Network+ Ethernet Switching and VLANs Flashcards
7 cards from real COMPTIA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Network+ Ethernet Switching and VLANs flashcards as text
A network engineer needs to extend a specific VLAN across geographically separated data centers. Which technology is commonly used for this?
Answer: VXLAN
VXLAN (Virtual Extensible LAN) encapsulates Layer 2 frames in UDP packets, allowing VLANs to be extended across Layer 3 networks between data centers.
Which type of VLAN is specifically used to carry IP phone traffic separately from data traffic on the same physical port?
Answer: Voice VLAN
A voice VLAN (auxiliary VLAN) is configured on access ports to carry IP phone traffic with QoS priority, while the data VLAN carries PC traffic on the same port.
What is the purpose of private VLANs (PVLANs)?
Answer: To isolate ports within the same VLAN from communicating directly
Private VLANs segment ports within the same VLAN so that isolated ports cannot communicate directly with each other, commonly used in hosting environments.
A switch port is configured with 'switchport nonegotiate'. What does this command do?
Answer: Prevents the port from sending DTP frames to negotiate trunking
'switchport nonegotiate' disables Dynamic Trunking Protocol (DTP) negotiation on the port, preventing automatic trunk formation — a recommended security hardening step.
Which Multiple Spanning Tree Protocol (MSTP) feature reduces the number of STP instances by mapping multiple VLANs to a single spanning tree instance?
Answer: MST region
MSTP uses MST regions, where multiple VLANs are mapped to a single spanning tree instance, reducing CPU and memory overhead compared to running one STP instance per VLAN.
A switch's MAC address table is full. How does this condition affect new incoming frames with unknown source MACs?
Answer: The switch begins flooding frames like a hub
When the CAM table is full, the switch cannot learn new MAC addresses and floods frames with unknown destinations out all ports, effectively behaving like a hub — this is the basis of MAC flooding attacks.
Which switch feature automatically detects and disables a port if it causes a switching loop by receiving its own BPDU?
Answer: BPDU guard
BPDU guard err-disables a port when it receives a BPDU, which is unexpected on a PortFast edge port and signals a potential loop-inducing device like a rogue switch.