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Read the evidence · explain the choice

AP Networking Network Components and Media Practice Test

Practice 75 network components and media questions: NICs, switches, routers, copper, fiber, Wi-Fi, PoE budgets, link evidence, and capacity troubleshooting.

Independent practice · Published and updated October 1, 2026 · Free for students and teachers
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What this test measures

This test checks device roles, medium selection, link state, PoE capacity, and controlled hardware comparisons. Each difficulty has 25 questions; complete all three for 75. Easy emphasizes direct application, Medium combines evidence, and Hard asks you to choose among plausible diagnoses or evaluate what a result actually proves.

These are independent instructional questions, not released College Board items or a replica of Bluebook. The difficulty labels are local teaching choices; a score here does not predict an AP score.

For explanation before testing, use the network components and media guide. Return to AP Networking Practice Tests by Topic to compare results across topics instead of repeating only your strongest subject.

Interactive testWorked reasoning75 explained questionsNext study step

Take the 25-question test for your selected level

Choose one answer to receive immediate feedback. Your first selection is scored; read the explanation before moving on. Use keyboard Tab to reach controls and arrow keys within the answer group. You can use these as untimed diagnostic practice, pausing to write your reasoning.

Changing difficulty or restarting clears the current attempt. Download your log first if you want to keep it.

Read the boundary before naming the fault

Representative reasoning

An AP is powered, its Ethernet link is up, and a client can ping the gateway. Those are three different observations: power delivery, link establishment, and one local IP exchange. None establishes that a public hostname resolves or that the website's TCP port accepts connections.

Separate power, physical signaling, link forwarding, IP delivery, and application response. A healthy result at one boundary does not certify every later dependency.

A tempting shortcut to avoid

Treating a link LED as proof of Internet access hides the very boundary a technician needs to test. Likewise, a 1 Gb/s negotiated rate describes one link, not a guarantee that a shared WAN or radio channel can deliver that throughput.

A worked decision

Eight APs requesting 20 W each need 160 W in aggregate. A switch with a 120 W budget cannot meet all of that demand even if each port supports 20 W. Count per-port requirements and the total allocation; then verify power-denial logs. Increasing the IP subnet cannot supply missing electrical power.

For a second representation of the same skill, review the related topic explanation. Compare its evidence with your calculation or packet-path sketch rather than memorizing the answer letter.

How to read the explained question library

All 75 items are available below as ordinary HTML. Open a question to view its choices, answer, and explanation. For retrieval practice, read the prompt, write a decision without opening it, then compare your reasoning. This library also gives teachers a stable question ID for discussion.

The six groups contain two halves of each difficulty, with 12 and 13 questions respectively. The interactive version uses the same questions and answer keys.

Easy explained questions · 1–12

Start by identifying the function or applying one explicit rule. These 12 questions are 1–12 of the easy set.

components-easy-1 · A desktop needs a wired connection to a switch. Which component supplies its Ethernet interface?
  1. NIC
  2. DHCP scope
  3. DNS resolver
  4. Routing table

Correct answer: A. NIC

The NIC sends and receives link-layer frames. DNS and DHCP are services; neither supplies a physical Ethernet interface.

components-easy-2 · Which device normally forwards Ethernet frames using learned MAC addresses?
  1. Switch
  2. Modem
  3. DNS server
  4. Passive patch panel

Correct answer: A. Switch

A switch learns source MAC locations and uses destination MAC entries to select an output port. A patch panel only terminates cabling.

components-easy-3 · Two IP subnets need to communicate. Which function is required?
  1. Layer 2 flooding only
  2. Routing
  3. SSID broadcasting
  4. Cable labeling

Correct answer: B. Routing

A Layer 3 function moves packets between subnets. Ordinary Layer 2 forwarding stays within its broadcast domain.

components-easy-4 · Which medium carries data as light pulses?
  1. Fiber-optic cable
  2. Radio antenna cable
  3. Twisted-pair copper
  4. Coaxial copper

Correct answer: A. Fiber-optic cable

Fiber carries optical signals rather than electrical data signals along copper conductors. Appropriate optical transceivers are still required.

components-easy-5 · A school needs to connect Wi-Fi clients to its wired LAN. Which device performs that role?
  1. Passive coupler
  2. Patch panel
  3. DNS cache
  4. Access point

