Internet

How time flies…..there’s come to the last lecture of telecommunication and networking.

For me, telecommunication and networking is informative and at the same time, it brings a lot of fun. I appreciate the moment when I attend this class. It was a sweet and memorable experience.

Okey, now back to our topic. J

Internet in simple terms is a network of the interlinked computer networking worldwide, which is accessible to the general public. These interconnected computers work by transmitting data through a special type of packet switching which is known as the IP or the internet protocol.

INTERNET INFRASTRUCUTRE

Network infrastructure, is also commonly used to refer to the grouping of physical hardware and logical components which are needed to provide a number of features for the network.

Hierarchy of network:

-From single computer to LAN

-From LAN to ISP

-From ISP to www

INTERNET PROTOCOL

Internet protocol (IP) is a connectionless, routable protocol which performs addressing and routing functions. IP places data into packets, and removes data from packets. The use of IP in the Internet is the integral part of the network, as they provide the services of the internet, through different layers organization through the IP data packets. There are other protocols that are the sub-classes of the IP itself, like the TCP, and the HTTP.

Every computer assign a unique IP address. IP address consist of 32 bits (shown as 4 octets of numbers from 0-225 represented in decimal form instead of binary.

Internet Protocol Address( IP address)

Each computer (known as a host) on the Internet has at least one IP address that uniquely identifies it from all other computers on the Internet. 

IP address consists of 2 part:

1) Identifying the network

2) Identifying the node/host

The “classful” IP addressing scheme divides the total IP address space into five classes, A through E. We can determine in advance which address ranges belong to each class. It also means the opposite is possible: we can identify which class is associated with any address by examining just a few bits of the address.

1. If the first bit is a “0”, it's a class A address and we're done. (Half the address space has a “0” for the first bit, so this is why class A takes up half the address space.) If it's a “1”, continue to step two. 

2. If the second bit is a “0”, it's a class B address and we're done. (Half of the remaining non-class-A addresses, or one quarter of the total.) If it's a “1”, continue to step three. 

3. If the third bit is a “0”, it's a class C address and we're done. (Half again of what's left, or one eighth of the total.) If it's a “1”, continue to step four. 

4. If the fourth bit is a “0”, it's a class D address. (Half the remainder, or one sixteenth of the address space.) If it's a “1”, it's a class E address. (The other half, one sixteenth.)

IP Address Class	First Octet of IP Address	Lowest Value of First Octet (binary)	Highest Value of First Octet (binary)	Range of First Octet Values (decimal)	Octets in Network ID / Host ID	Theoretical IP Address Range
Class A	0xxx xxxx	0000 0001	0111 1110	1 to 126	1 / 3	1.0.0.0 to126.255.255.255
Class B	10xx xxxx	1000 0000	1011 1111	128 to 191	2 / 2	128.0.0.0 to191.255.255.255
Class C	110x xxxx	1100 0000	1101 1111	192 to 223	3 / 1	192.0.0.0 to223.255.255.255
Class D	1110 xxxx	1110 0000	1110 1111	224 to 239	—	224.0.0.0 to 239.255.255.255
Class E	1111 xxxx	1111 0000	1111 1111	240 to 255	—	240.0.0.0 to 255.255.255.255

IP Address Class Bit Patterns, First-Octet Ranges and Address Ranges

Domain Name System (DNS)

The DNS translates Internet domain and host names to IP addresses. DNS automatically converts the names we type in our Web browser address bar to the IP addresses of Web servers hosting those sites.

For example: www.yahoo.com is converted into numerical IP address 204.62.131.129.

Domain Name System

Internet Service Provider (ISP)

An ISP is also called as IAP (Internet Access Provider). An ISP is a company that supplies Internet connectivity to home and business customers. ISPs support one or more forms of Internet access, ranging from traditional modem dial-up to DSL and cable modem broadband service. In addition to basic connectivity, many ISPs also offer related Internet services like email, Web hosting and access to software tools. A few companies also offer free ISP service to those who need occasional Internet connectivity. These free offerings feature limited connect time and are often bundled with some other product or service.

ISP in Malaysia

ISP in Malaysia

ISP in Malaysia

HTTP(Hypertext Transfer Protocol)

HTTP (Hypertext Transfer Protocol) is the set of rules for transferring files (text, graphic images, sound, video, and other multimedia files) on the World Wide Web. As soon as a Web user opens their Web browser, the user is indirectly making use of HTTP. HTTP is an application protocol that runs on top of the TCP/IP suite of protocols (the foundation protocols for the Internet).

