Cisco Certified Support Technician (CCST) Networking 100-150 Practice Test 1
Question 1
A service desk receives this network finding: At the fictional Lighthouse Research Annex after a user reports a recurring problem, the team observes: A capture shows an Ethernet frame delivered to a switch and an IP packet forwarded by a router, but a trainee says the Ethernet header survives unchanged across the routed hop. Which action MOST directly resolves the reported issue?
- Convert the file rate to approximately 96 Mb/s before comparing it with the 100 Mb/s connection.
- Explain that the router removes the inbound Layer 2 frame and encapsulates the IP packet in a new outgoing Layer 2 frame.
- Record round-trip delay in milliseconds separately from throughput in Mb/s or MB/s.
- Classify hosted email as SaaS and identify the customer's account, access and data responsibilities.
Explanation
Correct Answer
B:Correct. In the fictional Lighthouse Research Annex case, The trainee confuses local-link framing with the network-layer packet that is re-encapsulated on each routed link. The specified corrective action, “Explain that the router removes the inbound Layer 2 frame and encapsulates the IP packet in a new outgoing Layer 2 frame.”, directly targets that condition. Evidence of resolution: Compare the inbound and outbound source and destination MAC addresses while the packet IP destination remains the same.
Incorrect Answers
A:That action addresses a different network issue: A support engineer compares 12 MB/s file-transfer throughput directly with 100 Mb/s link speed and says 12 is much less than 100. The present fictional Lighthouse Research Annex finding instead needs “Explain that the router removes the inbound Layer 2 frame and encapsulates the IP packet in a new outgoing Layer 2 frame.”, verified by “Compare the inbound and outbound source and destination MAC addresses while the packet IP destination remains the same.”.
C:That action addresses a different network issue: A user calls the 10 ms ping round-trip time a 10 MB/s transfer speed. The present fictional Lighthouse Research Annex finding instead needs “Explain that the router removes the inbound Layer 2 frame and encapsulates the IP packet in a new outgoing Layer 2 frame.”, verified by “Compare the inbound and outbound source and destination MAC addresses while the packet IP destination remains the same.”.
D:That action addresses a different network issue: An employee subscribes to a hosted email application but the team says they must patch the service's virtual machines. The present fictional Lighthouse Research Annex finding instead needs “Explain that the router removes the inbound Layer 2 frame and encapsulates the IP packet in a new outgoing Layer 2 frame.”, verified by “Compare the inbound and outbound source and destination MAC addresses while the packet IP destination remains the same.”.
Question 2
Before changing settings, consider this issue: At the fictional Lighthouse Research Annex after a user reports a recurring problem, the team observes: A capture shows an Ethernet frame delivered to a switch and an IP packet forwarded by a router, but a trainee says the Ethernet header survives unchanged across the routed hop. What is the MOST specific underlying cause?
- The trainee confuses local-link framing with the network-layer packet that is re-encapsulated on each routed link.
- Link bandwidth is a capacity rating; throughput is the actual delivered rate after overhead and constraints.
- WLAN normally refers to a local Wi-Fi network rather than licensed mobile-carrier access.
- A network can have hybrid topologies with different connection structures at access and core layers.
Explanation
Correct Answer
A:Correct. This mechanism fits the observed network symptom at the fictional Lighthouse Research Annex: The trainee confuses local-link framing with the network-layer packet that is re-encapsulated on each routed link. The corresponding remedy is “Explain that the router removes the inbound Layer 2 frame and encapsulates the IP packet in a new outgoing Layer 2 frame.”. Confirmation: Compare the inbound and outbound source and destination MAC addresses while the packet IP destination remains the same.
Incorrect Answers
B:That cause belongs to a different case: A technician reports that a 1 Gb/s Ethernet interface guarantees a file copy will deliver 1 Gb/s of application data. The observed fictional Lighthouse Research Annex condition is specifically explained by “The trainee confuses local-link framing with the network-layer packet that is re-encapsulated on each routed link.”.
