Network Design - Paiet/Tech-Journal-for-Everything GitHub Wiki

Network Devices

• 1.1 Explain the functions and applications of various network devices
  • Router
    • OSI Layer 3
    • TCP/IP Layer 2
    • IP Addresses
    • Routes traffic between networks
  • Switch
    • OSI Layer 2
    • TCP/IP Layer 1
    • Functions
      • Forward
      • Filter
      • Flood
    • LAN Communication
  • Multilayer switch
    • OSI Layer 3
    • TCP/IP Layer 2
    • Performs both routing and switching
  • Firewall
    • OSI Layer 2,3,4,7
    • TCP/IP Layer All
    • SPI firewalls look at ports (OSI Transport)
  • HIDS
    • Examples
      • https://www.alienvault.com/
      • http://ossec.github.io/
  • IDS/IPS
    • Hardware-based
      • http://www.cisco.com/c/en/us/products/security/ngips/index.html
    • Software-base
      • https://www.snort.org/
  • Access point (wireless/wired)
    • OSI Layer 2
    • TCP/IP Layer 1
      • Provides wireless access to wired devices
  • Content filters
    • Software-based
      • http://www.handyfilter.com/
      • http://www.optenetpc.com/content-filter.html
    • Hardware-based
      • Cisco
      • Barracuda
      • WatchGuard
      • Ubiquiti
      • Dell SonicWall
  • Load balancer
  • Hub
    • OSI Layer 1
    • TCP/IP Layer 1
    • No Logic
    • Like a repeater for every port
    • Degrades performance
    • True hubs can be used to monitor
  • Analog modem
    • OSI Layer 2
    • TCP/IP Layer &
    • Modulator
    • Demodulator
    • Digital signals to tones
  • Packet shaper
    • Routers
    • Firewalls
    • Ensures that packets are not dropped (unlike filtering)
    • Packets are categorized, queued and directed
  • VPN concentrator
    • Used to increase the amount of simultaneous VPN connections without degrading the performance of the VPN communications
    • Performs encapsulation and decapsulation of multiple VPN communication

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| Device | OSI | TCP/IP | |--------|-----------|------------| |Router | Layer 3 | Layer 2 | |Switch | Layer 2 | Layer 1 | |MLS | Layer 2&3 | Layer 1&2 | |Firewall| MultiLyr | MultiLyr | |Hub | Layer 1 | Layer 1 | |Modem | Layer 2 | Layer 1 | |AP | Layer 2 | Layer 1 |

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Correction- I mentioned access points being layer 1 device of the OSI Model and it should be layer 2 as well for CSMA/CA and 802.11

TCP/IP Layer 1 OSI Layer 1 & 2