Correct answer: D. Access point

An access point bridges wireless clients into the network. It does not inherently replace routing or name-resolution services.

components-easy-6 · What does a passive patch panel do?
  1. Filters packets by port
  2. Terminates and organizes cable runs
  3. Assigns IP addresses
  4. Amplifies Wi-Fi signals

Correct answer: B. Terminates and organizes cable runs

A passive patch panel provides connection and labeling points. Active switching and addressing happen elsewhere.

components-easy-7 · What is the main job of a modem at a broadband connection?
  1. Resolves hostnames
  2. Adapts signals for the provider access technology
  3. Assigns VLAN IDs to frames
  4. Learns LAN MAC locations

Correct answer: B. Adapts signals for the provider access technology

A modem interfaces with the access medium. An integrated home gateway may also include routing, but that is a separate function.

components-easy-8 · What does PoE allow on a supported Ethernet link?
  1. Optical power to every fiber device
  2. DNS without IP
  3. Power and data over the copper cable
  4. Unlimited cable distance

Correct answer: C. Power and data over the copper cable

Power over Ethernet can power compatible devices through copper conductors. It does not remove distance or power-budget limits.

components-easy-9 · A NIC reports link down. Which check should come first?
  1. Cloud application password
  2. Browser cache expiration
  3. Remote DNS record TTL
  4. Cable connection and enabled switch port

Correct answer: D. Cable connection and enabled switch port

Link down points first to local physical/link dependencies. Name resolution and application credentials are later checks.

components-easy-10 · Which connector is commonly used for twisted-pair Ethernet patch cables?
  1. LC optical connector
  2. 8P8C connector commonly called RJ45
  3. HDMI
  4. SATA

Correct answer: B. 8P8C connector commonly called RJ45

The common copper Ethernet plug has eight positions and contacts. LC is an optical connector and is not interchangeable.

components-easy-11 · Which property describes the maximum rated data rate of a link?
  1. Lease duration
  2. DNS TTL
  3. Gateway metric
  4. Link bandwidth

Correct answer: D. Link bandwidth

Bandwidth describes capacity. Actual throughput can be lower because of protocol overhead, contention, or other bottlenecks.

components-easy-12 · A link permits sending and receiving simultaneously. Which mode is this?
  1. Broadcast-only
  2. Full duplex
  3. Half duplex
  4. Simplex receive-only

Correct answer: B. Full duplex

Full duplex supports simultaneous traffic in both directions. Half duplex shares the medium between directions.

Easy explained questions · 13–25

Start by identifying the function or applying one explicit rule. These 13 questions are 13–25 of the easy set.

components-easy-13 · Which is a shared transmission medium for Wi-Fi?
  1. Radio spectrum
  2. Dedicated fiber strand per client
  3. Private DNS zone
  4. Switch MAC table

Correct answer: A. Radio spectrum

Wi-Fi clients share radio airtime. Different IP addresses do not give each client a separate physical radio channel.

components-easy-14 · Which medium is immune to electromagnetic interference along the cable?
  1. Unshielded copper
  2. Twisted pair beside a motor
  3. Fiber
  4. Coaxial copper

Correct answer: C. Fiber

Fiber transports light through glass or plastic. Its electrical endpoint equipment still needs suitable installation and protection.

components-easy-15 · A device has an SFP slot. What is the slot for?
  1. A VLAN-only processor
  2. A password storage drive
  3. A DHCP address pool
  4. A supported interchangeable transceiver

Correct answer: D. A supported interchangeable transceiver

SFP-family modules adapt a compatible interface to a supported medium and speed. Slot and module compatibility must be checked.

components-easy-16 · What does an Ethernet link LED directly indicate when lit?
  1. DNS answers are correct
  2. The Internet is reachable
  3. A local link has been established
  4. Every application is available

Correct answer: C. A local link has been established

Link indication is local evidence. It cannot establish routing, resolver, or application health beyond that link.

components-easy-17 · Which home device commonly combines router, switch, and access-point functions?
  1. Integrated wireless gateway
  2. Passive patch panel
  3. Standalone antenna
  4. Fiber cleaning tool

Correct answer: A. Integrated wireless gateway

A consumer gateway often combines several functions. Troubleshooting should identify the failing function rather than treating the box as one service.

components-easy-18 · Which device provides backup power during a short mains outage?
  1. UPS
  2. DNS forwarder
  3. Cable tester
  4. Layer 2 bridge

