In the RSTP protocol, when the network topology changes, the mechanism to respond to the topology change is:

Question

Options

• AWhole network flooding
• BModify the lifetime of the MAC address table
• CImmediately delete the MAC address table
• DDelete the entire MAC address table

• A
  13% (4)
• B
  6% (2)
• C
  77% (24)
• D
  3% (1)

Explanation

RSTP responds to topology changes by immediately flushing (deleting) MAC address table entries on all ports except the one that received the TC notification - this forces switches to relearn correct paths through normal flooding, enabling rapid reconvergence without waiting for stale entries to age out.

Why the distractors are wrong:

• A (Whole network flooding) is a side effect of MAC table deletion (unknown destinations get flooded), not the mechanism itself - and RSTP specifically limits TC propagation to avoid network-wide flooding.
• B (Modify the lifetime) describes legacy STP/802.1D behavior, which shortened the MAC aging timer to 15 seconds (Forward Delay); RSTP replaced this slow approach with immediate deletion.
• D (Delete the entire MAC address table) is a subtle trap - RSTP deletes entries selectively (excluding the port that received the TC), and the critical keyword missing from D is immediately, which is what distinguishes RSTP from STP.

Memory tip: The "R" in RSTP stands for Rapid - remember that RSTP Rapidly Removes stale MAC entries the moment a topology change is detected, rather than waiting for a timer to count down like older STP.

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