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C-NNIC practice questions

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Question 1Network Cabling Systems and Structured Wiring

In a structured cabling system, which cabling subsystem connects the work area outlet to the telecommunications room and is limited to a 90-meter horizontal run plus allowance for patch cords?

  1. Backbone cabling
  2. Entrance facility cabling
  3. Horizontal cabling Correct answer.
  4. Equipment room cabling

Explanation

Horizontal cabling runs from the work area telecommunications outlet to the horizontal cross-connect in the telecommunications room. Standards cap the permanent link at 90 meters and allow up to 10 meters of combined patch cords to reach the 100-meter channel limit. Backbone cabling instead links telecommunications rooms, equipment rooms, and the entrance facility.

Question 2Network Cabling Systems and Structured Wiring

What is the maximum combined length of the permanent link and patch cords in a twisted-pair horizontal channel?

  1. 80 meters
  2. 100 meters Correct answer.
  3. 110 meters
  4. 90 meters

Explanation

The horizontal channel budget is 100 meters total. Of this, the permanent link (horizontal cable plus the outlet and cross-connect terminations) is limited to 90 meters, leaving up to 10 meters for patch cords at each end. This budget preserves signal integrity for the supported application.

Question 3Network Cabling Systems and Structured Wiring

Which cable category is specified for 10GBASE-T support at a full 100-meter channel length?

  1. Category 6A Correct answer.
  2. Category 6
  3. Category 3
  4. Category 5e

Explanation

Category 6A is characterized to 500 MHz and is specified to support 10GBASE-T over a 100-meter channel. Category 6 can support 10GBASE-T only over shorter distances, typically up to about 55 meters, because of alien crosstalk. Category 5e is rated for 1Gbps and Category 3 for voice or low-speed data.

Question 4Network Cabling Systems and Structured Wiring

Which connector interface is standardized for balanced twisted-pair cabling in commercial structured wiring?

  1. SC
  2. RJ-45 (8P8C) Correct answer.
  3. ST
  4. BNC

Explanation

The eight-position, eight-contact modular connector, commonly called RJ-45, is the standardized interface for balanced twisted-pair horizontal cabling. BNC, ST, and SC are coaxial or fiber-optic interfaces used in other parts of the system. Matching the connector to the media type is essential for interoperability.

Question 5Network Cabling Systems and Structured Wiring

In T568A wiring, which pair occupies pins 1 and 2 of an RJ-45 jack?

  1. Green pair Correct answer.
  2. Blue pair
  3. Orange pair
  4. Brown pair

Explanation

T568A assigns the green pair to pins 1 and 2, the orange pair to pins 3 and 6, the blue pair to pins 4 and 5, and the brown pair to pins 7 and 8. T568B differs by swapping the green and orange pair positions. Consistent pin assignment at both ends preserves pair-to-pin mapping and balanced transmission.

Question 6Network Cabling Systems and Structured Wiring

What is the primary purpose of a cross-connect in a telecommunications room?

  1. To provide a flexible patching point between cabling and active equipment Correct answer.
  2. To terminate outside plant fiber only
  3. To supply electrical grounding for racks
  4. To convert balanced twisted pair to coaxial media

Explanation

A cross-connect is a patching or termination field that lets technicians reconfigure connections between horizontal cabling, backbone cabling, and active equipment without recabling. It supports moves, adds, and changes efficiently. It is a connectivity and administration element, not a power or media-conversion device.

Question 7Network Cabling Systems and Structured Wiring

Which term describes the practice of separating power cabling from communications cabling to limit electromagnetic interference?

  1. Impedance matching
  2. Attenuation
  3. Bonding
  4. Separation distance Correct answer.

Explanation

Separation distance is the minimum spacing maintained between communications cable and sources of electromagnetic interference such as power feeders. Adequate spacing reduces coupled noise and preserves signal quality. Bonding, attenuation, and impedance matching address different concerns in cabling design.

Question 8Network Cabling Systems and Structured Wiring

Which document type records the identifiers, locations, and connections of cabling elements in a structured wiring system?