 A standard web address (such as http://www.google.com/) is called a URL; the prefix (http in the example) indicates its protocol.

How Does HTTP Work?

HTTP Is a request-response protocol.  For example, a Web browser initiates a

request to a server, typically by opening a TCP/IP connection.  The request itself

comprises

ü  A request line, 

ü  A set of request headers, and

ü  An entity.  

The server sends a response that comprises

ü  A status line, 

ü  A set of response headers, and

ü  An entity. 

The entity in the request or response can be thought of simply as the payload,

which may be binary data.  The other items are readable ASCII characters.  When the

response has been completed, either the browser or the server may terminate the

TCP/IP connection, or the browser can send another request.

Now I would like to share a video which shows the journey from domain name to a website….enjoy^^

Wireless technology

It's another brand new week!!!!

A new day brings new hope. So live the day to the fullest and hope to God that there's another day awaiting you. J

The topic for today was wireless technology. In this context, Dr Dayang taught us what is  the real definition for bluetooth.

Bluetooth

Bluetooth has becomes a part of our life now. However, all of you may wonder how exactly it works….So, here you go…. XD

How bluetooth work:

It utilizes a radio based, that means it does not require a line of sight connection in order to communicate.

2 bluetooth equipped devices simply have to come within 10 meter range of each other.

A device must request a connection either to accept or reject.

Concept:

Point to point and point to multiple connection with small network called piconets.

Each piconets hold up 8 active units.

When multiple network exist within the same room they become known as scatternet.

 To resist interference bluetooth employs spread-spectrum technique called frequency hoping.

Frequency hoping means several devices will be ON the same frequency at the same time.

Bluetooth and the future

The future of Bluetooth looks strong, with initiatives underway for higher throughput, more ubiquitous usage and links with Wifi and Ultra Wideband (UWB) broadcast technology.

Operating systems such as the Mac OS and Windows continue to have native support for Bluetooth.

The Bluetooth SIG partners are working on enabling Bluetooth information points, to enable advertising models based around users pulling information from ‘information points’, rather than having to ‘push’ information out.

Other emerging features include Bluetooth in cars; automatic configuration of piconets; and quality of service (QoS) improvements, for example enabling audio and video data to be transmitted at a higher quality.

Broadband

The term broadband refers to a telecommunications signal or device of greater bandwidth, in some sense, than another standard or usual signal or device (and the broader the band, the greater the capacity for traffic).

How is broadband different from dial-up service?

·         Broadband service provides higher-speed of data transmission. It allows more content to be carried through the transmission “pipeline.”

·         Broadband provides access to the highest quality Internet services—streaming media, VoIP (Internet phone), gaming, and interactive services. Many of these current and newly-developing services require the transfer of large amounts of data that may not be technically feasible with dial-up service. Therefore, broadband service may be increasingly necessary to access the full range of services and opportunities that the Internet can offer.

·         Broadband is always on. It does not block phone lines and there is no need to reconnect to network after logging off.

·         Less delay in transmission of content when using broadband.

Infrared

Infrared is a energy radiation with a frequency below our eyes sensitivity, so we cannot see it. Even that we cannot "see" sound frequencies, we know that it exist, we can listen them.

Infra-Red is interesting, because it is easily generated and doesn't suffer electromagnetic interference, so it is nicely used to communication and control, but it is not perfect, some other light emissions could contains infrared as well, and that can interfere in this communication. The sun is an example, since it emits a wide spectrum or radiation.

Infrared keyboard

The adventure of using lots of infra-red in TV/VCR remote controls and other applications, brought infra-red diodes (emitter and receivers) at very low cost at the market.

From now on you should think as infrared as just a "red" light.

This light can means something to the receiver, the "on or off" radiation can transmit different meanings.

Lots of things can generate infrared, anything that radiate heat do it, including out body, lamps, stove, oven, friction your hands together, even the hot water at the faucet. 

To allow a good communication using infra-red, and avoid those "fake" signals, it is imperative to use a "key" that can tell the receiver what is the real data transmitted and what is fake.  As an analogy, looking eye naked to the night sky you can see hundreds of stars, but you can spot easily a far away airplane just by its flashing strobe light.  That strobe light is the "key", the "coding" element that alerts us.

Before the end of our class, our classmates showed us how to use forum and chatting corner. They had provide us a lot of info about MSN,SKYPE and Yahoo Messenger. Thanks for their efforts!!! I had learnt a lot…..XD

MSN Messenger

Here's a video regarding the usage of infrared telescope to uncover hidden cosmic creatures, including the coolest stars, dark asteroids and the most luminous galaxies!!!

