Activity 1 5 minutes to discuss and feedback on the following: What is a computer network? Write down all the words / phrases / acronyms you already know about computer networking.

Computer Communications and Networking Topic 6 Lesson 1: LANs Computer Communications and Networking

(this can involve physical or wireless connections, or both) Networking - LANs Learning Objectives: i) Understand what is meant by computer networking ii) Explain the advantages of a Local Area Network (LAN) iii) Describe the hardware needed to create a LAN iv) Understand the different roles of computers in peer-to-peer and client-server networks v) Describe (using diagrams) bus, ring & star network topologies What is a Computer Network? Two or more computers connected together to share information and resources. (this can involve physical or wireless connections, or both)

Networking - LANs A school network An office network A home network Learning Objectives: i) Understand what is meant by computer networking ii) Explain the advantages of a Local Area Network (LAN) iii) Describe the hardware needed to create a LAN iv) Understand the different roles of computers in peer-to-peer and client-server networks v) Describe (using diagrams) bus, ring & star network topologies A school network An office network A home network

Networking - LANs Learning Objectives: i) Understand what is meant by computer networking ii) Explain the advantages of a Local Area Network (LAN) iii) Describe the hardware needed to create a LAN iv) Understand the different roles of computers in peer-to-peer and client-server networks v) Describe (using diagrams) bus, ring & star network topologies Learning Check? So What is a Computer Network? Two or more computers connected together to share information and resources.

Networking - LANs What is a LAN? A LAN is a Local Area Network. Learning Objectives: i) Understand what is meant by computer networking ii) Explain the advantages of a Local Area Network (LAN) iii) Describe the hardware needed to create a LAN iv) Understand the different roles of computers in peer-to-peer and client-server networks v) Describe (using diagrams) bus, ring & star network topologies What is a LAN? A LAN is a Local Area Network. It is a connected set of computers and other devices. Each device is called a node (e.g. computer, printer, etc.) A LAN is installed on one site. Relatively small All network infrastructure is owned by the organisation

Local Area Network (LAN) Advantages It allows communications between workers / students It allows data to be shared It allows peripherals (e.g. printers) to be shared It allows computers to be upgraded more easily It allows distributed processing – the ability for a single program to be run simultaneously at various computers.

Local Area Network (LAN) Disadvantages Expertise required to set up and maintain a large network (costly) Security issues from unauthorised access to data Measures to secure a network include: Passwords – strong passwords use a range of character types Changing passwords frequently Not allowing users to install software With wireless access, use encryption

Networking - LANs What is needed to make a LAN? Networking Equipment Learning Objectives: i) Understand what is meant by computer networking ii) Explain the advantages of a Local Area Network (LAN) iii) Describe the hardware needed to create a LAN iv) Understand the different roles of computers in peer-to-peer and client-server networks v) Describe (using diagrams) bus, ring & star network topologies What is needed to make a LAN? Networking Equipment

+ Hardware needed At least two computers (Nodes) Each having a NIC – network interface card (either wired or wireless) The NICs convert the data signals from the nodes into data signals that can be transferred across the network.

Hardware needed Data Transfer Media Wires Wireless Technology

OR Switch Hub A device that connects nodes together. An intelligent device that can create and connect to different segments of the network. This reduces network traffic because data packets are sent to the nodes or segment where they are needed rather than being broadcast to the whole network. Hub A device that connects nodes together. Makes all connected nodes act as a single segment. Not intelligent – data packets are transmitted across the whole of the network. Cheap devices – USB hubs useful in home computer installations.

Hardware needed If the LAN is to connect to the Internet, a Router is needed. Routers work with data packets to send data between networks (e.g. over the internet)

Side Track….Wireless Home Networks Wireless access point Wireless technology has many advantages over wired networks: No building work needed Quick to add new workstations Flexible deployment of nodes Visitors can access network / internet But there are drawbacks: Slower performance Security issues

Networking - LANs Two Types of Network in a LAN: Peer-to-Peer Learning Objectives: i) Understand what is meant by computer networking ii) Explain the advantages of a Local Area Network (LAN) iii) Describe the hardware needed to create a LAN iv) Understand the different roles of computers in peer-to-peer and client-server networks v) Describe (using diagrams) bus, ring & star network topologies Two Types of Network in a LAN: Peer-to-Peer Client-Server

Network types: peer-to-peer All computers have the same status. May be very slow because of data collisions shared processor power Only suitable for small, low traffic networks. Very popular for home networks

Network types: client-server At least one computer is designated as a server. This must be a high specification machine. It offers services to client machines, such as centrally held software, data, file storage and peripheral access. The server: controls the network traffic. Logs usage of resources. Provides security. Clients have to log in – this identifies users and assigns rights. Big networks may have hundreds of servers.

Networking - LANs Bus Ring Star Learning Objectives: i) Understand what is meant by computer networking ii) Explain the advantages of a Local Area Network (LAN) iii) Describe the hardware needed to create a LAN iv) Understand the different roles of computers in peer-to-peer and client-server networks v) Describe (using diagrams) bus, ring & star network topologies Different ways that LANs can be set up: …these network setups are known as topologies Bus Ring Star

Network Topology The topology is the physical layout of the network. It affects: cost, performance, ease of installation.

Bus topology One common linking cable Nodes connected off the cable Cheap But: Slows down when heavily trafficked Lots of data collisions Any breakage to cable affects the whole network Only practical over limited distances

Ring topology One common linking cable Data passes all nodes One direction traffic Fast performance BUT: any problems and the whole network goes down.

Star topology Now the most common topology Shared link to server(s) via hub or switch Few data collisions Fast Can set up independent segments BUT – the most expensive topology as it requires the most cable

Activity 2 30 minutes: What type of network (client-server OR peer-to-peer) is suitable for ten or more users? Explain your choice. (3 marks) State three types of resources that are commonly shared on a network. (3 marks) Name a type of computer that can provide services but also request services off other computers. (1 mark) Describe and illustrate a star network topology. (2 marks) A small company has a tight budget & four workers. Describe the type of network topology that is best suited for them. (3 marks) Explain what is meant by a client computer. (3 marks) List the hardware that is required to connect any device to a Local Area Network (LAN). (5 marks) In your own words, describe what a network switch does. (3 marks)