  1. Cable schedule
  2. As-built drawing
  3. Test report
  4. Administration record Correct answer.

Explanation

Administration records capture identifiers, labels, and connectivity information for cabling elements so the system can be managed over its life. Cable schedules and as-built drawings are related project documents but do not by themselves provide the full labeling and connectivity record. Test reports document performance measurements rather than administration data.

Question 9Network Cabling Systems and Structured Wiring

A technician must install a horizontal run of 95 meters of Category 6A cable between the outlet and the patch panel. What is the correct assessment?

  1. Acceptable if Category 5e patch cords are used
  2. Acceptable because the channel limit is 100 meters
  3. Not acceptable because the permanent link exceeds 90 meters Correct answer.
  4. Not acceptable because Category 6A is limited to 80 meters

Explanation

The permanent link, which includes the horizontal cable and its terminations, is limited to 90 meters. A 95-meter run exceeds that limit before any patch cords are added, so the channel could not meet the 100-meter budget. The installer must shorten the run or add an intermediate cross-connect.

Question 10Network Cabling Systems and Structured Wiring

A designer needs 10GBASE-T support over a 90-meter horizontal run in an electrically noisy area. Which cabling choice best satisfies the requirement?

  1. Category 6 unshielded twisted pair
  2. Category 3 unshielded twisted pair
  3. Category 5e unshielded twisted pair
  4. Category 6A shielded twisted pair Correct answer.

Explanation

Category 6A supports 10GBASE-T over a full 100-meter channel, and a shielded construction adds protection against alien crosstalk and external noise. Category 6 unshielded cable is generally limited to shorter distances for 10GBASE-T. Category 5e and Category 3 do not meet the bandwidth requirement.

Question 11Network Cabling Systems and Structured Wiring

A technician terminates one end of a twisted-pair cable to T568A and the other end to T568B. What is the result?

  1. A standard straight-through patch cord
  2. A shielded cable
  3. A crossover cable Correct answer.
  4. A cable that fails all continuity tests

Explanation

Mixing T568A at one end with T568B at the other swaps the transmit and receive pairs, producing a crossover cable. This is intentional in some legacy applications but is not a standard straight-through connection. Continuity would still pass because all conductors are terminated.

Question 12Network Cabling Systems and Structured Wiring

Why is the blue pair consistently placed on pins 4 and 5 in both T568A and T568B?

  1. It occupies the center pins to preserve pair geometry and reduce crosstalk Correct answer.
  2. It carries the highest-frequency signal
  3. It is the only pair that can be shielded
  4. It is reserved for power over Ethernet only

Explanation

Placing the blue pair on the center pins 4 and 5 keeps the pair positions consistent between the two schemes and helps maintain balanced pair geometry. That geometry controls crosstalk and impedance. The other pairs swap positions between T568A and T568B, but the blue pair does not.

Question 13Network Cabling Systems and Structured Wiring

When terminating a shielded twisted-pair cable at a patch panel, what must be done with the cable shield?

  1. Left floating at both ends
  2. Twisted together with the blue pair
  3. Connected to a signal conductor
  4. Bonded to the panel ground at the termination point Correct answer.

Explanation

The shield must be bonded to the grounding system at the termination to drain induced currents and preserve shielding effectiveness. Leaving it floating defeats the shield, and connecting it to a signal conductor would corrupt the signal. Proper bonding also supports equipotential grounding across the system.

Question 14Network Cabling Systems and Structured Wiring

A fiber backbone run between two buildings must span 1,500 meters and support high bandwidth. Which medium is most appropriate?

  1. Multimode fiber
  2. Category 5e twisted pair
  3. Single-mode fiber Correct answer.
  4. Category 6A twisted pair

Explanation

Single-mode fiber supports long inter-building spans well beyond the reach of multimode and copper. Its small core and laser-optimized transmission suit distances of several kilometers. Multimode fiber is typically used for shorter backbone runs within or between nearby buildings.

