Top 52 Cisco ACI Interview Questions and Answers (2024)

ACI-verse workers are in great demand as more and more companies update their data centers with ACI. It is necessary to have a thorough understanding of Cisco ACI's architecture, essential parts, and useful applications to prepare for a Cisco ACI interview.

This guide helps you prepare for Cisco ACI interview questions by covering basic to advanced questions on ACI's fundamental characteristics, such as its spine-leaf topology, APIC controller functionality, multi-tenant capabilities, and much more.

Regardless of your level of experience as a network engineer or your familiarity with ACI, this post will provide you with the knowledge you need to approach your next Cisco ACI interview with assurance.  

What is Cisco ACI?

A sophisticated software-defined networking (SDN) solution that streamlines, automates, and speeds up data center operations is Cisco Application Centric Infrastructure (ACI). Network specialists are in great demand for competence with ACI as more and more enterprises use it to manage their network environments.

This guide will offer a comprehensive collection of interview questions on Cisco ACI, covering everything from fundamental ideas to more complex subjects and advice on how to respond to them properly.  

Cisco ACI Interview Questions and Answers - Freshers

Here are some Cisco ACI interview questions for freshers or beginners. These questions can be asked for an entry-level job position. So if you are a fresher trying to join the Cisoc ACI workforce, you should know these questions.

Q1. What is the hardware series used in Cisco ACI?

The Cisco ACI solution utilizes the Cisco Nexus 9000 series switches, including spine and leaf switches, which serve as the foundational hardware for ACI deployments. 

Q2. What operational modes are available in Nexus 9000 series switches?

Nexus 9000 series switches operate in two distinct modes: NX-OS mode, which functions as a traditional switch, and ACI mode, which integrates with the Application Policy Infrastructure Controller (APIC) for a policy-driven networking environment. 

Q3. What is CLOS architecture or ACI Spine-Leaf Architecture?

CLOS architecture, also known as the Spine-Leaf topology in ACI, is a network design that features spine switches as the core and leaf switches that connect to all devices, ensuring low latency, high bandwidth, and scalability. 

Q4. What role does the APIC controller play in ACI?

The Application Policy Infrastructure Controller (APIC) is the central management component of ACI, responsible for fabric configuration, policy enforcement, network automation, and providing a single point of control. 

Q5. How many Spine, Leaf switches, and FEX units can be deployed in an ACI fabric?

ACI fabric supports multiple spine and leaf switches, along with Fabric Extenders (FEX), with specific deployment limits governed by the hardware capabilities and software version in use. 

Q6. What advantages does Cisco ACI offer compared to traditional network solutions?

Cisco ACI provides numerous benefits over traditional networking, including simplified management through centralized control, automated policy enforcement, enhanced security, faster application deployments, and better network visibility. 

Q7. What specific role does the APIC controller have in the ACI fabric?

The APIC controller orchestrates the entire ACI fabric by configuring switches, managing policies, and monitoring the overall network health, ensuring consistent network behavior. 

Q8. What happens if all APIC controllers in the fabric are down?

If all APIC controllers fail, the ACI fabric continues to operate based on the last-known configurations, but policy updates and management functions will be unavailable until an APIC controller is restored. 

Q9. Where do servers connect within the ACI Spine-Leaf architecture?

In ACI’s architecture, servers and other endpoint devices are connected to the leaf switches, which handle traffic forwarding to and from the spine switches. 

Q10. What is a Bridge Domain in Cisco ACI?

A Bridge Domain (BD) is a Layer 2 networking construct in ACI that defines a broadcast domain and specifies forwarding rules between endpoints within the domain. 

Q11. What is an Endpoint and an Endpoint Group (EPG) in ACI?

An Endpoint refers to any device that communicates within the ACI network, such as a server or virtual machine. An Endpoint Group (EPG) is a logical grouping of endpoints that share similar network and security policies. 

Q12. What is a Tenant in ACI? Explain the Common Tenant, Infrastructure Tenant, and MGMT Tenant.

A Tenant in ACI is an administrative and logical isolation unit that manages resources. The Common Tenant hosts shared resources, the Infrastructure Tenant manages fabric-wide policies, and the MGMT Tenant is used for management functions. 

Q13. What is an Interface Policy in ACI, and what are the effects of not having one?

Interface Policies in ACI set configurations like speed, duplex, and other settings for switch ports. Without these policies, the interfaces may not work as intended or might perform sub-optimally. 

Q14. Can trunk ports and access ports be included in the same EPG?

Yes, both trunk and access ports can coexist within the same Endpoint Group, allowing a combination of different types of connections under the same policy group. 

Q15. What is the concept of SHARDS in ACI?

SHARDS are partitions within the APIC database that help distribute data load and improve the performance of policy and configuration management across the ACI fabric. 

Q16. What routing protocol is utilized between ACI Spine and Leaf switches?

The ACI fabric uses the IS-IS (Intermediate System to Intermediate System) protocol to facilitate routing and communication between spine and leaf switches. 

Q17. How does multiport differ from multisite in ACI?

