Networking

• Network cables


  • Twisted pair: RJ45, RJ11
  • Fiber optic: SC, ST, LC
  • Coaxial: F-connector, BNC
  • Plenum-rated: Fire-resistant cable designed for airways, conduits, and regions where sprinklers cannot reach
• Cabling standards


  • Category 3: 10 Mb/s
  • Category 5: 100 Mb/s
  • Category 5e: 100 Mb/s and gigabit networks
  • Category 6/6a: gigabit and 10 Gb/s networks
  • Category 7: gigabit and 10 Gb/s networks
• Wiring patterns

  • T568A
  • T568B
• Thunderbolt


  • Version 1 is 10 Gb/s and uses DisplayPort
  • Version 2 is 20 Gb/s and also uses DisplayPort
  • Version 3 is 40 Gb/s and uses USB-C
• Universal Serial Bus (USB)


  • Can support up to 127 devices
  • USB 1.1 (full speed) runs at 12 Mb/s by a max cable length of 3m
  • USB 2.0 (high-speed) runs at 480 Mb/s by a max cable length of 5m
  • USB 3.0 (SuperSpeed) runs at 5 Gb/s
  • USB 3.1 (SuperSpeed+) runs at 10 Gb/s
  • Version 3.x ports are blue
  • Desktop/laptop computers use USB-A/B connectors
  • Tablets/smartphones use mini- and micro-connectors
  • USB-C: one-third size of USB-A plug; compatible with USB 3.1
• Bluetooth


  • Short-range technology for simplifying communication and connectivity among network devices
  • Bluetooth transmission range lengths: Class I: 100m, Class II: 10m (most popular), Class III: 1m (unpopular)
  • Bluetooth maximum data transfer rate: Version 1: 721 Kb/s, Version 2: 2.1 Mb/s, Version 3: 24 Mb/s
• IPv4 address


  • 32-bit number, consisting of four decimals from 0 to 255 separated by period (.)
  • Manual entry or Dynamic Host Configuration Protocol (DHCP) determines your IPv4 address
  • IPv4 loopback: 127.0.0.1
  • APIPA/link-local: 169.254.x.x
• IPv6 address


  • 128-bit hexadecimal number
  • IPv6 loopback: ::1 (unicast)
• IPv4 address classes


  • Class A: 1–126, 255.0.0.0, 10.x.x.x
  • Class B: 128–191, 255.255.0.0, 172.16.0.0–172.31.255.255
  • Class C: 192–223, 255.255.255.0, 192.168.x.x
• Wireless Ethernet


  • 802.11a: 54 Mb/s, 5 GHz
  • 802.11b: 11 Mb/s, 2.4 GHz
  • 802.11g: 54 Mb/s, 2.4 GHz
  • 802.11n: 300/600 Mb/s, 2.4, 5 GHz
  • 802.11ac: ≥1.7 Gb/s, 5 GHz
  • 802.11ax: ≤9.6 Gb/s, 2.4, 5, 6 GHz
• Ports and Protocols


  • 21: File Transfer Protocol (FTP)
  • 22: Secure Shell (SSH)
  • 23: Telnet
  • 25, 587: Simple Mail Transfer Protocol (SMTP)
  • 53: Domain Naming System (DNS)
  • 80: Hypertext Transfer Protocol (HTTP)
  • 110: Post Office Protocol (POP3)
  • 137–139: NetBIOS
  • 143: Internet Message Access Protocol (IMAP)
• Network speed


  • 1000 Mb/s (gigabit Ethernet)
  • 10 Gb/s (10 Gb Ethernet)
• IPv4 address classes


  • Class A: 1–126, 255.0.0.0, 10.x.x.x
  • Class B: 128–191, 255.255.0.0, 172.16.0.0–172.31.255.255
  • Class C: 192–223, 255.255.255.0, 192.168.x.x
• Wireless Ethernet


  • 802.11a: 54 Mb/s, 5 GHz
  • 802.11b: 11 Mb/s, 2.4 GHz
  • 802.11g: 54 Mb/s, 2.4 GHz
  • 802.11n: 300/600 Mb/s, 2.4/5 GHz
  • 802.11ac: ≥1.7 Gb/s, 5 GHz
  • 802.11ax: ≤9.6 Gb/s, 2.4/5/6 GHz
• Ports and Protocols


  • 21: File Transfer Protocol (FTP)
  • 22: Secure Shell (SSH)
  • 23: Telnet
  • 25, 587: Simple Mail Transfer Protocol (SMTP)
  • 53: Domain Naming System (DNS)
  • 80: Hypertext Transfer Protocol (HTTP)
  • 110: Post Office Protocol (POP3)
  • 137–139: NetBIOS
  • 143: Internet Message Access Protocol (IMAP)
  • 443: HTTP Secure (HTTPS)
  • 445: Server Message Block (SMB)
  • 548: Apple Filing Protocol (AFP)
  • 3389: Remote Desktop Protocol (RDP)