1. Unit 11- Computer Networks
BTEC First Extended Certificate
Unit 11- Computer Networks
L2-U11-CNW-A1.1 – Features and uses of Networks
Tutor: Mo Abdul

2. Objectives
By the end of this session you will understand the different features of computer networks such as:
Connection method
Scope or scale
Architecture
Topologies
Protocols
Utilities
Services
Users

3. What is a network
Computer networks are a collection of interconnected, wired or wireless, hardware and software that allow computer devices to communicate and share data with each other.

4. Connection Methods Home College
Generally, there are 2 method to connect a device to a network:
Wired AND Wireless
Home
College
A home network can be wireless and/or wired.
wired is a lot faster but requires a cable to connect to the internet
Wireless you do not need a wire and allow you to roam around the building within its range
The college network can be accessed wired and/or wirelessly.
Desktops are connected to the server by wired connection.
Laptops, pads and smart phones can be connected wirelessly

5. Scope or Scale
scope or scale is the type or size of the network. For example, there are the following networks:
Local Area Network (LAN)
Wide Area Network (WAN)
Metropolitan Area Network (MAN)
Personal Area Network (PAN)
Storage Area Network (SAN)

6. Local Area Network (LAN)
The definition of a LAN has become increasingly vague over the last ten years.
It was understood that it was interconnected computers at one location i.e. college or a workplace.
Know due to faster technology LAN devices can be used over longer distances.
A LAN can be as small as two computers by using a simple Ethernet connection or can divided into sub networks using switches and routers.

7. Wide Area Network (WAN)
A WAN is a complex network system, comprising of interconnected LANs.
WANs are used to connect LANs and other types of networks together, so that users and computers in one location can communicate with users and computers in other locations.
Network protocols including TCP/IP deliver transport and addressing functions.

8. Metropolitan Area Network (MAN)
Large computer network that spans a metropolitan area or campus.
The network size falls intermediate between LANs and WANs.
MANs provide Internet connectivity for LANs in a metropolitan region, and connect them to wider area networks like the Internet.
They typically use wireless infrastructure or optical fibre connections to link their sites.
A MAN (like a WAN) is not generally owned by a single organisation.
The MAN, its communications links and equipment are generally owned by either a consortium of users or by a network service provider who sells the service to the users.

9. Personal Area Network (PAN)
A computer network for an individual person/s.
PANs generally cover a range of less than 10 meters (about 30 feet).
PANs are a subset of local area network (LAN) that supports one person instead of a group.
An example of PAN is connecting 2 mobile phones to transfer an image.

10. Scope or Scale Home College
A home network is a small LAN as it is in a small geographical area.
Home networks can be accessed form anywhere within the house wired and/or wirelessly.
A college network can be a LAN and a WAN network.
Within a class they are a LAN.
Because staff need access across multiple sites, these sites form a WAN

11. Architecture
Architecture is the way computer form a network in relation to each others.
There are two types of architectures:
Peer-to-Peer
Client/Server

12. Architecture Home College A home network is a peer to peer network.
this is because all computers are equal.
it is simple and cheap to set up, compared to a client server network.
A college network is a Client/Server network.
All the data is saved centrally on the server.
This is so users can have secure access to their files form multiple computers in multiple classrooms.

13. Topologies
Topology is the way computers connect and communicate with each others.
Topologies include:
Physical
Star, Bus, Ring, Mesh, Tree
Logical
Ethernet and token ring
Ring - Passes a token between nodes to communicate; can be difficult to configure; a cable failure can bring down the whole network
Star - Attached to a central node; easy to add devices; most popular; nodes can fail without bringing down the network unless it is the central device
Bus - Single cable; simple to connect; must be terminated; network goes down with any break in the cable
Mesh - Each devices is connected to every other (full); good fault tolerance; expensive although wireless has brought the cost down; no centralisation; all nodes communicate

14. Protocols Some other known protocols are:
Protocols are agreed standards to communicate across networks.
Two of the main Protocols are:
Transmission Control Protocol (TCP) and Ethernet, Internet Protocol (IP) also known as TCP/IP
TCP - breaks data down into packets before they can be sent over a network. Reassembles the packets again when they arrive. Establishes and maintains network connections. Error control – acknowledges received data and requests retransmission if there are errors.
IP - addresses, send and receives data packets
Some other known protocols are:

15. Security
Security relates to files, folders, data, network access, resources
A secure network must have a secure method/s to access the network like requiring a username and password
Files and folders should have permissions to prevent users, who don not have the right from stealing or corrupting data.
Resources should be shared to minimise costs for example.

16. Utilities
Utilities are software programs and or applications such as virus protection, backup and remote desktop.
Anti virus is used to protect a network from attacks
Backups helps the network to recover from attacks
Remote desktop saves efforts and time by allowing technicians to access hardware remotely to troubleshoot problems.

17. Services
Services such as login, user account management, file/folder permissions to an individual user/group of users and print services.
These allow the network administrator to maintain the security the smooth running of the network.

18. Network Services Home College
Users on a home network can access the one and only printer in the home to print their documents.
This can save on printers initial cost as well as printing supplies.
Users on a college network have their own accounts which allow them to have access to their files and folders while stopping them from accessing other students work.

19. Users
Users can be individuals or groups of people arranged in different ways for different uses.
For example, you can have a teachers group to allow them access to students information such as phone numbers and home address.
Students can be put into groups to allow the to have the resources for their course such as Level 2 students having access to level 2 library on the shared drive.