N10-009 Networking Concepts Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  Spanning Tree Protocol (STP)

  Why it's wrong here

  The Spanning Tree Protocol (STP) is a Layer 2 protocol primarily used to prevent switching loops in networks with redundant paths by logically blocking redundant links. STP ensures a loop-free logical topology by placing specific ports in a forwarding or blocking state, thereby preventing broadcast storms and MAC address table instability. Its function is solely to manage redundant paths for network stability and availability, not to segment a single physical switch into multiple distinct broadcast domains.

  When this WOULD be correct

  A question asking: 'Which protocol prevents bridging loops in a redundant switched network?' would make STP the correct answer, as it ensures loop-free topology by blocking redundant links.

• ✓

  Virtual LAN (VLAN)

  Why this is correct

  Virtual LANs (VLANs) logically segment a single physical switch into multiple distinct Layer 2 broadcast domains, effectively creating several virtual switches from one physical device. This segmentation isolates traffic within each VLAN, preventing broadcasts from one VLAN from reaching devices in another, thereby enhancing security and reducing broadcast traffic overhead. For devices in different VLANs to communicate, a Layer 3 device, such as a router or a Layer 3 switch, is required to perform inter-VLAN routing.

• ✗

  Subnetting

  Why it's wrong here

  Subnetting is a Layer 3 concept that divides a larger IP network address space into smaller, distinct logical networks, each with its own unique network ID and broadcast address. While devices in different subnets cannot communicate without a router, subnetting itself does not inherently segment a physical switch into multiple Layer 2 broadcast domains. Without VLANs, all devices connected to the same physical switch ports remain within a single broadcast domain, regardless of their assigned IP subnets.

  When this WOULD be correct

  A network administrator needs to divide a single IP network into smaller, more manageable subnetworks to improve routing efficiency and reduce broadcast traffic at Layer 3, without changing the physical network topology.

• ✗

  Quality of Service (QoS)

  Why it's wrong here

  Quality of Service (QoS) mechanisms are designed to manage network traffic by prioritizing certain types of data, such as voice or video, over others to ensure optimal performance for critical applications. While QoS can influence how traffic is handled and forwarded by marking, queuing, and shaping packets based on defined policies, it operates at a different layer and does not create or modify Layer 2 broadcast domains or segment a physical switch into multiple logical entities.

  When this WOULD be correct

  A network administrator needs to prioritize voice traffic over data traffic on a congested link to ensure call quality. QoS policies would be the correct solution.

Option-by-option analysis

Why each answer is right or wrong

Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The N10-009 exam frequently reuses these exact scenarios with slightly different constraints.

Analysis generated from the official N10-009blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”