Multiport refers to utilizing multiple physical connections for redundancy or performance, while multisite connects and manages multiple ACI fabrics across different locations as a unified network. 

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Cisco ACI Interview Questions - Intermediate-level

If you are an intermediate candidate with less than 3 years of experience, you should prepare these intermediate-level Cisco ACI interview questions and answers.

Q18. What types of tables exist on Leaf Nodes in Cisco ACI?

Leaf Nodes in ACI have two main types of tables: the Local Station Table, which contains local endpoint information, and the Global Station Table, which handles routing information between different EPGs. 

Q19. Is connecting Access Layer switches to Leaf Nodes in ACI allowed?

Yes, Access Layer switches can be connected to Leaf Nodes in ACI, extending the reach of the ACI fabric and integrating traditional network devices. 

Q20. What is L3Out in ACI, and why is it needed?

L3Out is a configuration in ACI that provides external Layer 3 connectivity to outside networks, essential for routing traffic between the ACI fabric and external environments. 

Q21. What does Cisco ACI offer, and what are its primary benefits?

Cisco ACI is a software-defined networking solution that offers centralized policy management, simplified network operations, enhanced security, and improved scalability, making it ideal for modern data centers. 

Q22. What key features differentiate Cisco ACI from other networking solutions?

Key features of Cisco ACI include policy-driven automation, centralized management, application-centric design, and seamless integration with other Cisco technologies, which set it apart from traditional networking approaches. 

Q23. How does Cisco ACI simplify network architecture and management?

ACI reduces network complexity by centralizing policy and configuration management through APIC, automating many manual tasks, and enabling rapid network adjustments based on application requirements. 

Q24. Can you describe your experience with Cisco ACI’s policy-driven automation?

Cisco ACI’s policy-driven automation allows administrators to define how the network should behave based on application needs, significantly reducing manual configurations and errors while improving operational efficiency. 

Q25. How does the application-centric approach of Cisco ACI enhance network operations?

ACI’s application-centric model aligns network policies directly with application needs, ensuring that network resources are optimized for performance, security, and compliance, streamlining overall operations. 

Q26. What are the advantages of integrating Cisco ACI with other Cisco technologies like UCS or Nexus?

Integrating ACI with other Cisco technologies, such as UCS or Nexus switches, provides a cohesive infrastructure that improves performance, enhances security, and simplifies management across the entire data center ecosystem. 

Q27. What is your experience with deploying and configuring ACI fabrics?

Deploying and configuring ACI fabrics involves setting up the APIC controllers, configuring policies, integrating leaf and spine switches, and ensuring smooth communication between all fabric components. 

Q28. How does ACI’s multi-tenant architecture cater to the needs of various organizational units?

ACI’s multi-tenant architecture allows different departments or business units to operate within isolated environments, each with its policies and resources, while still leveraging shared infrastructure. 

Q29. How does the troubleshooting and problem-solving process work in an ACI environment?

ACI provides robust troubleshooting tools through APIC, including logs, health scores, and analytics, helping identify and resolve network issues quickly, and minimizing downtime. 

Q30. What security features does Cisco ACI offer, and how have you utilized them?

Cisco ACI includes security features such as micro-segmentation, firewalls, and policy enforcement, which protect network resources. These tools help enforce strict access controls and safeguard data. 

Q31. Describe your experience with developing software for Cisco platforms.

Developing software for Cisco platforms often involves working with APIs, programming automation scripts, and integrating third-party applications to enhance the functionality of Cisco devices. 

Q32. What programming languages and development frameworks are you skilled in, and how have you applied them?

Proficiency in languages like Python, Java, or Go, and frameworks such as REST APIs or Ansible can be leveraged for automating network tasks, developing custom integrations, and enhancing ACI’s capabilities. 

Q33. How have you leveraged network automation and programmability to solve business challenges?

Network automation and programmability allow for faster, error-free network changes, improved scalability, and reduced operational costs by automating repetitive tasks and simplifying complex configurations. 

Q34. Can you describe a recent project you worked on, and how you approached its development and implementation?

Successful project development typically involves thorough planning, defining clear objectives, iterative testing, and deploying solutions in a controlled manner to ensure performance and stability. 

Cisco ACI Interview Questions - Experienced Level

 These are the advanced Cisco ACI interview questions and answers. the questions are meant to help people with over 5 years of experience.

Q35. How do you keep up-to-date with advancements in software development and network automation?

Staying current involves continuous learning through industry certifications, attending webinars, reading technical blogs, and participating in community forums focused on network automation and software development. 

Q36. How do you work with cross-functional teams to develop new solutions?

Effective collaboration with cross-functional teams involves clear communication, aligning goals, sharing knowledge, and working together through agile processes to ensure that solutions meet all requirements. 

Q37. What is your experience with Agile methodologies, and how have you applied them?

Agile methodologies focus on iterative development, regular feedback, and adaptive planning. Applying these practices ensures that projects are delivered on time and can quickly adapt to changes. 

Q38. What are Contracts in ACI, and why are they important?

