Top 15 Cisco Data Center Interview Questions with Answers (Spine-Leaf, SAN, HCI)

Introduction

This guide covers important Cisco Data Center interview questions with clear explanations. These questions are commonly asked in CCNA, CCNP Data Center interviews and real-world networking roles.

Q1 - Which two devices would you choose to be a part of the core layer in the three-tier network design? (Choose two.)

• Cisco Nexus 9500 Series Switch
• Cisco Catalyst 9800 Series Switch
• Cisco UCS 6200 Series Fabric Interconnect
• hypervisor
• Cisco Nexus 9300 Series Switch

Answer: Cisco Nexus 9500 Series Switch and Cisco Catalyst 9800 Series Switch

Explanation:
The core layer requires high-performance devices that provide:

• High throughput
• High availability
• Fast forwarding

Cisco Nexus 9500 is designed for core/spine roles in data centers. Catalyst 9800 can also act in aggregation/core roles in some architectures. Devices like UCS Fabric Interconnect and hypervisors are not part of the core switching layer.

Q2 - Which option lists the three tiers of a three-tier architecture?

• core, aggregation, and access
• core, spine, and leaf
• base, spine, and leaf
• physical, data link, and network

Answer: core, aggregation, and access

Explanation:
The traditional enterprise/data center network is divided into:

• Core layer → backbone connectivity
• Aggregation layer → policy enforcement & routing
• Access layer → connects end devices

This model is now being replaced by spine-leaf architecture in modern data centers.

Q3 - Cisco Unified Data Center is based on which three pillars of Cisco innovation? (Choose three.)

• Cisco Unified Computing System
• Cisco Unified Fabric
• Cisco Unified Access
• Cisco Unified Communications
• Cisco Unified Management
• Cisco Overlay Transport Virtualization
• Cisco FabricPath

Answer: Cisco Unified Management, Cisco Unified Computing System, Cisco Unified Fabric

Explanation:
Cisco Unified Data Center is built on:

• UCS → compute and server infrastructure
• Unified Fabric → converged network (LAN + SAN)
• Unified Management → centralized control

These pillars simplify operations and reduce infrastructure complexity.

Q4 - Which device would you choose to be a part of the core layer in a three-tier network design?

• Cisco UCS 6400 Series Fabric Interconnect
• Cisco Nexus 9500, Cisco Catalyst 6800, or Cisco Catalyst 6500 Series Switch
• hypervisor
• Cisco ASA security appliance

Answer: Cisco Nexus 9500, Cisco Catalyst 6800, or Cisco Catalyst 6500 Series Switch

Explanation:
Core layer devices must handle:

• Large-scale traffic aggregation
• High-speed switching
• Redundancy

Nexus 9500 and Catalyst 6500/6800 are modular switches designed for core environments.

Important Note - Spine-Leaf vs Three-Tier

A spine-leaf architecture provides:

• Better scalability → add spine/leaf easily
• Predictable low latency → always 2-hop path
• Higher performance → optimized for east-west traffic

Spine-leaf can provide approximately 25% better scalability compared to traditional three-tier designs.

Q5 - Which option describes the topology design in a spine-and-leaf network?

• The design uses a partial mesh of links at the leaf layer
• The design uses a full mesh of links between the leaf and aggregation layers
• The design uses a full mesh of links between the spine and leaf layers
• The design uses a full mesh of links at the leaf layer

Answer: The design uses a full mesh of links between the spine and leaf layers

Explanation:
In a spine-leaf topology:

• Every leaf connects to every spine
• There are no leaf-to-leaf links
• Traffic always flows in predictable paths

This ensures consistent latency and scalability.

Q6 - What are three benefits of the two-tier storage network design? (Choose three.)

• It is recommended for larger storage environments
• It is elastic in case of failures
• It is recommended for small-to-medium environments
• It is redundant through dual-fabric design
• It is very expensive
• It is a single point of failure
• It is optimum for IP storage

Answer:

• It is recommended for larger storage environments
• It is elastic in case of failures
• It is redundant through dual-fabric design

Explanation:
Two-tier storage designs provide:

• Redundancy using dual fabrics
• Fault tolerance during failures
• Scalability compared to single-tier designs

This is commonly used in enterprise SAN environments.

Q7 - Which statement about Cisco Compute Hyperconverged with Nutanix is correct?

• It provides network connectivity with the Cisco Nexus 9500 series switches
• Hardware compute platforms used are Cisco UCS blade servers
• The solution is a combination of hardware and software
• It uses SAN protocols like Fibre Channel

Answer: The Cisco Compute Hyperconverged with Nutanix solution is a combination of hardware and software

Explanation:
Hyperconverged infrastructure (HCI):

• Combines compute + storage + networking
• Uses software-defined storage
• Eliminates traditional SAN dependency

Nutanix solutions integrate tightly with Cisco UCS hardware.

Q8 - Cisco Unified Data Center infrastructure eliminates silos and allows consolidation of which option?

• LAN and WAN
• LAN and SAN
• LAN and WLAN
• performance and security management

Answer: LAN and SAN

Explanation:
Unified Fabric merges:

• LAN (Ethernet traffic)
• SAN (storage traffic)

This reduces:

• Cabling
• Complexity
• Operational cost

Q9 - In a spine-and-leaf topology, what is the minimum number of spines for redundancy?

• one
• two
• four
• six

Answer: two

Explanation:
At least two spines are needed:

• To avoid single point of failure
• To ensure high availability

If one spine fails, traffic can still flow through the second.

Q10 - What are two benefits of SAN storage network design? (Choose two.)

• Allows easier maintenance
• Redundant through dual fabric design
• Very affordable
• Single point of failure
• Optimum for IP storage

Answer:

• Allows easier maintenance
• Redundant through dual fabric design

Explanation:
SAN provides:

• Centralized storage management
• High availability with redundancy
• Improved server maintenance

Q11 - Which are three characteristics of a hyperconverged storage system? (Choose three.)

• easy expansion
• no SAN network
• usage of multiple storage arrays
• usage of redundant SAN switches
• easy deployment and maintenance
• fast convergence

Answer:

• easy expansion
• no SAN network
• easy deployment and maintenance

Explanation:
Hyperconverged systems:

• Scale easily by adding nodes
• Remove need for external SAN
• Simplify deployment and operations

Q12 - Which option lists the two tiers of a Clos-collapsed core architecture?

• aggregation and access
• spine and leaf
• spine and access
• collapsed core and leaf

Answer: spine and leaf

Explanation:
Clos architecture simplifies traditional design into:

• Spine layer (backbone)
• Leaf layer (access)

This improves scalability and performance.

Q13 - Small company storage expansion scenario

Question: Which network design approach is required?

• cloud storage solution
• three-tier network with Cisco MDS multilayer switches
• directly attached network
• storage area network

Answer: storage area network

Explanation:
When scaling storage:

• DAS becomes inefficient
• SAN provides centralized storage
• Supports multiple servers

Q14 - If you are running out of physical ports, what should you do?

• Add a core switch to each leaf
• Add core switches together
• Add a leaf switch connected to all spines
• Add a leaf switch to each leaf

Answer: Add an additional leaf switch and connect it to each spine

Explanation:
In spine-leaf design:

• Leaf switches connect end devices
• Adding a leaf increases port capacity
• No changes required in existing topology