Unbounded /Unguided Media or Wireless Technology

The topic for this week’s lesson is unbounded /unguided media or as called as wireless technology. Unbounded / Unguided media or wireless media doesn't use any physical connectors between the two devices communicating. Usually the transmission is send through the atmosphere but sometimes it can be just across the rule. Wireless media is used when a physical obstruction or distance blocks are used with normal cable media.

TERRESTRIAL MICROWAVE

Terrestrial Micro waves are used are used to transmit wireless signals across a few miles. Terrestrial system requires that direct parabolic antennas can be pointed to each other. These systems operate in a low Giga Hertz range.

CHARACTERISTICS of terrestrial microwaves:

1)       Moderate to high cost.

2)       Moderately difficult installation

3)       1 M bps to 10 M bps capacity

4)       Variable attenuation

5)       Low immunity to EMI

6)       The taller the antenna, the longer the sight distance

There are 2 types of antenna:

ü  Parabolic dish

ü  Horn

PARABOLIC DISH

A parabolic dish is an antenna that uses a parabolic reflector, a curved surface with the cross-sectional shape of a parabola, to direct the radio waves.  

The main advantage of a parabolic dish is that it is highly directive; it functions similarly to a searchlight or flashlight reflector to direct the radio waves in a narrow beam, or receive radio waves from one particular direction only. Parabolic dish has some of the highest gains, that is they can produce the narrowest beam width angles, of any antenna type.

Parabolic Dish

HORN

A horn antenna is used for the transmission and reception of microwave signals. It derives its name from the characteristic flared appearance. The flared portion can be square, rectangular, or conical. The maximum radiation and response corresponds with the axis of the horn. In this respect, the antenna resembles an acoustic horn. It is usually fed with a wave guide.

Horn

In order to function properly, a horn antenna must be a certain minimum size relative to the wavelength of the incoming or outgoing electromagnetic field. If the horn is too small or the wavelength is too large (the frequency is too low), the antenna will not work efficiently.

SATELLITE

Satellite owns a similar principle as terrestrial microwave where it acts as a super tall antenna and repeater.

In general, a satellite is anything that orbits something else, as, for example, the moon orbits the earth. In a communications context, a satellite is a specialized wireless receiver/transmitter that is launched by a rocket and placed in orbit around the earth. There are hundreds of satellites currently in operation. They are used for such diverse purposes as weather forecasting, television broadcast, amateur radio communications, Internet communications, and the Global Positioning System, (GPS).

Transmission from earth to satellite----uplink

Transmission from satellite to earth---downlink

Satllite

RADIO FREQUENCY

How Does it Work	Radio frequency use electrical oscillation to transmit its signal. When an RF current is supplied to an antenna, an electromagnetic field is created that then is able to propagate through space.
Equipment	In order to receive radio signals an antenna must be used.
Distance covered	Different forms of electromagnetic energy are categorized by their wavelengths and frequencies. The RF part of the electromagnetic spectrum is generally defined as that part of the spectrum where electromagnetic waves have frequencies in the range of about 3 kilohertz (3 kHz) to 300 gigahertz (300 GHz).

Different Types of Radio Frequency

CELLULAR PHONE

How Does it Work	Make and receive telephone calls over a radio link whilst moving around a wide geographic area. It does so by connecting to a cellular network provided by a mobile phone operator, allowing access to the public telephone network. By contrast, a cordless telephone is used only within the short range of a single, private base station.
Equipment	Cellular phone
Distance covered	As the cellular telephone user moves from one cell or area of coverage to another, the telephone is effectively passed on to the local cell transmitter.

Cellular Phone

WIFI

How Does it Work	Wifi allows an electronic device to exchange data wirelessly (using radio waves) over a computer network, including high-speed Internet connections. The Wi-Fi Alliance defines Wi-Fi as any "wireless local area network (WLAN) products that are based on the Institute of Electrical and Electronics Engineers' (IEEE) 802.11 standards.
Equipment	A device that can use Wi-Fi (such as a personal computer, video game console, smartphone, tablet, or digital audio player) can connect to a network resource such as the Internet via a wireless network access point.
Distance covered	Access point (or hotspot) has a range of about 20 meters (65 feet) indoors and a greater range outdoors. Hotspot coverage can comprise an area as small as a single room with walls that block radio waves or as large as many square miles

I would like to share a video with you all. It is an interesting video regarding to the difference between 3G and 4G… J