Chapter 2 Review questions.
1. Describe the IP protocol. What is a DNS?
The Internet Protocol is the set of rules for sending data from one computer to another computer via the internet.
The IP protocol works by:
- Receiving the divided message that is being sent in packets, with each packet comprising of the senders address and the receivers address.
- Forwarding each packet to a gateway, until one is found that recognises the packet as containing the destination address within its domain.
- Once found the gateway forwards the packet to the computer within its domain that matches the receivers address.
DNS stands for Domain Name System and is a hierarchical naming system for Internet Protocol addresses. It uses a convention that provides a meaningful and easiily remembered name for an internet address.
2. Describe the TCP protocol. How is it related to the IP protocol?
The TCP stands for Transmission Control Protocol, it is a set of rules that work with the Internet Protocol to send data to computers over the internet.
Whereas the IP deals with the delivery of the data between computers, TCP:
- Divides the data into packets
- Numbers the packets
- Forwards the packets to the IP layer for delivery
- When the packets are successfully delivered to the delivery address, TCP reassembles them into the correct order.
It is related to the IP Protocol as together they form the TCP/IP protocol suite that is used for communications over the internet. TCP provides is responsible for dividing the message into packets from the senders computer and reassembling the packets into the message at the destination computer, whilst IP is responsible for the delivery of the packets through the internet.
3. Differentiate between intranets and extranets
An intranet is a collection of private networks within an organisation, that use internet technologies in a secure environment, to share internal communications between staff and services.
An extranet refers to a part of an organisations intranet that uses internet technologies for its networks, services and information, and extends to stakeholders who are not direct staff within an organisation.
4. Describe the different elements of the HTTP protocol.
HTTP stands for Hypertext Transfer Protocol. It is used for the distribution of any type of file (text, graphics, audio, video, and other multimedia files) over the internet. HTTP is an application protocol that runs on top of the TCP/IP protocol suite.
HTTP uses a client/server model and is a stateless protocol. A HTTP client such as a web browser opens a connection and sends a request message to an HTTP server, such as a web server. After receiving and processing the response the HTTP server will close the connection and no further communications are made until the process is again initiated by the HTTP client. It is a stateless protocol because it does not maintain an open state of communication between the client and the server.
The HTTP request and response messages are made up of the following elements:
- An initial request/response line
- Zero or more header lines
- A blank line
- An optional message body
The initial line of the request message contains three parts:
- A HTTP method, whose possible values are GET, POST or HEAD.
- The request URI (Uniform Resource Indicator)
- The HTTP version.
The initial line of the response message contains three parts separated by a space:
- The HTTP version.
- A response status code.
- An description of the status code in English.
The response status code is a three digit integer. The first digit of the status code identifies its category. The categories are comprised of:
- A first digit of 1 indicates an informational message
- A first digit of 2 indicates success
- A first digit of 3 redirects the client to another URL
- A first digit of 4 indicates a client error
- A first digit of 5 indicates a server error
Possible uses of the status code include:
- Testing for successful AJAX requests using client-side JavaScript by checking if the XmlHttpRequest object returns a status value of 200.
- Setting up a website generic error page for unfound URI’s within a site by setting a 404 error page.
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.
My experience with intranet based web portals has largely involved maintenance to a Sharepoint and PlumTree based portals. I have implemented content management systems which were a combination of external site and intranet. I have been involved with the development of online webshops which are small B2C applications, and I have used VPN to access client extranets for maintaining websites.
An example of an intranet/extranet application is Microsoft Sharepoint Services.
A web portal is a web application that retrieves information from varied sources and unifies the information, for the purpose of diseminating information to an online community. An example of a Web Portal is Plumtree.
B2B describes systems which involve transactions between two or more organisations, including information associated with development, manufacturing, delivery, sales and support. An example of a B2B application is BizTalk Server which is an EDI, Electronic Data Interchage, service. BizTalk is able to receive a document in almost any XML format from one organisation and forward that document in another XML format too a receiving organisation.
B2C describes transactions between an organisation and a consumer or client. Most banks provide an internet banking service, like the Commonwealth Bank’s Netbanking, that enables customers and businesses to conduct their banking transactions online.
VPN can be used for accessing secure areas of an extranet. An example of VPN is Microsofts VPN Server.
5. What role can VPN play in B2B e-commerce?
One example is in supply chain management whereby an organisation needs to be connected to a partners network for an extended period.
By collaboratively using VPN organisations can implement procedures where they share applications that aren’t available on their intranet. This enables access to real-time information such as inventory management and procurement.
References
Cisco, Internet Protocols (IP). (n.d.). Retrieved 11th June 2009 http://www.cisco.com/en/US/docs/internetworking/technology/handbook/Internet-Protocols.html
SearchWinDevelopment.com, HTTP. (n.d.). Retrieved 11th June 2009 from http://searchwindevelopment.techtarget.com/sDefinition/0,,sid8_gci214004,00.html
Wikipedia, Hypertext Transfer Protocol. (n.d.). Retrieved 11th June 2009 from http://en.wikipedia.org/wiki/Hypertext_Transfer_Protocol
James Marshall, HTTP Made Really Easy. (n.d.). Retrieved 11th June 2009 from http://www.jmarshall.com/easy/http/
Mike Cunningham. (2000). Smart Things to Know about E-commerce, pg 108 – 110: Capstone Publishing.
Allen, Attwood, Banrnett, Galloway, Haack. (2007). The Asp.net 2.0 Anthology, pg 308: Sitepoint Pty. Ltd.