Question 15Network Cabling Systems and Structured Wiring

What is the function of a consolidation point in horizontal cabling?

  1. To terminate the building entrance fiber
  2. To provide an intermediate connection point in an open office area Correct answer.
  3. To convert fiber to copper
  4. To house the main distribution frame

Explanation

A consolidation point is an intermediate interconnection in the horizontal cabling, often used in open-plan offices to allow flexible reconfiguration. It sits between the horizontal cross-connect and the work area outlet. It does not serve as an entrance facility, main distribution frame, or media converter.

Question 16Network Cabling Systems and Structured Wiring

A cable tester reports excessive insertion loss on a long horizontal run. Which factor most directly contributes to this result?

  1. Excessively short patch cords
  2. Cable length and conductor resistance Correct answer.
  3. Incorrect label color
  4. Use of a patch panel

Explanation

Insertion loss increases with cable length and conductor resistance, so longer runs attenuate more signal. Patch cord length, labeling, and the presence of a patch panel are not primary causes of excessive loss. Reducing run length or using higher-grade cable improves the result.

Question 17Network Cabling Systems and Structured Wiring

Which test is used to verify that a twisted-pair link meets the performance requirements of its category?

  1. Tone generator test
  2. Certification field test Correct answer.
  3. Visual inspection
  4. Continuity test only

Explanation

A certification field test measures parameters such as insertion loss, near-end crosstalk, and return loss and compares them to the category limits. Continuity and tone tests only confirm conductor paths, and visual inspection cannot verify electrical performance. Certification provides documented proof that the link supports its rated application.

Question 18Network Cabling Systems and Structured Wiring

In a telecommunications room, what is the recommended practice for managing patch cords?

  1. Coil excess length tightly around power conduits
  2. Bundle them with power cables for neatness
  3. Use cable management pathways and maintain bend radius Correct answer.
  4. Route them loosely across equipment to save time

Explanation

Patch cords should follow dedicated management pathways and respect minimum bend radius to avoid stress and signal degradation. Coiling tightly or bundling with power cables increases loss and noise coupling. Good management also simplifies administration and future changes.

Question 19Network Cabling Systems and Structured Wiring

Which standard defines the pin/pair assignments for an 8-position modular jack used in structured cabling?

  1. TIA-570
  2. TIA-569
  3. TIA-568 Correct answer.
  4. TIA-606

Explanation

TIA-568 covers commercial cabling standards including the T568A and T568B pin/pair assignments for modular jacks. TIA-569 addresses pathways and spaces, TIA-570 covers residential cabling, and TIA-606 covers administration. Knowing which standard governs which aspect prevents misapplication.

Question 20Network Cabling Systems and Structured Wiring

What is the purpose of a fiber distribution panel in a telecommunications room?

  1. To convert optical signals to electrical signals
  2. To provide power to network switches
  3. To terminate and manage fiber connections and splices Correct answer.
  4. To terminate coaxial cabling

Explanation

A fiber distribution panel provides a termination and splice point where fiber cables are organized, protected, and connected to patch cords. It does not perform optical-to-electrical conversion, which is the role of a media converter or transceiver. It also does not supply power or terminate coaxial cable.

Question 21Network Cabling Systems and Structured Wiring

A building has a main cross-connect in the equipment room and several horizontal cross-connects on each floor. Which cabling connects these levels?

  1. Work area cabling
  2. Horizontal cabling
  3. Patch cord cabling
  4. Backbone cabling Correct answer.

Explanation

Backbone cabling connects the main cross-connect to intermediate and horizontal cross-connects across floors and buildings. Horizontal cabling instead runs from the horizontal cross-connect to work area outlets. Work area and patch cord cabling are shorter local connections within those subsystems.

Question 22Network Cabling Systems and Structured Wiring

A designer places a consolidation point in a horizontal run. Which constraint applies to the cabling between the horizontal cross-connect and the consolidation point?

