Manav Goyal

Devices - Computer Networks

Hardwares

  • Cables
    • Guided/Wired
      • Transmission Media
      1. Unshielded/Twisted pair cable
        • 10 Base T or 100 Base T
          1. 10 => Bandwidth of 10 Mbps
          2. Base => Only one Signal can travel at a time, Opposite of this is Broadband
          3. T => Attenuation (Signal becomes weak) after 100 meter
        • Used in Ethernet LAN (Less than 10 Km)
        • Connectors Eg => UTP, STP, BNC, MGRT
        • UTP & STP
      2. Co-axial cable
        • 100 Base 2 => Attenuation after 200 meter
        • Co-axial
      3. Fibre Optic
        • Light signal instead of ELectrical signal
        • 100 Base Fx => Attenuation after 2 Km
        • Optical Fibre
        • Propagation Modes
        • Modes
    • Unguided/Wireless
      1. Radio Waves
        • Radio waves are used for multicast communications, such as radio and television, and paging systems. They can penetrate through walls. Highly regulated. Use omni directional antennas
      2. Microwaves
        • Microwaves are used for unicast communication such as cellular telephones, satellite networks, and wireless LANs. Higher frequency ranges cannot penetrate walls. Use directional antennas - point to point line of sight communications
      3. Infrared
        • Infrared signals can be used for short-range communication in a closed area using line-of-sight propagation
  • Operators/Repeaters
    • Regenerates the Signal strength to its original strength
    • 2 Port Device => Connected by 2 points
    • Forwarding => Forward the signal from one point to next
    • No Filtering => Can't stop Signal
    • Collision Domain = n => Does not stores value
    • High Traffic
  • Hubs
    • Multi-port Repeater
    • Forwarding
    • No Filtering
    • Collision Domain = n
    • High Traffic

Hardware + Software

  • Bridges (Physical & Data Link Layer)
    • Used to connect 2 different LAN
      • Structure => Source | Destination > Mac | Mac
    • Forwarding
    • Filtering
    • Collision Domain = 0 => No collision, as it Stores & Forward, have Buffer
    • Bridge data unit protocol => Creates a Spanning tree to remove Loops
    • Types
      1. Static
        • Each MAC address is given 1 of 2 values (P1 & P2) indicating which side it is Manually
        • If interface changes then all values have to be manually typed again
      2. Dynamic/Transparent
        • Bridge will make values dynamically, at start it will learn position
        • From 2nd time it can Filter
  • Switches (Physical & Data Link Layer)
    • Multi-port Bridge
    • Full Duplex Links => Signal can go & come at the same time
    • Traffic is Minimal
    • Collision Domain = 0
  • Routers (Physical & Data Link & Network Layer)
    • Used to connect 2 devices
    • Forwarding
      • Uses Routing Table
    • Filtering
      • Uses Address Resolution Protocol (ARP) request to get MAC address from IP Address
    • Routing
      • RIP Protocol
      • Distance Vector Routing Protocol
    • Flooding => Sending Signal in every direction
    • No Collision => Uses Store & Forward method
    • Collision vs Broadcast

Security

  • IDS
  • Firewall
    • Monitors and controls incoming and outgoing traffic based on predefined rules
    • Packet filtering firewall
      • Check IP/TCP header
      • Works on Network and Transport layer
      • Can block IP addresses or a Service
    • Application (Proxy) firewall
      • Works in layer 5

Others

  • Gateway
    • Devices capable of communicating in several standards
  • Modem
Share: