Installing a Physical Network–The Physical Network–NETWORKING, SECURITY, & MORE ESSENTIALS—CompTIA Network+ (N10-007) NETWORK-PLUS Certification Prep Course Notes

Installing a Physical Network

• Intro to Structured Cabling
  • Structured cabling defines how we install cabling (i.e.–cable organization).
    • Structured cabling systems will have:
      • 1). Telecommunication closet/equipment room. This room will contain all switches & centralized stuff that runs out via, 2). Horizontal Runs to individual 3). workstations/work areas.
  • TIA standards specify wiring standards for structured cabling.
  • Patch panels terminate one end of horizontal runs.
  • Patch cables connect switches to patch panels & computers to wall outlets.

• Terminating Structured Cabling
  • RJ-45 crimps are used only on patch cables.
  • Horizontal runs are terminated with 110-punchdowns.
    • Note: Horizontal runs are punched down to the back of a patch panel on one end, and on the back of the wall jack of a work area, at the other end.
  • Patch panels and RJ-45 connectors also have cat ratings.

• Equipment Room
  • The primary equipment room is called the main distribution frame (MDF).
  • Rack-mounted equipment is standardized at 19″ wide and a multiple of 1 3/4″ tall (1.75 inches tall) called a ‘U’, or ‘unit’.
  • The demarc separates the telecom company’s property from your responsibility.
  • MDF–Main Distribution Frame
  • IDF–Intermediate Distribution Frame (IDFs are found in their own equipment room, not in the MDF equipment room.)

• Alternative Distribution Panels
  • A 66-punchdown block is a very old patch panel, typically used in non-VoIP telephone systems.
  • A 110- punchdown block patch panel is the way to distribute copper wired networks.
  • A fiber distribution patch panel is used to distribute fiber-optic networks.

• Testing Cable
  • Understand how to read & interpret the wiremap feature of a cable tester.
  • Continuity testing will show if the cable has any breaks.
  • A time domain reflectometer (TDR) will show the length of the cable & help pinpoint mid-cable breaks.
  • Wiremap means each individual wire is punched down to the right location.
  • Continuity means that its actually connected at all.
  • TDR will test for distance.
  • OTDR-(Optical TDR)-same as TDR for fiber-optic.
  • TIA rules specify that an individual horizontal run, can be no more than 90 meters.
  • More complex, expensive pro-testing equipment includes:
    • NEXT (Near-end crosstalk)
    • FEXT (Far-end crosstalk)

• Troubleshooting Structured Cabling, Part 1
  • Loopback plugs test the NIC’s ability to send & receive.
    • 127.000.000.001 (or 127.0.0.1) is the loopback address.
  • Loopback plugs aren’t effective (but Network+ thinks they are!)
  • Patch cables & wall outlets are the most common part of structured cabling to fail.
  • Verify link lights on both the workstation & the switch.
  • Check the network settings in the OS.
  • Check the patch cable.

• Troubleshooting Structured Cabling, Part 2
  • Voltage monitors track & record problems with power.
  • Environmental/ temperature monitors track & record problems with heat & humidity.
  • TDR’s are great tools to check for breaks on horizontal runs.
  • Voltmeter–first make sure you’re getting good electricity to your equipment room.
  • Interference—
  • Modal distortion–Multi-modal distortion only happens in multi-mode fiber-optic cable, not Unshielded Twisted Pair.

• Using a Toner & Probe
  • Tone generators & tone probes are used to locate cables & connections.
  • Tone generators create the signal for the probe.
  • Tone probes translate the signal into an audible tone.
  • ex is Fox & a Hound^TM tool.

• Wired Connection Scenarios
  • For jitters in VoIP and video streaming, consider buffering or increasing speed.
  • Make sure the patch cable specification is up-to-date with the network speed.
  • If switch lights are not blinking, try different ports or check if it’s an uplink port.
  • Attenuation–over a distance, a signal begins to degrade
    • manifests as a slow problem; from poor observation of installation.
  • Incorrect cables–ex: Cat5 instead of Cat6; etc
  • No connections–bad ports –> use a different port;
  • TX/RX Reverse–crossover instead of straight; straight instead of crossover; crimped incorrectly.
    • Have good documentation; label crossover cables visibly!;
    • aka Transmit/Receive Reverse
  • Bent Pins–Don’t perturb (bother) the runs;
    • Solution–replace the switch
    • Test on another device
  • Open/Short–used a bad cable; Two pins stuck together;