  1. It may be any length as long as the total channel stays under 200 meters
  2. It counts toward the 90-meter permanent link budget Correct answer.
  3. It must be fiber only
  4. It is exempt from distance limits because it is intermediate

Explanation

The consolidation point is part of the horizontal cabling, so all cable from the horizontal cross-connect through the consolidation point to the outlet counts toward the 90-meter permanent link budget. There is no exemption for intermediate points. The 100-meter channel limit still applies to the complete path.

Question 23Network Cabling Systems and Structured Wiring

A certification test shows high near-end crosstalk at the patch panel end of a link. Which condition is the most likely cause?

  1. Poor termination with untwisted conductors at the connector Correct answer.
  2. Use of a shielded cable
  3. Excessive cable length
  4. Too many labels on the cable

Explanation

Near-end crosstalk rises when conductors are untwisted too far at a termination, because the pair geometry that controls coupling is lost. Excessive length mainly affects insertion loss rather than crosstalk. Shielding would reduce crosstalk, and labeling has no electrical effect.

Question 24Network Cabling Systems and Structured Wiring

An owner wants to reuse an existing Category 5e horizontal cabling plant for 10GBASE-T endpoints at 100 meters. What is the correct engineering conclusion?

  1. It will work if the cable is relabeled as Category 6
  2. It will not meet the requirement because Category 5e is not rated for 10GBASE-T at that distance Correct answer.
  3. It will work if the patch cords are Category 6A
  4. It will work because all twisted pair supports 10GBASE-T at 100 meters

Explanation

Category 5e is characterized to 100 MHz and is not specified for 10GBASE-T over a 100-meter channel. Upgrading patch cords or relabeling the cable does not change the installed cable's transmission characteristics. Meeting the requirement calls for a cable rated for 10GBASE-T at that distance, such as Category 6A.

Question 25Network Cabling Systems and Structured Wiring

A backbone run must pass through a riser shaft that penetrates several fire-rated floors. Which cable rating consideration applies?

  1. Any cable may be used because the shaft is enclosed
  2. The cable should carry the appropriate riser fire rating for the environment Correct answer.
  3. The cable must be coaxial to resist fire
  4. Only plenum-rated cable is permitted in any shaft

Explanation

Cables installed in vertical shafts that penetrate fire-rated floors must carry the appropriate riser rating for that environment. Plenum ratings apply to air-handling spaces, not automatically to every shaft. Fire resistance is a property of the cable construction, not of the conductor type.

Question 26Network Cabling Systems and Structured Wiring

In a structured cabling system, which cabling subsystem connects the telecommunications outlet in the work area to the horizontal cross-connect in the telecommunications room?

  1. The backbone cabling subsystem
  2. The equipment cabling subsystem
  3. The horizontal cabling subsystem Correct answer.
  4. The entrance facility subsystem

Explanation

The horizontal cabling subsystem runs from the work-area outlet to the horizontal cross-connect and is limited to a 90-meter permanent link plus patch cords. It is the portion most users physically touch at the wall plate. Backbone and entrance cabling serve inter-building and inter-floor transport instead.

Question 27Network Cabling Systems and Structured Wiring

Which element of a structured cabling system is defined as the space where building occupants connect their equipment to the cabling plant via a telecommunications outlet?

  1. The work area Correct answer.
  2. The zone cabling enclosure
  3. The entrance facility
  4. The intermediate distribution frame

Explanation

The work area is the occupant space containing the outlet and the user's cords and devices. It excludes the permanent horizontal cabling, which terminates at the outlet rather than extending into the room. Work-area cords are intentionally kept short to preserve link performance.

Question 28Network Cabling Systems and Structured Wiring

What is the maximum recommended length of a work-area cord connecting a device to the telecommunications outlet in a typical office layout?

  1. About 15 meters
  2. About 25 meters
  3. About 5 meters Correct answer.
  4. About 40 meters

Explanation

Work-area cords are generally kept short, on the order of a few meters, so that the combined channel of permanent link plus cords stays within the 100-meter limit. Longer cords erode the allowance for the horizontal permanent link. Excess cord length also degrades crosstalk and insertion-loss margins.

