1. Local & Wide Area Networks

2. Networks A network is two or more computers linked together
Networks are used to share programs, data and resources.
There are two main types of network
LAN (Local Area Network)
WAN (Wide Area Network)
Computers on a network are called stations.
One station on the network is a powerful computer called a file server.

3. Local Area Network (LAN)
covers a small area such as a room, building and is usually owned by an individual, company or small organisation
Is a fast network
Is connected by its own wiring

4. Advantages of LAN’s Share data and programs between stations
Share resources, e.g. peripherals such as printers, scanners.
Sharing makes it cheaper
Use service

5. Advantages of LAN’s Keep data secure using passwords
Reduce unauthorised access using different level of access (read-only)
Allow users to access their files from any computer on the network
Allow users to work on the same files at the same time (multi access)

6. LAN Transmission Media
copper wire
fibre optic (glass)
infrared
bluetooth
WiFi

7. WAN (Wide Area Networks)
A network that covers a large geographical area such as a country or the whole world!!
The Internet is one example

8. Advantages of WAN’s
Same as LAN’s except you do not usually share peripherals
Send worldwide
Video conferencing
Voice over data (Free phone calls worldwide)

9. WAN Transmission Media
Any communication carried over a long distance is called telecommunication.
A WAN uses the telephone system which includes:
Copper cables
Microwave transmission links
Satellite links
Optical fibres links

10. Network Security Data can be lost through accidents system failures
deliberate action (unauthorised access)
There are two ways of securing data:
physical security
electronic security

11. Physical Security locks on rooms
identity cards (Magnetic stripe or Smart card)
biometrics - fingerprint, iris scan or voice print
stand-alone computer

12. Electronic Security Passwords Levels of access
Encryption (putting into code)
Very important in wireless networks

13. Absolute Security
"Three may keep a secret if two of them are dead" Ben Franklin
NO NETWORK!!

14. Client & Server Network
A computer that delivers data and software to other computers (clients) linked by a network.
Usually has
Fast processor
Large memory
Large hard disc
Two-tier Client/Server In two-tier client/server, the database processing is done in the server. A SQL request is generated in the client and transmitted to the server. The DBMS searches for records at the server side and returns only matching records to the client. If 50 records met the criteria in our 100,000-record example, only 50KB would be transmitted over the LAN.
Three-tier Client/Server In three-tier client/server, the processing is divided between two or more servers, one typically used for application processing and another for database processing. This is common in large enterprises.
Because of the Internet, terms such as "Web based" and "Web enabled" have replaced the client/server buzzword, yet the client/server architecture is conceptually the same. Users' desktop and laptop computers are still clients, and there are hundreds of thousands of Web servers throughout the Internet delivering Web pages. Nevertheless, client/server is mostly used to refer to "legacy," non-Web based systems. What makes the term even fuzzier is the fact that many "old" client/server systems have been modified to include Web access. On the Web, the client runs the browser and just like legacy client/server can perform little or a lot of processing: simple displaying of HTML pages, more processing with embedded scripts or considerable processing with Java applets. A myriad of browser plug-ins provide all sorts of client-side processing. The server side of the Web is a multi-tier server architecture with interlinked Web servers, application servers, database servers and caching servers. See application server.

15. Types of servers File Mail CD Internet CD-Server
A CD-ROM reader designed for network use. It can be configured as a tower or jukebox. Towers contain several drives, and each drive holds one CD-ROM. Jukeboxes hold from a couple dozen to hundreds of discs, but have only a small number of drives. A robotic mechanism moves the discs to the drives as required.

16. File Server A file server stores
programs
data
list of all users allowed access to the network (authorised users)
Once you have logged-on the file server allows you access to the network (on-line)
Logging–on: identifies a user to the file server
( usually by entering username & password)
File server A high-speed computer in a network that stores the programs and data files shared by users. It acts like a remote disk drive. The difference between a file server and an application server is that the file server stores the programs and data, while the application server runs the programs and processes the data.

17. Network Interface Card (NIC)
This is a small circuit board that allows the computer to communicate with a computer network.
Some computers have a wireless network interface card that allows them to communicate with a nearby LAN

18. Social, Legal & Ethical Issues

19. Social Issues

20. Teleworking This is the process of
working from home and
using a computer
to connect to a wide area network
to communicate with the office.
There are several advantages to employees and employers:

21. Advantages of Teleworking
Advantages to employees:
Choose own working hours
Save money on fuel, child care costs
Reduce congestion on the roads, pollution and travelling time
Advantages to employers:
Do not have to provide premises, heating lighting, rent, rates.

