Exercise 4: Virtual Private Network

1. Internet protocols are the world's most popular open-system protocol which was developed in the mid-1970s by the Defense Advance Research Projects Agency(DARPA). They can be used to faciliate the communication between interconnected networks and also for the Local Area Network and Wide Area Network communication. (Cisco, 2009)


Figure1 Internet protocols span the complete range of OSI model layers. (Cisco, 2009)

Doman Name System, (DNS) is a system for converting hostname and domain into ip address on the internet or local network. It helps to translate domain names into meaningful for humans to identify the binary which is associated with networking equipment for the purpose to locate the world-wide addresses.(PCMag, 2009)

2. Transmission Control Protocol (TCP) is defined as a highly reliable host to host protocol between hosts in packet-switched computer communication networks, and also in the interconnected network systems. (Zapotoczky, 2002)

In the TCP/IP protocol suite, there are two main transport protocols, they are transmission protocol(TCP and user datagram protocol(UDP).

Role of TCP and UDP in TCP/IP refernce model ( Leung, 2005)

The relationship between the TCP and IP is IP takes care lower level transmissions from one computer to another as a message send across the internet, however, TCP works in a higher level concerned only with the two end systems.

3. Intranet is a private network to use the security internet technologies approach for sharing the information among the employees in an organisation. Extranet is almost the same like intranet approach, however it uses public telecommunication system to serve for the organisation's supplier, vendors, partners and customers. Business to Business and Business to Consumer is the same "state of mind" to provide other companies and consumers for the information sharing. (Wikipedia, 2009)
A Virtual Private Network (VPN) is a network that links between nodes and carried by open connection to for a larger network, authentication and encryptions are applied to the VPN to secure the network connection. (Wikipedia. 2009)

There are some basic rules on building up e-business applications as an intranet, extranet, web portal, b2b, b2c and vpn. - A Web server connected directly or indirectly to your computer network. The e-business application will stay on this server.
- A high speedy, company wide computer network so all employees can access the intranet.
- Applications developed with Hypertext Markup Language, the software authoring language of the World Wide Web.
- Remote access so off-site employees can access the intranet and suppliers and partners can access the extranet.
- Security functions so only authorized users can access the e-business application. Examples: Business to Business (b2b) site : http://www.easytrade.com/, Business to Customer (b2c) site : http://www.b2csite.com/,

4. VPN allows companies to connect their partners to consume web services sercurely and easily. VPN automatically create a virtual service tunnels between partners, allow b2b applications to utilize partner services without worrying about the complication and cost of setting up a security application (SOA, 2009)

References:

1. SOA, 2009, 'New B2B Services Security Solution for .Net Drives Partners Communication Using .Net Web Services' <http://www.soa.com/index.php/news/press_detail/digital_evolution_introduces_industrys_first_xml_vpn_for_net/> 2. Cisco, 2009, ' Internet Protocol' http://www.cisco.com/en/US/docs/internetworking/technology/handbook/Internet-Protocols.html
3. PCMag, 2009,' DNS Definition' <http://www.pcmag.com/encyclopedia_term/0,2542,t=domain+name+server&i=41620,00.asp>
4. Zapotoczky, 2002, ' TCP Header' <http://www.comp.hkbu.edu.hk/~comp2650/lecture/notes/Chapter3.pdf>
5. Wikipedia, 2009, 'Intranet' <http://en.wikipedia.org/wiki/Intranet>
6. Wikipedia, 2009, 'Extranet' <http://en.wikipedia.org/wiki/Extranet>
7. Wikipedia, 2009 ' Virtual Private Network' <http://en.wikipedia.org/wiki/VPN'>