CABLING

How time flies.....it’s coming to our 5th lecture class for telecommunication &networking .....

Yes, time is cruel, it doesn't wait for anyone. Can you believe that we 
had already go through almost 1 semester?? Can you believe that we 
had gone through the first quarter of 2012 already?

All assignments and homework suddenly say 'HI' to me and this had made me feel exhausted......T^T

I wish I can make the clock stop ticking right now.....>.<

So, I think it is the time for me to study hard since final exam is just around the corner…..

Ok, back to the topic…the topic for 5^th lecture class was CABLING…^^

Cabling sounds interesting for me..... o(^.^)o

First, you all may wonder what is the correct definition for cable……

Well, cable is the medium through which information usually moves

from one network device to another .

Several types of cable are commonly used with LANs.

In some cases, a network will utilize only one type of cable, while other networks will use a variety of cable types.

There are 4 types of cables:

1) Unshielded Twisted Pair (UTP) Cable

2) Shielded Twisted Pair (STP) Cable

3) Coaxial Cable

4) Fiber Optic Cable

Unshielded Twisted Pair (UTP) Cable

The cable has four pairs of wires inside the jacket. Each pair is twisted with a different number of twists per inch to help eliminate interference from adjacent pairs and other electrical devices.

The standard connector for unshielded twisted pair cabling is an RJ-45 connector. (RJ means registered jack)

A disadvantage of UTP is that it may be susceptible to radio and electrical frequency interference.

UTP Cable

Shielded Twisted Pair (STP) Cable

STP is a type of cable consists of two individual wires wrapped in a foil

shielding to help provide a more reliable data communication.

Hence, it is suitable for environments with electrical interference.

The disadvantage is the extra shielding can make

the cables quite bulky.

STP is often used on networks using Token Ring topology.

Coaxial Cable

Coaxial cabling has a single copper conductor at its center.

A plastic layer provides insulation between the center conductor and a

braided metal shield.

The metal shield helps to block any outside interference from fluorescent lights, motors, and other computers.

Fiber Optic Cable

Consists of a center glass core surrounded by several layers of protective materials

It transmits light rather than electronic signals eliminating the problem of

electrical interference.

It is ideal for certain environments that contain a large amount of electrical interference..

Fibre optic cable is superior than others since it is able to transmit signals over much longer distances than coaxial and twisted pair.

Fiber Optic Cable

Now, I am going to share a video so that all of you will be able to get a clearer image about fiber optics. 

Summary for Ethernet Cabling:

10 Base T: Unshielded Twisted Pair  :  100 meters

10 Base 2: Thin Coaxial  :  185 meters

10 Base 5: Thick Coaxial  :  500 meters

10 Base F: Fiber Optic  :  2000 meters

Cable and Topology:
Linear Bus : Coax, twisted pair, Fiber : Ethernet, Local Talk
Star : Twisted pair, Fier : Ethernet, Local talk
Star-Wired Ring : Twisted pair : Token Ring
Tree : Coax, Twisted Pair, Fiber ; Ethernet

That's all for this week's lecture.....see ya.....^^

Topology, Protocol, Architecture and ATM

HOORAY!!
It's coming to our 4th lesson for telecommunication &networking.
We are going to learn topology, protocol and architecture for this week's lesson.
At the beginning of the lesson, Dr Dayang showed us the definition of topology.


TOPOLOGY


Topology is the study of the arrangement or mapping of the elements such as links and nodes of a network.
Physical topology -The physical layout of devices on a network.It can also be defined as the way that the     devices on a network are arranged and how they communicate with each other

There are 6 types of physical topology:

1)Linear bus

2)Ring 

3)Star

4)Star-wired ring

5)Tree

6)Mesh

Linear bus topology

A linear bus topology consists of a main run of cable with a terminator at each end. All nodes are connected to the linear cable.

Ring topology

In a ring network, every device has exactly two neighbors for communication purposes. All messages travel through a ring in the same direction (either “clockwise” or “counterclockwise”). A failure in any cable or device breaks the loop and can take down the entire network.

Star topology

A star topology is designed with each node connected directly to a central network hub or concentrator.

Compared to the bus topology, a star network generally requires more cable, but a failure in any star network cable will only take down one computer’s network access and not the entire LAN. 

Star wired topology

In the star-wired ring physical topology, the hubs are "intelligent." If the physical ring is somehow broken, each hub is able to close the physical circuit at any point in its internal ring, so that the ring is restored.

