60 Most Asked Cisco ACI Interview Questions With Sample Answers

Once you've crafted an impressive resume and sailed through the HR round, it's time to brace yourself for the ultimate challenge: the final interview. The final interview is often regarded as the most arduous one, leaving us anxious about the questions the interviewer might throw our way. It's always wise to be prepared in advance, especially for the frequently asked technical questions. To assist you in your preparation, here are the top 60 Cisco ACI interview questions along with their corresponding answers.

Mastering these questions will undoubtedly position you as a competent candidate in the eyes of any Cisco ACI interviewer. These questions have been carefully compiled by our dedicated technical team, who have made a collective effort to ensure their relevance and effectiveness.

60 Cisco ACI interview questions and Answers

1. What is Cisco ACI?

Cisco ACI (Application Centric Infrastructure) is a software-defined networking (SDN) solution provided by Cisco that offers a centralized approach to managing and automating network infrastructure.

2. What are the key components of Cisco ACI?

The key components of Cisco ACI are Application Policy Infrastructure Controller (APIC), ACI Fabric, and Nexus 9000 series switches.

3. What is the role of the Application Policy Infrastructure Controller (APIC)?

APIC serves as the centralized management and policy enforcement point in the Cisco ACI architecture. It provides a single point of control for managing the entire ACI fabric.

4. What is an ACI Fabric?

ACI Fabric is the physical infrastructure that consists of Nexus 9000 series switches and provides the network connectivity and forwarding within the Cisco ACI architecture.

5. How does Cisco ACI simplify network management?

Cisco ACI simplifies network management by abstracting network policies from the underlying physical infrastructure. It provides a policy-based approach to networking, enabling administrators to define application-specific policies and have them automatically applied across the fabric.

6. What is the ACI policy model?

The ACI policy model is a declarative model that allows administrators to define and manage policies using a high-level language. It enables the enforcement of policies across the network infrastructure without the need to configure individual devices.

7. What is an EPG in Cisco ACI?

EPG (End Point Group) is a logical construct in Cisco ACI that defines a group of endpoints with similar networking requirements. It allows administrators to apply consistent policies to a group of endpoints, such as virtual machines or physical servers.

8. What is a contract in Cisco ACI?

A contract in Cisco ACI is a set of rules that define the communication and interaction between EPGs. Contracts specify the permitted traffic flows, protocols, and other parameters that govern the communication between EPGs.

9. What is microsegmentation in Cisco ACI?

Microsegmentation is the practice of dividing a network into smaller segments and applying security policies at a granular level. In Cisco ACI, microsegmentation can be achieved by using EPGs and contracts to enforce fine-grained access control between application components.

10. How does Cisco ACI integrate with virtualization platforms?

Cisco ACI integrates with popular virtualization platforms such as VMware vSphere and Microsoft Hyper-V. It provides integration capabilities through the Cisco Application Virtual Switch (AVS) or the Cisco ACI Virtual Edge (AVE) to extend policy enforcement to virtual machines.

11. What is the ACI Multi-Site feature?

The ACI Multi-Site feature enables the interconnection and management of multiple ACI fabrics across different geographical locations. It allows consistent policy enforcement and workload mobility across sites.

12. What are the advantages of using Cisco ACI?

Advantages of using Cisco ACI include simplified network management, automation capabilities, policy-driven approach, improved security through microsegmentation, scalability, and multi-site deployment support.

13. How does Cisco ACI handle network traffic forwarding?

Cisco ACI uses a combination of hardware forwarding in the Nexus 9000 series switches and software intelligence in the APIC to handle network traffic forwarding. The switches perform the actual packet forwarding based on the policies defined in the APIC.

14. What is the difference between ACI mode and NX-OS mode on Nexus switches?

ACI mode is the operating mode for Nexus switches when they are part of a Cisco ACI fabric. In ACI mode, the switches are managed and controlled by the APIC, and the network policies are defined and enforced at the fabric level. NX-OS mode is the traditional operating mode for standalone Nexus switches, where they are managed individually and configured using the NX-OS CLI.

