Friday, 1 June 2012

Seventh Footmark on 30th May

Introduction to Internet Infrastructure


 Have the courage to act on your dreams - leave behind you the internal forces that hold you back.

Relax Corner

The Perfect Son.

A: I have the perfect son.
B: Does he smoke?
A: No, he doesn't.
B: Does he drink whiskey?
A: No, he doesn't.
B: Does he ever come home late?
A: No, he doesn't.
B: I guess you really do have the perfect son. How old is he?
A: He will be six months old next Wednesday. 


* Quite funny *

* Enjoy *

....How do I feel.... 
Today is the last day to attend this class...
It is hard to describe the feeling...
Just hope that every moments in the classroom can be kept in our mind and will not forget the effort made by our lecturer and ourselve as well...
To be sure, this subject benefits me a lot espcially the wireless technology...
We gain as much knowledge as possible...
Althought it is last lesson, the spirit on this subject will be last in our heart...

<<For beautiful eyes, look for the good in others;
for beautiful lips, speak only words of kindness;
and for poise, walk with the knowledge
that you are never alone.>>

The lesson I learned.... 

1.       Internet infrastructure
       Hierarchy of Networks:
      From a single computer to LAN
      From LAN to ISP
      From ISP to www
       In order to connect urself to the internet, u just need a few things:
      Web browser
      Internet access
       However policy & procedures to bring u to internet is quite complicated.
      Every computer that is connected to the Internet is part of a network, even the one in your home. For example, you may use a modem and dial a local number to connect to an Internet Service Provider (ISP). At work, you may be part of a local area network (LAN), but you most likely still connect to the Internet using an ISP that your company has contracted with. When you connect to your ISP, you become part of their network. The ISP may then connect to a larger network and become part of their network. The Internet is simply a network of networks.

      Most large communications companies have their own dedicated backbones connecting various regions. In each region, the company has a Point of Presence (POP). The POP is a place for local users to access the company's network, often through a local phone number or dedicated line. The amazing thing here is that there is no overall controlling network. Instead, there are several high-level networks connecting to each other through Network Access Points or NAPs.

2.       Internet Protocol (IP)

      The Internet Protocol (IP) is the principal communications protocol used for relaying datagrams (also known as network packets) across an internetwork using the Internet Protocol Suite. Responsible for routing packets across network boundaries, it is the primary protocol that establishes the Internet.

      IP is the primary protocol in the Internet Layer of the Internet Protocol Suite and has the task of delivering datagrams from the source host to the destination host solely based on the addresses. For this purpose, IP defines datagram structures that encapsulate the data to be delivered. It also defines addressing methods that are used to label the datagram source and destination.

      Historically, IP was the connectionless datagram service in the original Transmission Control Program introduced by Vint Cerf and Bob Kahn in 1974, the other being the connection-oriented Transmission Control Protocol (TCP). The Internet Protocol Suite is therefore often referred to as TCP/IP.

      The first major version of IP, Internet Protocol Version 4 (IPv4), is the dominant protocol of the internet. Its successor is Internet Protocol Version 6 (IPv6), which is increasing in use.
       Is the internet standard protocol that provide a common layer over dissimilar network
       To move packets among “host” computer tru gateways
       Every computer assign 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 )
       IP add  consists of 2 part:
       Identifying the network
       Identifying the node/host
       Class of addresses determines which part belongs to the network add & which part belongs to node
       All nodes on a given network share the same network prefix but must have a unique host number
3.       Class A network

      The Class A networking address scheme is designed for the government and large institutions needing a great deal of unique nodes. Although the Class A network has only 254 unique network addresses, it can contain approximately 17 million unique nodes, which can make subnetting such a network a nightmare.

      Getting up to speed with subnetting Class A addresses requires a little forethought, some basic information, and a lot of practice. 

      This network is 8-bit network prefix. Its highest bit is set to 0, and contains a 7-bit network number and a 24-bit host number.

      A maximum of 126, which is (2 7 -2,) networks can be defined; two is subtracted because all an (0 and 1) subnet cannot be used in certain routers using RIP-1 Protocol. Each network supports a maximum of 16,777,214 (2 24 -2) hosts per network. You must subtract two because the base network represents host “0”, and the last host on the network is actually used for 1s ("broadcast") and may not be assigned to any host.

      The class A network address block contains 2 31 power (2,147,483,648) individual addresses. The IPv4 address space contains a maximum of 2 32 power (4,294,967,296) addresses, which mean that a class A network address space is 50% of the total IPv4 unicast, address space.
       Binary add start with 0 therefore decimal number can be anywhere from 1 to 126
 •       The first 8 bits (the first octet) identify the network and the remaining 24 bits indicate the host within the network.

