100-150 Infrastructure Practice Test 2 — 15 Questions

Question 1

What is the function of the Default Gateway in an IP configuration?

Accepted Answer

To provide a path for traffic destined for remote networks. The default gateway is the IP address of the local router interface that provides the path to external networks. When a device attempts to send data to an IP address outside its own subnet, it encapsulates the frame for the gateway's MAC address. Without a correctly configured default gateway, endpoints remain isolated within their local segment and cannot reach the internet or other remote subnets.

Answer

To resolve domain names to IP addresses

Answer

To manage the local broadcast domain traffic

Answer

To perform dynamic IP address assignment

Question 2

Which TWO protocols are commonly used to remotely manage Cisco network devices? (Choose two.)

Accepted Answer

SSH. Secure remote management is critical for operational efficiency and network security. Administrators use terminal emulation protocols to access the Command Line Interface (CLI) from anywhere on the network. While older methods were insecure, modern standards prioritize encryption, ensuring that administrative traffic remains protected against sniffing and credential theft during routine configuration or monitoring tasks in an enterprise environment.

Answer

Telnet

Answer

ICMP

Answer

SMTP

Question 3

What is the primary function of a network switch's 'store-and-forward' switching method?

Accepted Answer

To verify the frame integrity before forwarding. Store-and-forward is a high-integrity switching method where the switch receives the entire frame, verifies its checksum (FCS), and only then forwards it. This approach ensures that corrupted frames are discarded at the switch level, preventing them from propagating across the network. This method is critical for maintaining high reliability in environments where physical layer errors might otherwise cause complex intermittent issues.

Answer

To forward frames as soon as the destination address is read

Answer

To route packets between different IP subnets

Answer

To provide high-speed connections for wireless access

Question 4

Which mechanism does the Spanning Tree Protocol (STP) use to detect and prevent Layer 2 loops in a network with redundant links?

Accepted Answer

Exchange of Bridge Protocol Data Units (BPDUs). STP prevents loops by designating certain redundant ports as 'blocked'. It uses Bridge Protocol Data Units (BPDUs) to communicate between switches, elect a Root Bridge, and calculate the shortest path to that root. By logically disabling redundant paths, STP ensures a loop-free topology while maintaining the ability to automatically restore connectivity if a primary link fails, providing essential resilience for switched LANs.

Answer

Broadcast storm suppression

Answer

Source MAC address learning

Answer

Packet TTL expiration

Question 5

An enterprise network administrator needs to deploy a secure out-of-band management network for enterprise switches and routers. Which infrastructure design approach provides the highest level of isolation and security?

Accepted Answer

Deploy a physically separate management network utilizing dedicated management Ethernet ports and an independent access switch infrastructure.. Dedicated management ports combined with an isolated physical switch infrastructure completely separate management traffic from production data paths. This structural isolation ensures that even if user data planes experience severe congestion, storms, or security compromises, administrators retain reliable access to device consoles and management daemons for troubleshooting and remediation.

Answer

Configure a dedicated management VLAN on the primary production access switches with restricted access control lists.

Answer

Implement Virtual Routing and Forwarding instances inside the core routing layer for carrying all administrative terminal sessions.

Answer

Tunnel all interactive administrative SSH sessions through high-priority IP Service Level Agreements and weighted fair queuing.

Question 6

A network engineer is troubleshooting high CPU utilization on a core switch caused by excessive broadcast traffic across multiple VLANs. Which infrastructure technology should be deployed to contain broadcast domains while maintaining Layer 3 connectivity?

Accepted Answer

Configure inter-VLAN routing using Layer 3 interfaces to restrict broadcast propagation between separate logical segments.. Implementing routing between VLANs using switched virtual interfaces or routed ports naturally isolates broadcast domains. Broadcast frames operate strictly at Layer 2 and are dropped by routers and Layer 3 switches, preventing localized broadcast storms from propagating across the enterprise network infrastructure and degrading overall system performance.

Answer

Deploy Rapid Spanning Tree Protocol across all core trunk links to prune redundant physical paths dynamically.

