Tuesday, 29 May 2012
Unbounded Media/Wireless Transmission Media.
This kind of media is commonly used because it is more convenient and could be used in locations that is impossible to install cables.
Other than that, we also learned two types of antenna which arePARABOLIC DISH and HORN ANTENNA.
PARABOLIC DISH (SATELLITE DISH)
In networking, cabling is used as transmission media to exchange information between two or more devices. There are 4 types of cables which are unshielded twisted pair (UTP) cable, shielded twisted pair (STP) cable, co-axial cable, and fibre-optic cable.
1. Unshielded Twisted Pair (UTP) cable.
This is called "twisted pair". This type of cable contains four pairs of wires and each of them are twisted so that it will avoid or prevent any interference from adjacent pair and other electrical devices. The standard connector for this cable is RJ-45 (Register Jack).
The disadvantage of this type of cable is that it brings harm to radio and electrical frequency interference.
2. Shielded Twisted Pair (STP) Cable
It is almost the same as the Unshielded Twisted Pair cable (above) because each of the wire is twisted. However, what makes it different is that each pair of the twisted wire is wrapped in a foil shielding so that it becomes more reliable for data communication. In addition, it is commonly used in a network that uses Token Ring topology.
3. Co-axial Cable
It consists of a single coopered wire with three layers which are: insulating material, waven/braided material, and outer plactic coating. The waven/braided material is to block any interference, while the outer plastic coating functions as insulator. This type of cable is usually used by Cable Television (CATV) because it can be cabled over long distance. It uses Bayone-Neill-Concelman (BNC) as the connector.
4. Fibre-optic Cable
These are dozens/hundreds of thin strands-glass/plastic in the fibre-optic cable which act as the core.
This type of cable uses light to transmit signals from one device to another. It also consists of insulating glass caddling and protective coating. The advantages of this cable are faster, less susceptible to noise/interference, better security, smaller and carry more signals. However, the disadvantages are it will costs more, and difficult to be installed and modified.
It is also known as - Network Topology. Network Topology is the arrangement of a connection between nodes. In addition, these devices/nodes are connected via links such as twisted pair copper wire cable or optical fiber cable.
There are 5 types of network topology:
This type of network topology connects nodes in a linear arrangement which has a main connected at each end. Just like a bus (public transport) which sends passengers along the route from one end to another. In term of network, the information is transferred along the way from one end to another. Therefore, each nodes will get the same information. If one of the nodes fails to work, it will not affect other nodes. However, if the main is not working, the whole system will stop functioning.
The 'Star' Network Topology connects nodes to only one main. As you can see in the diagram above, the arrangement of this type of network is exactly like a star. The difference of this arrangement from the bus network topology is that the nodes are directly connected to the main. If one of the nodes malfunction, it will not affect other nodes. However, if the main malfunctions, the whole system will not run.
From the arrangement, it is obvious why it is named RING network topology. Unlike the BUS and STAR network topology which is connected with a main, this type of network topology connects the nodes with each other. Each node is connected to two other devices (from left and right). However, if one of the nodes fails to function, the whole system will not be working.
This week, we've learned the Introduction to Networking. Firstly, networking is about linking two or more devices such as computers. The main purpose of networking is actually to share files. The network is formed through all sort of cables either wireless or direct cabling.
LAN- Local Area Network