Networks

• Issues of Wi-Fi


  Security as broadcast can be intercepted

  Limited range - affceted by walls
• Rules of Ethernet are

  Make sure data is unused

  Make sure data takes turns to transfer (handshaking)
• Benefits of layers


  The products can work together even if one layer is not in use
• A standard is a


  A set of procedures that defines how networks interact and allows hardware and software to interact
• A protocol is


  Used to define how devices on networks interact
• Peer to peer advantages and disadvantages

  Advantages - don't have to log in

  Easier to set up

  Disadvantages - backups are made from individual work station

  If printer running from one peer no one can print work
• Peer to peer characteristics

  In small office or house

  Share parts of files
• Hub v switch


  *in switch data transmitted to specific node but hub data transmitted to every node

  *In switch less data collisions

  *Switch more expensive

  *switch better security
• Router v switch


  Router uses zip address but switch uses MAC address

  Router connects network but switch connects nodes
• Role of cables


  Joins individual nodes to form lans
• Switches pros and cons

  PROS:

  High security

  Low data collisions

  CONS:

  Expensive

  Only in high bandwidth networks
• NIC(Network Interface Card) is used to


  Converts data from nodes into a suitable format
• Wi-Fi v cables


  Cables are wired Wi-Fi wireless

  Cables less interference

  Cables are faster

  Cables have longer range before lost

  Wi-Fi not very secure
• Hub pros and cons

  PROS:

  Straight from one node to another

  Extends space of network

  Cheap

  CONS:

  Not secure

  High data collisions
• Characteristics of client server networks

  Have to log in

  Use authentication

  Request files on server
• Network architecture


  The way the components of a computer are arranged
• Wans advantages and disadvantages

  PROS:

  Connects companies in far geographical proximity

  Workers can collaborate

  CONS:

  expensive

  Have to hire lots of bandwidth

  Have to rely on external supplier if network fails
• Lans advantages and disadvantages

  PROS:

  Files can be shared

  User can log onto any workstation

  CONS:

  Costly

  Support staff needed

  If problem no one can access files
• Client server advantages and disadvantages

  PROS:

  Can log onto any computer on network

  Backups made centrally

  Software updates made from central server

  CONS:

  Need specialist staff

  More expensive

  If central file unavailable no one can access files
• A router is


  Device that transfer data from one network to another
• Pros and cons of star topology

  PROS:

  Fast data transfer

  Rare data collisions

  Good security

  Reliable

  CONS:

  expensive

  Need technical knowledge

  If central device down no one can access network
• Pro and cons external hosting.

  PROS:

  Hosts maintain server

  Won't run out of bandwidth

  Hosts perform backups

  CONS:

  Expensive

  If company server offline website unavailable
• Malware is


  Software designed to cause harm
• Viruses infect computers by

  Replicating code in other progrmas and comps and delete , corrupt files
• Worms infect by


  Replicating and slow down computer
• Trojan horse works by


  Disguising as a program that the user wants but once inside ,hidden code takes control and causes damage to comp
• Ransomware is


  Holds computer hostsge by locking or encrypting access, once paid access restored
• Unpatched software


  Software and security updates not installed so vulnrable
• Out of date antiware


  Antivirus not regularly updated so virus not detected
• Social engineering


  Obtain information by deceiving people
• The Cloud is


  Software and devices that run on comp
• Shoulder surfing


  Obtain info by observing as they input either over their shoulder or cctv camera
• Phishing


  An attack that sends an email or displays a Web announcement that falsely claims to be from a legitimate enterprise in an attempt to trick the user into surrendering private information
• Brute force attack


  Tries every combo of password till correct
• Antimalware


  Detects and eliminates malicious software
• Signature is a


  Unqiue code for a virus
• Pros and cons local hosting

  PROS:

  Run faster

  Less expensive

  Full control of website

  Full control

  CONS:

  Need knowledge

  Bandwidth issue

  Responsible for backups
• Passwords rules


  Lower cse

  Upper case

  Symbol

  Number
• Physical security


  Prevented by physicsl methods e.g guard , locks , fences
• Penetration testing


  Emply poeple to hack systems to find security holes