Cisco Certified Support Technician (CCST) Networking 100-150 Practice Test 58
Question 570
The local support team reports: At the fictional Cascade Science Lab in a technician onboarding review, the team observes: A remote site uses a legacy serial WAN interface but a technician attaches a modern USB flash-memory cable expecting it to carry the circuit. What is the MOST specific underlying cause?
- Serial WAN ports and USB peripheral ports have different functions and physical signaling.
- IPv4 routers decrement TTL to help prevent packets from looping indefinitely.
- Longest-prefix matching selects a specific matching route over a less-specific default route.
- VLAN membership confines ordinary Layer 2 broadcasts to their respective broadcast domains.
Explanation
Correct Answer
A:Correct. This mechanism fits the observed network symptom at the fictional Cascade Science Lab: Serial WAN ports and USB peripheral ports have different functions and physical signaling. The corresponding remedy is “Identify the supported serial interface and its cable type from the device documentation.”. Confirmation: The proper serial connection can be verified by the interface's status and service configuration.
Incorrect Answers
B:That cause belongs to a different case: A technician sees that packet TTL decreases at a routed hop and calls it corruption that must be repaired by disabling routing. The observed fictional Cascade Science Lab condition is specifically explained by “Serial WAN ports and USB peripheral ports have different functions and physical signaling.”.
C:That cause belongs to a different case: A branch router has a specific route to 10.20.0.0/16 and a default route, but the trainee expects all 10.x.x.x traffic to use the default. The observed fictional Cascade Science Lab condition is specifically explained by “Serial WAN ports and USB peripheral ports have different functions and physical signaling.”.
D:That cause belongs to a different case: A technician sends an ARP broadcast in VLAN 20 and expects it to flood into VLAN 30 without routing or relay. The observed fictional Cascade Science Lab condition is specifically explained by “Serial WAN ports and USB peripheral ports have different functions and physical signaling.”.
Question 571
The technician must verify the following scenario: At the fictional Cascade Science Lab in a technician onboarding review, the team observes: A remote site uses a legacy serial WAN interface but a technician attaches a modern USB flash-memory cable expecting it to carry the circuit. The approved corrective action is: “Identify the supported serial interface and its cable type from the device documentation.” Which result BEST demonstrates success?
- The reported port status matches the active LED mode and the device's management interface.
- Both remote optical interfaces establish their intended link without a local loopback.
- A trace verifies the exact physical endpoints required by the network diagram.
- The proper serial connection can be verified by the interface's status and service configuration.
Explanation
Correct Answer
D:Correct. This is the required observable acceptance evidence for “Identify the supported serial interface and its cable type from the device documentation.” at the fictional Cascade Science Lab. It demonstrates correction of the original cause: Serial WAN ports and USB peripheral ports have different functions and physical signaling.
Incorrect Answers
A:That result is evidence for a separate corrective action, “Identify the current LED display mode and consult the model's port-status legend.”. It does not establish the intended outcome “The proper serial connection can be verified by the interface's status and service configuration.” for the fictional Cascade Science Lab case.
B:That result is evidence for a separate corrective action, “Correct the two-strand fiber polarity according to the transceiver and diagram.”. It does not establish the intended outcome “The proper serial connection can be verified by the interface's status and service configuration.” for the fictional Cascade Science Lab case.
C:That result is evidence for a separate corrective action, “Use the cable labels and tester to reconnect panel 24 to switch B port 7.”. It does not establish the intended outcome “The proper serial connection can be verified by the interface's status and service configuration.” for the fictional Cascade Science Lab case.
Question 572
A change reviewer considers: At the fictional Cascade Science Lab in a technician onboarding review, the team observes: A remote site uses a legacy serial WAN interface but a technician attaches a modern USB flash-memory cable expecting it to carry the circuit. During “Identify the supported serial interface and its cable type from the device documentation.”, which precaution MOST specifically prevents a related risk?
- Do not bridge separate VLANs accidentally just to bypass a routing design requirement.
- Do not disable unrelated VLAN boundaries merely to bypass a MAC-filtering denial.
- Do not assume USB and serial WAN ports are interchangeable because both are called serial in casual speech.
