RCDD (RCDD): Network Design Principles and Practice 5 — Questions and Answers
Question 1: An RCDD is designing an entrance facility (EF) for a campus building. Which function is the EF NOT intended to perform?
- Provide the demarcation point between outside plant and inside plant cabling
- House protectors and surge protection devices
- Serve as the primary work area outlet location for end users (Correct answer)
- Provide transition between outdoor and indoor cable types
Correct answer: Serve as the primary work area outlet location for end users
The entrance facility is an infrastructure space for service provider demarcation and outside-to-inside plant transition, not a location for end-user work area outlets.
Question 2: What is the primary purpose of the telecommunications bonding backbone (TBB) in a multi-story building?
- Carry electrical load current for IT equipment
- Provide a low-impedance path connecting telecommunications grounding busbar (TGBS) on each floor (Correct answer)
- Replace the building's electrical grounding system
- Ground individual cable shields at each work area outlet
Correct answer: Provide a low-impedance path connecting telecommunications grounding busbar (TGBS) on each floor
The TBB interconnects the telecommunications grounding busbars on each floor to the telecommunications main grounding busbar (TMGB), creating a single-point bonding reference per TIA-607.
Question 3: A designer must choose between using individual conduits versus cable trays for a high-density data center backbone. Which advantage is specific to open cable trays?
- Better protection against physical damage
- Easier future capacity additions and cable management (Correct answer)
- Lower cost of initial material purchase only
- Compliance with all fire codes without additional treatment
Correct answer: Easier future capacity additions and cable management
Open cable trays allow easy addition, removal, and rerouting of cables without pulling new conduit, which is a major operational advantage in dynamic data center environments.
Question 4: When calculating the number of telecommunications outlets required per ANSI/TIA-568, what is the minimum number of outlets specified for each individual work area?
- One outlet with one port
- Two outlets or one outlet with two ports (Correct answer)
- One outlet per person in the work area
- Three outlets minimum regardless of occupancy
Correct answer: Two outlets or one outlet with two ports
TIA-568 requires a minimum of two telecommunications outlets (or one two-port outlet) per work area to support both voice and data simultaneously.
Question 5: In a fiber optic loss budget, which value represents the maximum allowable attenuation for a specific application and determines if a proposed cable plant design will work?
- Optical time-domain reflectometer (OTDR) trace length
- Receiver sensitivity minus transmitter output power
- System gain or link power budget (Correct answer)
- Dispersion-shifted fiber specification
Correct answer: System gain or link power budget
The link power budget (system gain) equals the difference between transmitter output and receiver sensitivity, defining the maximum tolerable loss the cable plant can introduce.
Question 6: Which ANSI/TIA standard provides guidance specifically for the design and installation of outside plant (OSP) telecommunications infrastructure?
- TIA-568.3-D
- TIA-758-B (Correct answer)
- TIA-942-B
- TIA-1005-A
Correct answer: TIA-758-B
ANSI/TIA-758-B establishes customer-owned outside plant telecommunications infrastructure requirements including pathways, spaces, and cabling.
Question 7: An RCDD is reviewing a cable plant test report and notes that one channel fails the NEXT (Near-End Crosstalk) parameter but passes insertion loss. What is the most likely cause?
- Cable is too long for the application
- Poor termination quality or mismatched connector at the near end (Correct answer)
- The wrong fiber type was installed
- Insufficient power at the transmitter
Correct answer: Poor termination quality or mismatched connector at the near end
NEXT failures are typically caused by improper termination technique or connector quality issues at the end of the channel closest to the test instrument, not cable length.
RCDD (RCDD): Network Design Principles and Practice 5
An RCDD is designing an entrance facility (EF) for a campus building.
Which function is the EF NOT intended to perform?