C:That cause belongs to a different case: An office wireless access point connects several clients to the local wired network, but the trainee says WLAN means a cellular carrier network. The observed fictional Lighthouse Research Annex condition is specifically explained by “The trainee confuses local-link framing with the network-layer packet that is re-encapsulated on each routed link.”.
D:That cause belongs to a different case: A multi-building installation combines a star of access switches with redundant mesh uplinks but is described as one pure star without redundancies. The observed fictional Lighthouse Research Annex condition is specifically explained by “The trainee confuses local-link framing with the network-layer packet that is re-encapsulated on each routed link.”.
Question 3
A reviewer evaluates a proposed repair for: At the fictional Lighthouse Research Annex after a user reports a recurring problem, the team observes: A capture shows an Ethernet frame delivered to a switch and an IP packet forwarded by a router, but a trainee says the Ethernet header survives unchanged across the routed hop. The approved corrective action is: “Explain that the router removes the inbound Layer 2 frame and encapsulates the IP packet in a new outgoing Layer 2 frame.” Which result BEST demonstrates success?
- The upstream measurement exposes the constrained egress direction while LAN traffic remains normal.
- The diagram demonstrates alternate links if one inter-switch connection fails.
- Client association and SSID map to the WLAN while the modem's carrier link maps to cellular service.
- Compare the inbound and outbound source and destination MAC addresses while the packet IP destination remains the same.
Explanation
Correct Answer
D:Correct. This is the required observable acceptance evidence for “Explain that the router removes the inbound Layer 2 frame and encapsulates the IP packet in a new outgoing Layer 2 frame.” at the fictional Lighthouse Research Annex. It demonstrates correction of the original cause: The trainee confuses local-link framing with the network-layer packet that is re-encapsulated on each routed link.
Incorrect Answers
A:That result is evidence for a separate corrective action, “Test upstream throughput on the affected path and compare it with internal LAN transfer results.”. It does not establish the intended outcome “Compare the inbound and outbound source and destination MAC addresses while the packet IP destination remains the same.” for the fictional Lighthouse Research Annex case.
B:That result is evidence for a separate corrective action, “Label the interconnected switch arrangement a mesh and record redundant paths.”. It does not establish the intended outcome “Compare the inbound and outbound source and destination MAC addresses while the packet IP destination remains the same.” for the fictional Lighthouse Research Annex case.
C:That result is evidence for a separate corrective action, “Identify the Wi-Fi WLAN and its wired LAN uplink separately from cellular WAN connectivity.”. It does not establish the intended outcome “Compare the inbound and outbound source and destination MAC addresses while the packet IP destination remains the same.” for the fictional Lighthouse Research Annex case.
Question 4
The technician plans a correction for: At the fictional Lighthouse Research Annex after a user reports a recurring problem, the team observes: A capture shows an Ethernet frame delivered to a switch and an IP packet forwarded by a router, but a trainee says the Ethernet header survives unchanged across the routed hop. During “Explain that the router removes the inbound Layer 2 frame and encapsulates the IP packet in a new outgoing Layer 2 frame.”, which precaution MOST specifically prevents a related risk?
- Do not equate remote-work access with SaaS hosting.
- Do not leave customer-managed guest operating systems unpatched under an IaaS assumption.
- Do not claim that the source and destination Ethernet MAC addresses remain unchanged across a router.
- Do not promise that SaaS removes the customer's responsibility for user access and data handling.
Explanation
Correct Answer
C:Correct. This precaution prevents a second fault while applying “Explain that the router removes the inbound Layer 2 frame and encapsulates the IP packet in a new outgoing Layer 2 frame.” at the fictional Lighthouse Research Annex. The required protection is “Do not claim that the source and destination Ethernet MAC addresses remain unchanged across a router.”; success still requires “Compare the inbound and outbound source and destination MAC addresses while the packet IP destination remains the same.”.
Incorrect Answers
A:This caution is appropriate for a separate failure pattern: A freelancer works from home through a VPN to an internal application and the team assumes a VPN automatically makes it a cloud-hosted application. The principal adjacent risk here is controlled by “Do not claim that the source and destination Ethernet MAC addresses remain unchanged across a router.”.