- Do not improvise extra Ethernet loops just to create apparent redundancy.
Explanation
Correct Answer
C:Correct. This precaution prevents a second fault while applying “Identify the supported serial interface and its cable type from the device documentation.” at the fictional Cascade Science Lab. The required protection is “Do not assume USB and serial WAN ports are interchangeable because both are called serial in casual speech.”; success still requires “The proper serial connection can be verified by the interface's status and service configuration.”.
Incorrect Answers
A:This caution is appropriate for a separate failure pattern: Two PCs connected to one physical switch are in separate access VLANs and cannot talk without routing, but the help desk assumes all switch ports share one broadcast domain. The principal adjacent risk here is controlled by “Do not assume USB and serial WAN ports are interchangeable because both are called serial in casual speech.”.
B:This caution is appropriate for a separate failure pattern: A switch's port-security list blocks an unknown device MAC, but the technician removes all VLAN segmentation and calls the result normal switching. The principal adjacent risk here is controlled by “Do not assume USB and serial WAN ports are interchangeable because both are called serial in casual speech.”.
D:This caution is appropriate for a separate failure pattern: A field engineer provides a port-to-port cable schedule for a small three-switch network, but the technician connects each switch to every other switch without checking loop control. The principal adjacent risk here is controlled by “Do not assume USB and serial WAN ports are interchangeable because both are called serial in casual speech.”.
Question 573
During entry-level network support, consider: At the fictional Seabrook Bakery while checking a service ticket, the team observes: A help desk operator inserts a flash drive into a switch USB port and assumes it has added a new Ethernet forwarding interface. Which action MOST directly resolves the reported issue?
- Send a controlled frame and inspect the source MAC's learned table entry on port 5.
- Check the model's USB purpose and use a supported Ethernet port for LAN uplink needs.
- Identify the console jack and attach a compatible USB or serial console adapter as specified.
- Correct the two-strand fiber polarity according to the transceiver and diagram.
Explanation
Correct Answer
B:Correct. In the fictional Seabrook Bakery case, A device USB port is commonly for compatible peripherals or storage, not automatically a switched network port. The specified corrective action, “Check the model's USB purpose and use a supported Ethernet port for LAN uplink needs.”, directly targets that condition. Evidence of resolution: The uplink appears in Ethernet interface status rather than being inferred from attached storage.
Incorrect Answers
A:That action addresses a different network issue: An access switch sees a source MAC arrive on port 5 but a trainee claims the MAC table can only learn destination MAC addresses. The present fictional Seabrook Bakery finding instead needs “Check the model's USB purpose and use a supported Ethernet port for LAN uplink needs.”, verified by “The uplink appears in Ethernet interface status rather than being inferred from attached storage.”.
C:That action addresses a different network issue: A work order specifies a dedicated console cable from a notebook to a switch for initial setup but the tech plugs into the switch's user-data uplink instead. The present fictional Seabrook Bakery finding instead needs “Check the model's USB purpose and use a supported Ethernet port for LAN uplink needs.”, verified by “The uplink appears in Ethernet interface status rather than being inferred from attached storage.”.
D:That action addresses a different network issue: An engineer's drawing shows an indoor fiber connection with separate transmit and receive channels, but the technician loops each optic's transmit back into its own receive. The present fictional Seabrook Bakery finding instead needs “Check the model's USB purpose and use a supported Ethernet port for LAN uplink needs.”, verified by “The uplink appears in Ethernet interface status rather than being inferred from attached storage.”.
Question 574
The local support team reports: At the fictional Seabrook Bakery while checking a service ticket, the team observes: A help desk operator inserts a flash drive into a switch USB port and assumes it has added a new Ethernet forwarding interface. What is the MOST specific underlying cause?
- A device USB port is commonly for compatible peripherals or storage, not automatically a switched network port.
- Dedicated system, stack and port LEDs indicate different categories of information.
- Mode-selectable switch LED indicators must be interpreted in the selected mode shown by the device.
- A locator or identification LED may be intentionally controlled to find a specific unit in a rack.
