You are designing an overlay solution for two Data Centers based on the Aruba CX platform. Each Data Center has two rooms and each room is its own fabric. There is a requirement for multicast…

Question

Options

• AChange the design to extend a single fabric across all rooms and both sites
• BChange the design to use one fabric per site
• CUse HPE Aruba CX switches' selective split horizon feature
• DEstablish a separate data center interconnect fabric for multicast traffic only

• A
  25% (6)
• B
  8% (2)
• C
  63% (15)
• D
  4% (1)

Explanation

Option C is correct because Aruba CX's selective split horizon feature solves the specific problem of multicast traffic crossing fabric boundaries in a multi-fabric VXLAN overlay. Normally, split horizon rules prevent a VTEP from forwarding traffic received on one VXLAN tunnel out another - this stops loops but also blocks multicast from traversing between separate fabrics. Selective split horizon lets you surgically override this rule for specific traffic or tunnels, enabling cross-fabric multicast without any architectural redesign.

A and B are wrong because they both require scrapping the existing multi-fabric design - A merges everything into one giant fabric (expanding the failure domain), and B reduces to one fabric per site (still a redesign) - when the platform already has a native feature that handles the requirement as-is. D is wrong because adding a dedicated DCI fabric just for multicast is expensive, operationally complex, and completely unnecessary given the built-in capability.

Memory tip: Think of "selective" as a surgical scalpel - options A, B, and D all grab a sledgehammer and rebuild the architecture, while C precisely targets only the traffic that needs special handling. If the platform has a native feature that fits, that's almost always the right Aruba exam answer over a redesign.

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