ACA Aruba Associate Switching & VLANs 2 — Questions and Answers
Question 1: What is Spanning Tree Protocol (STP) designed to prevent in a switched network?
- Layer 2 loops (Correct answer)
- IP address conflicts
- VLAN mismatches
- MAC address flooding
Correct answer: Layer 2 loops
STP prevents Layer 2 loops in switched networks by blocking redundant paths and allowing only one active path between switches.
Question 2: Which STP port state actively forwards traffic in a classic 802.1D implementation?
- Forwarding (Correct answer)
- Listening
- Learning
- Blocking
Correct answer: Forwarding
The Forwarding state is the only STP port state where a port actively forwards user traffic on the network.
Question 3: What is MSTP and what problem does it solve over classic STP?
- Multiple Spanning Tree Protocol; maps multiple VLANs to fewer STP instances for efficiency (Correct answer)
- Multiple Security Tree Protocol; prevents VLAN hopping attacks
- Multicast Spanning Tree Protocol; manages multicast traffic paths
- Modified STP; reduces convergence time to under 1 second
Correct answer: Multiple Spanning Tree Protocol; maps multiple VLANs to fewer STP instances for efficiency
MSTP maps multiple VLANs to a smaller number of spanning tree instances, reducing CPU overhead compared to running one STP instance per VLAN.
Question 4: What is the function of a link aggregation group (LAG) on Aruba switches?
- To bundle multiple physical links into one logical link for increased bandwidth and redundancy (Correct answer)
- To assign multiple VLANs to a single access port
- To create a virtual switch across multiple physical chassis
- To load-balance wireless clients across APs
Correct answer: To bundle multiple physical links into one logical link for increased bandwidth and redundancy
A LAG bundles multiple physical Ethernet links into a single logical link to increase bandwidth and provide link-level redundancy.
Question 5: Which protocol dynamically negotiates link aggregation between Aruba switches?
- LACP (Correct answer)
- RSTP
- LLDP
- OSPF
Correct answer: LACP
LACP (Link Aggregation Control Protocol) is the IEEE 802.3ad standard that dynamically negotiates and manages link aggregation groups.
Question 6: What is VLAN pruning on a trunk link?
- Limiting which VLANs are allowed to traverse a trunk to reduce unnecessary traffic (Correct answer)
- Removing unused VLANs from the VLAN database
- Deleting the native VLAN from a trunk port
- Blocking VLAN 1 traffic for security reasons
Correct answer: Limiting which VLANs are allowed to traverse a trunk to reduce unnecessary traffic
VLAN pruning restricts which VLANs are allowed on a trunk link, preventing broadcast traffic from flooding into segments that do not need it.
ACA Aruba Associate Switching & VLANs 2
What is Spanning Tree Protocol (STP) designed to prevent in a switched network?