Correct answer: A. UPS

A UPS supplies temporary electrical power. Runtime depends on load and battery condition, not network speed.

components-easy-19 · Which measurement best describes delay for a packet exchange?
  1. Address prefix length
  2. Latency
  3. Port density
  4. Cable category

Correct answer: B. Latency

Latency measures time, often as round-trip delay. Bandwidth measures capacity and does not directly specify delay.

components-easy-20 · A copper cable has damaged contacts. What is the sensible replacement test?
  1. Increase the DHCP lease
  2. Use a known-good compatible cable
  3. Change all DNS zones
  4. Disable the firewall globally

Correct answer: B. Use a known-good compatible cable

A known-good cable isolates one physical dependency with a small change. Unrelated settings obscure the diagnosis.

components-easy-21 · What does an Ethernet frame contain for local link delivery?
  1. Only a hostname
  2. Source and destination MAC addresses
  3. Only a DHCP lease timer
  4. A list of all Internet routers

Correct answer: B. Source and destination MAC addresses

MAC addresses support delivery on the current link. IP destination addresses guide routing beyond the link.

components-easy-22 · Which identifier names a Wi-Fi network for client selection?
  1. SSID
  2. DNS serial number
  3. TCP sequence number
  4. Subnet mask

Correct answer: A. SSID

The SSID is the wireless network name. It does not alone specify security settings or guarantee legitimate ownership.

components-easy-23 · What is a physical topology diagram most useful for showing?
  1. Authoritative DNS record ownership
  2. Application permission inheritance
  3. Device and cable connections
  4. Password complexity

Correct answer: C. Device and cable connections

Physical topology documents actual connections. Logical VLAN and subnet relationships may differ and need their own evidence.

components-easy-24 · A firewall denies traffic according to rules. What is its relevant function?
  1. Enforcing traffic policy
  2. Providing unlimited bandwidth
  3. Cleaning fiber connectors
  4. Repairing broken copper pairs

Correct answer: A. Enforcing traffic policy

A firewall permits or denies traffic based on configured criteria and state. It cannot repair a disconnected physical medium.

components-easy-25 · For ordinary 1000BASE-T over compliant copper cabling, what is the common channel length limit?
  1. 1 kilometer
  2. 10 meters regardless of cable
  3. Unlimited with a static IP
  4. 100 meters

Correct answer: D. 100 meters

A compliant 1000BASE-T channel is normally limited to 100 meters including patching. Longer links need a suitable design and medium.

Medium explained questions · 1–12

Combine the configuration with the symptom before selecting a decision. These 12 questions are 1–12 of the medium set.

components-medium-1 · A PC has no link, but another PC works on the same switch port and cable. What should you inspect next?
  1. Every switch uplink
  2. The school's DNS zone
  3. The remote server certificate
  4. The failing PC's NIC state and driver

Correct answer: D. The failing PC's NIC state and driver

The replacement PC narrows the fault toward the original endpoint. The shared cable and port worked during the comparison.

components-medium-2 · A new 1 Gb/s desktop negotiates 100 Mb/s on a run; another short cable gives 1 Gb/s. What is the strongest lead?
  1. The original cable path or termination
  2. Insufficient subnet addresses
  3. A low DNS TTL
  4. The remote default route

Correct answer: A. The original cable path or termination

The endpoint supports gigabit on the short cable. The original channel may have pair or quality problems; a speed reading alone does not identify the exact defect.

components-medium-3 · A 150 m building link is planned with ordinary 1000BASE-T. What change addresses the distance concern?
  1. Increase DHCP lease time
  2. Use a suitably rated fiber link with compatible optics
  3. Choose a /16 subnet
  4. Set a longer hostname

Correct answer: B. Use a suitably rated fiber link with compatible optics

The proposed copper channel exceeds the usual 100 m limit. Fiber type, optics, and reach must be selected together.

components-medium-4 · A camera requires 18 W; its switch port supports only a 15.4 W PoE class at the source. What is the appropriate response?
  1. Set the VLAN to 1
  2. Check and provide a compatible higher-power PoE solution
  3. Replace the DNS resolver
  4. Force a lower IP address

Correct answer: B. Check and provide a compatible higher-power PoE solution

The power requirement exceeds the stated source limit, before cable losses. Data compatibility alone does not establish power compatibility.

