Networks Including The Internet (Copy)

Networking

• Networking Devices
  • Benefits of Networking Computers and Devices
    • Shared devices and reducing costs
    • Software licenses can be shared and used cheaply
    • Share files and data
    • Reliable data from central source such as file server
    • Central back up
    • Communication between users
    • Network manager can oversee the process
  • Drawbacks
    • Cabling and servers expensive
    • Complex management
    • Device breakdown and servers issues.
    • Hacking issues
• Networked Computers
  • Have a hardware, software and services infrastructure
  • Private Networks
    • Single company or organizations
    • Responsible for equipment and maintenance etc.
  • Public networks
    • Owned by communications carrier company
    • Many organizations with sub-network security management
• WAN and LAN
  • LAN
    • Local area network
    • In a small area
    • Uses hubs and switches
    • Needs router or modem for internet access
      • This makes it part of a WAN
  • WLAN
    • No wires or cables
    • But a LAN
    • Wireless access points (WAPs)
      • Connected into wired network at fixed locations
    • Either spread spectrum is used (longer distance)
      • Or Infrared used for shorter distances
    • WAP receives and transmits data between WLAN and wired network
  • WANs
    • WAN are long distance
    • Many LANs joined can form a WAN too
    • Like an ATM network system

Client-Server and Peer-To-Peer Networking Models

• Client-server model
  • • Dedicated servers and client work stations
  • Users access most files on dedicated servers
  • Dictates which user can access which file
  • Installation of software on client computer
  • Central security database for shared resources
  • Only assigned resources can be accessed
  • Central server for delivery of emails.
  • Stable system
  • Bottlenecked if too many clients requests
  • Central storage and management of data files
  • Share information without need for offline devices
  • Configured as host machine and as file server
• Peer-to-Peer Network
  • Each node joins the network to allow
    • Provision of services to all network users
    • Simply access data from another node
    • Peers connected to the network
    • Suppliers and consumers are peers
    • Equals on a network
  • No central server
  • No central storage
  • No authentication of users
  • No more than 10 nodes required
  • Little data security
• Thin Clients and Thick Clients
  • Thin client
    • Heavily dependent on access to server to allow constant access to  files and allow applications to run uninterrupted
    • Needs connection to computer at all times
    • Benefits
      • Less expensive to expand
      • All devices are linked to a server
      • Protection against hacking and malware
    • Drawbacks
      • High reliance on server
      • Running costs are extremely high
    • Relies on connection to remote server
    • Few local resources
    • Fast and stable connection
    • Connected on a remote server
  • Thick Client
    • Can work both offline and online
    • Run some features offline
    • Relies on local resources
    • Tolerant in slow network conditions
    • Can store data on local resources like HDD and SSD
    • Benefits
      • More robust
      • Clients have more control
    • Drawbacks
      • Less secure
      • Update required individually
      • Data integrity issues

Network Topologies

• Bus Network
  • Single central cable system
  • All cables and devices connected
  • Expand and cabling easy