Introduction to Networking

Again we attended the Telecommunication & Networking class with much enthusiastism after having to delay the lesson last week :)

The new topic learnt this week is " Introduction to Networking".

Dr. Dayang has provided an intriguing example to explain the term "networking" in a highly comprehensible way :D

Firstly, let's take a ride of time machine to travel back to the Stone Age. Put your safety belt on and here we go !! :D

Now you're caveman A. You normally use drums to transmit message.

One day, you want to invite your friend, the caveman B for a game of hurling rocks at each other.

 But caveman B is living too far away that he is unable to hear you banging the drum for invitation sake.

You have 3 options :

1. walk over to B's place
2. get a bigger drum
3. ask C who lives halfway in between to forward the message.

Performing NETWORKING, you'd choose the 3rd option.

Caveman C is equal to the data-sharing linkage between caveman A and B .o

In another context, NETWORKING is a collection of connected intelligent computing devices for the purpose of sharing data.

To be more precise, COMPUTER NETWORKING connects a computer with other computers or devices to bridge the communication.

The various types of network are categorized based on geographic coverage.

The most common ones are

LAN  ---> Local Area Network

• confined to relatively small area
• eg: lab, schook. building
• rarely a mile apart ( between LANs computers )
• typical configuration : 1 computer acts as a server to store all the softwares that control the network and to be shared by all the computers attached to the network.

 WAN  ---> Wide-Area Network

• Connect larger geographic areas
• eg : JB, Malaysia, the world.
• Schools in JB can communicate with places like KL
• cable and satellite uplinks 
• uses multiplexing

MAN ---> Metropolitan Area Network

• spans a city or a large campus
• interconnects a number of LANs using technologies like fibre-optical links
• provides up-links service to WAN and the internet.

PAN --->  Personal Area Network

• used for communication among computerized devices, including telephone and personal digital assistants
• intrapersonal communication 

How are networks categorized? Using 3 properties:

- Topology ( geometric arrangement of the network )
- Protocol ( common set of rules & signals )
- Architecture ( peer to peer, client/server )


Network topology indicates how a network is designed ; there are 4 main types of network structures :

Bus Network Structure

• Only 1 computer can transfer information at a time.
• Information moves through the entire length of the cable.
• There is a terminator at the end of each cable
• Terminator absorbs signals transmitted, prevents the signals from bouncing back and causing interference.
• Advantage : simple
• Disadvantage: difficult expansion, computer malfunction affects the entire network, expensive

 Star Network Structure

• Individual computer connected to a centre point of the network
• Most common type of network
• Central network connector : hub
• Cable length betwwen the hub and the computers < 100 meters.
• Advantage: easy, computer malfunction doesn't affect the network.
• Disadvantage : relies a lot on the hub to function, costly, large amounts of cable are used.

 Ring Strucure Structure

•  individual computers connected to a single length of cable arranged in a ring.
• The information travels in 1 direction only.
• Used to connect computers locate close to each other.
• No beginning or end in a ring network.
• Advantage: easy to install, low cost, easy to determine the location of faulty connection, help prevent network shutdown.
• Disadvantage: difficult expansion, expensive.

 Hybrid Network Structure

• A mixture of many different kinds of network structures.
• Centralization network layout.

Transmission Media:

* Bounded Media ( twisted pair wire, co-axial cable, fibre optic cables)
* Unbounded Media ( AM/FM radio, TV broadcasting, Satellite communication, Microwave radio, Infrare signals)

Network Electronic Device

1.  Bridges
2. Router
3. private brance exhange (PBX)
4. multiplexer
5. concentrator
6. front end processor
7. hubs
8. gateways

My little reflection of the day :

This life is also all about networking, isn't it ? XD

Befriend, Socialize, Study, Love....

and those are the stepping stones which get us nearer and make it easier to reach our destination :)

Data Communication

So soon that it's already my second official lecture XD

I have been blogging for quite some years but never ever blog in such a way of summarising class harvest week in and week out.

Guess what? I'm gradually falling in love with the making of this very personal learning trace :）

What I write is just all what I stand for and belong to in terms of knowledge.

This awesome week, we learnt about Data Communication.

It's about：

collection and distribution 

  of the  

  electronic information （What)

  from & to  

  remote facilities （Where)

  by means of

electrical transmission system.(How)

Data can appear in a variety of styles...

Be it TEXT

Be it STILL PICTURE

Be it ANIMATED GRAPHIC

Or even VIDEO

All these types of raw data must be digitized ( converted into signal that can be understood by the communication media ).

There are 2 forms of signal which can be converted into.

1. Analogue signal

* Formed by continuously varying voltage levels that create a wave

* Represented by characteristic sine wave.

*Frequency is the number of oscillations or wavelength cycles per second. It is measured in Hertz (Hz).

*Amplitude = Wave's height (V)/ decibel (dB) 

2. Digital signal 

* Transmission of binary electrical/ light pulses that only have to state 0 & 1.

* Need to be changed into analogue signal to be transmitted through PSTN line.

The process of changing...

 The hardware used in a computer to perform this process is the MoDem.

There are 2 types of data transmission mode:

1. Parallel transmission, where a group of bits is transmitted simultaneously by using a separate line for each bit.

 like a supermarket having a number of cashier counters to serve groups of customer separately at the same time 

XD

2. Serial transmission transmits all the bits one after one another on a single line.

similar to... a single long queue !

Next, we'll take a look on Data Flow

There are 3 operation styles :

1. Simplex 
- Data is transmitted in one direction.
- The role of transmitter and receiver are fixed.
- eg: radio station, Television

2. Half-duplex 
- Message can flow in two direction.
- The role of transmitter and receiver can be exchanged.
- eg: walkie-talkie
- Better than simplex

3. Full-duplex
- Consists of 2 simplex channel
- Both station can transmit and receive simultaneously
- eg: onlie chatting, phone call

Multiplexing 

* a set of techniques that enable more than one device to combine and send their signals simultaneously through a single data link.

* Networks can transfer several types of information. Each type uses a different method.

* The latest technology of the link includes high-bandwith media eg coaxial cable, optical fibre and terrestrial and satellite microwaves.

* Each of the links has an adequate carrying capacity. When two or more devices share the same link, it will be cost-effective.

My little reflection of the day:

Have learnt the importance of being pro-active without having to wait for briefing and instruction all the time, as the only one in the class who emailed her blog url to Dr.Dayang, Sara managed to get full mark for the first class entry  due to her willing to take initiative ;)


A thousand miles of journey begins with a single step. So why afraid of taking the first move? 


We always wait for the right moment with the right self at the right place to do the right thing.


But realise it or not? We're living in a world which is elapsing..there's only RIGHT NOW.