components-medium-5 · An AP powers up but has no wired link. Which conclusion is justified?
  1. All cable pairs are good
  2. Power delivery works but data-link health is unproven
  3. The DHCP server is healthy
  4. The WAN route is missing

Correct answer: B. Power delivery works but data-link health is unproven

PoE power and Ethernet data are related but distinct. A powered device can still have a cable, interface, or negotiation fault.

components-medium-6 · Twenty Wi-Fi clients are slow while a wired client to the same local server is fast. What evidence should come next?
  1. WAN modem replacement
  2. Channel utilization and wireless retries
  3. Server default route only
  4. Authoritative DNS serial only

Correct answer: B. Channel utilization and wireless retries

The wired comparison reduces suspicion of the common server. Wireless airtime, interference, and client conditions need measurement.

components-medium-7 · A user sees full Wi-Fi signal but high retries. What should the technician avoid concluding?
  1. Signal and noise are separate observations
  2. Strong signal guarantees a clean radio channel
  3. Retry counters deserve attention
  4. Interference may exist

Correct answer: B. Strong signal guarantees a clean radio channel

Signal strength measures received power, not successful airtime use. Interference or contention can persist with strong signal.

components-medium-8 · Two 1 Gb/s PCs share a 100 Mb/s uplink to storage. Which component can limit aggregate storage traffic?
  1. The PCs' unique MAC addresses
  2. The 100 Mb/s uplink
  3. The DNS record name
  4. The storage subnet mask alone

Correct answer: B. The 100 Mb/s uplink

Traffic crosses the common uplink, whose capacity is below each access link. Fast endpoint ports do not remove the shared bottleneck.

components-medium-9 · An optical link uses a 1310 nm single-mode optic at one end and an incompatible multimode optic at the other. What should be checked?
  1. Only the switch hostname
  2. Optic type, wavelength, fiber type, and supported reach together
  3. Only DNS forwarders
  4. Only DHCP reservations

Correct answer: B. Optic type, wavelength, fiber type, and supported reach together

Optical compatibility requires a matched supported link design. Similar connector shapes do not prove compatible signaling.

components-medium-10 · A PC can ping its gateway but cannot load a website by name. What does the ping establish?
  1. A working route through every provider
  2. Healthy remote HTTPS service
  3. A working local IP exchange with the gateway
  4. Correct DNS resolution

Correct answer: C. A working local IP exchange with the gateway

Gateway reachability is bounded local evidence. Test name resolution and remote reachability separately.

components-medium-11 · A cable tester reports an open conductor. What is the useful next step?
  1. Create a larger DNS cache
  2. Replace the site's certificates
  3. Disable all VLANs
  4. Locate and repair the faulty termination or cable section

Correct answer: D. Locate and repair the faulty termination or cable section

An open conductor is physical evidence. Repair and retest the channel before changing higher-layer configuration.

components-medium-12 · A lab needs removable links between patch-panel ports and switch ports. What should be used?
  1. DNS aliases
  2. Compatible patch cords
  3. Routing metrics
  4. Firewall logging rules

Correct answer: B. Compatible patch cords

Patch cords connect terminated runs to active ports. Labels should document which physical run each connection serves.

Medium explained questions · 13–25

Combine the configuration with the symptom before selecting a decision. These 13 questions are 13–25 of the medium set.

components-medium-13 · Wi-Fi coverage improves after moving an AP away from a metal cabinet. What did the comparison support?
  1. DNS TTL caused weak signal
  2. VLAN IDs determine signal strength
  3. The Internet route changed necessarily
  4. Placement affected the wireless path

Correct answer: D. Placement affected the wireless path

Physical placement can alter obstruction and attenuation. The comparison supports a radio-path hypothesis rather than a name-service diagnosis.

components-medium-14 · A fiber link fails after maintenance; transmit and receive are connected to the wrong strands. What should be corrected?
  1. The application username
  2. The DHCP pool size
  3. The supported transmit-to-receive fiber pairing
  4. The DNS search suffix

Correct answer: C. The supported transmit-to-receive fiber pairing

A duplex optical link needs the transmit path at each end to reach the other end's receiver. IP changes cannot correct crossed optical roles.

components-medium-15 · A switch port reports many CRC errors while neighboring ports are clean. What is the best initial focus?
  1. The remote server's disk size
  2. All user passwords
  3. The entire DNS zone
  4. That link's cable, connectors, optics, and interface