15. What is the role of the Cisco Application Virtual Switch (AVS)?

The Cisco AVS is a virtual switch that runs on hypervisor hosts and provides connectivity between virtual machines and the ACI fabric. It allows the enforcement of ACI policies within the virtualization infrastructure.

16. What is the ACI Group-Based Policy Model (GBP)?

ACI Group-Based Policy (GBP) is an extension of the ACI policy model that enables the integration of ACI with external network services, such as firewalls and load balancers. GBP allows administrators to define policies that span multiple domains and enforce them consistently.

17. How does Cisco ACI support automation and orchestration?

Cisco ACI provides a comprehensive set of APIs (Application Programming Interfaces) that allow for programmatic access and automation of ACI configuration and management tasks. It also integrates with orchestration platforms like Cisco UCS Director, VMware vRealize, and Cisco CloudCenter.

18. What is the ACI Multi-Pod feature?

The ACI Multi-Pod feature enables the interconnection of multiple ACI pods within the same data center. It allows for the extension of the ACI fabric across multiple pods while maintaining centralized policy control.

19. How does Cisco ACI support integration with external Layer 4-7 services?

Cisco ACI provides integration with external Layer 4-7 services through the Service Graph framework. The Service Graph allows administrators to define the traffic flow between application components and insert service devices such as firewalls and load balancers into the traffic path.

20. How does Cisco ACI handle network upgrades and maintenance?

Cisco ACI provides a rolling upgrade mechanism that allows for non-disruptive upgrades of the ACI fabric. The upgrade process is performed in a controlled manner, ensuring that network traffic is not impacted during the upgrade.

21. What is a spine switch in Cisco ACI?

In Cisco ACI, spine switches are high-performance switches that provide the backbone connectivity for the ACI fabric. They handle the forwarding of traffic between leaf switches and provide the scalability and high-bandwidth connectivity required in large-scale deployments.

22. What is a leaf switch in Cisco ACI?

Leaf switches in Cisco ACI provide the network connectivity for the endpoints in the fabric. They connect to the spine switches and handle the traffic between the endpoints and the fabric.

23. What is a VLAN Pool in Cisco ACI?

A VLAN Pool is a logical grouping of VLANs that can be dynamically assigned to EPGs in Cisco ACI. It allows for flexible assignment and management of VLANs within the fabric.

24. How does Cisco ACI handle Layer 2 and Layer 3 forwarding?

Cisco ACI uses a combination of VXLAN (Virtual Extensible LAN) encapsulation and hardware forwarding in the Nexus 9000 series switches to handle Layer 2 and Layer 3 forwarding. VXLAN provides the overlay encapsulation, and the switches perform the forwarding based on the VXLAN headers.

25. What is the role of the APIC GUI in Cisco ACI?

The APIC GUI (Graphical User Interface) provides a web-based interface for managing and configuring the Cisco ACI fabric. It allows administrators to define policies, monitor the fabric, and perform day-to-day management tasks.

26. What is the ACI Network Centric Mode?

The ACI Network Centric Mode is an alternative operating mode for Cisco ACI that allows for the integration of existing network infrastructure into the ACI fabric. In this mode, the fabric is configured to operate in a more traditional network-centric manner.

27. What is a VRF in Cisco ACI?

A VRF (Virtual Routing and Forwarding) is a virtual routing table that separates the forwarding and routing context within the ACI fabric. It allows for the isolation of network traffic and the enforcement of different routing policies.

28. What is the ACI Anywhere concept?

ACI Anywhere is the idea that the ACI architecture can extend beyond the data center and be deployed in multiple environments, such as public clouds or remote sites. It enables consistent policy enforcement and workload mobility across different locations.

29. How does Cisco ACI integrate with third-party orchestration tools?

Cisco ACI provides integration with third-party orchestration tools through APIs and plugins. It allows for the seamless integration and automation of ACI with popular orchestration platforms like VMware vRealize Automation or OpenStack.

