When networking, in order to ensure network reliability, corresponding backup technology can be deployed according to user requirements. Which of the following descriptions of common backup…

Question

Options

• AAfter deploying VRRP dual-machine hot backup, when the main AC fails, the backup AC will directly take over the work.
• BAfter deploying dual-link hot backup, when the main AC fails, the AP establishes a CAPWAP link with the backup AC and the backup AC takes over the work.
• CAfter N+1 backup is deployed, when the primary AC fails, the AP re-establishes a CAPWAP link with the backup AC and the backup AC takes over.
• DAfter deploying dual-link hot backup, when the main AC fails, the AP switches to the backup link and the backup AC takes over the work.

• A
  19% (5)
• B
  11% (3)
• C
  70% (19)

Explanation

C and D are correct because they accurately describe the failover behavior of their respective technologies. In N+1 backup (C), APs only maintain a CAPWAP link to their primary AC; when it fails, the AP has no pre-existing connection to the backup, so it must actively discover and re-establish a new CAPWAP tunnel. In dual-link hot backup (D), APs simultaneously maintain live CAPWAP connections to both primary and backup ACs at all times, so when the primary fails, the AP simply switches to the already-existing backup link - no re-establishment required.

Option A is wrong because VRRP hot standby does not produce a seamless, instant takeover from the AP's perspective. The VRRP failover process involves a timeout/election period, and the AP sessions must still be re-established with the backup AC after the virtual IP transitions - it is not a "direct" handoff.

Option B is wrong because it mischaracterizes dual-link hot backup. The defining feature of dual-link is that CAPWAP links to both ACs are pre-established and running - when the primary fails, the AP switches to the existing backup link rather than building a new one from scratch.

Memory tip: Match the backup type to what the AP does when failure occurs - "N+1 = New link (re-establish from zero), Dual-link = No new link (switch to the one already there)." If an answer says "establishes" for dual-link, it's automatically wrong.

No community discussion yet for this question.