300-615 Exam Preparation Material | Troubleshooting Cisco Data Center Infrastructure (DCIT)

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Prepare for the 300-615 Troubleshooting Cisco Data Center Infrastructure (DCIT) exam with CertQueen's independently developed study resources. Review important concepts, practice scenario-based questions, and use clear explanations to identify areas that require further study.

Question#1

An engineer configures FCoE between a set of ESXi hosts and a Cisco Nexus 5000 Series Switch. The Converged Network Adapter of the host fails to receive the response from the Cisco Nexus device. Also, the VFC interface is in a down state and the FIP adapter fails to receive 802.1q tagged frames. The host interface is configured for VLAN trunking.
Which action resolves the issue?

A. Activate the reception of Xoff pause frames from the server
B. Configure the UF link as a spanning-tree edge port
C. Enable the active STP port state on the bound Ethernet interface
D. Set the bound Ethernet trunk interface to non-FCoE native VLAN

Explanation:
The correct answer is Set the bound Ethernet trunk interface to non-FCoE native VLAN. Cisco MDS and Nexus SAN troubleshooting is driven by fabric state: the host and target must be in the correct VSAN, must complete FLOGI/PLOGI where applicable, and must be permitted by active zoning, fcdomain, FSPF, NPV/NPIV, or port-security policy. This question focuses on FCoE, Cisco Nexus, so the selected action fixes the dependency that prevents the initiator, target, or inter-switch link from becoming usable. Cisco documentation emphasizes checking VSAN membership, active zonesets, correct port mode, fabric binding, device-alias consistency, and the relevant FC databases before changing unrelated server settings. The distractors either target a different database, use the wrong port role, or would not cause the observed Fibre Channel state to change. After the fix, the engineer should confirm the interface state, FLOGI database, name-server entries, zoneset activation, and successful initiator-to-target reachability with tools such as fcping or fabric show commands.

Question#2

Refer to the exhibit.



The vPC neighborship between two switches is in suspended state.
Which configuration change resolves the issue and brings up the vPC neighborship?

A. Change STP Port Type to Network on the peer switch
B. Enable Bridge Assurance on the local switches
C. Configure QoS MTU value of 9216 on the peer switch
D. Add VLAN 400-401 to the configuration on the local switch

Explanation:
The correct remediation is Configure QoS MTU value of 9216 on the peer switch. In Cisco data center troubleshooting, the first priority is to isolate whether the failure is caused by the underlay, overlay control plane, first-hop gateway behavior, or a consistency parameter. This item is centered on vPC, so the selected action targets the condition that prevents normal forwarding rather than masking the symptom. Cisco Nexus and ACI guidance treats vPC, VXLAN EVPN, OTV, OSPF, BGP, HSRP, and LACP issues as state-dependent technologies: a neighbor, peer, VLAN, VNI, multicast group, timer, MTU, or policy mismatch can leave the protocol partially operational while traffic is still dropped. The rejected alternatives either change unrelated attributes, introduce a new inconsistency, or affect only a secondary behavior. The operational check after applying the fix should be to confirm adjacency or peer state, validate the relevant route/MAC/endpoint table, and test traffic in the affected VLAN or VRF. This aligns with Cisco DCIT network troubleshooting methodology for isolating control-plane state before changing data-plane policy.

Question#3

A network engineer troubleshoots an issue at a Cisco data center environment with these conditions:
• The data center has Cisco Nexus 9000 Series Switches running the vPC setup.
• The gateway of the servers is an HSRP IP address between the VLAN interfaces configured on both Cisco Nexus switches.
• Some of the client application servers are implementing fast-path forwarding for the return traffic.
• Those servers are sending the return traffic to the VLAN interface MAC address instead of the HSRP MAC address.
The network engineer discovers that some traffic is dropped because it passes the vPC peer link to be forwarded out the vPC interface.
What must be configured on the vPC switches to resolve the issue?