30. What is the role of the Cisco ACI Virtual Edge (AVE)?

The Cisco ACI Virtual Edge (AVE) is a virtual appliance that extends the ACI fabric into virtualized environments. It provides policy enforcement and connectivity for virtual machines running on VMware ESXi hosts.

31. How does Cisco ACI handle multi-tenancy?

Cisco ACI provides a multi-tenant architecture that allows for the isolation and segregation of network resources between different tenants or organizations. It enables the enforcement of separate policies and the isolation of tenant traffic.

32. What is an L3Out in Cisco ACI?

An L3Out is a connectivity link between the ACI fabric and external Layer 3 networks. It allows the ACI fabric to connect to external routers and provide connectivity to networks outside the fabric.

33. How does Cisco ACI support integration with external storage?

Cisco ACI integrates with external storage systems through features like Fibre Channel over Ethernet (FCoE) and iSCSI. It allows for the provisioning and management of storage resources within the ACI fabric.

34. What is the role of the Cisco ACI App Center?

The Cisco ACI App Center is a centralized repository for ACI applications and integrations. It provides a marketplace-like platform where administrators can discover, deploy, and manage applications that extend the functionality of the ACI fabric.

35. What is an EPG contract in Cisco ACI?

An EPG contract is a policy construct that defines the communication and interaction between two EPGs in Cisco ACI. It specifies the allowed traffic flows, protocols, and other parameters for the communication between the EPGs.

36. What is the ACI Multi-Site Orchestrator (MSO)?

The ACI Multi-Site Orchestrator (MSO) is a centralized management and orchestration tool for managing multiple ACI fabrics in a multi-site deployment. It provides a unified view and control over the distributed ACI fabrics.

37. What is the ACI Network Assurance Engine (NAE)?

The ACI Network Assurance Engine (NAE) is a tool that provides advanced analytics and verification capabilities for the ACI fabric. It allows administrators to gain insights into the fabric's behavior, validate policies, and troubleshoot issues.

38. What is the ACI Service Insertion feature?

The ACI Service Insertion feature allows for the insertion of network services, such as firewalls or load balancers, into the traffic path of applications. It enables the enforcement of security and service policies at the application level.

39. How does Cisco ACI handle IP multicast traffic?

Cisco ACI uses a distributed multicast mechanism called Multipod IP Multicast (MPIM) to handle IP multicast traffic. It leverages the underlying multicast capabilities of the Nexus 9000 switches to provide efficient and scalable multicast forwarding.

40. What is the ACI Microsegmentation feature?

The ACI Microsegmentation feature allows for the application of fine-grained security policies at the endpoint level. It enables administrators to define and enforce access control between individual endpoints, enhancing the security posture of the network.

41. How does Cisco ACI handle traffic load balancing?

Cisco ACI supports traffic load balancing through the use of Equal-Cost Multipath (ECMP) and Link Aggregation Group (LAG) techniques. It allows for the distribution of traffic across multiple paths or links to achieve higher throughput and redundancy.

42. What is the role of the Cisco ACI Telemetry feature?

The Cisco ACI Telemetry feature provides real-time monitoring and visibility into the fabric's performance and health. It allows administrators to collect and analyze telemetry data for troubleshooting, capacity planning, and optimization purposes.

43. What is the ACI Virtual Machine Manager (VMM) domain?

The ACI Virtual Machine Manager (VMM) domain represents the virtualization infrastructure within the ACI fabric. It defines the integration points between the ACI fabric and the virtualization platform, enabling policy enforcement and visibility at the virtual machine level.

44. How does Cisco ACI support integration with container platforms?

Cisco ACI integrates with container platforms like Kubernetes through the Cisco ACI Container Networking Interface (CNI) plugin. It allows for the enforcement of ACI policies within containerized environments and enables seamless connectivity between containers and the ACI fabric.

45. What is the ACI Tenant?

The ACI Tenant is a logical construct that represents an isolated administrative domain within the ACI fabric. It allows for the separation and management of network resources, policies, and tenants within the fabric.