B:This caution is appropriate for a separate failure pattern: A team rents cloud virtual machines and believes the provider must configure every guest OS account and application patch. The principal adjacent risk here is controlled by “Do not claim that the source and destination Ethernet MAC addresses remain unchanged across a router.”.
D:This caution is appropriate for a separate failure pattern: An employee subscribes to a hosted email application but the team says they must patch the service's virtual machines. The principal adjacent risk here is controlled by “Do not claim that the source and destination Ethernet MAC addresses remain unchanged across a router.”.
Question 5
A service desk receives this network finding: At the fictional Summit Print Shop during a physical cabling audit, the team observes: A workstation sends a browser request and the technician labels TCP port 443 a physical-layer address. Which action MOST directly resolves the reported issue?
- Document the shared-responsibility split for cloud VMs including guest hardening and updates.
- Locate TCP or UDP source and destination port fields in the transport header and distinguish them from link and IP addresses.
- Mark each site's LAN and the provider-managed intersite WAN transport on the map.
- Label the interconnected switch arrangement a mesh and record redundant paths.
Explanation
Correct Answer
B:Correct. In the fictional Summit Print Shop case, Transport-layer port numbers identify application endpoints, not electrical or MAC-layer links. The specified corrective action, “Locate TCP or UDP source and destination port fields in the transport header and distinguish them from link and IP addresses.”, directly targets that condition. Evidence of resolution: A layered packet diagram places port 443 in TCP, IP addresses in the network header and MAC addresses in Ethernet.
Incorrect Answers
A:That action addresses a different network issue: A team rents cloud virtual machines and believes the provider must configure every guest OS account and application patch. The present fictional Summit Print Shop finding instead needs “Locate TCP or UDP source and destination port fields in the transport header and distinguish them from link and IP addresses.”, verified by “A layered packet diagram places port 443 in TCP, IP addresses in the network header and MAC addresses in Ethernet.”.
C:That action addresses a different network issue: A provider connects two distant corporate offices through its backbone and a technician calls the service a wireless LAN. The present fictional Summit Print Shop finding instead needs “Locate TCP or UDP source and destination port fields in the transport header and distinguish them from link and IP addresses.”, verified by “A layered packet diagram places port 443 in TCP, IP addresses in the network header and MAC addresses in Ethernet.”.
D:That action addresses a different network issue: A redundant core diagram shows direct links between every pair of distribution switches but calls it a simple line topology. The present fictional Summit Print Shop finding instead needs “Locate TCP or UDP source and destination port fields in the transport header and distinguish them from link and IP addresses.”, verified by “A layered packet diagram places port 443 in TCP, IP addresses in the network header and MAC addresses in Ethernet.”.
Question 6
Before changing settings, consider this issue: At the fictional Summit Print Shop during a physical cabling audit, the team observes: A workstation sends a browser request and the technician labels TCP port 443 a physical-layer address. What is the MOST specific underlying cause?
- Transport-layer port numbers identify application endpoints, not electrical or MAC-layer links.
- Hybrid architecture combines private/on-premises and public-cloud services within one solution.
- Bursty congestion and buffering can introduce queueing latency even when physical link negotiation is fast.
- DHCP supplies dynamically assigned IPv4 settings including address, mask and often gateway and resolver.
Explanation
Correct Answer
A:Correct. This mechanism fits the observed network symptom at the fictional Summit Print Shop: Transport-layer port numbers identify application endpoints, not electrical or MAC-layer links. The corresponding remedy is “Locate TCP or UDP source and destination port fields in the transport header and distinguish them from link and IP addresses.”. Confirmation: A layered packet diagram places port 443 in TCP, IP addresses in the network header and MAC addresses in Ethernet.
Incorrect Answers
B:That cause belongs to a different case: A hospital retains sensitive databases on-site while using hosted analytics and labels the design exclusively public cloud with no private component. The observed fictional Summit Print Shop condition is specifically explained by “Transport-layer port numbers identify application endpoints, not electrical or MAC-layer links.”.
C:That cause belongs to a different case: A technician sees intermittent application delays and assumes any fast Ethernet link prevents queueing delay. The observed fictional Summit Print Shop condition is specifically explained by “Transport-layer port numbers identify application endpoints, not electrical or MAC-layer links.”.
