350-401 Question #980: Real Exam Question with Answer & Explanation

Question

Refer to the exhibit. The administrator configures an ERSPAN session, but no packets are received on the destination host. Which action is required to complete the configuration?

Options

• AEnsure that the ERSPAN destination addresses are not reachable through the Mgmt-vrf VRF.
• BEnsure that the ERSPAN destination is reachable from the switch.
• CConfigure the ERSPAN destination VLAN as an RSPAN VLAN.
• DEnable the ERSPAN session.

Explanation

ERSPAN Session Enablement

When configuring ERSPAN (Encapsulated Remote SPAN) on Cisco switches, the session must be explicitly enabled using the no shutdown command after all parameters (source, destination, origin IP, etc.) are defined - without this step, the session remains in a shutdown/inactive state by default, which is why no packets reach the destination host.

Why the distractors are wrong:

• Option A is incorrect because ERSPAN typically uses the default VRF for routing, not Mgmt-vrf; unreachability through Mgmt-vrf is irrelevant to the issue.
• Option B is plausible but incorrect as the context implies routing is already functional - the missing piece is the session activation, not reachability.
• Option C is incorrect because ERSPAN encapsulates traffic in GRE/IP and does not require an RSPAN VLAN, unlike traditional RSPAN configurations.

Memory Tip: Think of ERSPAN like a network service - you can configure it completely, but it won't work until you "flip the switch." Remember: "Configure it, then ACTIVATE it" - always check for no shutdown on ERSPAN/SPAN sessions when troubleshooting missing mirrored traffic.

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