From the previous post, the frame is the chunk of data that sends information from one computer to next. It can be sent in any way for example if its WiFi data will be sent in radio waver and if its Fiber optics it will be flashes of lights. In short frames are chunks of data that go from host to another host.
Now the question is how are we connected together? where do the cables go?
Well, that’s what we call topology.
What is Topology?
Topology is the organizations of how 1z and 0z in the frame move from host to host.
a lot of topologies exist let’s discuss them one by one what they are and how they work.
In bus topology, all of the hosts are connected on a single chunk of cable called bus.So if you need to connect to network your host should be connected with the bus.This technology is pretty much vanished.
In, ring topology is structured the same as a ring so anyone wants to connect to a network that has to connect to the ring. This topology was invented by IBA with a technology name token ring which is almost vanished.
This topology is a bit modern than ring and bus topology. In star topology, individual hosts are connected with kind of a block in a middle link hub, switches. Bus some advance that star topology is a hybrid topology and let’s talk about the most famous one.
Well this one is a mixture of start and bug topology lets you have computers connected to a hub/switch so if we look at cables it will be a start topology but logically the wires are connected in a bug topology.
We should keep in mind the difference between physical and logical topology. when we are talking about physical it means we are working on its physical look how the structure actually looks physically. While when we talk about logical topology we are talking about the electronics, diagrams and how to stuff is going to work.
Star bug topology is the most primary topology we use today. If you are connected to an ethernet it means you are using a star bus topology.
Now let’s talk about cables that you are going to see in your network I will go through them a little bit so that any time you saw a cable you should remember yes I have seen it before.
This is one of the oldest cables out there.Its date all the way back to world war 2.When you are going to use this cable make sure you see its name on it and that name will be mostly starting with RG for example RG-59.
Now this RG specifies the thickness of the conductors. insulation and shielding.Coaxial Cable has two conductors one center point and other tubular conducting layer. RG-59 has a 75ohm rating and uses a threaded F-type connector.
Twisted Pair Cabling:
In Networking the most used cable type is twisted-pair cabling.You must have seen it if you have every used a LAN internet.In a normal LAN cable you will find 4 pairs twisted cable.There are also 25 pairs twisted cables.
Now in twisted pair cables, there are two further types of shielded (metal or foil covering) and unshielded (no covering).
Things you should remember are modern twisted pair has 4 or more pairs of the cable.UTP cable is unshielded and subject to signals intrference from environmental factors.568A and 568B are the wirings standards for how to wire are connected to a connector.
Cable Cat Ratings:
UTP cat ratings define the speed and cable length specification.In cat rating, we have different no. of twists per inches below you can see the table which shows which cat number supports how much data transfer. for example, cat 6a and cat 7 are both rated for 10 GBPS speed and upto 100-meter cable length.
Fiber Optic Cabling:
This cable has a fiber optic which is the core and carries the light. it’s surrounded by a cladding and then we have a cable jacket. Now fiber optic cables have a lot of types of connectors and they are used for different purposed.
There are two types of cables one is Multimode cable which carries LED signals and the other one is a single-mode cable that carries laser signals.
Fire rating is the rating of a cable which tells how much sooner it burns if its places near fire.This is important because you have to select the cable when you are working in any place, for example, it you are i a ice facary you would select a different cable and if you are in a place where the fire in involved or hot temperature you will select different cable.
Remember Plenum-rated cable is the most fire resistant.The cable fire rating is normally clearly marked on the manufacturer’s box.Also remember non-plenum is not considered fire/smoke resistant.
Legacy Network Connections:
There are two type of ports serial ports and parallel ports. Serial ports are the oldest IO connections exists. IBM PC in 1980 has serial ports with low speed.Now there are two types of port options in serial port DB-9 and DB-25 which is the converter from 25 to 9 and 9 to 25 pins.Both DB-9 and DB-25 are legacy serial network connections.
The parallel port is a DB connector as a female port. These were typically used in printer connections.One more thing you should remember is a yost or rollover cable is a serial cable used to configure a router or a switch.
Hope you enjoyed this article for more articles like this keep visiting as this is a series of lectures.