In VSX, the ISL (InterSwitch Link):

Question

Options

• ACan be indirectly connected
• BMust be directly connected
• CCan be used for keep alive communications
• DThey must be routed links

• A
  3% (1)
• B
  88% (35)
• C
  5% (2)
• D
  5% (2)

Explanation

In HPE Aruba VSX, the ISL must be a direct physical connection between the two VSX peer switches - indirect paths through intermediate devices are not supported, as the ISL carries critical control plane synchronization and data plane traffic that requires guaranteed, low-latency connectivity.

Option A is wrong because an indirect ISL path introduces failure points and is explicitly unsupported in VSX design. Option C is wrong because keep-alive communication uses a separate dedicated keep-alive link (KAL), not the ISL - this separation is intentional so a failed ISL doesn't also silence the heartbeat. Option D is wrong because the ISL is a Layer 2 trunk link carrying VLANs, not a routed (Layer 3) link.

Memory tip: Think of ISL as "I See L2 Directly" - it's a direct Layer 2 trunk, while the keep-alive is the separate "pulse check" on its own link.

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