You are proposing new CX 8360 VSX switches to replace a customers existing core switches. The customer Is concerned about the possibility of a split-brain scenario between the VSX pair. How Is the…

Question

Options

• AThe VSX node with lower system-id continues forwarding.
• BBoth VSX nodes will automatically reboot and keep LAG interfaces shutdown.
• CBoth VSX nodes still forward tame
• DThe VSX node with higher uptime continues forwarding.

• A
  22% (8)
• B
  11% (4)
• C
  58% (21)
• D
  8% (3)

Explanation

When both the ISL and the keepalive link are simultaneously down, neither VSX node can determine whether its peer is still alive, so both nodes independently assume they are the sole active switch and continue forwarding traffic - this is the classic split-brain state. VSX is designed with a "stay up" philosophy: rather than risk a complete network outage by shutting down, both peers keep forwarding to maintain connectivity, accepting the tradeoff of potential duplicate traffic or inconsistent state.

Why the distractors are wrong:

• A is wrong because VSX does not use system-ID as a tiebreaker in this scenario - system-ID matters in some STP elections, not VSX split-brain resolution.
• B is wrong because VSX never automatically reboots both nodes; that would cause a full network outage, which is exactly what VSX is designed to prevent.
• D is wrong because uptime is not a VSX tiebreaker criterion - VSX uses a configured primary/secondary role, and even then, the keepalive (not uptime) is what determines split-brain behavior.

Memory tip: Think of it as the "no news, no shutdown" rule. VSX only takes corrective action (secondary shuts down VSX LAGs) when the keepalive is up and confirms the peer is reachable but ISL is broken. When both links are dark, VSX has no basis to act, so both nodes keep forwarding - C is always the answer when everything is down.

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