#Reflection 8

Assalamualaikum. 


Hello everyone! :D
This is going to be the last post in this blog. 


Today, we will go through a quick and simple reading on INTERNET INFRASTRUCTURE


Internet Infrastructure is a hierarchy of network:

• From single computer to LAN
• From LAN to ISP (Internet Service Provider)
• From ISP to WWW (World Wide Web)

In order to connect all of these, you need:

• computer
• web browser
• internet access

Next, let's take a look at INTERNET PROTOCOL (IP)

• IP provides a common layer over dissimilar network.
• It is also a standard protocol to connect LAN.
• It also functioned to move packet among host computer through gateways
• Every computer assign  unique IP adress.

The IP adress:

• Divided into 2:
• Identifying the network
• Identifying the node/host
• Consist of 32 bits
• Shown as 4 octets of numbers from 0-225 represented in decimal form instead of binary.

eg: 10101110 = 1 octet (8 binary)

eg: 168.212.226.204 = Decimal form (4 octet = 32 binary)

• Class of addresses determines which part belongs to the network address and which part belongs to the node.
• All nodes on a given network share the same network prefix but must have a unique host number.

Example:

CLASS A NETWORK

• Binary starts with 0
• Decimal number can be anywhere from 1-126
• The first 8 bits identify network
• Other 24 bits indicate the host within the network

CLASS B NETWORK

• Binary starts with 10
• Decimal number can be anywhere from 128-191
• The number 127 is reserved for loop back and is used for internal testing on the local machine
• First 16 bits will identify the network
• Other 16 bits indicate the host

CLASS C NETWORK

• Binary starts with 110
• Decimal number can be anywhere from 192-223
• The first 24 bits identify the network

CLASS D NETWORK

• Binary starts with 1110
• Decimal number can be anywhere from 224-239
• This type of network usually used to support multicasting.

CLASS E NETWORK

• Binary starts with 1111
• Decimal number can be anywhere from 240-254
• Used for experimenting
• Never been documented or utilized in a standard way. (-__-")

DOMAIN NAME SYSTEM (DNS)

It is a type of internet service that translate domain names into numerical address.

Eg: www.yahoo.com => into 204.62.131.129

Why use DNS? = It is easier to remember because the names are alphabetic :D

INTERNET SERVICE PROVIDER (ISP)

The ISP is the company that will provide the internet service to public.

• Example of ISP in Malaysia is like the one for broadband;
• TM Net
• Streamyx
• P1
• Celcom Broadband
• Maxis Broadband

HYPERTEXT TRANSFER PROTOCOL (HTTP)

HyperText Transfer Protocol is the underlying protocol used for the World Wide Web.

• It defines how messages are formatted and transmitted.
• Determine what actions should be taken by Web servers and browsers to response to various commands.

HTTP also called as a stateless protocol because each command is executed independently, without any knowledge of the commands that came before.

That is why it is difficult to implement Web sites! :O

Other new technologies such as Java, JavaScript and cookies has been invented to encounter the HTTP shortcomings.

That is all for now. Till then, I'm going to miss Dr Dayang so much. She is so warm and cheerful all the time. I hope our path will intersect later in the future.

Have a sweet day, all!

Toddles! :) 

Reflection #7

Wireless Technology


Dr. Dayang has proceeded the topic about wireless technology but unfortunately I couldn't come to class :(


Nevertheless, here is my entry to wrap up about the wireless technology. Well, I did some revision on my own about this topic.


WIRELESS

• Wireless telecommunications networks are a type of information transmission system that uses electromagnetic waves.

BLUETOOTH

The Bluetooth logo

• Bluetooth is an industrial specification for wireless personal area network or PANs.
• Bluetooth is acceptable for situations when two or more devices are in proximity to each other and don't require high bandwidth
• The distance covered only a very short range which is less than 10 meters. 
• Devices involved : mobile phones, laptops, PCs, printers, digitial cameras and video game consoles. 

The devices that use Bluetooth can be connected to the laptop as well.

INFRARED DATA TRANSMISSION

The IrDA logo.

• IrDA (Infrared Data Association) is a technology where we can transfer any files from any devices by using infrared light, the one that is non RF.
• The characteristic of infrared transmissions are: 
• The power to transfer data is not so high.
• Only can transfer in a short range, for example the remote control.
• Mainly attached to mobile phones to transfer the data or files from one to another.
• Nevertheless, many laptops sold today are equipped with an IrDA-compatible transceiver that enables communication with other devices, such as printers, modems, LANs, or other laptops.
• However, the limit of transfer speed ranges from 2400 bps to 4 Mbps.
• Requires line of sight transmission.