Correct answer: D. That link's cable, connectors, optics, and interface

Localized frame corruption points toward the affected link. Counters guide inspection but do not prove one specific component failed.

components-medium-16 · A PC works by Ethernet but disconnects on Wi-Fi in one classroom. What comparison best isolates location effects?
  1. Test the same PC in another room and another client in this room
  2. Compare unrelated websites only
  3. Restart all DNS servers
  4. Change every switch route

Correct answer: A. Test the same PC in another room and another client in this room

Controlled client/location comparisons separate endpoint-specific and environment-specific wireless problems.

components-medium-17 · A router has a 1 Gb/s WAN port but subscribed service is 200 Mb/s. Which statement is accurate?
  1. A static IP removes the service limit
  2. Every client has a dedicated 200 Mb/s
  3. The port speed does not guarantee 1 Gb/s Internet throughput
  4. DNS can raise the subscription speed

Correct answer: C. The port speed does not guarantee 1 Gb/s Internet throughput

Physical port capacity and provider service capacity are different limits. Shared traffic and overhead can lower actual throughput further.

components-medium-18 · A local file transfer is slow only when many Wi-Fi clients are active. Which test is most informative?
  1. Change the subnet mask randomly
  2. Increase all DNS TTLs
  3. Rename the file server
  4. Compare wired transfer and radio airtime under the same load

Correct answer: D. Compare wired transfer and radio airtime under the same load

Comparable-load tests distinguish shared wireless airtime from server or broader network limits.

components-medium-19 · A replacement transceiver fits the slot but is not recognized. What should be verified?
  1. DNS reverse lookup
  2. Device support matrix and module speed/type
  3. Wi-Fi passphrase
  4. Lease renewal timer

Correct answer: B. Device support matrix and module speed/type

Mechanical fit is insufficient. The platform may not support the module's interface, speed, or coding.

components-medium-20 · A switch's total PoE budget is 120 W; eight APs request 20 W each. What problem is plausible?
  1. The total requested power exceeds the switch budget
  2. Each AP must use a different DNS suffix
  3. A /24 cannot hold eight devices
  4. Fiber attenuation is necessarily high

Correct answer: A. The total requested power exceeds the switch budget

Eight times 20 W is 160 W, above 120 W. Per-port support alone does not establish aggregate availability.

components-medium-21 · A throughput test is 90 Mb/s on a negotiated 100 Mb/s link. What is the defensible interpretation?
  1. Protocol overhead and conditions can make throughput lower than link rate
  2. DNS sets the physical speed
  3. The link must actually be 10 Gb/s
  4. The link is necessarily broken

Correct answer: A. Protocol overhead and conditions can make throughput lower than link rate

Payload throughput excludes some framing and protocol overhead. This result alone does not diagnose a fault.

components-medium-22 · A lab uplink is unplugged; PCs still exchange local traffic on the switch. Why?
  1. DNS forwards their Ethernet frames
  2. The missing uplink must be working
  3. Local switching can continue without the upstream path
  4. Every PC became a router

Correct answer: C. Local switching can continue without the upstream path

Same-VLAN local frames can stay on the switch. Remote services needing the uplink may fail independently.

components-medium-23 · A power outage takes down a modem while the router stays on a UPS. Why does Internet access fail?
  1. DNS TTL is zero during outages
  2. The router cannot route on battery
  3. The access path still depends on the unpowered modem
  4. A UPS must assign IPs

Correct answer: C. The access path still depends on the unpowered modem

Availability depends on all required components. Backup power for one device does not protect the entire path.

components-medium-24 · A new copper run beside industrial equipment has intermittent errors. What comparison is useful?
  1. Change the browser homepage
  2. Test a known-good alternate path away from the interference source
  3. Delete DNS aliases
  4. Increase the subnet size

Correct answer: B. Test a known-good alternate path away from the interference source

A controlled alternate path tests the environmental/physical hypothesis. The original cable still needs standards-based inspection.

components-medium-25 · An AP advertises an SSID, but clients receive no IP address. Which conclusion follows?
  1. Radio advertising works; DHCP and LAN attachment need separate checks
  2. The optical WAN failed definitely
  3. The entire network works
  4. The clients have valid gateways

Correct answer: A. Radio advertising works; DHCP and LAN attachment need separate checks

Seeing an SSID establishes only part of the wireless process. Association, VLAN mapping, DHCP, and routing remain separate dependencies.

