MIDTERMS

• Computer network


  A collection of interconnected computers and other devices that are capable of sharing resources and information
• Purpose of a computer network

  To enable communication and collaboration between different devices, allowing them to share data, applications, and resources
• Network components


  • Nodes
  • Links

  
• Nodes


  The individual devices connected to the network (computers, servers, routers, switches, printers, and other devices)

  
• Links


  The communication pathways that connect nodes in a network (wired or wireless)
• Topology


  The physical or logical arrangement of nodes and links in a network

  
• Common topologies


  • Star
  • Bus
  • Ring
  • Mesh
  • Hybrid
• Protocols


  A set of rules and conventions that govern communication between devices on a network (e.g. TCP/IP)
• Local Area Network (LAN)


  A network limited to a small geographic area, such as a single building or a campus, that allows computers and devices to share resources and information locally

  
• Computer network

  A collection of interconnected computers and other devices that are capable of sharing resources and information

  
• Purpose of a computer network

  To enable communication and collaboration between different devices, allowing them to share data, applications, and resources

  
• Network components


  • Nodes
  • Links
• Nodes


  The individual devices connected to the network (computers, servers, routers, switches, printers, and other devices)

  
• Links


  The communication pathways that connect nodes in a network (wired or wireless)
• Topology


  The physical or logical arrangement of nodes and links in a network

  
• Common topologies


  • Star
  • Bus
  • Ring
  • Mesh
  • Hybrid
• Protocols


  A set of rules and conventions that govern communication between devices on a network (e.g. TCP/IP)
• Local Area Network (LAN)


  A network limited to a small geographic area, such as a single building or a campus, that allows computers and devices to share resources and information locally
• Wide Area Network (WAN)


  A network that covers a larger geographical area, often connecting multiple LANs across cities, countries, or even continents (the internet is an example)

  
• Metropolitan Area Network (MAN)


  A network that falls between a LAN and a WAN in terms of size, covering a larger area than a single building but smaller than a city, designed to provide network connectivity within a metropolitan area

  
• Internetwork


  A networked collection of LANs tied together by devices such as routers, created for reasons like separating groups of users/computers or accommodating a growing number of computers in a single LAN

  
• Physical topology


  The arrangement of cabling and how cables connect one device to another in a network
• Logical topology


  The data path that signals travel between computers on a network

  
• Basic physical topologies


  • Bus
  • Star
  • Ring
  • Point-to-point
• Bus topology


  • Continuous length of cable connecting one computer to another in daisy-chain fashion
  • Limit of 30 computers per cable segment
  • Maximum total length of 185 meters
  • Both ends must be terminated
  • Any break brings down the entire network
  • Adding/removing a machine temporarily brings down the network
  • Limited to 10 Mbps half-duplex communication
• Star topology


  • Uses a central device (hub or switch) to connect computers
  • Faster technologies than bus
  • Allows centralized monitoring and management of network traffic
  • Easier network upgrades
• Extended star topology


  • Several hubs or switches connected with one device as the central connecting point
• Ring topology


  • Devices daisy-chained with cabling brought around from the last device back to the first to form a ring
• Specialized networks


  • Storage area network (SAN)
  • Wireless personal area network (WPAN)
• WPAN


  Short-range networking technology designed to connect personal devices to exchange information (e.g. cell phones, PDAs, GPS devices, MP3 players, watches)
• How data travels in a physical bus

  • Electrical pulses (signals) travel the cable's length in all directions
  • Signal continues until it weakens or is absorbed by a terminator
  • Terminator is a resistor that absorbs the signal instead of allowing it to bounce back
  • Signal travel is called signal propagation
  • If not terminated, signal bounces or is reflected at end of medium
• Bus topology


  • Advantages
  • Disadvantages
• Star topology


  • Advantages
  • Disadvantages
• Mesh topology

  • Connects each device to every other device for redundancy and fault tolerance
  • Expensive due to multiple interfaces and cabling
  • Found in large WANs and internetworks
  • Every node not only sends its own signals but also relays data from other nodes
• FDDI


  Fiber Distributed Data Interface, a network backbone technology using fiber optic cable at 100 Mbps, with a dual ring design for redundancy
• Hybrid topology

  A combination of two or more standard topologies, such as star-bus or star-ring
• Star-bus hybrid


  • Two or more star topologies connected using a bus trunk as the backbone
• Network model


  Defines how and where resources are shared and how access to these resources is regulated
• Network models


  • Peer-to-peer
  • Server-based
• Peer-to-peer network


  Computers function as both clients and servers, with no centralized control over access to resources