In a campus topology using VSX with two aggregation switches and downlinks to access switches, which LAG interface configuration at the aggregation layer is correct based on the parameters below?…

Question

Options

• Ainterface lag 150 multi-chassis
• Binterface lag 150 multi-chassis
• Cinterface lag 150 multi-chassis
• Dinterface lag 150

• A
  62% (16)
• B
  12% (3)
• C
  19% (5)
• D
  8% (2)

Explanation

Option A is correct because it uses multi-chassis LAG, which is required in a VSX deployment to provide redundant uplinks across both aggregation switches - without it, you lose the active-active forwarding that VSX delivers. Critically, the correct configuration must include VLAN 1001 as the native (untagged) VLAN so that access switches undergoing ZTP can receive an IP address and boot without any pre-existing configuration, while VLAN 2002 must be tagged to preserve management connectivity throughout the ZTP process - before, during, and after.

Why B and C are wrong: Although they also specify multi-chassis, their VLAN tagging configurations are incorrect - either VLAN 2002 is set as native (breaking tagged MGMT connectivity) or VLAN 1001 is tagged (preventing ZTP from functioning since a zero-touch device can't process tagged frames on boot). One configuration breaks ZTP; the other breaks MGMT continuity.

Why D is wrong: Omitting multi-chassis makes this a standard single-chassis LAG, which defeats the purpose of VSX and eliminates redundancy at the aggregation layer.

Memory tip: Think "ZTP = naked, MGMT = dressed." The ZTP VLAN must be untagged (naked - no config needed to receive it), while the MGMT VLAN must be tagged (dressed - explicitly identified). And in VSX, LAGs are always multi-chassis or they're just wasted redundancy.

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