46. How does Cisco ACI handle traffic flow between ACI and non-ACI environments?

Cisco ACI provides connectivity and integration options for traffic flow between ACI and non-ACI environments. This can be achieved through features like L2Out, L3Out, or the ACI Network Centric Mode, depending on the specific requirements of the deployment.

47. What is the role of the Cisco ACI Fabric Extender (FEX)?

The Cisco ACI Fabric Extender (FEX) is a device that extends the ACI fabric into a non-ACI environment, such as a traditional access layer network. It allows for the integration and connectivity between the ACI fabric and the external network.

48. How does Cisco ACI handle network segmentation and isolation?

Cisco ACI provides network segmentation and isolation through the use of EPGs, contracts, and VRFs. EPGs allow for the grouping and segmentation of endpoints, contracts enforce communication rules between EPGs, and VRFs provide isolation at the routing level.

49. What is the role of the Cisco ACI App Center Developer Toolkit?

The Cisco ACI App Center Developer Toolkit provides a set of tools, APIs, and documentation to facilitate the development of applications and integrations for the ACI fabric. It enables developers to create custom solutions and extend the capabilities of the ACI fabric.

50. How does Cisco ACI handle policy enforcement for external network services?

Cisco ACI provides policy enforcement for external network services through the Service Graph framework. The Service Graph allows administrators to define the traffic flow between application components and insert external services into the traffic path while enforcing the desired policies.

51. What is the ACI Multi-Site Orchestrator (MSO) Federation?

The ACI Multi-Site Orchestrator (MSO) Federation allows for the centralized management and coordination of multiple MSO instances across different administrative domains. It enables the deployment of consistent policies and configurations across the federated MSO instances.

52. How does Cisco ACI handle traffic filtering and access control?

Cisco ACI handles traffic filtering and access control through the use of contracts and filters. Contracts define the allowed traffic flows between EPGs, and filters provide the fine-grained control over the traffic based on various criteria like IP addresses, ports, or protocols.

53. What is the ACI Fabric Discovery Process?

The ACI Fabric Discovery Process is the initial process of discovering and bringing the Nexus switches into the ACI fabric. It involves connecting the switches to the fabric infrastructure, registering them with the APIC, and establishing the control and data plane connectivity.

54. What is the role of the Cisco ACI Fabric Access Policy?

The Cisco ACI Fabric Access Policy defines the configuration and behavior of the physical and virtual interfaces in the ACI fabric. It includes settings for link policies, interface profiles, and access port configurations.

55. How does Cisco ACI handle network virtualization?

Cisco ACI handles network virtualization through the use of VRFs, bridge domains, and EPGs. VRFs provide the routing and forwarding separation, bridge domains define Layer 2 broadcast domains, and EPGs allow for the grouping and segmentation of endpoints.

56. What is the ACI Health Score?

The ACI Health Score is a metric that provides a visual representation of the overall health and compliance status of the ACI fabric. It takes into account various factors like fault severity, configuration compliance, and operational status to calculate the score.

57. What is the role of the Cisco ACI Traffic Map?

The Cisco ACI Traffic Map provides a visual representation of the traffic flow within the ACI fabric. It allows administrators to identify the communication patterns between EPGs and endpoints, helping with troubleshooting, capacity planning, and optimization.

58. How does Cisco ACI handle network troubleshooting?

Cisco ACI provides various troubleshooting features, including real-time monitoring, fault detection and analysis, and packet capture capabilities. It also integrates with tools like the ACI Network Assurance Engine (NAE) to provide advanced analytics and automated troubleshooting.

59. What is the ACI Application Network Profile (ANP)?

The ACI Application Network Profile (ANP) is a policy construct that defines a collection of EPGs, contracts, and other policy elements that are associated with a specific application or tenant. It allows for the holistic definition and management of application-specific policies.

60. How does Cisco ACI support integration with security solutions?

Cisco ACI supports integration with security solutions through the use of the Cisco ACI Security Group Tag (SGT) framework. SGTs allow for the classification and tagging of traffic based on security policies, enabling the enforcement of security policies within the ACI fabric and integration with third-party security systems.