Answer

Implement Port Security with maximum address limits on all access ports to drop unauthorized endpoint broadcasts.

Answer

Activate Storm Control with custom rising and falling threshold percentages for multicast and broadcast traffic.

Question 7

An organization is designing a redundant campus distribution layer to ensure high availability and fast failover. Which TWO infrastructure features should be implemented to achieve sub-second convergence and eliminate routing loops? (Choose two)

Accepted Answer

Virtual Switching System or StackWise technology to merge multiple physical switches into a single logical control plane.. Option A is correct because Virtual Switching System (VSS) or StackWise merges multiple physical switches into one logical control plane, enabling Multichassis EtherChannel (MEC) and eliminating the need for Spanning Tree to block redundant links, which removes Layer 2 loops and supports fast, deterministic failover. Option C is correct because Bidirectional Forwarding Detection (BFD) provides sub-second (often 50-300 ms) link failure detection and, when integrated with routing protocols like OSPF, EIGRP, or BGP, triggers rapid reconvergence far faster than default protocol hellos. Option B is not appropriate because classic STP with default 20-second max age and 2-second forward delay yields convergence in tens of seconds, not sub-second, and does not meet the design goal. Option D is not appropriate because UDLD in normal mode only logs unidirectional link conditions without shutting down the interface, so it does not provide fast failover or loop prevention. Option E is not appropriate because static floating routes to secondary ISPs are for WAN/Internet redundancy and do not address campus distribution-layer loop elimination or sub-second convergence.

Answer

Classic Spanning Tree Protocol with default port-cost metrics and standard 20-second maximum age timers.

Answer

Unidirectional Link Detection running in normal mode to log fiber transceiver misbehaviors without interface shutdown.

Answer

Static routing configurations with floating backup routes pointing to secondary internet service providers.

Question 8

Which cabling infrastructure standard should an engineer deploy to support 10 Gigabit Ethernet transmissions across a 300-meter horizontal run inside a modern enterprise building?

Accepted Answer

OM3 laser-optimized multimode fiber optic cabling terminated with LC duplex connectors.. Multimode fiber optic cabling, specifically laser-optimized OM3 or OM4 fiber, supports 10 Gigabit Ethernet up to 300 or 400 meters respectively. Copper cabling such as Category 6 is strictly limited to 100 meters for standard Ethernet, making fiber the mandatory physical medium for distances exceeding that threshold within enterprise horizontal runs.

Answer

Category 6 unshielded twisted-pair copper cable terminated with standard RJ-45 modular plugs.

Answer

Category 5e structured copper cabling tested to 100 MHz bandwidth performance profiles.

Answer

Coaxial broadband cabling utilizing 50-ohm impedance connectors and barrel adapters.

Question 9

Refer to the exhibit. An engineer observes that the interface status for Vlan100 is listed as 'up' but the protocol status is 'down'. What is the most likely root cause of this operational state?

Accepted Answer

No active physical access ports exist within that VLAN, or all assigned ports are currently in the spanning-tree blocking state.. An interface protocol state of down while the physical or logical status is up indicates that Layer 2 or higher encapsulation parameters are failing. For a Switched Virtual Interface, this typically occurs when no active physical ports are assigned to that VLAN or when all assigned access ports are currently in a blocked or disabled state.

Answer

The SVI administrative configuration contains a mismatched IP subnet mask compared to the connected default gateway.

Answer

The global routing command has not been enabled on the multilayer switch using the ip routing configuration command.

Answer

The physical transceiver connected to GigabitEthernet0/1 has experienced a complete hardware optical laser failure.

Question 10

An administrator is configuring Power over Ethernet on an enterprise access switch to power IP security cameras requiring up to 25.5 watts of power each. Which IEEE standard must the switch ports support?

