Among the following WAC backup solutions, which one has the fastest master-slave switchover speed?

Question

Options

• ADual-link cold backup A
• BN+1 backup
• CVRRP hot backup
• DDual-link hot backup

• A
  4% (1)
• B
  4% (1)
• C
  76% (19)
• D
  16% (4)

Explanation

VRRP Hot Backup provides the fastest master-slave switchover because VRRP (Virtual Router Redundancy Protocol) is specifically designed for near-instantaneous failover - the backup WAC continuously monitors the master via heartbeat messages and assumes control within seconds (often sub-second) with no manual intervention and full state pre-synchronization.

Why the distractors are wrong:

• (A) Dual-link cold backup is the slowest option - the backup device is idle and unsynchronized, requiring a full restart and reconfiguration when the master fails.
• (B) N+1 backup uses one standby WAC to cover N active WACs, which introduces additional negotiation and reconfiguration time before the backup can fully assume control.
• (D) Dual-link hot backup is faster than cold backup but still slower than VRRP; "dual-link" emphasizes link redundancy rather than a protocol optimized for controller-level state synchronization and rapid failover.

Memory tip: Think of VRRP as a "hot seat" - the backup is already warmed up, sitting right next to the master, ready to jump in the moment the master stops responding. Cold = slow start, N+1 = must cover multiple devices, dual-link hot = link redundancy first. VRRP = fastest protocol-driven controller switchover.

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