Most asked Cisco ACI-related questions:

1. What is Cisco ACI, and what are its key features and benefits?

2. How does Cisco ACI differ from traditional network architectures?

3. What are the main components of a Cisco ACI fabric?

4. How does Cisco ACI support multi-tenancy and isolation of tenant resources?

5. What is an Application Network Profile (ANP) in Cisco ACI, and how is it used?

6. How does Cisco ACI implement microsegmentation and endpoint group-based policies?

7. Explain the concept of Application EPGs (End Point Groups) in Cisco ACI.

8. What is the purpose of the Cisco Application Policy Infrastructure Controller (APIC)?

9. How does Cisco ACI integrate with hypervisors and virtualization technologies?

10. How is network automation achieved in Cisco ACI, and what role does the Cisco Application Policy Infrastructure Controller (APIC) play in automation?

11. What is an ACI Fabric Access Policy, and how is it used to control communication between different endpoint groups?

12. How does Cisco ACI handle east-west and north-south traffic within the data center?

13. What are the different deployment modes in Cisco ACI, and when is each mode appropriate?

14. How does Cisco ACI support integration with external Layer 3 networks?

15. What are the advantages of using an ACI fabric for load balancing?

16. How does Cisco ACI facilitate integration with external services, such as firewalls and load balancers?

17. What is the role of Contracts in Cisco ACI, and how do they enable communication between endpoint groups?

18. How does Cisco ACI handle traffic flow when there are multiple paths between endpoints?

19. Explain the process of implementing Quality of Service (QoS) policies in Cisco ACI.

20. What are the different methods of monitoring and troubleshooting a Cisco ACI fabric?

Here are answers

• What is Cisco ACI, and what are its key features and benefits?

• Answer: Cisco ACI, or Application Centric Infrastructure, is a data center networking solution that provides centralized automation and policy-driven application profiles. It aims to simplify data center operations, enhance security, and accelerate application deployment. Key features include a policy-driven approach, unified management through the Cisco Application Policy Infrastructure Controller (APIC), network automation, support for multi-tenancy, and integration with virtualization technologies.

• How does Cisco ACI differ from traditional network architectures?

• Answer: Unlike traditional network architectures that are based on manual configuration of individual network devices, Cisco ACI provides a centralized policy-based approach. It abstracts the underlying network infrastructure from applications and uses application-centric policies for managing network behavior. This allows for easier application deployment, better scalability, and improved security.

• What are the main components of a Cisco ACI fabric?

• Answer: The main components of a Cisco ACI fabric include the Cisco Nexus 9000 Series switches, the Cisco Application Policy Infrastructure Controller (APIC), and the Cisco ACI fabric interconnects. The Nexus switches provide the hardware for the ACI fabric, the APIC is the centralized policy controller, and the fabric interconnects enable communication between the Nexus switches and the APIC.

• How does Cisco ACI support multi-tenancy and isolation of tenant resources? Answer: Cisco ACI uses Virtual Routing and Forwarding (VRF) instances and Bridge Domains (BDs) to achieve multi-tenancy. Each tenant in ACI can have its own VRF, allowing isolation of resources and policies. Bridge Domains are used to define Layer 2 segments for each tenant, further ensuring segregation of tenant traffic.

• What is an Application Network Profile (ANP) in Cisco ACI, and how is it used? Answer: An Application Network Profile (ANP) is a collection of policies and configurations that define how an application will be deployed and managed within the ACI fabric. ANPs encapsulate the network, security, and Quality of Service (QoS) requirements of an application, simplifying its deployment and management.

• How does Cisco ACI implement microsegmentation and endpoint group-based policies?

• Answer: Cisco ACI implements microsegmentation by grouping endpoints into logical segments called Endpoint Groups (EPGs). Policies are applied to these EPGs, defining how communication should occur between them. This microsegmentation approach allows fine-grained control over traffic flows within the data center.

• Explain the concept of Application EPGs (End Point Groups) in Cisco ACI. Answer: Application End Point Groups (EPGs) are logical groups of endpoints that share the same network and security policies. EPGs can contain physical servers, virtual machines, or other network devices related to an application. They allow administrators to apply consistent policies to all endpoints within the group.

• What is the purpose of the Cisco Application Policy Infrastructure Controller (APIC)?