Explanation
Correct Answer
A:Correct. This mechanism fits the observed network symptom at the fictional Seabrook Bakery: A device USB port is commonly for compatible peripherals or storage, not automatically a switched network port. The corresponding remedy is “Check the model's USB purpose and use a supported Ethernet port for LAN uplink needs.”. Confirmation: The uplink appears in Ethernet interface status rather than being inferred from attached storage.
Incorrect Answers
B:That cause belongs to a different case: A technician photographs a stack member LED and labels it a line-rate speed indicator on a switch model with separate stacking status. The observed fictional Seabrook Bakery condition is specifically explained by “A device USB port is commonly for compatible peripherals or storage, not automatically a switched network port.”.
C:That cause belongs to a different case: A switch displays several selectable LED modes and a technician reads a power-over-Ethernet status LED as though it were showing duplex. The observed fictional Seabrook Bakery condition is specifically explained by “A device USB port is commonly for compatible peripherals or storage, not automatically a switched network port.”.
D:That cause belongs to a different case: A field tech sees a rapidly blinking identifier LED intentionally activated by a remote engineer and opens an outage ticket for the device. The observed fictional Seabrook Bakery condition is specifically explained by “A device USB port is commonly for compatible peripherals or storage, not automatically a switched network port.”.
Question 575
The technician must verify the following scenario: At the fictional Seabrook Bakery while checking a service ticket, the team observes: A help desk operator inserts a flash drive into a switch USB port and assumes it has added a new Ethernet forwarding interface. The approved corrective action is: “Check the model's USB purpose and use a supported Ethernet port for LAN uplink needs.” Which result BEST demonstrates success?
- A traceroute reaches the remote subnet and replies return without an asymmetric black hole.
- The escalation includes the model-specific meaning rather than a universal claim that amber always means failure.
- The report distinguishes stack membership indication from Ethernet port speed.
- The uplink appears in Ethernet interface status rather than being inferred from attached storage.
Explanation
Correct Answer
D:Correct. This is the required observable acceptance evidence for “Check the model's USB purpose and use a supported Ethernet port for LAN uplink needs.” at the fictional Seabrook Bakery. It demonstrates correction of the original cause: A device USB port is commonly for compatible peripherals or storage, not automatically a switched network port.
Incorrect Answers
A:That result is evidence for a separate corrective action, “Add or verify the approved route toward 10.7.0.0/16 and any necessary return path.”. It does not establish the intended outcome “The uplink appears in Ethernet interface status rather than being inferred from attached storage.” for the fictional Seabrook Bakery case.
B:That result is evidence for a separate corrective action, “Record the exact model, LED name, color and blink pattern and interpret it using the model's documented table.”. It does not establish the intended outcome “The uplink appears in Ethernet interface status rather than being inferred from attached storage.” for the fictional Seabrook Bakery case.
C:That result is evidence for a separate corrective action, “Use the correct switch model legend to identify the stack LED and its current operating state.”. It does not establish the intended outcome “The uplink appears in Ethernet interface status rather than being inferred from attached storage.” for the fictional Seabrook Bakery case.
Question 576
A change reviewer considers: At the fictional Seabrook Bakery while checking a service ticket, the team observes: A help desk operator inserts a flash drive into a switch USB port and assumes it has added a new Ethernet forwarding interface. During “Check the model's USB purpose and use a supported Ethernet port for LAN uplink needs.”, which precaution MOST specifically prevents a related risk?
- Do not assume all Cisco amber indicators have one universal meaning.
- Do not troubleshoot DHCP before establishing a working physical Ethernet link.
- Do not treat a USB storage slot as an ordinary RJ-45 data port.
- Do not assume routers select an output based on visually similar IPv4 digits.
Explanation
Correct Answer
C:Correct. This precaution prevents a second fault while applying “Check the model's USB purpose and use a supported Ethernet port for LAN uplink needs.” at the fictional Seabrook Bakery. The required protection is “Do not treat a USB storage slot as an ordinary RJ-45 data port.”; success still requires “The uplink appears in Ethernet interface status rather than being inferred from attached storage.”.