Question 29Network Cabling Systems and Structured Wiring

Which term describes the cable that connects a horizontal cross-connect to backbone cabling when the two reside in different rooms on the same floor?

  1. Backbone cabling Correct answer.
  2. Work-area cabling
  3. Horizontal cabling
  4. Equipment cabling

Explanation

Backbone cabling carries traffic between cross-connects, including between a horizontal cross-connect and a main or intermediate cross-connect. It may traverse risers, corridors, or campus routes. Horizontal cabling by contrast stops at the horizontal cross-connect.

Question 30Network Cabling Systems and Structured Wiring

A designer must provide a horizontal cross-connect for a 40-meter run in a small office where moves are frequent. Which practice best supports frequent reconfiguration?

  1. Terminate horizontal cables onto the same block as backbone without cross-connects
  2. Extend the horizontal cable into the work area with no outlet
  3. Splice the horizontal cable directly to the backbone cable
  4. Use an interconnection with patch cords at the horizontal cross-connect Correct answer.

Explanation

A cross-connect or interconnection at the horizontal cross-connect lets staff re-arrange connections with patch cords instead of re-terminating cable. This supports frequent moves and adds manageable flexibility. Direct splicing removes that flexibility and complicates fault isolation.

Question 31Network Cabling Systems and Structured Wiring

A technician is terminating a 25-pair backbone cable on a 110-type wiring block. Which practice preserves pair integrity and simplifies administration?

  1. Terminate pairs in random order to save time
  2. Terminate only the pairs in active use
  3. Twist all pairs together before termination
  4. Terminate pairs in sequence and label each pair position Correct answer.

Explanation

Sequential termination on 110 blocks keeps pair positions predictable and matches standard color codes, which simplifies testing and future changes. Random order makes administration and fault isolation difficult. Terminating only active pairs leaves no capacity for growth.

Question 32Network Cabling Systems and Structured Wiring

A designer is planning a horizontal run in an open ceiling above a data center with high-EMI equipment nearby. Which combination of choices best addresses both pathway and interference concerns?

  1. Route in metal conduit away from power feeders and use shielded twisted pair Correct answer.
  2. Route through the same conduit as power feeders and use fiber
  3. Route randomly through the plenum and rely on cable jacket insulation
  4. Route parallel to power feeders and use unshielded twisted pair

Explanation

Separating communications pathways from power feeders limits coupled noise, and metal conduit adds both physical protection and shielding. Shielded twisted pair further improves immunity in high-EMI areas. The two measures complement each other rather than substitute.

Question 33Network Cabling Systems and Structured Wiring

Which practice is recommended for supporting horizontal cables in an overhead pathway?

  1. Hang cables from sprinkler pipes
  2. Support cables at regular intervals with approved hardware Correct answer.
  3. Bundle cables tightly with cable ties at wide spacing
  4. Lay cables directly on ceiling tiles

Explanation

Cables must be supported at manufacturer-recommended intervals using approved hardware so that the cable weight does not stress conductors or jackets. Proper support preserves electrical characteristics and prevents sagging. Ceiling tiles and sprinkler pipes are not load-rated supports.

Question 34Network Cabling Systems and Structured Wiring

A technician must install a telecommunications outlet in a drywall wall where the owner wants a clean flush finish. Which method is most appropriate?

  1. Surface-mount the jack with adhesive directly on the drywall
  2. Mount the jack on the exterior of the building wall
  3. Run the cable through a hole with no plate and leave the jack loose
  4. Cut an opening and mount a low-voltage mounting bracket with a faceplate Correct answer.

Explanation

A low-voltage mounting bracket cut into the drywall provides a secure, flush mount for a faceplate and jack. The faceplate protects the termination and presents a professional finish. Adhesive mounting and loose jacks do not provide durable, code-compliant support.

Question 35Network Cabling Systems and Structured Wiring

In a telecommunications room, which practice best supports thermal management of active equipment and cabling?