A. peer-switch
B. peer-gateway
C. arp synchronize
D. spanning-tree

Explanation:
peer-gateway is the valid corrective action because the failure described is a protocol or fabric state problem, not a generic connectivity issue. For vPC, HSRP, Cisco Nexus, Nexus 9000, Cisco Nexus 9000, Cisco troubleshooting expects the engineer to compare both endpoints of the relationship: vPC peers must agree on consistency parameters, HSRP peers must exchange hellos in the same VLAN and version context, OSPF/BGP peers must match the attributes required for stable adjacency, and VXLAN EVPN must advertise the correct host or prefix information. The selected option restores that required state. The other options either operate on the wrong layer, change a value that is not used to form the relationship, or would make the peer relationship less deterministic. A clean validation is to inspect the control-plane table first, then verify the forwarding table, and finally test end-to-end traffic. This is the Cisco-preferred approach because it avoids random changes and confirms that the fabric is forwarding based on correct protocol state.

Question#4

Refer to the exhibit.



A web browser displays a “not secure” warning message when accessing the web interface of Cisco UCS Manager.
Which action resolves the issue?

A. Load third-party certificate to UCS Manager.
B. Use the correct TCP port for HTTP
C. Use a supported web browser.
D. Use a supported version of UCS Manager.

Explanation:
The correct action is Load third-party certificate to UCS Manager. Cisco UCS troubleshooting depends on the relationship between policy, inventory discovery, firmware state, and server identity. The question involves UCS, UCS Manager, certificate, so the selected option fixes the UCS component or policy that directly controls the failure. In UCS Manager, service profiles, vNIC/vHBA templates, boot policies, firmware packages, server pools, adapters, fabric interconnects, and I/O modules are applied through a managed model; a server can fail even when basic IP reachability exists if the relevant policy is incomplete or the hardware inventory has not been acknowledged correctly. The distractors typically change an unrelated object, force a disruptive recovery without fixing the policy, or apply to a different UCS mode. Cisco guidance is to verify faults, FSM stage, inventory status, association status, and the specific boot or connectivity policy before taking action. After the remediation, validate that the fault clears, the FSM completes, and the server or fabric component returns to the expected operable state.

Question#5

A network engineer experiences the error “DDR3_P1_B1_ECC” when upgrading Cisco UCS firmware.
Which action resolves the issue?

A. Reset the DIMM
B. Reset the BMC firmware
C. Reflash the controller firmware
D. Reflash the DIMM

Explanation:
Reset the DIMM is correct because the failure is tied to the UCS managed state of UCS, firmware. In Cisco UCS, policies are not advisory; they are the source from which fabric interconnects program adapters, boot targets, server identity, firmware, and external integrations. A mismatch between the policy and the actual hardware or upstream storage/network state can cause boot, discovery, KVM, firmware, or connectivity failures. The selected action addresses the object that UCS Manager uses to build the final operational configuration. The distractors either solve a different fault domain or bypass the policy model. A disciplined DCIT validation sequence is to check the fault code, the FSM history, the equipment inventory, the service profile association, and the relevant adapter or boot table. If those states are correct after the change, the UCS component should return to operable service without unnecessary reconfiguration.

Exam Code: 300-615
Q & A: 221 Q&As         Updated:  Oct 27,2026

 

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What This 300-615 Study Resource Helps You Do

Review Key Concepts

Review the technologies, products, processes, and practical skills covered by the current 300-615 exam objectives.

Practice Scenario-Based Questions

Work through independently developed questions designed to strengthen your understanding of technical scenarios and decision-making.

Identify Knowledge Gaps

Use your results and the provided explanations to find weaker areas and focus your study more effectively.

How to Use This 300-615 Preparation Material

Review the Exam Scope

Start by reviewing the topics covered by the 300-615 exam. Compare them with the official exam objectives to understand the required technologies, operational tasks, and practical skills, then identify the areas that deserve the most attention.

Practice Independently

Complete a focused set of practice questions for each topic. On your first attempt, avoid referring to notes, answers, or other study resources so that you can evaluate your current understanding more accurately.

Study the Explanations

Review the answers and explanations after completing each practice session. Understand why the correct option is appropriate for the given scenario and why the other options may be incorrect or less suitable.

Close Knowledge Gaps

Keep track of incorrect answers, unfamiliar concepts, and weaker knowledge areas. Review these topics using official documentation and practical experience, then answer the related questions again to reinforce your understanding and monitor your progress.

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Exam Code: 300-615
Q & A: 221 Q&As
Updated:  Oct 27,2026

 

 Access Complete 300-615 Preparation Material