Incorrect Answers
A:This caution is appropriate for a separate failure pattern: A network engineer tells a junior tech to report an amber status light on a particular switch module; the tech immediately replaces the module without reading the model instructions. The principal adjacent risk here is controlled by “Do not treat a USB storage slot as an ordinary RJ-45 data port.”.
B:This caution is appropriate for a separate failure pattern: A field worker sees no link light on an attached Ethernet port and configures a new DHCP scope before checking the cable. The principal adjacent risk here is controlled by “Do not treat a USB storage slot as an ordinary RJ-45 data port.”.
D:This caution is appropriate for a separate failure pattern: A router receives a destination IP not found in any specific route and has no default route, but an operator insists it must choose the nearest numerically named interface. The principal adjacent risk here is controlled by “Do not treat a USB storage slot as an ordinary RJ-45 data port.”.
Question 577
During entry-level network support, consider: At the fictional Lighthouse Research Annex after a user reports a recurring problem, the team observes: A VoIP phone requires power through its Ethernet cable but a technician connects it to an otherwise working non-PoE Ethernet interface. Which action MOST directly resolves the reported issue?
- Restore the gateway's link and verify the host can reach its local router before testing the remote service.
- Identify a PoE-capable port and confirm the switch's available PoE budget.
- Verify port VLAN membership and provide an authorized inter-VLAN routing path if communication is required.
- Use the cable labels and tester to reconnect panel 24 to switch B port 7.
Explanation
Correct Answer
B:Correct. In the fictional Lighthouse Research Annex case, Ethernet data capability does not imply that a given port offers Power over Ethernet. The specified corrective action, “Identify a PoE-capable port and confirm the switch's available PoE budget.”, directly targets that condition. Evidence of resolution: The phone powers and negotiates its Ethernet link on the correct powered interface.
Incorrect Answers
A:That action addresses a different network issue: A PC sends traffic to a remote server but the gateway's Ethernet interface is down and the technician tries to edit only the server's application port. The present fictional Lighthouse Research Annex finding instead needs “Identify a PoE-capable port and confirm the switch's available PoE budget.”, verified by “The phone powers and negotiates its Ethernet link on the correct powered interface.”.
C:That action addresses a different network issue: Two PCs connected to one physical switch are in separate access VLANs and cannot talk without routing, but the help desk assumes all switch ports share one broadcast domain. The present fictional Lighthouse Research Annex finding instead needs “Identify a PoE-capable port and confirm the switch's available PoE budget.”, verified by “The phone powers and negotiates its Ethernet link on the correct powered interface.”.
D:That action addresses a different network issue: A diagram explicitly labels rack A panel 24 to switch B port 7, but the installer connects panel 23 and concludes that logical VLAN changes will repair the wrong patch. The present fictional Lighthouse Research Annex finding instead needs “Identify a PoE-capable port and confirm the switch's available PoE budget.”, verified by “The phone powers and negotiates its Ethernet link on the correct powered interface.”.
Question 578
The local support team reports: At the fictional Lighthouse Research Annex after a user reports a recurring problem, the team observes: A VoIP phone requires power through its Ethernet cable but a technician connects it to an otherwise working non-PoE Ethernet interface. What is the MOST specific underlying cause?
- Ethernet data capability does not imply that a given port offers Power over Ethernet.
- The physical patch plan designates a power-providing switch interface for the AP.
- VLANs separate Layer 2 broadcast domains even on the same physical switch.
- LED colors and patterns can indicate different states across Cisco models and operating modes.
Explanation
Correct Answer
A:Correct. This mechanism fits the observed network symptom at the fictional Lighthouse Research Annex: Ethernet data capability does not imply that a given port offers Power over Ethernet. The corresponding remedy is “Identify a PoE-capable port and confirm the switch's available PoE budget.”. Confirmation: The phone powers and negotiates its Ethernet link on the correct powered interface.
Incorrect Answers
B:That cause belongs to a different case: A PoE access point is shown on port Gi1/0/12 but the technician patches it into a non-PoE port and it stays dark. The observed fictional Lighthouse Research Annex condition is specifically explained by “Ethernet data capability does not imply that a given port offers Power over Ethernet.”.