Contracts in ACI define the rules and policies that govern communication between Endpoint Groups (EPGs). They specify what kind of traffic is allowed or denied, enhancing security and ensuring proper communication within the ACI fabric. 

Q39. What is a Service Graph in ACI, and how is it used?

A Service Graph in ACI is a logical representation of service nodes, such as firewalls or load balancers, used within a network to apply specific traffic policies between EPGs. It helps integrate external services directly into the ACI policy model. 

Q40. How does micro-segmentation work in ACI?

Micro-segmentation in ACI allows for granular control of traffic within a network, isolating endpoints even within the same EPG based on policies. This enhances security by limiting communication between endpoints to only what is explicitly allowed. 

Q41. What is GOLF (Global Orchestrator for L3Out Fabrics) in ACI?

GOLF is a feature that allows for simplified and scalable Layer 3 connectivity across multiple ACI fabrics. It provides a streamlined way to manage external routing connections for multiple ACI sites, enhancing operational efficiency. 

Q42. How does Cisco ACI handle VLAN pooling, and what are its benefits?

VLAN pooling in ACI allows multiple VLANs to be grouped together and dynamically assigned to EPGs. This helps efficiently manage VLAN resources, reduce configuration overhead, and avoid VLAN exhaustion. 

Q43. What is VXLAN, and why is it used in ACI?

VXLAN (Virtual Extensible LAN) is a tunneling protocol used in ACI to encapsulate Layer 2 traffic over Layer 3 networks, enabling greater scalability and segmentation capabilities within the data center. 

Q44. What methods does ACI provide for integrating with external security appliances?

ACI integrates with external security appliances through service insertion, contracts, and service graphs, enabling seamless deployment of third-party firewalls, intrusion prevention systems, and other security solutions. 

Q45. Explain the concept of Fabric Membership in ACI.

Fabric Membership in ACI refers to the process of registering and managing leaf and spine switches within the fabric. Each switch is authenticated and assigned a role, ensuring it functions correctly within the overall topology. 

Q46. How can Cisco ACI be integrated with public cloud environments?

Cisco ACI can extend to public clouds using solutions like ACI Multi-Site or Cloud APIC, which manage consistent policy enforcement and connectivity between on-premises ACI fabrics and cloud environments like AWS, Azure, or Google Cloud. 

Q47. What are Faults and Events in ACI, and how do they impact the fabric?

Faults are error conditions detected by ACI, while Events are significant occurrences within the network, such as configuration changes. Both are crucial for monitoring the health of the fabric and ensuring prompt troubleshooting. 

Q48. Describe your experience with ACI Fabric Upgrade processes.

ACI fabric upgrades involve updating the APIC controllers and fabric switches in a staged manner to minimize disruption. Experience in this area includes planning, executing pre-checks, running upgrades, and validating post-upgrade stability. 

Q49. What role does the Inband Management network play in ACI?

The Inband Management network in ACI provides a path for managing APIC controllers and switches within the fabric. It allows operational traffic to flow through the same paths as data traffic, reducing the need for dedicated out-of-band networks. 

Q50. What is the significance of Multicast in ACI, and how is it managed?

Multicast in ACI is used for efficient traffic distribution, such as streaming or data replication scenarios. It is managed using IGMP (Internet Group Management Protocol) snooping and PIM (Protocol Independent Multicast) to control multicast traffic within the fabric. 

Q51. How does Cisco ACI handle Quality of Service (QoS)?

ACI implements QoS policies that prioritize network traffic based on application needs, ensuring critical traffic gets precedence. QoS can be configured on EPGs and enforced across the fabric to manage bandwidth, latency, and packet loss. 

Q52. What tools do you use for monitoring and analyzing Cisco ACI environments?

Tools like Cisco Network Insights, ACI App Center, or third-party solutions like SolarWinds and Splunk are used to monitor, analyze, and visualize ACI fabric performance, troubleshoot issues, and optimize network operations. 

Interview Tips for Cisco ACI Candidates 

● Understand Core Concepts: Make sure you have a solid understanding of basic ACI concepts like EPGs, BDs, Tenants, and how the APIC functions. 

● Know the Architecture: Be able to explain the Spine-Leaf architecture, VXLAN usage, and how traffic flows through the ACI fabric. 

● Hands-On Experience: Practical knowledge of configuring and troubleshooting ACI is highly valuable. Highlight any relevant projects or deployments you have worked on. 

●  Security Features: Be prepared to discuss ACI’s security mechanisms, such as micro-segmentation, contracts, and service graphs. 

● Integration Capabilities: Understand how ACI integrates with external systems, including cloud environments and third-party security appliances. 

ACI Interview Questions with Answers - Summing Up! 

Prepare for your Cisco ACI interview with confidence! Whether you're a fresher, at an intermediate level, or experienced, mastering key ACI interview questions is essential. Familiarize yourself with common interview questions with answers that cover fundamental concepts and advanced topics.

Focusing on questions for Cisco ACI can help you stand out as a qualified candidate. Summing up, thorough preparation is key to success in your ACI interview journey!