Saturday, 2 June 2012

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. 
  1. 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. 
  1. 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. 
  1. 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^^




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