If the current dual-link hot backup, the engineer configures the OAPWAP heartbeat detection interval to be 20 seconds, and enables the dual-link backup function, then the time when the AP detects…

Question

Options

• A75 seconds
• B60 seconds
• C45 seconds
• D90 seconds

• A
  5% (1)
• B
  5% (1)
• C
  77% (17)
• D
  14% (3)

Explanation

Option C (45 seconds) is correct because in Huawei's CAPWAP dual-link hot backup implementation, the primary-link timeout is calculated as: (heartbeat interval × 2) + 5 seconds. With a 20-second heartbeat interval, this gives 20 × 2 + 5 = 45 seconds before the AP declares the primary AC unreachable and triggers the active-standby switchover.

Why the distractors are wrong:

• B (60 seconds): This is the result of naively multiplying the interval by 3 (3 × 20), which reflects a simple 3-retransmission count without accounting for the dual-link hot backup timing formula.
• A (75 seconds) and D (90 seconds): These suggest even longer multipliers (e.g., ×3 + 15 or ×4 + 10) that don't correspond to any standard CAPWAP hot backup detection parameter in Huawei's implementation.

Memory tip: Think "double plus five" - in dual-link hot backup, the AP waits for two full missed heartbeats plus a 5-second detection buffer. If the interval is 20 s → 20+20+5 = 45 s. The "+5" represents the switchover detection overhead unique to dual-link mode, which is what disqualifies the simpler ×3 answer (60 s).

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