Apr 26, 2012

Reflection #5

This week, the topic that has been focused is about cabling. What is cabling? We'll see the meaning and types of cabling for internet with further reading. 


Cable is the medium through which information usually moves from one device to another.

There are five types of cables that we will go through:

1. Unshielded Twisted Pair (UTP) Cable
2. Shielded Twisted Pair (STP) Cable
3. Coaxial Cable
4. Fiber Optic Cable
5. Wireless LANs

The different types of cables are divided into two categories, the guided and unguided.

Unshielded Twisted Pair (UTP) Cable

  • Has four pairs of wires inside.
  • Each pair is twisted with different numbers of twists per inch.
  • The advantage of twists: to help eliminate noise from adjacent pairs and other electrical device.
Shielded Twisted Pair (STP) Cable

  • Consist of two individual wires wrapped in a foil shielding.
  • The cable is quite bulky.
  • Usually used for Token Ring topology.

Coaxial Cable

  • Has a single copper conductor at its center.
  • Insulation of plastic layer between the center conductor and a braided metal shield.
  • Function of metal shield: block any outside interference: 
    • Fluorescent light
    • Motors
    • Other computers

Fiber Optic Cable

  • A center glass core is surrounded by several layers of protective materials.
  • Transmit signals over much longer distance.
  • Move in a form of light.
  • Capable of eliminating the problem of electrical interference.

Apr 8, 2012

Reflection #4

This week, we are introduced deeper to three integral part in networking:

  • Topology
  • Protocol
  • Architecture

Network Topology is the study of the mapping of elements of a network between nodes

This includes the physical and logical interconnection of the network. Topology is divided into two type:
  • Physical Topology (real)
  • Logical Topology (virtual)
Physical Topology is the way devices are arranged and communicate with each other.

Logical Topology, on the other hand, is the mapping of the flow of data between the nodes in the network determines the logical topology of the network.

There are many types of topology but for now, we had learned few of them:
  • Linear bus
  • Star
  • Ring
  • Tree

Linear bus topology consists of a main run cable with terminator at each end. In this type of topology, the nodes are connected to linear cable. The Ethernet and LocalTalk networks usually use this type of topology.

Star topology connecting each nodes directly to a central network hub or concentrator. The data on a star networking will passes through the hub or the concentrator. These hub and concentrator are also known as repeater for the data flow.

Now, let see how the ring topology works. Each of the system in ring topology is connected to its respective neighbour thus forming a ring. On the diagram above, we can see how all the nodes are connected in a form of circular motion. The ring topology does not require termination because all nodes connected in a loop, which means no beginning and no end point.

The tree topology is a combination of star topology that connected to a linear bus backbone cable. It is also known as hybrid. This type of topology will allows the expansion of an existing network.

It is a set of rules that governs the communications between computers on a network.

There are many types of protocol:
  • Ethernet - Logical linear bus topology protocol
  • LocalTalk - Star topology protocol
  • Token Ring - Ring topology protocol
  • TCP/IP and WAP
  • WiFi
  • Bluetooth

Asynchronous Transfer Mode (ATM)

  • It is a standard switching technique to unify telecommunication and computer networks.

  • ATM is quite different than Ethernet that used variable size of frames, it uses asynchronous time division multiplexing that will encode data into small and fixed-sized cells.