D:That cause belongs to a different case: A laptop receives a valid link but has no address on a DHCP-managed LAN and the technician adds a random static public IP. The observed fictional Summit Print Shop condition is specifically explained by “Transport-layer port numbers identify application endpoints, not electrical or MAC-layer links.”.
Question 7
A reviewer evaluates a proposed repair for: At the fictional Summit Print Shop during a physical cabling audit, the team observes: A workstation sends a browser request and the technician labels TCP port 443 a physical-layer address. The approved corrective action is: “Locate TCP or UDP source and destination port fields in the transport header and distinguish them from link and IP addresses.” Which result BEST demonstrates success?
- The aggregate and per-client measurements explain the observed congestion without multiplying the physical uplink bandwidth.
- The service inventory records the owned hardware and the internal maintenance responsibilities.
- The inventory separately records on-premises hosting and secured remote VPN connectivity.
- A layered packet diagram places port 443 in TCP, IP addresses in the network header and MAC addresses in Ethernet.
Explanation
Correct Answer
D:Correct. This is the required observable acceptance evidence for “Locate TCP or UDP source and destination port fields in the transport header and distinguish them from link and IP addresses.” at the fictional Summit Print Shop. It demonstrates correction of the original cause: Transport-layer port numbers identify application endpoints, not electrical or MAC-layer links.
Incorrect Answers
A:That result is evidence for a separate corrective action, “Measure total uplink utilization and per-client rates under concurrent load.”. It does not establish the intended outcome “A layered packet diagram places port 443 in TCP, IP addresses in the network header and MAC addresses in Ethernet.” for the fictional Summit Print Shop case.
B:That result is evidence for a separate corrective action, “Identify server, operating-system, application and backup ownership for the on-premises ERP system.”. It does not establish the intended outcome “A layered packet diagram places port 443 in TCP, IP addresses in the network header and MAC addresses in Ethernet.” for the fictional Summit Print Shop case.
C:That result is evidence for a separate corrective action, “Identify where the application actually runs and treat the VPN as an access path.”. It does not establish the intended outcome “A layered packet diagram places port 443 in TCP, IP addresses in the network header and MAC addresses in Ethernet.” for the fictional Summit Print Shop case.
Question 8
The technician plans a correction for: At the fictional Summit Print Shop during a physical cabling audit, the team observes: A workstation sends a browser request and the technician labels TCP port 443 a physical-layer address. During “Locate TCP or UDP source and destination port fields in the transport header and distinguish them from link and IP addresses.”, which precaution MOST specifically prevents a related risk?
- Do not treat network type and physical topology as interchangeable concepts.
- Do not compare MB/s and Mb/s as numerically equivalent measures.
- Do not use a TCP port number as a substitute for an IP or MAC address in troubleshooting.
- Do not equate remote-work access with SaaS hosting.
Explanation
Correct Answer
C:Correct. This precaution prevents a second fault while applying “Locate TCP or UDP source and destination port fields in the transport header and distinguish them from link and IP addresses.” at the fictional Summit Print Shop. The required protection is “Do not use a TCP port number as a substitute for an IP or MAC address in troubleshooting.”; success still requires “A layered packet diagram places port 443 in TCP, IP addresses in the network header and MAC addresses in Ethernet.”.
Incorrect Answers
A:This caution is appropriate for a separate failure pattern: A help desk sees switches arranged in a ring on a diagram and assumes the topology is a star because all switches are in one office. The principal adjacent risk here is controlled by “Do not use a TCP port number as a substitute for an IP or MAC address in troubleshooting.”.
B:This caution is appropriate for a separate failure pattern: A support engineer compares 12 MB/s file-transfer throughput directly with 100 Mb/s link speed and says 12 is much less than 100. The principal adjacent risk here is controlled by “Do not use a TCP port number as a substitute for an IP or MAC address in troubleshooting.”.
D:This caution is appropriate for a separate failure pattern: A freelancer works from home through a VPN to an internal application and the team assumes a VPN automatically makes it a cloud-hosted application. The principal adjacent risk here is controlled by “Do not use a TCP port number as a substitute for an IP or MAC address in troubleshooting.”.
