Network Connectors and Wireless Technology

Types of Connectors

  • Three main types:
    • LC (Lucent Connector): Often in pairs, locking connector with a locking mechanism.
    • SC (Subscriber Connector): Larger, bulkier square connector.
    • ST (Straight Tip): Has a distinctive tip that sticks out.

Coaxial Cable

  • Used for old cable connections (Time Warner).
  • F-type connector: Used to screw into the port behind TVs.
  • Shielded with a core signal conductor (single copper line).
  • Applications:
    • CCTV (still common).
    • Cable TV and broadband cable modems (historical).
    • Internet access (still in use, but better options exist).

Wireless Access Points (WAPs)

  • Also known as WAPs.
  • Commonly found in ceilings or on the side of desks.
  • Extends the wireless signal.
  • Functions as a connection-level extension of a switch.
  • Uses radio waves for data transmission.

Infrastructure Mode

  • Most common setup where each client connects via the access point.
  • Basic Service Set (BSS): Connection between client and access point.
    • BSSID: MAC address or serial number of the access point.
    • SSID: Service Set Identifier, the name you see when selecting a Wi-Fi network (e.g., "Rocco's internet").

Wireless Standards

  • 802.11: Standard for Wi-Fi.
  • 802.3: Standard for Ethernet.
  • Knowing that a 802.11 connection is down means your Wi-Fi is down.
  • Acts as a "bridge", sending information straight through without directing traffic.

Frequency Bands

  • Frequencies include 2.4 GHz, 5 GHz, and 6 GHz.

Channels

  • Frequency ranges grouped into channels to avoid interference.

Bandwidth

  • Common bandwidths: 20 MHz, 40 MHz, 80 MHz, 160 MHz.
  • 2.4 GHz spectrum:
    • limited frequencies.
    • potential for interference.
    • three non-overlapping 20 MHz channels.
  • 5 GHz spectrum:
    • more frequencies available.
    • supports 20 MHz, 40 MHz, 80 MHz, or 160 MHz bandwidths.
  • 6 GHz spectrum:
    • more spectrum to work with.
    • allows many different bandwidths.

Other Wireless Technologies

  • Bluetooth:
    • Uses 2.4 GHz range (Unlicensed ISM frequencies).
    • Used in wireless headsets and speakers.
    • Consumer devices have a range of about 10 meters.
  • RFID (Radio-Frequency Identification):
    • Uses: access badges, product tags, pet identification.
    • Powered by scanner's radio frequency.
    • Can be actively powered with batteries for longer range.
  • NFC (Near Field Communication):
    • Builds on RFID technology with two-way communication.
    • Uses: mobile payments, device configuration, identification.

Frequency Bands: 2.4 GHz vs. 5 GHz

  • 2.4 GHz:
    • Longer signal range.
    • Better for penetrating solid surfaces (walls).
    • Slower wavelength is less disrupted by walls.
  • 5 GHz:
    • Faster.
    • Doesn't penetrate walls well (disrupted by concrete, metal, and water).
    • Used when there are barriers that interfere the signal.

AirDrop

  • Combines Wi-Fi and Bluetooth for proximity.

2.4 GHz Channel Congestion

  • Problem: fewer channels, more interference.
  • Select channels 1, 6, and 11 for 2.4 GHz Wi-Fi routers to minimize overlap.
  • Channel Overlap: Signals bleed over to other channels.

Heat Maps

  • Show Wi-Fi signal strength.
  • Different colors indicate different signals (e.g., dark orange for 5 GHz, lighter orange for 2.4 GHz).
  • Used to determine best signal for a location.
  • Multiple access points: Use channels 1, 6, and 11.
  • Only two access points: Use channels 1 and 11.

Setting Up a Wireless Access Point

  • Consider:
    • Network diagram.
    • Heat map.
    • Network specifications (subnet mask, etc.).
    • Security settings.

Wi-Fi Standards

  • Evolution of standards:
    • a: 5 GHz.
    • b: Switched to 2.4 GHz.
    • g: Combined speed of 5 GHz with 2.4 GHz.

MIMO (Multiple Input, Multiple Output)

  • Introduced with n.
  • Multiple antennas send signals independently.
  • MU-MIMO (Multiple User MIMO): Introduced with Wi-Fi 5, even more streams.

Wi-Fi 5 and 6 naming conventions

  • Can be letters (AC, AX) after 5, BE for 7.

Cheat Sheet

  • Chart to memorize:
    • Standards: A, B, G, N, AC, AX, BE.
    • Frequencies.
    • Speeds (throughput).
    • MIMO versions.

Generations of Improvement

  • a: 5 GHz, 54 Mbps.
  • b: 2.4 GHz, 11 Mbps (better wall penetration, slower speed).
  • g: 2.4 GHz, 54 Mbps (best of both).
  • n: 2.4 GHz and 5 GHz, introduced MIMO (multiple channels), 600 Mbps (combining channels).
  • ac: 5 GHz, MU-MIMO (more streams), 6.9 Gbps.
  • ax: Backwards compatible, using MU-MIMO, 9.6 Gbps.
Memorization Tips:
  • Write down the standards in order: A, B, G, N, AC, AX, BE.
  • Remember the speeds.
  • Note MIMO versions.

CAT Standards

  • 100BaseT: 1G.
  • Remember distances: Always 100 meters, but Cat 5e can do 10G at 55 meters.

Test Taking Tips

  • Write down key information at the start of the exam to calm nerves.
  • This includes: chart, CAT standards, troubleshooting methods.
Examples
  • If an office needs over 1 Gbps throughput, recommend AC standard.
  • For a place with lots of microwave interference needing a 5 GHz connection and 2 Gbps throughput -> use AC.