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.

   • A MESH NETWORK is: where some or all of the workstations or other devices are conected directly to each other. Most are usually connected to the node that they exchange the most data with.
   • A STAR NETWORK: 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.

2. Ethernet Benefits: Stable Connection, Reduced possibility to be hacked, More secure, Faster traffic speed, Generally has a good quality signal.

3. WIFI Benefits: Cheap set-up costs, More vulnerable to hacking, The signal quality will reduce through walls or obstructions, Can connect multiple devices without the need of extra hardware, Interference can occur, May not be able to receive signal, Tends to slow transfer speeds.

4. WIFI IS WIRELESS FREQUENCY. Radio waves are used to transmit data packets without the need for wires.

5. ENCRYPTION is a method of scrambling data with a keycode which makes no sense. In order to read the data the user is required to decrypt the data using the key.

6. IP ADDRESS: A unique string of numbers separated by full stops that identifies each computer using the internet protocol to communicate over a network.

   • IP CLASSES: 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.

7. MAC ADDRESSES or MEDIA ACCESS CONTROL ADDRESSES, uniquely identify a device on a network by identifying the network adapter that the device is using.

   • The MAC ADDRESS is embedded into the device when it is manufactured and the owner cannot change it.
     • The 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.

8. PROTOCOLS: Network Protocols are a set of rules or conventions which control the communication between devices on a network.

   • KEY PROTOCOLS: TCP/IP, HTTP, HTTPS, FTP, POP, IMAP, SMTP.

9. LAYERS: As a packet is prepared the data travels through layers where protocols manage it, adding or removing extra information as required.

10. PACKET SWITCHING; When you take something apart, send it and then reassemble it.

11. POP3 is a client/server protocol in which e-mail is received and held for you by your Internet server.

    • The Post Office Protocol is an application layer Internet standard Protocol used by local e=mail clients to retrieve e-mail from a remote server over a TCP/IP connection.

12. Types of Layers: Layer 1 (Physical Layer), Layer 2 (Data link