Tree topology

A tree topology combines characteristics of linear bus and star topologies. It consists of groups of star-configured workstations connected to a linear bus backbone cable. Tree topologies allow for the expansion of an existing network, and enable schools to configure a network to meet their needs.

Mesh Topology

Mesh topologies involve the concept of routes. Unlike each of the previous topologies, messages sent on a mesh network can take any of several possible paths from source to destination.

PROTOCOL

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

Logical topology are bound to network protocols and describe how data is moved across the network.

Examples of protocol:

1. Ethernet

2. LocalTalk

3.Token Ring

4. FDDI


ETHERNET


Is a common logical bus topology protocol.
Early Ethernet network were half duplex, uses an access method called CSMA/CD (Carrier Sense Multiple Access/Collision Detection), a system where each computer listens to the cable before sending anything through the network to avoid collisions.


LOCAL TALK

Is a network protocol that was developed Macintosh computers.

Used a method called CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance), where a computer signals its intent to transmit before it actually does so.

The disadvantage of local talk is its slow speed (only 230 Kbps).

TOKEN RING

Its access method involves token-passing.

The computers are connected so that the signal travels around the network from one computer to another in a logical ring. 

FDDI

Fiber Distributed Data Interface is a network protocol that is used primarily to interconnect two or more local area networks, often over large distances.

A major advantage of FDDI is speed. It operates over fiber optic cable at 100 Mbps.

ARCHITECTURE

Network architectures are sometimes classified into two broad categories:

1）Peer to peer architecture 

2）Client server architecture

Peer to Peer architecture
In a peer-to-peer network, all computers are considered equal; they all have the same abilities to use the resources available on the network.

Client server architecture

Client server architecture allows the network to centralize functions

and applications in one or more dedicated file servers. The file servers become the heart of the

system, providing access to resources and providing security.

ATM (ASYNCHRONOUS TRANSFER MODE)

ATM is a network technology based on transferring data in cells or packets of a fixed size. The cell used with ATM is relatively small compared to units used with older technologies. The small, constant cell size allows ATM equipment to transmit video, audio, and computer data over the same network, and assure that no single type of data hogs the line.

Reflective of lecture class on 21/3/12

The topic for telecommunication class on 21th of March was 'Computer Networking'.^^
Before this, what I thought means by Computer Networking is we construct a network using computer....


After the class, I had realized that the real definition for computer networking is connecting a computer with other computers or other devices to enable them to communicate with each other. What a big mistake I had made !!!>.<

Computer Network enables us to communicate with each other instantaneously by only using our fingertips.

According to Dr Dayang, there are 2 types of computer network,that are basic network and LAN(local area network).

A basic network enables the sharing of data by connecting two computers via cable. A LAN is a network too.The difference is it serves as a communications infrastructure for computerized systems. This includes computers, printers, storage systems, and any other device that has a processor, and an ability and need to communicate with another system.

There are few types of area network type as well,such as LAN (Local Area Network), WAN (Wide Area Network)and MAN(Metropolitan Ares Network).They are distinguished based on their geographic coverage.

Besides that, Dr Dayang had also explained what is networking components to us also.Networking components can be categorize  into terminal,workstations and transmission media.

There are two types of transmission media:bounded media and unbounded media.Examples of bounded media are twisted pair wire and fiber optic cables.While examples of unbounded media are AM,FM radio and microwave radio.

Microwave radio

Network electronic devices are devices that controls data transmission from sources to destinations.It also act as interfere between different transmission media or communication protocol.Here are some examples:

Devices	Function
Bridge	- Bridge, or network bridge, is a device that can also connect networks, but unlike a router, its operation does not include the network layer of the OSI model. - It can only connect existing networks that you can access. It is basically unable to distinguish networks, unlike a router. - They can only be used when you intend to connect networks of same type. -Bridges reduce the amount of traffic on a LAN by dividing it into two segments. It reads the outermost section of data on the data packet, to tell where the message is going.
Router	-A router is used to route data packets between two networks. When data comes through the router it is forwarded to the correct computer. -A router, or routing, is considered more intelligent than a bridge, or bridging, because they make smarter decisions. - It only sends a packet to its intended destination, eliminating unnecessary traffic.
Hub	A hub is the simplest of these devices. Any data packet coming from one port is sent to all other ports. - A hub is a very simple (or dumb) device, once it gets bits of data sent from computer A to B, it does not check the destination, instead, it forwards that signal to all other computers (B, C, D…) within the network. B will then pick it up while other nodes discard it. - This amplifies that the traffic is shared.
Gateway	-Gateways are very intelligent devices or else can be a computer running the appropriate software to connect and translate data between networks with different protocols or architecture. -Hence, their work is much more complex than a normal router.

