Friday, 23 March 2012

3rd entry

these are few information that I gained from my last class.....

a connection between 2 computer by direct cabling = basic network

-connecting computer with other computer/other devices to enable them to communicate with each other.
-a collection of hardware components and computers interconnected by a communication channel that allow sharing of resources and information.

- server is a computer hardware system dedicating to running one or more such services (as a host), to serve the needs of users of the other computers on the network.

1.LAN=local area network
2.WAN=wide area network
3.MAN=metropolitan area network
4.PAN=personal area network

-confined to a relatively small area
-cable are used to connect the network
-1 computer=1 server

-connect larger geographic area
 eg. Johor Bahru, Malaysia,
-cable or satellite uplinks used to connect them
-is complicated
-use multilexing to connect local & metropolitan network=hybrid network

-interconnects users in a region larger than LAN but smaller than WAN
-The latter usage is also sometimes referred to as a campus network

-computer network organized around an individual person.
-it can be constructed with cables or wireless.
-personal area networks genarally cover a range of less than 10 meters (about 30 feet).

# topology
# protocol
# architecture
--- topology describes the arrangement of system on a computer network. It defines how the computer or nodes, whithin the network are arranged and connected to each other. Some common network topologies include star, ring, line, bus and tree configuration.
---network protocol is a set of rules that governs the communication between computers on a networks. These rules include guidelines that regulate the following characteristic of a network: access method, allowed physical topologies, type of cabling, and speed of data transfer.
Below is some of the common-used network symbols to draw different kind of network protocol:
---network architecture is the design of a communication network. It ia a framework for a specification of a network's phisical component and their functional organization and configuration, its operational principles and procedures, as well as data formats used in its operation.

+bounded media
+unbounded media

-phisical links through signals are confined to narrow path
-also called guided media
-made up of an external conductor(usually copper) bounded by jacket material
-they offer high speed, good security and low cast.
-3 common types of bounded media are coaxial cable, twisted pairs cable and fibre optics cable.
-eg. bridges, routers

-no phisical connection is required.
-space of air is the transmission medium for electromagnetic waves
-source and destinatio can be static or mobile.
-broad spectrum from low to high bandwidth is available.
-can be quickly implemented.
-eg. switches, hubs gateways

    bridges--devices that filter data traffic at network boundary. Bridges reduce the amount of traffic on a LAN by dividing it into 2 segment.

     routers--devices that forward data packets between computer networks, creating an overlay internetwork. A routers is connected to two or more data lines from different networks.

   switches--is a small hardware device that joins multiple computers together within one local area  network(LAN)
    hubs--a common connection point for a devices in network. Commonly used to connect segments of a LAN.
hub system

    gateway--an internetworking system capable of joining together two networks that use different base protocols. It can be implemented completely in a software, completely in hardware, or as a combination of both.

Hopefully u will gain some benefits from these information...tq :D


Wednesday, 7 March 2012

second entry

Hi everyone :)

First of all I want to beg for forgiveness if my by blog is quite messy cause I'm still please forgive me....

Now, let's move on to the main topic. Yeahh!!! 

               these were basically what I have learnt in class........

  • Basically DATA COMMUNICATION is the collection and distribution of the electronic representation of informations FROM and TO remote facilities using electrical transmission system:- telephones lines, satellite or coaxial cable.
coaxial cable
  • The info can appear in any format:- data,text,voice etc…
                                 but most important!
                      RAW DATA must be DIGITIZED

  -Analogue signal
  -Digital signal                                                 
o   Like human voice 
o   Formed by continuously varying voltage level
                                                                                                       DIGITAL SIGNAL
  • the signals are converted into a binary code:- 0 & 1
Analogue to digital: modulation
Digital to analogue: demodulation
v         Hardware used to do the process: MODEM

  Unit of binary digits:-
               1 bit= a single digit, either 1 or 0            
               1 byte = 8 bits
               1 kilobytes=1024 Bytes
               1 megabytes=1024 Kilobytes
               1 gigabytes=1024 Megabytes
               1 terabytes=1024 gigabytes

1.      Parallel Transmission
-A group of bit is transmitted simultaneously by using a separate line for each bit 
2.      Serial Transmission
-Transmit all the bits one after another on a single line
-bit slower compared to parallel
-2 serial transmission modes
Ø  Synchronous Transmission
Ø  Asynchronous Transmission

Synchronous Transmission
o   A large group of data transmit in a block called a FRAME
Asynchronous Transmission
o   Bits divided into small groups(bytes) & send independently.
o   A bits can be send at any time & receiver never know when they will arrive.

- Simplex
2.      -Half-duplex
3.      -Full-duplex
  i.            SIMPLEX
        One direction of data transmit                             
·         Role of transmitter & receiver are FIXED          
·         Eg. Radio station, TV

ii.            HALF- DUPLEX
·         Message flow at 2 direction but NEVER at the same time
·         One station transmit into another without any interruption. The other station will response after that transmission has been completed
       Eg. Walkie-talkie                                                        

 iii.            FULL- DUPLEX
·         Can respond at the same time
·         Eg. Chatting, phonecall

fuhh!!! last but not the least is.......

·       =  Technique that enable more than 1 device to combine & send their signals simultaneously through a single      data link at the same time
·        = Different data uses different method to transfer
·        = Each link has a carrying capacity
·       =  Eg. Coaxial cable, optical tube

  i think that's all from me bye2......       

Sunday, 4 March 2012

first entry

Assalamualaikum and hye there!!! I'm so excited about this blog because this is my first blog. I'm speechless but today I will talk about the introduction of network and telecommunication.

It was our first lesson in this class. I really likes the way Dr. Dayang explained the topic to us. It was a very simple and clear explanation. First and foremost, she explained to us the definition of communication and telecommunication. For me communication and telecommunication have quite a same meaning which is the transfer of data, it just that in telecommunication the transferring is through a long distance.

Besides that, she also explained to us the elements of computer and communication. Basically, there are six elements of computer and telecommunication which include of people,procedure,data,hardware,software and communication. 

I think that's all from me...bye2 see yaa... :)