Hard explained questions · 1–12

State what the evidence proves and reject conclusions that reach beyond it. These 12 questions are 1–12 of the hard set.

components-hard-1 · A PC has 1 Gb/s link, no CRC errors, valid address, and successful gateway ping; only one remote application fails. What is the next useful test?
  1. Test the application's destination port and service state
  2. Replace every patch cable
  3. Move the AP
  4. Buy higher-power PoE

Correct answer: A. Test the application's destination port and service state

Local link and gateway evidence make broad physical replacement poorly targeted. Application reachability requires service-specific evidence.

components-hard-2 · Six APs draw 15 W each on a 100 W PoE switch; adding two identical APs leaves some unpowered. What best explains the threshold?
  1. The subnet has fewer than eight addresses necessarily
  2. Aggregate requested power rises to 120 W
  3. A trunk supports only six radios
  4. DNS limits AP count to six

Correct answer: B. Aggregate requested power rises to 120 W

The aggregate demand crosses the stated power budget. Verify actual allocation and power logs before replacing working data links.

components-hard-3 · A gigabit copper link drops to 100 Mb/s after retermination; basic continuity passes on four conductors. What is the best next test?
  1. Change gateway metric
  2. Test all four pairs and their terminations for gigabit compliance
  3. Clear DNS cache only
  4. Create a new SSID

Correct answer: B. Test all four pairs and their terminations for gigabit compliance

1000BASE-T uses all four pairs. A limited continuity check cannot establish that the whole channel supports gigabit signaling.

components-hard-4 · A fiber link shows low received optical power after a connector was handled; routing configuration is unchanged. What action fits the evidence?
  1. Increase DHCP scope
  2. Replace DNS records
  3. Inspect and professionally clean/test connectors and optical levels
  4. Disable STP

Correct answer: C. Inspect and professionally clean/test connectors and optical levels

The change and optical reading point toward the light path. Follow safe optical procedures and verify power levels after correction.

components-hard-5 · Wireless retries rise at lunch while RSSI stays strong; wired local-server traffic is stable. What should be measured before adding APs?
  1. Airtime utilization, channel overlap, and interference during lunch
  2. Only the WAN port duplex
  3. Only server hostnames
  4. Only DHCP lease length

Correct answer: A. Airtime utilization, channel overlap, and interference during lunch

Strong RSSI and a stable wired baseline narrow the investigation toward shared radio conditions. Extra APs on overlapping channels may worsen contention.

components-hard-6 · A 10 Gb/s uplink serves 48 gigabit ports. What claim is unjustified from port ratings alone?
  1. Traffic demand determines actual utilization
  2. All 48 clients can sustain 1 Gb/s through the uplink simultaneously
  3. The uplink is shared
  4. Some traffic may remain local

Correct answer: B. All 48 clients can sustain 1 Gb/s through the uplink simultaneously

Aggregate access capacity is 48 Gb/s, exceeding the uplink. Oversubscription may be acceptable, but full simultaneous upstream line rate is not guaranteed.

components-hard-7 · One endpoint loses link using two known-good cables and two working switch ports; a second endpoint works on each. What is the most isolated suspect?
  1. The remote application
  2. The first endpoint's NIC or configuration
  3. Both tested switch ports equally
  4. The DNS service

Correct answer: B. The first endpoint's NIC or configuration

Repeated controlled substitutions keep the failing endpoint as the common factor. Inspect its hardware, driver, and enabled state.

components-hard-8 · An AP boots, then resets when additional radios start; PoE logs show power-denied events. What should be checked first?
  1. DNS negative cache
  2. The web server certificate
  3. Negotiated power standard, cable losses, and available budget
  4. Subnet broadcast address

Correct answer: C. Negotiated power standard, cable losses, and available budget

Resets coincide with increased power demand and power-denial logs. This is stronger evidence than assuming a general wireless coverage problem.

components-hard-9 · A multimode fiber run within the optic's rated reach fails with clean connectors; each transceiver works on a short known-good link. What remains to test?
  1. Only browser extensions
  2. Only VLAN names
  3. Only DHCP pool exhaustion
  4. Installed fiber loss, continuity, and actual path/strand type

Correct answer: D. Installed fiber loss, continuity, and actual path/strand type

The short-link tests establish endpoint operation under those conditions. The installed path may still have damage, excess loss, or a different specification.

