Cisco ACI is a software-defined networking (SDN) solution for enterprise data centers and cloud environments. It is designed to simplify network infrastructure and reduce operational costs. Cisco ACI uses a centralised policy model to automate network configuration and provisioning. It also includes an application programming interface (API) for integration with third-party applications.
• Cisco Nexus 9000 Series Switches: A family of high-performance, energy-efficient, and scalable 10, 40, and 100 Gigabit Ethernet switches that support the Cisco ACI fabric.
• Cisco APIC: The Cisco ACI controller that centrally manages the Cisco ACI fabric.
• Cisco ACI Fabric: A high-performance, scalable, and resilient network fabric that interconnects Cisco Nexus 9000 Series Switches.
The Cisco Nexus 9000 Series Switches are available in two models: the Nexus 9300-EX and the Nexus 9300-FX. The Nexus 9300-EX provides a choice of 10, 40, or 100 Gigabit Ethernet ports. The Nexus 9300-FX provides fixed 100 Gigabit Ethernet ports.
The Cisco ACI fabric is based on the Cisco Nexus 9000 Series Switches and uses their features and capabilities. The Cisco Nexus 9000 Series Switches support various features that are required for the Cisco ACI fabric, such as:
• Quality of Service (QoS): Prioritises traffic to ensure that mission-critical applications receive the bandwidth they need.
• Security: Provides data-plane security to help protect the Cisco ACI fabric from attacks.
• Multicast: Supports efficient delivery of traffic to multiple destinations.
• Virtual Extensible LAN (VXLAN): A Layer 2 overlay technology that helps extend the Cisco ACI fabric over long distances.
• Overlays: Enables the creation of multiple virtual networks (overlays) on top of a common physical infrastructure.
The Cisco ACI fabric is designed to be scalable and resilient. It uses a leaf-and-spine architecture in which the Cisco Nexus 9000 Series Switches are interconnected in a non-blocking, two-tier hierarchy. The leaf switches provide connectivity to endpoints, such as servers and storage devices. The spine switches provide high-bandwidth, low-latency connectivity between the leaf switches.
The Cisco Nexus 9000 Series Switches that make up the Cisco ACI fabric can be deployed in a variety of topologies, including:
• Full mesh: In a full mesh topology, every leaf switch is connected to every spine switch. This provides the highest level of resiliency, as traffic can be rerouted around any failed leaf or spine switch.
• Partial mesh: In a partial mesh topology, some leaf switches are connected to every spine switch, while other leaf switches are only connected to a subset of the spine switches. This topology provides a balance between resiliency and cost.
• Spine-leaf: In a spine-leaf topology, the leaf switches are connected to a single spine switch. This is the simplest and most cost-effective topology.
The Cisco ACI fabric is designed to be highly available. All components in the Cisco ACI fabric are redundant and can be replaced without disrupting service. The Cisco Nexus 9000 Series Switches support various high-availability features, such as:
• Non-stop forwarding: Ensures that traffic is forwarded even if a switch fails.
• In-service software upgrades: Allows software upgrades to be performed without disrupting service.
• Stateful switchover: Maintains switch state information, such as forwarding tables and ARP tables, so that it can be quickly restored in the event of a switch failure.
The Cisco ACI fabric is designed to be easily managed and operated. The Cisco APIC provides a centralised point of management and control for the Cisco ACI fabric. It uses an intuitive graphical user interface (GUI) and a REST-based API for integration with third-party applications.
The Cisco ACI fabric is designed to be easily deployed. All components in the Cisco ACI fabric are hardware and software agnostic. This means that the Cisco ACI fabric can be deployed on any type of hardware or virtualised environment.