Networking!

1. Networking! Wednesday, August 7th 2013 By the Improvisors

2. What is an IP address • An Internet Protocol (IP) address is a protocol rule which contains the address of a digital device connected to the internet and similarly to a mailing address a computer needs an IP address to communicate with other computers over the internet (website). • IP addresses consist of four sets of numbers, for example 192.168.2.100.

3. Static and Dynamic • However some IP addresses will be subject to change, each IP address is either a static or dynamic IP address. Static IP addresses never change as opposed to dynamic IP address which are only temporary addresses and always change. A static IP address has been set for this computer, it will never change.

4. What is a Domain Name Server? • A Domain Name Server (DNS) is a web server which stores IP addresses to other more commonly known web servers such as Microsoft. However unlike a URL, the domain for Microsoft is split into Microsoft and .com. All of these are parts of a domain name which are stored with their associated websites in a DNS

5. Client/Server Models

6. Client/Server Models • The client/server model consists of computers or devices and server(s) • The clients are the computers or devices • Computers, mobiles, tablets. • The server is the information provider • A server in a company, school or university or ISP

7. This is how a C/S model works. • When the client is ‘waiting’ information is being sought from the server. • When the server is ‘waiting’, it is awaiting instruction from you!

8. So this a more ‘real’ view. • The clients are requesting information • The server is supplying the requested information.

9. Worked Example • Client requests a web page – enters URL • This goes to the operating server • The domain name server then converts this to an IP address • Web browser then sends request to web server • The info is sought • The client is given the page on their screen – request granted! Key Blue server waiting Green client waiting Source: Information Processes and Technology. “The Client Server Model ”(2009) Available at http://ipt2009.wikidot.com/the-client-server-model(accessed 10/07/2013)

10. Cookies & Cache

11. Cookies • Cookies are used by websites in an effort to gather information about the user viewing the web page. This is to offer a better user experience due to that page ‘remembering’ you. • Cookies are stored on the users local machine and can be accessed/edited/deleted by that same machine. • Advantages :- Tailors user experience, holds preferences for next time • Disadvantages :- Can hold personal Data, can grow to large sizes if not emptied BBC. (2013)

12. Cache • Internet cache is commonly used in the context of "browser cache". • Cache is designed to speed up the computer by prioritizing its contents for quick access. • cache holds copies of recently accessed data such as a web page and pictures on web pages. It keeps this data ready to "swap" onto your screen within fractions of a second. • Advantages:- Can deliver web pages quickly using saved versions • Disadvantages:- Can grow to a large size if not emptied, Has to update every time a change is made on a web page Gil, P. (2013).

13. How Cache can be used • A song is played • It can be stored locally • The song is Downloaded To a location on the computer • Can be accessed whenever

14. MAC Address

15. MAC Addresses MAC stands for Media Access Control It is a 12 digit hexadecimal number (48 bits in length) which uniquely identifies an adapter on a Local Area Network. The 1st half is the ID number of the adapter manufacturer The 2nd half represents the serial number assigned to the adapter by the manufacturer. For example: 00:A0:C9:14:C8:29 00:A0:C9 means that it belongs to Intel Corporation

16. Functions MAC addresses allow computers to uniquely identify themselves at the data link layer (layer 2 in OSI model. • OSI refers to Open Systems Interconnection Model

17. Advantages • It supports the hardware implementation of the network stack • Remains fixed whereas IP addresses change as the device changes from one network to another • Follows the network device • Bradley Mitchell, An introduction to MAC addresses • http://compnetworking.about.com/od/networkprotocolsip/l/aa062202a.htm [10/07/2013] • MAC addresses image • http://upload.wikimedia.org/wikipedia/commons/thumb/9/94/MAC-48_Address.svg/475px-MAC-48_Address.svg.png

18. References • BBC. (2013). Privacy & Cookies. Available: http://www.bbc.co.uk/privacy/cookies/about/?source_url=/privacy/bbc-cookies-policy.shtml. Last accessed 10/07/13. • Gil, P. (2013). Definition: "Cache" in Computers. Available: http://netforbeginners.about.com/od/c/g/def_cache.htm. Last accessed 10/07/13. • Information Processes and Technology. “The Client Server Model ” (2009) Available at http://ipt2009.wikidot.com/the-client-server-model(accessed 10/07/2013) • whatismyipaddress (2013) "What is an IP address?" http://whatismyipaddress.com/ip-address [accessed 10th July 2013]. • Gill, P (2013) What is a Domain Name? http://netforbeginners.about.com/od/d/f/domain_name.htm [accessed 10th July 2013]. • Bradley Mitchell, An introduction to MAC addresses • http://compnetworking.about.com/od/networkprotocolsip/l/aa062202a.htm [10/07/2013] • MAC addresses image http://upload.wikimedia.org/wikipedia/commons/thumb/9/94/MAC-48_Address.svg/475px-MAC-48_Address.svg.png