same time.
What is an Ethernet Hub
For any two devices to be connected, they need a common place, or a hub, as it is called in the computer world. It basically connects multiple computers together. Most of the hubs available in the market today support Ethernet standards. This is why they are called Ethernet hubs, and are most commonly used in computers for networking purposes at home.
Ethernet hubs are available in different types, depending on the speed of the network connection or broadband speed. Also, the number of ports supported by the hub varies, there are some that support only one port whereas others with eight or more ports are common in large offices with many computers inter-connected. The newer range of hubs found in the market are relatively smaller and don't make any noise as against the ones used in early days which had a built in fan to keep the system cool.
Ethernet Hubs – How they Work
The main purpose of the Ethernet hub is to transmit the large pockets or cluster of data it receives from one computer onto another through all the ports connected to it. The only drawback of this system is that data can be transferred from only one system at a time. If there are multiple systems sending out data to others, it is likely that a collision will occur. A good analogy could be that of a road with one-way traffic: vehicles coming in the wrong direction might cause chaos.
Some of the Ethernet hubs available come with a screen that displays network usage information, which lets the user know how much data is being transferred between computers. A hub is usually placed in a corner or in a place where there is not much of movement as any kind of motion can disrupt its services. Hubs are found in almost all computer networks today, including those in homes that interconnect computers for internet usage.
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