RCDD (RCDD): Network Design Principles and Practice 2 — Questions and Answers
Question 1: When designing a hierarchical network for a large enterprise campus, which layer is responsible for aggregating access layer connections and enforcing policy?
- Core layer
- Distribution layer (Correct answer)
- Access layer
- Demarcation layer
Correct answer: Distribution layer
The distribution layer aggregates wiring closet connections from the access layer and enforces routing, security, and QoS policies before passing traffic to the core.
Question 2: A designer specifies OM4 multimode fiber for a 400 Gbps link spanning 100 meters. What is the primary advantage of OM4 over OM3 in this scenario?
- Lower cost per meter
- Higher bandwidth-distance product supporting longer reaches (Correct answer)
- Easier field termination
- Greater resistance to bend-induced loss
Correct answer: Higher bandwidth-distance product supporting longer reaches
OM4 has a higher effective modal bandwidth than OM3, allowing it to support higher data rates over longer distances.
Question 3: Which TIA standard defines the minimum performance requirements for horizontal cabling in commercial buildings?
- TIA-568.0-D
- TIA-568.2-D (Correct answer)
- TIA-942-B
- TIA-606-C
Correct answer: TIA-568.2-D
TIA-568.2-D specifies the minimum performance requirements and test methods for balanced twisted-pair horizontal cabling systems.
Question 4: An RCDD is designing a telecommunications room (TR) that must serve a floor plate of 1,200 m². According to ANSI/TIA-569, what is the minimum recommended TR floor area?
- 5 m²
- 10 m²
- 14 m² (Correct answer)
- 20 m²
Correct answer: 14 m²
ANSI/TIA-569 specifies a minimum TR floor area of 14 m² for a served area up to approximately 1,000 m², with larger spaces requiring proportionally more area.
Question 5: In a structured cabling design, the consolidation point (CP) is permitted only in which cabling subsystem?
- Backbone cabling
- Horizontal cabling (Correct answer)
- Equipment room cabling
- Work area cabling
Correct answer: Horizontal cabling
A consolidation point is an optional interconnection point within the horizontal cabling subsystem between the TR and the work area outlet.
Question 6: A network designer needs to ensure voice traffic receives priority treatment across a converged IP network. Which mechanism should be implemented at the access layer switch port connected to an IP phone?
- Spanning Tree PortFast
- 802.1Q VLAN tagging only
- 802.1p Class of Service (CoS) marking (Correct answer)
- LACP port channel
Correct answer: 802.1p Class of Service (CoS) marking
802.1p CoS markings in the Ethernet frame header allow access layer switches to classify and prioritize voice traffic before it enters the network core.
Question 7: Which factor most directly determines the maximum supportable channel length for Cat 6A horizontal cabling per TIA-568.2-D?
- Ambient temperature exceeding 20°C
- Number of connectors in the channel
- Total channel insertion loss budget (Correct answer)
- Jacket color of the cable
Correct answer: Total channel insertion loss budget
The total channel insertion loss budget—encompassing cable, connectors, and patch cords—determines the maximum compliant channel length.
RCDD (RCDD): Network Design Principles and Practice 2
When designing a hierarchical network for a large enterprise campus, which layer is responsible for aggregating access layer connections and enforcing policy?