When troubleshooting a LAN connectivity issue, you notice a failed uplink from the Cisco UCS Fabric Interconnects to the upstream LAN switch. What two could be causing the issue? (Choose two )

The correct answer is B. Misconfigured QoS parameters on the failed uplink C. A port channel mismatch between the Fabric Interconnects and the upstream LAN switch. Misconfigured QoS (B) matters here because Cisco UCS uses Data Center Bridging (DCB) with the DCBX protocol to negotiate QoS parameters - including priority flow control for FCoE traffic - with upstream switches. If these parameters don't match, the uplink can be placed in an err

Troubleshoot Cisco UCS B-Series

Question

Options

AMisconfigured VLAN on the failed uplink
BMisconfigured QoS parameters on the failed uplink
CA port channel mismatch between the Fabric Interconnects and the upstream LAN switch
DA SFP Type mismatch between the Fabric Interconnects and the upstream LAN switch
EA port speed configuration mismatch between the Fabric Interconnects and the upstream LAN

How the community answered

(27 responses)

A
4% (1)
B
81% (22)
D
4% (1)
E
11% (3)

Explanation

Misconfigured QoS (B) matters here because Cisco UCS uses Data Center Bridging (DCB) with the DCBX protocol to negotiate QoS parameters - including priority flow control for FCoE traffic - with upstream switches. If these parameters don't match, the uplink can be placed in an error-disabled state, causing the link to fail entirely. Port channel mismatch (C) is a classic uplink killer: if one side is configured for LACP while the other uses static bundling, or the channel group numbers don't align, the logical uplink fails even if the physical cables are fine.

A (VLAN mismatch) would cause traffic for specific VLANs to be dropped or blocked, but the uplink itself would still remain up - the physical or logical link stays operational. D (SFP mismatch) would cause a physical layer (Layer 1) failure, making it a valid real-world suspect, but the exam focuses on configuration-layer causes specific to UCS uplink behavior. E (port speed mismatch) is similarly a Layer 1 issue that would prevent the link from establishing, but is considered a hardware/auto-negotiation issue rather than a UCS-specific configuration problem.

Memory tip: Think "UCS uplinks fail when you mess up the deal - the DCB exchange needs matching QoS, and your Channel must Confirm both sides agree." QoS = DCB negotiation, port Channel = bundle configuration - both are software config problems unique to the UCS-to-upstream handshake.

Topics

#UCS Fabric Interconnect#Port Channel Configuration#QoS Parameters#Uplink Troubleshooting

Community Discussion

No community discussion yet for this question.

Full 500-920 Practice