The various devices that can transfer files and data by using infrared communication.

BROADBAND TECHNOLOGY

• It refers to a telecommunications signal or device of greater bandwidth with greater the information-carrying capacity.
• Today, broadband is widely use to enable the internet access to laptop and mobile devices.
• The device that is simply used is the broadband stick with different service providers.

The different service providers in Malaysia.

• Mobile broadband allows for mobility so that the user can get internet access where ever there are. However, it depends on the service provider's coverage as well.
• Fixed broadband are mainly used for home or business and more stable because it uses cable and usually runs on fibre.

Router

Reflection #6

UNBOUNDED MEDIA / UNGUIDED MEDIA

• The media transport electromagnetic wave without physical conductor.
• Signal are broadcasting through air which means it is available to anyone who has device that capable of receiving the signal.

TERRESTIAL MICROWAVE

• It requires line of sight transmission and reception equipment.
• The taller the antennas, the longer the sight distance.
• Make tower on the hills or mountain to be higher than the ground.
• The signal transferred one way at a time.

To increase the distance, a system called repeater can be installed with the antenna.

2 TYPES OF ANTENNAS:

1. Parabolic dish
2. Horn

PARABOLIC DISH

• Based on geometry repeater of parabola.
• Works like a funnel (catching a wide range of waves and directing to a common point called focus)
• This is used by line namely maxis celcom and digi to catch the data.

HORN

• Looks like a gigantic scoop
• Outgoing transmission are broadcast up to a stern and deflected outward in a series of narrow parallel beams by the scooped shaped of the horn.
•  

SATELLITE

• Same principal as the terrestrial microwave
• Super tall antenna and repeater
• Single bounce
• Capability = any location on earth no matter how remote
• High quality communication without requiring a huge investment in ground-based infrastructure.

Now let see the equipment used and distance covered of four transmission:

1. RADIO FREQUENCY
2. CELLULAR PHONE
3. WIFI
4. BLUETOOTH

The equipment used and distance covered of four transmission:
 
RADIO FREQUENCY

• The rate of oscillation in the range of about 3 kHz to 300 GHz.
• Corresponds to the frequency of radio waves, and the alternating currents which carry radio signals.
• Antenna must be used to received the signal.
• Usually done via a resonator – a circuit with a capacitor and an inductor forming a tuned circuit.
• Resonator act as amplifier to the oscillations within a particular frequency band
• It also reducing oscillations at other frequencies outside the band.

 
CELLULAR PHONE
Cellular phone is using various transmission
1G  

• 1G is short for first-generation wireless telephone technology.
•  This generation of phones and networks is represented by the brick-sized analog phones introduced in the 1980’s.
•  Subsequent numbers refer to newer and upcoming technology.

2G  

• 2G phones use digital networks.
• 2G networks and their digital nature also made it more difficult to eavesdrop on mobile phone calls.
  

3G 

• 3G networks are an in between standard. 
• 3G is seen more as pre4G instead of a standard of its own. The advantage 3G networks have over 2G networks is speed.  
• 3G networks are built to handle the needs of today’s wireless users.
• This standard of wireless networks increases the speed of internet browsing, picture and video messaging, and handheld GPS use.

4G 

• 4G (AKA Beyond 3G) is like the other generations in that its advantage lies in promised increased speeds in data transmission. There is currently no formal definition for 4G, but there are objectives.  
• One of these objectives is for 4G to become a fully IP-based system, much like modern computer networks.  
• The supposed speeds for 4G will be between 100 Mbit/s and 1 Gbit/s.

WiFi

• WiFi is the original technology of wireless local area network or WLAN.
• It is usually based on IEEE 802.11 specifications.
• uses the same radio frequencies as Bluetooth, but with higher power consumption resulting in a stronger connection.
• The devices that are able to access this type of transmission are mobile computing devices such as laptops.
• With the frequency of 2.4 GHz, WiFi has the range 100-300 feet indoor and 300-900 feet outdoor.

All in all, we already used all these transmission and the evolution of these transmission are still going on today. Maybe in future, we might have a new technology that way more intelligent than today. Who knows?

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. 

WHAT IS CABLE?


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.