Core Layer 2 switch functions that increase effective bandwidth include which items? (Address learning, Routing, Forwarding and filtering, Creating network loops, Loop avoidance, IP addressing)

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:

  • Candidates: (1) Address learning, (2) Routing, (3) Forwarding and filtering, (4) Creating loops, (5) Loop avoidance (e.g., STP), (6) IP addressing.
  • Focus is strictly Layer 2 operations.


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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