• Answer: The Cisco Application Policy Infrastructure Controller (APIC) is a centralized, policy-driven controller in the Cisco ACI fabric. It provides a single point of management for the entire ACI fabric, allowing administrators to define and enforce policies that govern network behavior and application deployment.

• How does Cisco ACI integrate with hypervisors and virtualization technologies?

• Answer: Cisco ACI integrates with leading hypervisors, such as VMware vSphere, Microsoft Hyper-V, and Red Hat KVM. The integration allows ACI to automatically discover and manage virtual machines, apply policies to VMs, and provide seamless communication between virtual and physical environments.

• How is network automation achieved in Cisco ACI, and what role does the Cisco Application Policy Infrastructure Controller (APIC) play in automation? Answer: Network automation in Cisco ACI is achieved through a policy-driven approach. Administrators define policies at the APIC, and the fabric automatically implements these policies across the network. The APIC acts as the centralized policy controller and communicates with the switches to automate the provisioning and configuration of network resources.

• What is an ACI Fabric Access Policy, and how is it used to control communication between different endpoint groups?

• Answer: An ACI Fabric Access Policy is a set of rules that define how communication between different Endpoint Groups (EPGs) should be handled within the ACI fabric. Access policies control traffic between EPGs, ensuring that only authorized communication is allowed based on defined policies.

• How does Cisco ACI handle east-west and north-south traffic within the data center? Answer: Cisco ACI handles east-west traffic (communication between endpoints within the same data center) through microsegmentation using Endpoint Groups (EPGs) and policies. North-south traffic (communication between endpoints in the data center and external networks) is managed using ACI's external Layer 3 integration and policies.

• What are the different deployment modes in Cisco ACI, and when is each mode appropriate? Answer: Cisco ACI supports three deployment modes: a. Fabric Mode: A fully integrated mode with the APIC controlling all aspects of the fabric. b. Mixed Mode: A transitional mode that allows both ACI and traditional networking to coexist. c. Network Centric Mode: A mode where the fabric operates as a traditional network with limited ACI features. The appropriate mode depends on the organization's existing infrastructure and migration strategy.

• How does Cisco ACI support integration with external Layer 3 networks? Answer: Cisco ACI supports integration with external Layer 3 networks through the Border Gateway Protocol (BGP) and the use of External Bridge Network (L3Out) policies. This integration enables communication between ACI endpoints and devices outside the ACI fabric.

• What are the advantages of using an ACI fabric for load balancing?

• Answer: Cisco ACI provides built-in support for load balancing through its Application Network Profiles (ANPs). Load balancing policies can be defined within the ANPs, enabling intelligent distribution of traffic to optimize application performance and availability.

• How does Cisco ACI facilitate integration with external services, such as firewalls and load balancers? Answer: Cisco ACI allows seamless integration with external services through Service Graphs. Service Graphs define the path of traffic flow between the endpoints and external services, such as firewalls, load balancers, or WAN optimization devices. This integration is essential for applying additional security and services to the application traffic.

• What is the role of Contracts in Cisco ACI, and how do they enable communication between endpoint groups? Answer: Contracts are policy elements in Cisco ACI that define the allowed communication between different Endpoint Groups (EPGs). Contracts act as filters that permit or deny specific types of traffic between EPGs, enforcing segmentation and security policies.

• How does Cisco ACI handle traffic flow when there are multiple paths between endpoints?

• Answer: Cisco ACI uses Equal-Cost Multipath (ECMP) routing to efficiently load balance traffic across multiple paths between endpoints. ECMP allows traffic to be distributed evenly across available paths, improving network performance and avoiding congestion.

• Explain the process of implementing Quality of Service (QoS) policies in Cisco ACI.

• Answer: In Cisco ACI, QoS policies are implemented using QoS classes and the Application Network Profile (ANP). QoS classes define different levels of service, such as Platinum, Gold, Silver, etc. The ANP incorporates these QoS classes, allowing administrators to assign the desired QoS level to each application.

• What are the different methods of monitoring and troubleshooting a Cisco ACI fabric?

• Answer: Cisco ACI provides various monitoring and troubleshooting tools, including the APIC GUI, show commands on switches, the ACI Troubleshooting Health Score, and integration with third-party monitoring systems. These tools allow administrators to monitor fabric health, analyze logs, and troubleshoot network issues efficiently.