Unit 5 Communication

Unit 5 Communication

1. Networks

   • WAN
   • LAN
   • Advantages:
     • Use of the same usernames and passwords on multiple connected systems
     • can share files and resources
   • Disadvantages
     • Expensive
     • Easier to experience security issues
     • More likely to encounter errors
     • Difficult to manage , expertise required
   • Topologies
     • Bus topology
       • advantage
         • easy to set up
         • cheap, less hardware required
       • disadvantages
         • risk of collisions
         • catastrophic failure if the wire is damaged
     • Ring topology
       • no collisions
       • catastrophic failure if the wire or one computer is damaged
       • hard to add more devices
     • Star topology
       • expensive, hub or switch require expertise to use
       • if one wire or computer fails to connect to the hub ,the network still works
       • no collisions
       • Easy to connect new devices to network
     • Mesh topology
       • pathfinding
         • Circuit switching
           • pathway locked until transmission is complete
             • large transmissions prevent others being sent for longer periods
         • Packet switching
           • data transmitted in chunks called packets
             • the packets take random pathways and must be put in order at their location
               • transmissions have a lag as a result
           • Must contain
             • source address
             • destination address
             • packet number
             • payload
             • checksum
       • no catastrophic failure in complete mesh
       • always a path to any connected device

2. Network Hardware

   • Switch
     • analyses packets and sends them only to the intended recipient
   • Hub
     • Routes packets round a network by blindly sending them to every device its connected to
   • Bridge
     • Connects two networks of the same type
   • Gateway
     • Connects two different networks
   • Router
     • Stores the address of computers on one network and transfers their data to devices on other networks
   • WAP
     • Wireless Access Point
     • creates a wireless network and allows other devices to connect
   • NIC
     • Network Interface Card
     • connects to a computer or other device and joins a network

3. Protocols

   • Ethernet
     • Wired protocol
   • Wi-Fi
     • Wireless protocol
   • HTTP
   • HTTPS
   • SMTP
   • FTP
   • IP
   • TCP

4. OSI 7 Layer Model

   • Session
   • Application
   • Presentation

5. Cybersecurity

   • Hacking techniques/threats
     • Malware
     • Phishing
     • SQL Injection
     • Social Engineering
     • Brute force
     • Denial of Service
   • Security methods/Defenses
     • Penetration Testing
     • Anti-malware

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