After almost one hour of lecture by Dr. Dayang, it is our turn to make our presentation about email application.We try to explain to our classmate so they will be able to create a free hotmail ,understand the features of it and Thunderbird application.

Our group had learnt a lot through this presentation.We had learnt how to conduct a class so that others can pay attention to what we said.

Dr Dayang had mentioned that she felt interested to Thunderbird since she never heard that before.

Thunderbird

So,I am going to share a video about the tutorial of Thunderbird.Hope that it can help you all to have a clearer picture about this application.

Reflective of lecture class on 7/3/12

Hi all, it's coming to my third lecture class of telecommunication and networking.
For your information, the topic of today's class was DATA COMMUNICATION.o(^^)o
Well,in last week lecture's class,Dr Dayang discuss what is communication with us...
This week,we are going deeper into this topic..^^

I wonder what is data communication??

After the class,I had learnt that data communication is actually a kind of communication which is the collection and distribution of the electronic representation of information from and to remote facilities.It uses electrical transmission system such as telephone lines,satellites or coaxial cable.

Telephone Lines

Using my previous knowledge,I understand that data can come in many types such as images and texts.
After today's class,I realized that all of these types of data need to be converted into a specific signal so that communication media can transfer it.
There are 2 types of signal:
1)Analogue signal
2)Digital signal

Analogue signal

Digital Signal

Comparison between Analogue Signal and Digital Signal

Analogue signal is commonly sent through PSTN line or commonly we known as 'phone line'.
While digital signal need to be converted into analogue signal before it can be transferred by PSTN line.


What I felt interesting for today's class was human voice is actually one of the analogue signal!!!!

After today's class,I realized that data communication is one of the common type of communication which used by all of the people around the world. I can understand the importance of data communication since it had become a part of our life now.It is unneglilible.
We can hardly imagine what will be happen to our world if data communication had lost its role.
Here's an interesting video which I would like to share with all of you!!
It tells what will be happen to our life with and without data communication.
From this video,I hope all of us will appreciate the conveniences and advantages that data communication had brought to us....^^

Reflective of lecture class on 29/02/12

Hi all....it's a new day of March...
And today is my very FIRST time to write a blog as well....please support ya....^^


This blog was created to write weekly reflection regarding my class of telecommunication and networking requested by my lecturer,Dr Dayang.It is one of my assignments....


OK,back to the reflection of my telecommunication class at 29th of February~
29th of February should be special for all since it occur only once in four years....^^
Now let's start with my impression to Dr Dayang...o(^-^)o
For me,Dr Dayang is a patient and well-manner lecturer,I had found out that she had put some sense of humour too while conducting her lecture session...

29th of February is my second lecture class of telecommunication & networking.
The purpose of this lecture class is mainly to the introduction to telecommunication. I had found out that this subject is actually a bit linked to one of my subject which I taken in last semester,that is educational technology~


When discussing about telecommunication,we must be wonder what is the meaning of communication,am I right?
Well,communication is the imparting,conveying or exchange of thoughts,messages,ideas,knowledge or information by sign and sounds like speech,signals,writing or behavior.

Now let me show you a video about the history of communication.Have a look!!

While the second video is about the evolution of communication.....^^enjoy ya....

TELECOMMUNICATIONS refer to the transfer of DATA from a TRANSMITTER to a RECEIVER across a DISTANCE.

What is a data?Data is represented by electromagnetic waves such as electricity,radio waves,lights and it is transmitted through medium like wire,cable and atmosphere.

It is awesome to have this kind of technology since it connects people all around the world!!

There are two categories of people that involved in computer and telecommunication:
1)PROFESSIONAL and
2)END USER

The first type or we called as the professional user is referring to those who have gone through training in technical or theory aspects,they are computer engineer or programmer,etc.

While the second type or end user is those who uses this kind of technology without training,they are clerk,secretary or teacher,etc.

That's all for my reflection for this week's lecture class.The world is becoming increasingly interconnected and the amount of information to be transferred via networks is staggering.

It is necessary for us to know and develop the latest technology to overcome this mishap.
I hope by taking this subject,I will be able to explore more and deeply about the secrets that hidden behind the telecommunication and networking.