Unit 1.5 - Network Topologies, protocols and layers

Unit 1.5 - Network Topologies, protocols and layers

1. A computer network is a number of computers linked together to allow them to share resources. Networked computers can share hardware, software and data.

2. A Mesh Network is …. Where some or all of the workstations or other devices are connected directly to each of other. Most are usually connected to the node that they exchange the most data with.  A Star Network …..

3. WiFi is Wireless Frequency - radio waves are used to transmit data packets without the need for wires. This method is slower and more vulnerable to attack but it removes the need for cabling and networks This means that it can be set up in remote locations such as in vehicles, in parks or on planes etc.

4. Encryption is a method of scrambling data with a key code which makes no sense. On an open or public WiFi network anyone can join and sniff out packets of data from other users. Therefore encryption is used. If intercepted the data will have no meaning In order to read the data the user is required to decrypt the data using the key.

5. When you are using a secure site for example your bank, or purchasing on Amazon, encryption applied to keep your details safe: The encryption method used is called 'SSL' (Secure Socket Layer). A tiny padlock appears in your browser window, usally on the left hand side of the address bar and the website address starts with HTTPS://

6. A computer network is a number of computers linked together to allow them to share resources. Networked computers can share hardware, software and data. Remember also that connected devices could be printers, tablets, laptops or a webcam.

7. A unique string of numbers separated by full stops that identifies each computer using the Internet Protocol to communicate over a network. They are similar to as a postcode that is used to identify a house in a county on a street.

8. example ip address 192.168.1.23

9. Data travelling on a Network are sent as packets Each device on the internet has a unique IP address which is sent with the packets to identify which computer to send the data to. The address is broken down into four numbers which can represent a number between 0 and 255 separated by a full stop.

10. IP addresses also have different classes which identify the class of Network that the user is on. This indicates the number of total possible users and the purpose of the network

11. MAC addresses, or Media Access Control Addresses, uniquely identify a device on a network by identifying the network adapter that the device is using. This enables you to distinguish between different devices. Try this! On a windows computer you can locate your MAC address: Go to the start menu Type cmd Type ipconfig/ all The MAC address is listed as ‘Physical Address’

12. The MAC address is embedded into the device when it is manufactured and the owner cannot change it. A MAC address is a unique code which is built into the Network Interface Card (NIC) Each address is individual and is made up of 48 bits, usually written in hexadecimal for ease. The MAC address is embedded into the device when it is manufactured and the owner cannot change it. A MAC address is a unique code which is built into the Network Interface Card (NIC) Each address is individual and is made up of 48 bits, usually written in hexadecimal for ease.

13. an example mac address AA-34-G4-44-23-F1

14. Network protocols are a set of rules or conventions which control the communication between devices on a network

15. TCP/IP (Transmission Control Protocol/Internet Protocol) HTTP (Hyper Text Transfer Protocol) HTTPS (Hyper Text Transfer Protocol Secure) FTP (File Transfer Protocol) POP (Post Office Protocol) IMAP (Internet Message Access Protocol) SMTP (Simple Mail Transfer Protocol)

16. Networks transfer and receive a lot of data In one minute on the Internet: 640TB data transferred. This lesson considers how such a huge amount of data is sent to ensure that it arrives at the correct computer

17. The header also contains the packet number as well as the total number of packets, for example packet 4 of 60, packet 45 of 60. When the packets arrive at the destination this information is used to reassemble the data. Packets can be lost so sometimes the computer request the packet to be sent again, if a packet never arrives then it is deleted by the router.

18. layers

19. packet switching

20. In graphics software, a layer is the term used to describe the different levels at which you can place an object or image file. In the program you can stack, merge or define layers when creating a digital image.

21. In a star network, each device is connected by an individual cable directly to the server. Star networks are usually the layout of choice in schools and offices because they tend to be the most reliable of the topologies.