In the WAC high-reliability networking mode, which of the following is correct when sorting the active/standby switching speed from fast to slow?

Question

Options

• AN+1 backup > VRRP hot backup > dual-link hot backup / dual-link cold backup
• BVRRP hot backup > dual-link hot backup/dual-link cold backup > N+1 backup
• CVRRP hot backup > N+1 backup > dual-link hot backup/dual-link cold backup
• DDual-link hot backup/dual-link cold backup > VRRP hot backup > N+1 backup

• A
  4% (1)
• B
  85% (22)
• C
  4% (1)
• D
  8% (2)

Explanation

Option B is correct because VRRP hot backup operates at the network/protocol layer with sub-second hello-based detection and automatic failover, making it the fastest. Dual-link (both hot and cold) modes rely on WAC-level redundancy-hot backup has pre-synchronized state and cold does not, but both are slower than VRRP because failover involves AP re-association at the controller level rather than a protocol-layer switch. N+1 backup is the slowest because a single standby WAC must potentially absorb the entire workload of a failed primary, requiring the most complex state reconstruction and AP recovery.

Why the distractors fail: A and C both incorrectly rank N+1 as faster than dual-link, which contradicts the overhead of a shared-backup architecture. D places dual-link first, ignoring that VRRP's lightweight protocol-level detection (no session state to rebuild) is inherently faster than any controller-level mechanism.

Memory tip: Think of it as layers of complexity - protocol switch (VRRP, instant handoff) → direct controller swap (dual-link, more work) → shared controller takeover (N+1, most work). More resources shared = slower recovery.

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