Chapter 6.7, Problem 6.3ARQ

Explanation of Solution

The Internet is an Internet:

The Internet simply called as “the Net” is a global network that connects millions of computers throughout the world via dedicated routers and servers. When two computers are connected they can send and receive all kinds of information such as text, images, graphics, etc.

IP Address:

A number which is used to identify a particular device is called an IP address, which also referred as an Internet address.

• It has two formats called “IPv4” and “IPv6”.

Reason for delivering packets with IP address:

Before sending a packet, it is important to provide internet address on the packet.

• Because, when a user enter a domain name in the browser, user’s system sends a request to the DNS server for asking its corresponding IP address.
• Finally, DNS server replies with the IP address and packets to be sent for that site.

Purpose of domain name:

Before sending a packet, it is important to provide domain name or IP address on the packet. It is difficult to remember the IP address to find a particular site; but it is easy to remember the domain name such as www.pondi.edu.in, www.yahoo.com and so on.

Way of associate domain names with IP address:

• The domain name can be defined as identification of any of the authority and control over the internet that contains rules and procedures known as the Domain Name System (DNS) where the domain name can be registered with the DNS.
• The domain name can be obtained by registering the name of any organization with any domain name system.
• DNS is used to assign the domain name to IP address.

Role of agencies like GoDaddy:

The role of GoDaddy Company is to register the domain name and gets approved from Internet Corporation for Assigned Names and Numbers (ICANN).

• It finds whether the name is unique. If the name is unique, then it applies the name for register.
• Finally, the applicant can associate a public IP address with the name once the registration is completed.

URL:

URL stands for “Uniform Resource Locator”, provides a method to locate a resource on the web.

• Basically, it contains protocols such as “http://”, “ftp://” and so on, followed by an Internet address or Domain name.

Three-tier architecture:

The three-tier architecture is a fundamental design of user computers and servers that contains three major components or tiers such as follows:

• User tier
• Server tier
• Database tier

Role of each tier in above architecture:

User tier:

• This tier contains computers and mobile devices which have web browsers that request the web page to process it.

Server tier:

• It consists of computers that execute web servers and process the requesting application programs.

Database tier:

• It also contains computers that execute DBMS, which process the user request to fetch and store data in the database.

Working methodology of three-tier architecture:

• When user enter an e-commerce website to buy products online, example “www.zulily.com” in their browser, the browser send a request to a computer in the server tire. Server tier computers can execute applications like web server, a commerce server and so on.
• The requested “www.zulily.com” page will be displayed on the user’s computer. If the user had clicked any product such as shoe, then the commerce server will send a request to the DBMS to retrieve shoe’s data from the database.
• Finally the server formats the page with the data and sends that web page to the user’s computer.

SOA:

SOA stands for “Service-Oriented Architecture”. It is a philosophy that states, each interaction among computing devices are referred as services in a prescribed, standard way.

Reason for encapsulation:

According to SOA terms, the work of each department is encapsulated in the department.

• By using SOA philosophies, each department will formally state the services it provides...