3.4.3 Explain the hardware required in networking.
Teaching Note:
Hardware should include communications links (cables, microwave,
fibre optics and so on) hub, switch, node and router.
Sample Question 1:
State one advantage and one disadvantage of using fibre optics to carry data in a
network. [2 marks]
Sample Question 2:
...A central database, connected to the LAN, holds the records of all patients.
(a) ...
(b) Briefly describe two functions of the hardware component that will allow the
current LAN to connect to the Internet. [2 marks]
JSR Notes:
Probably a key thing here is to keep straight the differences between hub, router, and so on. So here's my take:
Hub: Think USB hub - it collects all in-coming signals and distributes them everywhere. In the case of a USB hub, that "everywhere" is everywhere within the system bus of the computer. We say that the signal is "broadcast", and though all "destinations" on the bus will have the signal pass by, only the intended destination will accept the signal. In the case of a "dumb" hub in a network, it too distributes signals everywhere, but only the destination computer will do the receiving.
Router: Though we can think of a router working within a LAN to "route" signals through the network - in a non-broadcast way, but not as efficiently as a switch, it is probably better for our purposes to think of a router simply in terms of the Internet. Routers route signals from one LAN to another, and so it is the all the Internet routers themselves, along with cables and wireless connections that "are" the Internet.
Switch: Though both hubs and routers can be used to direct signals within a LAN, now-a-days the device that does this is the switch. Unlike the hub, it does not broadcast signals everywhere, and unlike the router, it picks the most efficient route for a signal to go. Switches therefore have a lot of processing power built into them, which makes them more expensive than hubs and routers.
Gateway: Whereas the above three are physically hardware devices separate from computers, the "gateway" is most often a computer. And so it is the gateway software itself that is the distinguishing feature. The main idea here is that there are all sorts of different network protocols that have to be handled, interpreted, and translated when various different networks are connected. The gateway computer does this. The easiest example is our school's gateway which acts as the interface between our LAN and the Internet. The gateway computer very well may also act as the security firewall, though such protection is not necessarily part of "gateway" capabilities.
But, having gotten the above hardware straight in your mind, don't forget there are other hardware components necessary for networking, not least of which are network cards and cables.