leejunkim

Computer Networking

2 min read

  • Devs mainly do these 2 tasks
    • Making programs
    • Maintaining programs (유지보수)
  • computer networking knowledge is useful for both fields

Basics

  • A network is made out of the hosts (the outermost nodes), network devices (hosts in the middle), communication media (wired/wireless), and the messages
  • A network is a graph data structure
  • The graph
    • Nodes
      • Any device connected to a network that can send, receive, or forward data
      • includes all hosts and networking devices
    • Edges

What’s in a network

  • Host
    • A host is a device connected to a network that can send and receive data, services, and applications. Examples include computers, laptops, smartphones, servers, and other network-enabled devices.
    • Client
      • sends request to host
    • Server
      • sends response to host
  • Network devices (네트워크 장비)
    • hardware and software that connect devices to a network and allow data to flow between them
    • NOT hosts because they don’t directly participate in user applications
    • Hub
    • Switch
    • Router
  • communication media (통신메체)
    • pathways used to transmit data
    • guided/wired
    • unguided/wireless
  • Message
    • The messages/data sent to and from hosts

Switching

Switching is the process of data being transferred from one device to another

  • Circuit switching
    • Using pre-defined circuits/channels between 2 hosts and using them to send messages
      • connection is established before any communication takes place
      • no devices are able to use that channel until session is complete
    • data travels in the same dedicated path in sequential order
    • usually used in telephone systems
    • Makes use of a circuit switch
  • Packet switching
    • packet = unit of sending messages
      • Payload
      • header
        • address
      • trailer (optional)
    • Makes use of a packet switch
      • router
      • switch
    • unlike circuit switching that uses predefined pathways, packet switching is more flexible
      • data is broken down into individual packets that take different routes to the destination
      • which means data may not arrive in the correct order, but the receiving device will reassemble the packets in the correct order so the data can be read
    • Types of ways to send packets
      • unicast (1 to 1)
      • broadcast - sending the packets to all hosts except itself in the network
        • broadcast domain - the range of the broadcast

Graph View

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