Accepted Answer

IEEE 802.3at delivering up to 30 watts of direct current power per individual port interface.. IEEE 802.3at (PoE+) delivers up to 30 watts of DC power per port, which comfortably exceeds the 25.5-watt requirement of the IP cameras. This standard uses two pairs of Cat5e or better cabling to provide the higher power budget while maintaining backward compatibility with 802.3af devices. The switch port must support 802.3at to guarantee sufficient power for each camera without overloading the power budget.

Answer

IEEE 802.3af delivering a maximum of 15.4 watts of direct current power per individual port interface.

Answer

IEEE 802.3bt Type 3 delivering up to 60 watts of power across all four wire pairs within the structured copper cable.

Answer

IEEE 802.3ab defining Gigabit Ethernet physical layer transmission parameters over copper infrastructure.

Question 11

An enterprise network design incorporates Power over Ethernet to supply power to VoIP desk phones and wireless access points. A technician notes that the power supply unit inside the switch is operating near maximum capacity. Which feature should be configured to prevent unexpected power drops?

Accepted Answer

Configure port-level PoE priority to ensure critical devices retain power during budget exhaustion events.. Power over Ethernet policing and priority mechanisms allow administrators to manage power budgets intelligently. Configuring port power priorities ensures that if total power consumption exceeds switch power supply limits, critical infrastructure devices maintain power while less critical ports are shut down safely.

Answer

Enable BPDU Guard across all access switch ports connected to powered VoIP telephone hardware.

Answer

Activate Storm Control with strict multicast drop thresholds to reduce switch power draw.

Answer

Implement Port Security with maximum static MAC address bindings to restrict power usage.

Question 12

A network administrator needs to connect two switches using a link that allows multiple VLANs to traverse a single physical path. Which configuration step is essential to ensure this functionality is enabled properly?

Accepted Answer

Configure the switch port mode to trunk.. To allow multiple VLANs across a single physical link, the ports must be configured as trunks using the 802.1Q encapsulation protocol. This process involves tagging frames to identify their originating VLAN. Understanding trunking is critical for scalable network design, as it eliminates the need for individual cables for every VLAN, thereby optimizing port density and simplifying cabling management across enterprise distribution and core layers.

Answer

Set the switch port mode to access and assign it to VLAN 1.

Answer

Configure the port as a static EtherChannel member.

Answer

Enable Spanning Tree Protocol on all interfaces.

Question 13

Refer to the exhibit. An administrator observes high error counts on a switch port. Based on the output, what is the most likely cause of the issue?

Accepted Answer

A duplex mismatch on the physical connection.. High error counts (CRC errors, late collisions, runts, giants) on a switch port are the classic signature of a duplex mismatch. When one side is set to full-duplex and the other to half-duplex, the full-duplex side transmits whenever it wants while the half-duplex side detects collisions and reports late collisions and FCS errors. The exhibit typically shows 'Late collisions' and 'CRC' counters incrementing.

Answer

A VLAN mismatch between the switch and the connected device.

Answer

The switch port has been disabled by Port Security.

Answer

An incorrect IP address assigned to the interface.

Question 14

Which TWO of the following are primary benefits of implementing a hierarchical network design like the Cisco Three-Tier Model?

Accepted Answer

It provides improved scalability and modularity.. Hierarchical designs provide scalability, modularity, and simplified management by dividing the network into Core, Distribution, and Access layers. This structure limits the scope of failure domains and makes troubleshooting more predictable. Mastering these concepts is essential for building robust networks that can grow with organizational needs without requiring a complete redesign of the underlying topology or complex routing protocols.

Answer

It eliminates the need for routing protocols.

Answer

It completely prevents all Layer 2 loops.

Answer

It ensures that all devices use a flat addressing scheme.

Question 15

Which device is primarily responsible for performing inter-VLAN routing in a modern enterprise network?

Accepted Answer

Layer 3 Switch. A Layer 3 switch is primarily responsible for performing inter-VLAN routing in modern enterprise networks. It combines the functionality of a switch and a router, allowing it to route traffic between VLANs at wire speed using hardware-based routing. This is more efficient than using a traditional router for inter-VLAN routing.

Answer

Layer 2 Switch

Answer

Hub

Answer

Repeater