22. Disadvantages of Teleworking
Disadvantages to Employees:
May not be given same rights to health & safety (electrical faults)
Workers may become isolated or lonely
Disadvantages to Employers
Must ensure all electrical equipment complies with health & safety issues
Must take responsibility for ‘information security’ of remote workers

23. Social Benefits of WAN Advantages:
Improve communication in isolated areas & reduce isolation
Allow people to keep in contact with family abroad via & websites
People connected to the Internet have access to a large pool of information (Information rich)
Disadvantages:
May increase social isolation as more people go on-line (become detached from real world)
Costly – those not connected may be further disadvantages (Information poor)

24. Legal Issues

25. Legal Issues Laws which affect computers include: Computer Misuse Act
The Data Protection Act
The Copyright, Designs & Patents Act
The Privacy and Electronic Communications Regulations 2003

26. Computer Misuse Act Unauthorised access (hacking) Creating a virus
A progam
that copies itself
that may cause harm

27. The Data Protection Act (1998)
This Act compels any company to take specific measures to ensure that all personal information held about living (identified or identifiable) individuals is processed according to eight Data Protection Principles

28. Data Protection Act Principles
Data users must
Obtain and process the data fairly and lawfully
Register the purpose for which they hold it
Use only for this purpose
Hold only adequate and relevant data
Keep data accurate and up-to-date
Not keep data longer than necessary
Give individuals access to their own data
Take appropriate security measures

29. Data Protection Act Exemptions
Law Enforcement
National Security
Examination Marks and Examiners’ Comments
Adoption Records and Reports
Lawyer-client communications.

30. The Copyright, Designs and Patents Act (1988)
“intellectual property”
“expression of an idea”
all computer software, whether covered by a specific licence or not, is copyrighted under this Act.
the program itself
screen shots
associated documentation

31. Privacy and Electronic Communications Regulations 2003
This act makes it illegal for companies to send you unsolicited (Junk Mail). Note: Unsolicited means something that you did not ask for.
Companies must get permission from an individual before they can send them an
or text
An Individual must be given the choice of refusal
Unsolicited means something that you did not ask for. Note: this does not mean it is unwanted 1
NEW RULES ON MARKETING
WHAT DO THEY MEAN FOR INDIVIDUALS?
From 11 December 2003, two new rules will apply to marketing when
the Privacy and Electronic Communications (EC Directive) Regulations 2003 come
into force.
1st New Rule
This rule applies to all marketing messages sent by electronic mail, regardless
of who the recipient is.
• The sender must not conceal their identity and
• The sender must provide a valid address for opt-out requests
2nd New Rule
This rule only applies to unsolicited marketing messages sent by electronic
mail to individual subscribers.
• Senders cannot send such messages unless they have the recipient’s
prior consent to do so.
This strict “opt-in” rule is relaxed if three exemption criteria are satisfied.
These three exemption criteria are as follows
1. The recipient’s address was collected “in the course of a
sale or negotiations for a sale”
2. The sender only sends promotional messages relating to their
“similar products and services” AND
3. When the address was collected, the recipient was given the
opportunity to opt out (free of charge except for the cost of
transmission) which they didn’t take. The opportunity to optout
must be given with every subsequent message.
GLOSSARY OF TERMS
“Electronic mail”
This means and text/picture/video messages
“Individual subscriber”
This means a residential subscriber, a sole trader or an unincorporated
partnership in England, Wales and N. Ireland.
“unsolicited”
This means something that is not invited. However, it does not mean
something that is “unwanted”. For example, you might welcome information
about special promotions from a company that you trust and who always
offers a good deal. You have not specifically “invited” these offers but you
have told the company that you don’t mind receiving information about
special promotions that they choose to send you. You may or may not take up
the offer if it interests you.

32. Ethical Issues

33. Ethical Issues
These are concerned with people’s judgement as to what is right or wrong.
Invasion of personal privacy
Is it acceptable for government bodies [NSA(US), GCHQ(UK)] to intercept private data sent across networks to prevent terrorism & crime
Censorship & freedom of speech
Should anyone be able to set up a website even though it is used to incite hatred & racism
Should the government be able to block these web sites, e.g. bomb making

34. Local & Wide Area Networks
End of presentation