C:That cause belongs to a different case: Two PCs connected to one physical switch are in separate access VLANs and cannot talk without routing, but the help desk assumes all switch ports share one broadcast domain. The observed fictional Lighthouse Research Annex condition is specifically explained by “Ethernet data capability does not imply that a given port offers Power over Ethernet.”.
D:That cause belongs to a different case: A network engineer tells a junior tech to report an amber status light on a particular switch module; the tech immediately replaces the module without reading the model instructions. The observed fictional Lighthouse Research Annex condition is specifically explained by “Ethernet data capability does not imply that a given port offers Power over Ethernet.”.
Question 579
The technician must verify the following scenario: At the fictional Lighthouse Research Annex after a user reports a recurring problem, the team observes: A VoIP phone requires power through its Ethernet cable but a technician connects it to an otherwise working non-PoE Ethernet interface. The approved corrective action is: “Identify a PoE-capable port and confirm the switch's available PoE budget.” Which result BEST demonstrates success?
- The host resolves and reaches its gateway and then the routed server.
- Interface status and a test route confirm that the physical switch-to-router link exists.
- The topology converges with no uncontrolled forwarding loop and broadcasts return to normal.
- The phone powers and negotiates its Ethernet link on the correct powered interface.
Explanation
Correct Answer
D:Correct. This is the required observable acceptance evidence for “Identify a PoE-capable port and confirm the switch's available PoE budget.” at the fictional Lighthouse Research Annex. It demonstrates correction of the original cause: Ethernet data capability does not imply that a given port offers Power over Ethernet.
Incorrect Answers
A:That result is evidence for a separate corrective action, “Restore the gateway's link and verify the host can reach its local router before testing the remote service.”. It does not establish the intended outcome “The phone powers and negotiates its Ethernet link on the correct powered interface.” for the fictional Lighthouse Research Annex case.
B:That result is evidence for a separate corrective action, “Cable the access switch uplink to the router's identified Ethernet port from the approved diagram.”. It does not establish the intended outcome “The phone powers and negotiates its Ethernet link on the correct powered interface.” for the fictional Lighthouse Research Annex case.
C:That result is evidence for a separate corrective action, “Examine the physical loop and the approved spanning-tree or port-channel design.”. It does not establish the intended outcome “The phone powers and negotiates its Ethernet link on the correct powered interface.” for the fictional Lighthouse Research Annex case.
Question 580
A change reviewer considers: At the fictional Lighthouse Research Annex after a user reports a recurring problem, the team observes: A VoIP phone requires power through its Ethernet cable but a technician connects it to an otherwise working non-PoE Ethernet interface. During “Identify a PoE-capable port and confirm the switch's available PoE budget.”, which precaution MOST specifically prevents a related risk?
- Do not hard-code stale MAC-to-port entries to hide a moving endpoint.
- Do not claim link redundancy when both supposed paths terminate in one unverified connection.
- Do not assume all active Ethernet interfaces provide power.
- Do not add parallel Layer 2 links without appropriate loop-prevention controls.
Explanation
Correct Answer
C:Correct. This precaution prevents a second fault while applying “Identify a PoE-capable port and confirm the switch's available PoE budget.” at the fictional Lighthouse Research Annex. The required protection is “Do not assume all active Ethernet interfaces provide power.”; success still requires “The phone powers and negotiates its Ethernet link on the correct powered interface.”.
Incorrect Answers
A:This caution is appropriate for a separate failure pattern: A technician moves a workstation to a different port and the switch initially sends some traffic to its old location. The principal adjacent risk here is controlled by “Do not assume all active Ethernet interfaces provide power.”.
B:This caution is appropriate for a separate failure pattern: A rack elevation places two redundant uplinks on separate switch ports but the installer connects both strands to the same unsupported transceiver and records two working paths. The principal adjacent risk here is controlled by “Do not assume all active Ethernet interfaces provide power.”.
D:This caution is appropriate for a separate failure pattern: A junior engineer creates two direct Ethernet connections between switches and sees broadcast storms but disables all VLANs instead of checking Layer 2 loops. The principal adjacent risk here is controlled by “Do not assume all active Ethernet interfaces provide power.”.