4.       Class B network
       Binary add start with 10 = decimal number can be anywhere from 128 to 191
       The number 127 is reserved for loopback and is used for internal testing on the local machine)
       The first 16 bits (first 2 octet) = identify the network & the remaining 16 bit indicate the host 
 •      This network is a 16-bit network prefix; its highest bit order is set to 1-0. It is a 14-bit network number with a 16-bit host number.

 •      This class defines 16,384 (2 14 ) /16 networks, and supports a maximum of 65,534 (2 16 -2) hosts per network. Class B /16 block address is (1,073,741,824) = 2 30; therefore it represent 25% of the total IPV4.

5.       Class C network
       Binary add start with 110 = decimal number can be anywhere from 192 to 223
       The first 24 bits (first 3 octets) = identify the network
      This is a 24-bit network prefix; it has a 3 bit set to the highest order 1-1-0. It is a 21-bit network number with 8-bit host number.

      This class defines a maximum of 2,097,152 (2 21 ) /24 networks. And each network supports up to 254 (2 8 -2) hosts. The entire class C network represents 2 29 (536,870,912) addresses; therefore it is only 12.5 % of the total IPv4.

6.       Class D network
       Binary add start with 1110 = decimal number can be anywhere from 224 to 239
       Used to support multicasting

7.       Class E network
       Binary add start with 1111 = decimal number can be anywhere from 240 to 225
       Used for experimentation, never been documented or utilized in a standard way

       Internet service that translates domain names like into numerical IP address like
       Why we use DNS? = domain names are alphabetic (easier to remember)
      The Domain Name System (DNS) is a hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities. A Domain Name Service resolves queries for these names into IP addresses for the purpose of locating computer services and devices worldwide. By providing a worldwide, distributed keyword-based redirection service, the Domain Name System is an essential component of the functionality of the Internet.

      An often-used analogy to explain the Domain Name System is that it serves as the phone book for the Internet by translating human-friendly computer hostnames into IP addresses. For example, the domain name translates to the addresses (IPv4) and 2620:0:2d0:200::10 (IPv6). Unlike a phone book, however, DNS can be quickly updated and these updates distributed, allowing a service's location on the network to change without effecting the end users, who continue to use the same hostname. Users take advantage of this when they recite meaningful Uniform Resource Locators (URLs) and e-mail addresses without having to know how the computer actually locates the services.

      The Domain Name System distributes the responsibility of assigning domain names and mapping those names to IP addresses by designating authoritative name servers for each domain. Authoritative name servers are assigned to be responsible for their particular domains, and in turn can assign other authoritative name servers for their sub-domains. This mechanism has made the DNS distributed and fault tolerant and has helped avoid the need for a single central register to be continually consulted and updated. Additionally, the responsibility for maintaining and updating the master record for the domains is spread among many domain name registrars, who compete for the end-user's, domain-owner's, business. Domains can be moved from registrar to registrar at any time.

      The Domain Name System also specifies the technical functionality of this database service. It defines the DNS protocol, a detailed specification of the data structures and communication exchanges used in DNS, as part of the Internet Protocol Suite.

                                        Basics of the Domain Name System (DNS)

                                                       How does DSN work???


       IAPs (Internet access providers) 
      An Internet service provider (ISP) is an organization that provides access to the Internet.
      Internet service providers can be either community-owned and non-profit, or privately owned and for-profit.
      Access ISPs directly connect clients to the Internet using copper wires, wireless or fiber-optic connections.Hosting ISPs lease server space for smaller businesses and other people (colocation). Transit ISPs provide large amounts of bandwidth for connecting hosting ISPs to access ISPs.

      Short for HyperText Transfer Protocol, the underlying protocol used by the World Wide Web. HTTP defines how messages are formatted and transmitted, and what actions Web servers and browsers should take in response to various commands. For example, when you enter a URL in your browser, this actually sends an HTTP command to the Web server directing it to fetch and transmit the requested Web page.
        The other main standard that controls how the World Wide Web works is HTML, which covers how Web pages are formatted and displayed.
         HTTP is called a stateless protocol because each command is executed independently, without any knowledge of the commands that came before it. This is the main reason that it is difficult to implement Web sites that react intelligently to user input. This shortcoming of HTTP is being addressed in a number of new technologies, including ActiveX, Java, JavaScript and cookies

                                                           How Does the Internet Work ?    

<<<The power of one -
one thought, one action, one solution.>>>


1 comment:

  1. I have read your full post and i think it is very effective for me as well as others. Great job buddy thanks for your post.

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