Question 9
A service desk receives this network finding: At the fictional Maplecrest Office during a scheduled lab validation, the team observes: A help-desk note identifies a network switch as the device that routes every frame by destination IP address on a flat access VLAN. Which action MOST directly resolves the reported issue?
- Classify hosted email as SaaS and identify the customer's account, access and data responsibilities.
- Trace the destination MAC lookup and forwarding decision before treating the event as IP routing.
- Reclassify the short-range phone-to-earbuds link as PAN and explain its limited scope.
- Describe the star-shaped access wiring and meshed distribution uplinks as a hybrid topology.
Explanation
Correct Answer
B:Correct. In the fictional Maplecrest Office case, Ordinary Layer 2 Ethernet switching forwards using learned destination MAC addresses in the local VLAN. The specified corrective action, “Trace the destination MAC lookup and forwarding decision before treating the event as IP routing.”, directly targets that condition. Evidence of resolution: An observed switch MAC table entry leads the frame to the correct access port without an IP route lookup.
Incorrect Answers
A:That action addresses a different network issue: An employee subscribes to a hosted email application but the team says they must patch the service's virtual machines. The present fictional Maplecrest Office finding instead needs “Trace the destination MAC lookup and forwarding decision before treating the event as IP routing.”, verified by “An observed switch MAC table entry leads the frame to the correct access port without an IP route lookup.”.
C:That action addresses a different network issue: An inventory lists a phone and nearby wireless earbuds and classifies their Bluetooth pairing as a WAN between cities. The present fictional Maplecrest Office finding instead needs “Trace the destination MAC lookup and forwarding decision before treating the event as IP routing.”, verified by “An observed switch MAC table entry leads the frame to the correct access port without an IP route lookup.”.
D:That action addresses a different network issue: A multi-building installation combines a star of access switches with redundant mesh uplinks but is described as one pure star without redundancies. The present fictional Maplecrest Office finding instead needs “Trace the destination MAC lookup and forwarding decision before treating the event as IP routing.”, verified by “An observed switch MAC table entry leads the frame to the correct access port without an IP route lookup.”.
Question 10
Before changing settings, consider this issue: At the fictional Maplecrest Office during a scheduled lab validation, the team observes: A help-desk note identifies a network switch as the device that routes every frame by destination IP address on a flat access VLAN. What is the MOST specific underlying cause?
- Ordinary Layer 2 Ethernet switching forwards using learned destination MAC addresses in the local VLAN.
- In SaaS the provider normally manages the hosted application platform and underlying infrastructure.
- On-premises infrastructure remains under the organization's operational responsibility rather than becoming SaaS by name.
- Latency is elapsed time while transfer speed is a quantity of data delivered per time unit.
Explanation
Correct Answer
A:Correct. This mechanism fits the observed network symptom at the fictional Maplecrest Office: Ordinary Layer 2 Ethernet switching forwards using learned destination MAC addresses in the local VLAN. The corresponding remedy is “Trace the destination MAC lookup and forwarding decision before treating the event as IP routing.”. Confirmation: An observed switch MAC table entry leads the frame to the correct access port without an IP route lookup.
Incorrect Answers
B:That cause belongs to a different case: An employee subscribes to a hosted email application but the team says they must patch the service's virtual machines. The observed fictional Maplecrest Office condition is specifically explained by “Ordinary Layer 2 Ethernet switching forwards using learned destination MAC addresses in the local VLAN.”.
C:That cause belongs to a different case: A company hosts its own ERP database in a server room but calls it a public-cloud SaaS service with no local maintenance obligations. The observed fictional Maplecrest Office condition is specifically explained by “Ordinary Layer 2 Ethernet switching forwards using learned destination MAC addresses in the local VLAN.”.
D:That cause belongs to a different case: A user calls the 10 ms ping round-trip time a 10 MB/s transfer speed. The observed fictional Maplecrest Office condition is specifically explained by “Ordinary Layer 2 Ethernet switching forwards using learned destination MAC addresses in the local VLAN.”.