Difficulty: Easy
Correct Answer: 1, 3 and 5
Explanation:
Introduction / Context:Layer 2 switches improve LAN throughput by learning where stations reside and by controlling frame propagation. Recognizing which functions are Layer 2 responsibilities clarifies how bandwidth is preserved.
Given Data / Assumptions:
Concept / Approach:Switches learn source MACs and build a table, then forward known unicasts only out the correct port (filtering others), and use loop-avoidance mechanisms to prevent storms. Routing and IP addressing are Layer 3 and do not apply to L2 switching.
Step-by-Step Solution:
(1) Address learning → yes, L2 core function.(3) Forwarding and filtering → yes, central to switching.(5) Loop avoidance → yes, via STP/RSTP/MSTP.(2) Routing and (6) IP addressing → L3, not L2.(4) Creating loops → harmful, not a feature.Verification / Alternative check:Switch command outputs (show mac address-table, show spanning-tree) evidence learning and loop prevention.
Why Other Options Are Wrong:Any set that includes routing/IP addressing or loop creation mixes non-L2 or undesirable behaviors.
Common Pitfalls:Assuming IP addressing is required for switching; it is only needed for management or L3 SVIs, not for pure L2 forwarding.
Final Answer:1, 3 and 5
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