What is the transit VLAN that runs between VSX members?

Question

Options

• AMust not be assigned IP addresses on any switch.
• BIt is used as a keepAlive mechanism
• CIt is a routed VLAN allowed in the ISL to ensure that the two switches within a VSX pair can learn
• DMust be assigned identical IP address on both of the switches

• A
  4% (1)
• B
  7% (2)
• C
  89% (25)

Explanation

Option C is correct because the VSX transit VLAN is a Layer 3 routed VLAN carried across the Inter-Switch Link (ISL), enabling both VSX peer switches to exchange routing information and ensure traffic can be forwarded even when a packet arrives on one switch but must be routed via the other.

Why the distractors fail:

• A is wrong - The transit VLAN requires IP addresses; it is a routed (Layer 3) interface, so denying it IPs would break its core function.
• B is wrong - The keepalive mechanism is a separate dedicated link/function in VSX, not the transit VLAN's role; confusing the two is a classic trap.
• D is wrong - Each switch must have a different IP address on the transit VLAN (they form two ends of a routed link), not identical ones; identical IPs would cause an IP conflict.

Memory tip: Think of the transit VLAN as the "routing bridge" between VSX peers - it transits Layer 3 traffic across the ISL so both switches stay in sync on reachability. If you remember "transit = routed + different IPs per side," you can eliminate all three distractors instantly.

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