CompTIA Updated N10-009 Exam Questions and Answers by hadi

Single-mode fiber is best suited for long-distance communication, often exceeding 10 km (6.2 miles). It's immune to EMI and offers high bandwidth — making it the ideal choice for connecting buildings across a city.

Coaxial (A) and Twinaxial (B) are used for shorter distances and specific use cases (e.g., storage or legacy systems).

Cat 5 (D) is limited to 100 meters and is not suitable for city-level interconnects.

✅ For long-distance, high-speed, and reliable communication between buildings, Single-mode fiber is the professional choice.

The maximum recommended length for Ethernet cable runs is 100 meters (328 feet). At 150 meters, the Cat 6 cable is too long, causing signal degradation and connectivity issues. Running fiber from the distribution switch to an access switch in the annex will allow for reliable connectivity over longer distances, as fiber can cover greater distances without signal loss. (Reference: CompTIA Network+ Study Guide, Chapter on Network Cable Standards)

Using a /30 subnet mask is the most efficient way to conserve IP space for a point-to-point connection between two routers. A /30 subnet provides four IP addresses, two of which can be assigned to the router interfaces, one for the network address, and one for the broadcast address. This makes it ideal for point-to-point links where only two usable IP addresses are needed.References: CompTIA Network+ study materials and subnetting principles.

When a switch is improperly connected to a network, it can cause widespread connectivity issues, especially if there’s a misconfiguration in VLAN settings. A Native VLAN mismatch occurs when two switches connected via a trunk link have different native VLANs configured for untagged traffic. This can cause traffic to be sent to the wrong VLAN or dropped, resulting in connectivity loss for users.

Scenario Analysis: The intern likely connected the switch without ensuring that the trunk port’s native VLAN matched the existing network configuration. This is a common issue in Cisco-based networks when trunk links are misconfigured.

Why not VTP update? VLAN Trunking Protocol (VTP) updates propagate VLAN configurations across switches. While a VTP misconfiguration could cause issues, it’s less likely to immediately disrupt connectivity for many users unless the VTP server deleted critical VLANs, which is not implied here.

Why not Port security issue? Port security restricts access based on MAC addresses, typically affecting individual ports, not causing widespread outages.

Why not LLDP misconfiguration? Link Layer Discovery Protocol (LLDP) is used for device discovery, and misconfiguration is unlikely to cause a broad loss of connectivity.