In VXLAN implementation, which of the following is the mapping relationship between VNI and BD?

Question

Options

• AN:M
• B1:N
• CN:1
• D1:1

• A
  7% (3)
• B
  5% (2)
• C
  17% (7)
• D
  71% (29)

Explanation

In VXLAN, each VNI (VXLAN Network Identifier) maps exclusively to one Bridge Domain (BD), and each BD maps to exactly one VNI - a strict 1:1 relationship. This pairing ensures that a single VXLAN overlay segment corresponds to exactly one Layer 2 forwarding domain, maintaining clean network boundary isolation and deterministic traffic forwarding.

Why distractors fail:

• A (N:M) - Many-to-many would create ambiguity: the switch could not determine which BD to forward traffic into for a given VNI, or which VNI to encapsulate traffic from a given BD.
• B (1:N) - One VNI feeding multiple BDs would split a single VXLAN segment across separate L2 domains, fragmenting what should be a unified broadcast domain.
• C (N:1) - Multiple VNIs sharing one BD would collapse distinct VXLAN segments into the same L2 domain, defeating the segmentation purpose of having separate VNIs.

Memory tip: Think "one tunnel, one room" - a VNI is the tunnel label, a BD is the room it leads into; you can't have one label open multiple rooms or multiple labels lead to the same room.

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