FCoE Native VLAN Restriction and VSAN Configuration
The end users report issues with datastore reachability between the newly installed virtual machines (VMs) and the storage array. The VMs are deployed on a Cisco C-Series server, directly connected with Cisco Nexus 5672UP switches over FCoE VLAN. The data traffic on VLAN 99, which is designated as a native VLAN, reaches its default gateway, but FCoE VLAN 99 fails to access the datastore. Which action resolves the problem?
Community Votes
67% of anonymous learners picked answer C. Votes are pick records left by other test-takers — they are not the verified answer.
Community Insight
The core trap is assuming any VLAN can carry FCoE; the key insight is that FCoE is explicitly prohibited on native VLANs, requiring both VLAN separation and VSAN mapping.
This question examines the critical restriction that FCoE traffic cannot traverse a native VLAN on Cisco Nexus switches. It establishes that resolving datastore reachability requires moving FCoE to a non-native VLAN and ensuring proper VSAN database configuration.
Many learners select option A solely because it moves FCoE off the native VLAN, overlooking the mandatory requirement to configure the FCoE VLAN in the switch's VSAN database for FCoE initialization.
Community Discussion (3 comments)
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Expert Analysis
Why the Answer Is Correct
Correct answer: C — Configure the FCoE VLAN in the VSAN database before including it in the trunk port.FCoE (Fibre Channel over Ethernet) relies on a specific mapping between Ethernet VLANs and Fibre Channel VSANs. For the Nexus switch to process FCoE frames correctly, the VLAN must be mapped to a VSAN in the switch's VSAN database. Without this mapping, the switch treats the traffic as standard Ethernet or drops it, preventing access to the storage array. While option A addresses the native VLAN issue, option C is the definitive technical step required to enable FCoE functionality on the switch platform, as the VSAN mapping is prerequisite for FCoE convergence.
Why the Other Options Are Wrong
Option A suggests implementing FCoE on VLAN 10, which avoids the native VLAN restriction, but it does not address the fundamental need for VSAN database configuration. Without the VSAN map, even a non-native VLAN will not function for FCoE. Option B involves Spanning Tree PortFast, which is relevant for edge ports but does not solve the protocol-level FCoE/VSAN mapping issue. Option D suggests separate interfaces, which is unnecessary if the switch supports multiple VSANs/VLANs on trunks, and again fails to mention the critical VSAN configuration step.Community Comment Notes
Commenter Wasamela highlights that the FCoE VLAN needs to be configured in the VSAN database for the switch to recognize the traffic, aligning with the correct technical requirement. OLENDE points out that FCoE is not supported on native VLANs, referencing Cisco documentation, which validates why VLAN 99 (native) fails. Another user agrees with C, confirming the consensus on the necessity of VSAN configuration.Official Reference
Exam Strategy
Always check for VSAN-to-VLAN mapping when troubleshooting FCoE issues. Remember that FCoE cannot run on native VLANs, so you may need to move traffic, but the VSAN configuration is the enabler.
Frequently Asked Questions
Why can't FCoE run on a native VLAN?
FCoE frames require specific tagging and processing that conflicts with native VLAN handling, which expects untagged frames. Cisco NX-OS prohibits FCoE on native VLANs.
Is moving to VLAN 10 enough to fix FCoE?
No. While it avoids the native VLAN restriction, you must still map the VLAN to a VSAN in the switch's VSAN database for FCoE to function.