components-hard-10 · The help desk reports slow Internet; local wired transfers are fast and WAN utilization is near capacity. Which response is best supported?
  1. Replace all local NICs
  2. Double every access-port speed immediately
  3. Delete the DNS zone
  4. Investigate shared WAN demand before replacing access switches

Correct answer: D. Investigate shared WAN demand before replacing access switches

The measurements distinguish local capacity from the saturated shared WAN. Access-switch replacement does not directly address that bottleneck.

components-hard-11 · A switched full-duplex port reports a duplex mismatch with a legacy peer and poor throughput. What is the focused correction?
  1. Change the SSID
  2. Make both ends use compatible negotiated or matching supported settings
  3. Disable all routes
  4. Increase the subnet size

Correct answer: B. Make both ends use compatible negotiated or matching supported settings

Mismatched duplex can produce poor behavior despite link indication. Verify both endpoints rather than forcing only one side blindly.

components-hard-12 · A contractor proposes copper between buildings with different electrical grounding conditions. What design consideration deserves attention?
  1. A properly engineered fiber path can avoid a conductive data connection
  2. A longer DHCP lease prevents surges
  3. A VLAN isolates electrical potential
  4. DNS will eliminate voltage differences

Correct answer: A. A properly engineered fiber path can avoid a conductive data connection

Fiber avoids copper data conductors between buildings. Electrical, installation, and local code requirements still need appropriate professional design.

Hard explained questions · 13–25

State what the evidence proves and reject conclusions that reach beyond it. These 13 questions are 13–25 of the hard set.

components-hard-13 · A topology map shows switch A linked to B, but LLDP reports a different neighbor on the labeled port. What should happen before changing routes?
  1. Erase the route table
  2. Replace all endpoint NICs
  3. Verify patching and update the physical map from observed connections
  4. Assume LLDP is a DNS result

Correct answer: C. Verify patching and update the physical map from observed connections

Observed neighbor evidence challenges the documentation. Confirm physical connections so later logical troubleshooting uses the actual path.

components-hard-14 · A Wi-Fi speed test is low on a distant client but normal on a nearby client and wired baseline. What is the best inference?
  1. Client radio conditions or capability may constrain that connection
  2. The DNS record is missing
  3. The WAN is down
  4. The shared server is definitely broken

Correct answer: A. Client radio conditions or capability may constrain that connection

The comparison points to the affected wireless link/client. Check negotiated rate, retries, obstruction, and capability before global changes.

components-hard-15 · An uplink has zero CRC errors but persistent output drops during backups. What evidence fits best?
  1. Every drop proves corrupt cable bits
  2. PoE voltage must be incorrect
  3. DNS uses too much TTL
  4. Offered traffic may exceed queue or link capacity

Correct answer: D. Offered traffic may exceed queue or link capacity

Output drops can indicate congestion even with clean received frames. Inspect utilization and queues; CRC errors describe a different failure class.

components-hard-16 · A powered AP stops passing traffic after its switch port is moved to another VLAN; link stays up. Which boundary changed?
  1. Optical wavelength
  2. Cable length necessarily
  3. The AP's power class necessarily
  4. Logical LAN membership rather than physical link availability

Correct answer: D. Logical LAN membership rather than physical link availability

VLAN membership can change DHCP and reachable services while link and power remain healthy. Check the intended VLAN design.

components-hard-17 · A fiber uplink fails only when a rack door closes. What is the best controlled investigation?
  1. Change the DNS suffix
  2. Increase route preference
  3. Reinstall every client
  4. Inspect bend stress and routing while comparing optical levels in both positions

Correct answer: D. Inspect bend stress and routing while comparing optical levels in both positions

The physical movement correlates with failure. Bend radius and cable strain can impair optical transmission; compare measured conditions.

components-hard-18 · Two WAN circuits exist, but both modem power supplies use the same unprotected outlet. What risk remains?
  1. Two DNS resolvers always prevent outages
  2. Different IPs eliminate common dependencies
  3. A single power failure can disable both circuits
  4. Fiber cannot lose endpoint power

Correct answer: C. A single power failure can disable both circuits

Path redundancy does not remove a common electrical dependency. Availability design must include shared power and equipment.

