Free CompTIA Network+ Ethernet Switching Features Questions and Answers 1 — Questions and Answers
Question 1: A network administrator is configuring a new switch and wants to prevent Layer 2 loops, which can cause broadcast storms and MAC address table instability. Which of the following features should be enabled to achieve this?
- Port Security
- 802.1Q Trunking
- Spanning Tree Protocol (STP) (Correct answer)
- Port Mirroring
Correct answer: Spanning Tree Protocol (STP)
Spanning Tree Protocol (STP), defined in IEEE 802.1D, is specifically designed to prevent Layer 2 loops in a network with redundant paths. STP does this by logically blocking redundant paths, ensuring there is only one active path between any two network segments, thus preventing broadcast storms and MAC table corruption.
Question 2: A technician needs to connect a new high-power Pan-Tilt-Zoom (PTZ) security camera that requires 20W of power to a switch port. Which IEEE Power over Ethernet (PoE) standard should the switch port support at a MINIMUM?
- 802.3bt (Type 4)
- 802.3af
- 802.3ad
- 802.3at (Correct answer)
Correct answer: 802.3at
The IEEE 802.3at standard, also known as PoE+, can deliver up to 25.5W of power to a powered device. Since the PTZ camera requires 20W, 802.3at is the minimum standard that meets this requirement. The older 802.3af (PoE) standard only provides up to 12.95W, which is insufficient. 802.3bt could also work but provides more power than minimally required. 802.3ad is the standard for link aggregation, not power.
Question 3: A network engineer needs to analyze traffic from a server's switch port on a separate workstation running packet capture software. The engineer wants to send a copy of all traffic from the server's port to the workstation's port without impacting the server's network connectivity. Which switch feature should be used?
- Port Aggregation
- Port Mirroring (Correct answer)
- VLAN Tagging
- Port Security
Correct answer: Port Mirroring
Port Mirroring, also known as Switched Port Analyzer (SPAN), is a feature that copies network traffic from one or more source ports to a single destination port. This allows a network analyzer connected to the destination port to monitor the traffic without affecting the original data flow.
Question 4: To increase bandwidth and provide redundancy between two switches, an administrator has physically connected two ports from each switch to the other. To make these multiple physical links act as a single logical link, which protocol should be configured?
- Spanning Tree Protocol (STP)
- Link Aggregation Control Protocol (LACP) (Correct answer)
- Dynamic Host Configuration Protocol (DHCP)
- Address Resolution Protocol (ARP)
Correct answer: Link Aggregation Control Protocol (LACP)
Link Aggregation Control Protocol (LACP), part of the IEEE 802.3ad standard, is used to bundle multiple physical ports into a single logical channel, known as a Link Aggregation Group (LAG). This increases the total available bandwidth and provides fault tolerance if one of the physical links fails.
Question 5: A switch maintains a table that maps the MAC addresses of connected devices to the switch ports they are connected to. When the switch receives a frame with an unknown destination MAC address, what is the default action it takes?
- It sends an ARP request to the default gateway.
- It drops the frame.
- It forwards the frame to the root bridge.
- It floods the frame out all ports except the one it was received on. (Correct answer)
Correct answer: It floods the frame out all ports except the one it was received on.
When a Layer 2 switch receives a frame intended for a destination MAC address that is not in its MAC address table, its default behavior is to flood the frame out of all ports within the same VLAN, except for the port on which the frame was received. This is known as an unknown unicast flood. The switch learns the location of the destination device when that device eventually responds.
Question 6: Which of the following allows a single physical switch port to carry traffic for multiple VLANs by adding a special tag to the Ethernet frames?
- Port Security
- IEEE 802.1Q (Correct answer)
- Spanning Tree Protocol (STP)
- Native VLAN
Correct answer: IEEE 802.1Q
The IEEE 802.1Q standard defines a system of VLAN tagging for Ethernet frames. When a port is configured as a trunk, it uses 802.1Q to insert a 4-byte tag into the frame header, which identifies the VLAN to which the frame belongs. This allows a single link to transport traffic for many different VLANs between switches or other network devices.
Free CompTIA Network+ Ethernet Switching Features Questions and Answers 1
A network administrator is configuring a new switch and wants to prevent Layer 2 loops, which can cause broadcast storms and MAC address table instability.
Which of the following features should be enabled to achieve this?