  1. Seal all room vents to keep dust out
  2. Maintain front-to-rear airflow clearances and avoid blocking vents with cable bundles Correct answer.
  3. Stack spare equipment directly on top of active units
  4. Pack all cables tightly against the equipment intakes

Explanation

Active equipment relies on unobstructed intake and exhaust airflow, so cable bundles should be routed clear of vents and racks should respect manufacturer clearances. Proper thermal management extends equipment life and prevents intermittent failures. Blocking intakes or stacking equipment traps heat.

Question 36Network Cabling Systems and Structured Wiring

A certification report shows a horizontal link passing insertion loss but failing return loss at the outlet end. Which condition most likely explains the failure?

  1. Incorrect pair sequence at the patch panel
  2. High ambient temperature in the room
  3. A poorly mated or damaged connector at the outlet Correct answer.
  4. Excessive cable length in the run

Explanation

Return loss measures reflected energy caused by impedance discontinuities, which commonly arise at poorly mated, dirty, or damaged connectors. Length and temperature primarily affect insertion loss. A pair-sequence error would instead show as a wiring or crosstalk failure.

Question 37Network Cabling Systems and Structured Wiring

A technician must bond the metallic sheath of a shielded backbone cable entering a telecommunications room. Which practice is correct?

  1. Bond the shield to the telecommunications bonding infrastructure at the entry point Correct answer.
  2. Leave the shield floating to avoid ground loops
  3. Bond the shield only at the far end of the run
  4. Connect the shield to the nearest convenience outlet neutral

Explanation

Shields must be bonded to the building's telecommunications bonding infrastructure so that induced currents have a defined low-impedance path. Floating shields allow the sheath to act as an antenna. Bonding only at one remote end leaves the entry point unprotected.

Question 38Network Cabling Systems and Structured Wiring

A designer is laying out a horizontal cross-connect room serving four floors of a building. Which arrangement best matches structured cabling principles for cross-connect hierarchy?

  1. Omit cross-connects and rely on work-area cords
  2. Connect every outlet directly to the main cross-connect
  3. Provide one horizontal cross-connect for the entire building with no backbone
  4. Provide a horizontal cross-connect per floor linked to a main cross-connect Correct answer.

Explanation

Structured cabling uses a hierarchy in which horizontal cross-connects serve each floor or zone and connect through backbone cabling to a main cross-connect. This limits cable lengths and simplifies administration. Flattening the hierarchy or omitting cross-connects increases run lengths and reduces manageability.

Question 39Network Cabling Systems and Structured Wiring

A certification test on a new horizontal link shows a split pair. Which termination condition most likely caused this result?

  1. Cable run longer than 90 meters
  2. Conductors from different pairs terminated on the wrong pins at one end Correct answer.
  3. Shield left unbonded at the outlet
  4. Excessive bend radius at the patch panel

Explanation

A split pair occurs when one conductor from a pair is terminated on a pin belonging to another pair, breaking the intended twist relationship. Testers detect this as a wiring fault even when pin-to-pin continuity exists. Bend radius, length, and shield bonding produce different failure signatures.

Question 40Network Cabling Systems and Structured Wiring

A building owner plans to add a new floor of offices above an existing telecommunications room. Which design change best preserves backbone scalability and administration?

  1. Add a second independent main cross-connect with no link to the existing one
  2. Extend backbone cabling from the existing main cross-connect to a new horizontal cross-connect on the added floor Correct answer.
  3. Run new horizontal cabling from the added floor directly to the main cross-connect
  4. Rely on wireless access points and omit any cabling to the added floor

Explanation

Extending the backbone to a new horizontal cross-connect on the added floor preserves the hierarchy and keeps horizontal runs within length limits. It also keeps administration consistent with the existing plant. Direct horizontal runs to the main cross-connect or a disconnected second main cross-connect break those principles.

Question 41Network Infrastructure Design and Topologies

Which network topology connects every device to a single central switch or hub?

  1. Bus topology
  2. Ring topology
  3. Mesh topology
  4. Star topology Correct answer.

Explanation

In a star topology each endpoint has its own dedicated link to a central device such as a switch, and all traffic passes through that center. This makes fault isolation simple because one failed cable affects only that endpoint.

