In connecting computers to one another or to peripherals, the network switch has largely replaced the Ethernet hub, although the latter will still perform its intended functions. The difference is that the less advanced hub sends identical data between ports whereas the network switch (also known as a switching hub, bridging hub or MAC bridge) sends data only to a single or multiple devices as required by each operation.
By way of background, most computers have multiple USB ports, which allow direct connection to the main data bus. When a device connects via USB hub to a computer, it in effect becomes a part of the computer. The input and output ends of a USB cable are different and not interchangeable.
An Ethernet connection, in contrast, is between two identical RJ 45 ports. In the computer, directly connected to the Ethernet socket, is a network interface card (NIC), a small printed circuit board that is necessary for the Ethernet connection to function. For this reason, computers ordinarily have only a single Ethernet port. The networking of more than one machine requires an Ethernet hub or a better equivalent (switch, router, server). A USB hub is only necessary if you run out of USB slots in the computer. Other instruments such as advanced oscilloscopes, also have multiple USB slots and a single Ethernet port.
Ethernet cables (typically Cat 5e or Cat 6a) cannot be spliced using small blue wire nuts, crimpable bugs or soldering, as when the same cable is used for telephone lines. Nor can Ethernet cable be branched out to parallel lines using a splitter like coaxial cable conveying audio-video signals.
To create multiple input/outputs, a network switch is used. It may have 5 to 50 ports and requires connection to an external power source. A battery-powered unit works where ac power is not available.
In the 10/100/1000 BASE-T format, Cat 6 cable is limited to a length of 100 m. If a longer span is needed, it is possible to use one or more network switches between 100-m runs. This presupposes the existence of a power supply at the site of the switch, unless a battery-powered switch is used.
There are some variations in the simple network configurations that we have discussed. In larger applications such as office buildings, modular or built-in interfaces allow for connection to various types of networks other than Ethernet. These include Fiber, RapidIQ, ATM, G.hn and 802.11.
Layer 3 switches are the simplest form of routers. There are also devices that plug into ports and improve network performance and security.
Brooke McAvoy says
It is interesting that a unit like this can work off of a battery. What type of battery would you need? Your diagram is actually really helpful to me, and I have an easier time visualizing what you are talking about. Thank you for a thorough and informative article!
Joe Romanowski says
Will the same cat6 ethernet cable transmit data in and out on an ethernet switch? On an ethernet hub?