components-hard-19 · An SFP link works at 1 Gb/s but a proposed 10 Gb/s module fails in the same slot. What should be verified before diagnosing fiber damage?
  1. Whether the hostname is short
  2. Whether the slot and platform support that 10 Gb/s module
  3. Whether DHCP uses UDP
  4. Whether the subnet is /24

Correct answer: B. Whether the slot and platform support that 10 Gb/s module

A 1 Gb/s-only slot need not support SFP+ operation. Test platform compatibility before attributing failure to the medium.

components-hard-20 · A client has a 2.5 Gb/s NIC, 1 Gb/s switch port, and 300 Mb/s WAN. What is the best Internet-capacity interpretation?
  1. The WAN can cap throughput below both local interface ratings
  2. The switch provides 1 Gb/s per Internet destination
  3. The slowest DNS TTL controls throughput
  4. The NIC guarantees 2.5 Gb/s Internet

Correct answer: A. The WAN can cap throughput below both local interface ratings

End-to-end capacity depends on every relevant segment. Interface capability cannot bypass the provider access limit.

components-hard-21 · A loopback ping succeeds but Ethernet link is down. What has the successful test established?
  1. The switch is reachable
  2. The router is forwarding
  3. The DHCP server offered a lease
  4. Local IP-stack response rather than cable connectivity

Correct answer: D. Local IP-stack response rather than cable connectivity

Loopback stays inside the host. It does not traverse the NIC cable or prove any external network path.

components-hard-22 · All cameras lose video during heavy uploads; they remain powered and output-queue drops rise on their shared uplink. What intervention should be evaluated?
  1. Replacing every camera lens
  2. Higher-power injectors first
  3. Traffic scheduling or additional uplink capacity based on measured load
  4. Changing DNS names

Correct answer: C. Traffic scheduling or additional uplink capacity based on measured load

Power remains stable while forwarding queues drop traffic. Capacity and scheduling address the measured shared data bottleneck.

components-hard-23 · An AP supports many clients but airtime is dominated by slow clients sending frequent frames. Why can faster clients also slow down?
  1. Each client's IP shares a CPU core necessarily
  2. MAC addresses impose equal bit rates
  3. DNS restricts fast clients
  4. They share finite radio airtime on that channel

Correct answer: D. They share finite radio airtime on that channel

Low-rate transmissions can consume disproportionate airtime. Shared-medium time, not just nominal peak rate, determines contention.

components-hard-24 · A new cable passes simple continuity but has high crosstalk in a certification test. Which conclusion is sound?
  1. The subnet mask must be wrong
  2. The link is certified because wires connect
  3. DNS caused crosstalk
  4. Continuity alone did not prove category-level performance

Correct answer: D. Continuity alone did not prove category-level performance

Performance certification tests signal properties beyond conductor continuity. Retermination or cable replacement may be required.

components-hard-25 · A link is restored after changing both cable and switch port. What can the technician claim?
  1. DNS was proven responsible
  2. The original cable was proven faulty
  3. The combined change restored service but did not isolate which component caused failure
  4. The original switch port was proven faulty

Correct answer: C. The combined change restored service but did not isolate which component caused failure

Changing two variables restores operation without separating their causal effects. Record that limitation and use controlled tests if isolation is needed.

If device and medium roles are secure, diagnose the wireless stages next in AP Networking Wi-Fi and Wireless Troubleshooting Practice Test. Its 75 explained questions add a separate Easy, Medium, and Hard diagnostic for that next reasoning step.

Use the result to choose your next study step

Use a comparison matrix: original endpoint on known-good cable/port, known-good endpoint on the suspect path, and the same workload over a wired baseline. Keep one variable fixed where possible. If cable and port are changed together, record that service returned without claiming either component was independently proven faulty.

Record whether each miss concerned link evidence, media compatibility, capacity. Copy one decisive observation and one rejected inference into your error log. Then review the focused supporting resource, explain a missed item without its options, and retry the relevant level after a separate study session.

For course-level transfer, move to Unit 1 practice, Unit 2 practice, Unit 3 practice. When the topic labels no longer guide your answer, use full practice exams and artifact analysis to combine selection, evidence, and explanation.

Teacher use

Assign one level as a diagnostic, collect explanations for two missed items, and group students by the missing step rather than total score alone. Ask pairs to compare a correct conclusion with a tempting overclaim. Do not treat repeated exposure to the same answer as independent evidence of mastery.