Question 42Network Infrastructure Design and Topologies

What is the primary benefit of a full mesh topology in a wide area network?

  1. Maximum path redundancy Correct answer.
  2. Simplest configuration management
  3. Lowest possible cabling cost
  4. Reduced need for routing protocols

Explanation

A full mesh provides a dedicated link between every pair of nodes, so any single link or node failure leaves alternative paths available. The tradeoff is a large number of links and high cost, which grows quickly with node count.

Question 43Network Infrastructure Design and Topologies

Which cabling standard supports 10GBASE-T over twisted-pair copper at distances up to 100 meters?

  1. Cat 6
  2. Cat 3
  3. Cat 5e
  4. Cat 6A Correct answer.

Explanation

Cat 6A is specified for 10GBASE-T at the full 100-meter channel length because its higher bandwidth and improved shielding control alien crosstalk. Cat 6 can carry 10GBASE-T only over shorter distances.

Question 44Network Infrastructure Design and Topologies

A designer needs a fiber type that allows a single long-haul link of 40 km without repeaters. Which choice fits best?

  1. Coaxial cable
  2. Multimode fiber with an LED source
  3. Shielded twisted pair
  4. Single-mode fiber with a laser source Correct answer.

Explanation

Single-mode fiber has a very small core that supports one propagation path, which minimizes modal dispersion and allows laser sources to reach tens of kilometers. Multimode fiber suffers modal dispersion that limits distance.

Question 45Network Infrastructure Design and Topologies

Which IPv4 private address range is defined for use in home and small-office networks?

  1. 10.0.0.0/8
  2. 192.168.0.0/16 Correct answer.
  3. 169.254.0.0/16
  4. 172.16.0.0/12

Explanation

RFC 1918 reserves three private blocks, and 192.168.0.0/16 is the one commonly used for small office and home networks. The other two RFC 1918 blocks are 10.0.0.0/8 and 172.16.0.0/12.

Question 46Network Infrastructure Design and Topologies

How many usable host addresses does a /27 IPv4 subnet provide?

  1. 32
  2. 14
  3. 62
  4. 30 Correct answer.

Explanation

A /27 leaves 5 host bits, so the block size is 32 addresses. Subtracting the network and broadcast addresses leaves 30 usable host addresses.

Question 47Network Infrastructure Design and Topologies

Which protocol provides loop-free Layer 2 forwarding by electing a root bridge?

  1. VRRP
  2. OSPF
  3. LACP
  4. Spanning Tree Protocol Correct answer.

Explanation

Spanning Tree Protocol builds a loop-free logical tree by electing one root bridge and blocking redundant ports. This prevents broadcast storms in switched networks that contain physical loops.

Question 48Network Infrastructure Design and Topologies

What is the purpose of a VLAN in a campus design?

  1. To assign public IP addresses
  2. To increase cable bandwidth
  3. To segment broadcast domains logically Correct answer.
  4. To encrypt traffic between switches

Explanation

A VLAN creates a logical broadcast domain on shared physical switching infrastructure, containing broadcast traffic and supporting separate subnets. Devices in different VLANs require Layer 3 routing to communicate.

Question 49Network Infrastructure Design and Topologies

A company wants two data center switches to act as one logical Layer 2 switch with a shared management address. Which technology should be used?

  1. Storm control
  2. Stacking or switch virtualization Correct answer.
  3. Port mirroring
  4. Private VLAN

Explanation

Stacking or switch virtualization combines multiple physical switches into one logical device with a single control plane and management address. This simplifies topology and allows cross-switch link aggregation.

Question 50Network Infrastructure Design and Topologies

Which routing approach uses a central controller to compute and push paths to forwarding devices?

  1. Static routing
  2. Policy-based routing
  3. SDN centralized control Correct answer.
  4. Distance-vector routing

Explanation

Software-defined networking separates the control plane from the data plane, letting a central controller compute paths and program forwarding tables. This gives a global view of the topology.