study guide exercise 4

1. Describe the IP protocol. What is DNS?

IP protocol is the main protocol in the Internet Layer of the Internet Protocol Suite. The main task of the IP protocol is to deliver datagrams/packets from the source machine to the destination machine solely based on their addresses. Considering machine addresses are based on numbers, it is a bit difficult for human to manage. This is where DNS role is important.
The Domain Name System (DNS) is a naming system for computers, services, or any resource that connects to the Internet. DNS most important use is that it translates domain names that is understandable to humans into numerical (binary) values that associates with networking equipment for the purpose of locating and addressing these devices world-wide. For example, www.something.com translates to 111.222.123.88.

Reference:
Internet Protocol (2007), Last accessed April 5th, 2009 from
http://en.wikipedia.org/wiki/Internet_Protocol

Domain Name System (2008), Last accessed April 5th, 2009 from
http://en.wikipedia.org/wiki/Domain_Name_System

2. Describe the TCP protocol. How is it related to the IP protocol?

The Transmission Control Protocol (TCP) is one of the main protocols of the Internet Protocol Suite. As a matter of fact TCP was one of the two original components, along with Internet Protocol (IP),that is why the entire suite is known as TCP/IP. Whereas IP handles datagram/packet transmissions from computer to computer, TCP is concerned only with the two end systems. TCP provides reliable, ordered delivery of a stream of bytes from a program on one computer to another program on another computer. Besides the Web, other common applications of TCP include e-mail and file transfer. Among its other management tasks, TCP controls message size, the rate at which messages are exchanged, and network traffic congestion.

Reference:
Transfer Control Protocol (2008), Last accessed April 5th, 2009 from
http://en.wikipedia.org/wiki/TCP

3. Differentiate between intranets and extranets.

Intranet is a private network that use Internet technologies to share any part of an organization's information, documents, and/or other digital resources among its employees. Sometimes the term intranet refers only to the organization's internal website, but often it is a more extensive part of the organization's computer infrastructure and private websites are an important component and focal point of internal communication and collaboration. A simple exlanation of the intranet would be to understood it as a private version of the Internet.
While extranet is a private network that uses the Internet system to securely share some part of an organization's information or operations with suppliers, vendors, partners, customers or other businesses. An extranet can be viewed as part of a company's intranet that is extended to users outside the company.
Intranets differ from extranets in that the former are generally restricted to employees of the organization while extranets may also be accessed by customers, suppliers, or other approved parties. Extranets extend a private network onto the Internet with special provisions for access, authorization and authentication.

Reference:
Intranets (2007), Last accessed April 5th, 2009 from
http://en.wikipedia.org/wiki/Intranets

Extranets (2007), Last accessed April 5th, 2009 from
http://en.wikipedia.org/wiki/Extranet

4. Describe the different elements of HTTP protocol.

HTTP defines eight methods:
HEAD:
Asks for the response identical to the one that would correspond to a GET request, but without the response body.
GET
Requests a representation of the specified resource. Note that GET should not be used for operations that cause side-effects, such as using it for taking actions in web applications. One reason for this is that GET may be used arbitrarily by robots or crawlers.
POST
Submits data to be processed (e.g., from an HTML form) to the identified resource. The data is included in the body of the request. This may result in the creation of a new resource or the updates of existing resources or both.
PUT
Uploads a representation of the specified resource.
DELETE
Deletes the specified resource.
TRACE
Echoes back the received request, so that a client can see what intermediate servers are adding or changing in the request.
OPTIONS
Returns the HTTP methods that the server supports for specified URL. This can be used to check the functionality of a web server by requesting '*' instead of a specific resource.
CONNECT
Converts the request connection to a transparent TCP/IP tunnel, usually to facilitate SSL-encrypted communication (HTTPS) through an unencrypted HTTP proxy.

Reference:
Hypertext Transfer Protocol (2008), Last accessed April 5th, 2009 from
http://en.wikipedia.org/wiki/HTTP

5. What do you know about building e-business applications as an Intranet,
Extranet, Web portal, B2B, B2C or Virtual Private Network (VPN)? Find
some examples on the Web.

Building e-business application for different e-business models need to consider a lot of different aspects. For example extranet although only slightly differerent from intranet the security consideration is a lot different. The extranet need extra security since it involves parties outside the organization. Other than that they also have different priority. The Web Portal demands fast connection without less focus on the design, while B2B and B2C website needs to have an interesting design so that it can interest potential customer to visit their website.

6. What role can a VPN play in business-to-business e-commerce?

A virtual private network (VPN) is a computer network in which some of the links between nodes are carried by open connections or virtual circuits in some larger network (e.g., the Internet) as opposed to running across a single private network. The link-layer protocols of the virtual network are said to be tunneled through the larger network.
By using VPN, B2B e-commerce such as extranets can use the existing underlying network such as the Internet to establish their connection. This allows for huge cost reduction because organizations need not to build their own network to collaborate with their business partners.

Reference:
Virtual Private Network (2008), Last accessed April 5th, 2009 from
http://en.wikipedia.org/wiki/VPN