Networking essentials - lecture 1

• Network


  Anything that enables two or more computers to communicate with each other and/or other devices
• Computer network


  • Interconnected collection of autonomous computers (i.e. independent of others)
  • Collection of computers and other devices (e.g. printers, switches, routers, etc)
  • Uses a common protocol (e.g. TCP/IP)
  • Shares resources over a network medium

  
• Network components


  • Devices
  • Media
  • Services
• End devices


  Where a message originates from or where it is received
• Intermediary network devices


  Interconnect end devices in a network (e.g. switches, wireless access points, routers, firewalls)<|>Manage data flow through the network (e.g. regenerate and retransmit data signals, maintain information about network pathways, notify of errors and communication failures)

  
• Network media


  Communication across a network is carried through a medium which allows a message to travel from source to destination (e.g. metallic wires, glass, wireless transmission)
• Network representations


  Network diagrams/topology diagrams use symbols to represent devices within the network

  
• Network Interface Card (NIC), Physical Port, Interface are important terms to understand in network representations
• There are key differences between physical location of devices vs. ports and network addressing schemes in topology diagrams

  
• Advantages of networking computers over stand-alone machines

  • File sharing
  • Resource sharing
  • High reliability
  • Scalability
  • Communication medium
• You do not need to be present in a school anymore to attend a class due to online learning opportunities
• The globalization of the Internet has empowered individuals to create information that can be accessed globally
• Forms of communication enabled by networks include texting, social media, collaboration tools, blogs
• Ways to classify networks

  • Based on transmission media (wired, wireless)
  • Based on network size (LAN, WAN, MAN)
  • Based on management method (peer-to-peer, client/server)
  • Based on topology (bus, star, ring)

  
• Local Area Network (LAN)


  Spans a small geographic area owned or operated by an individual or IT department
• Wide Area Network (WAN)


  Spans a large geographic area typically involving one or more telecommunications service provider

  
• Characteristics of WANs


  • Interconnect LANs over wide geographical areas
  • Usually administered by multiple service providers
• The Internet


  Worldwide collection of interconnected LANs and WANs
• Clients and servers


  Clients are computers that send requests to servers to retrieve information<|>Servers are computers that provide information and services to clients
• Advantages of client/server networks

  • Facilitate resource sharing
  • Facilitate system backup and improve fault tolerance
  • Enhance security
  • Support more users
• Disadvantages of client/server networks

  • High cost for servers
  • Need expert to configure the network
  • Introduce a single point of failure
• Main types of network topology

  • Star
  • Mesh
  • Bus
  • Ring

  
• Star Topology


  A network topology where all devices connect to a central hub or switch, and data is forwarded from the hub to the intended device.
• Distance Constraints

  Star Topology is limited by the physical distance between the central device and the peripheral devices. Longer distances can result in signal degradation or attenuation.
• Difficult to Upgrade


  Upgrading the central device can be challenging, as it may require replacing the entire device, which can be time-consuming and expensive.
• Limited Scalability


  As the network grows, the central device can become a bottleneck, limiting network performance and scalability.
• Expensive


  The Star Topology requires a dedicated central device, which can be costly, especially for large networks.
• Single Point of Failure


  If the central hub or switch fails, the entire network becomes unavailable and all devices are unable to communicate with each other.