Acis

ACIs, in information technology, most often refer to Application Centric Infrastructure, a software-defined networking architecture developed by Cisco for data center networks. The plural form ACIs can denote multiple deployments of this architecture, or refer to different uses of the acronym in other domains. The central idea is to align network provisioning and security with application requirements rather than configuring devices individually.

A Cisco ACI deployment typically centers on the Application Policy Infrastructure Controller (APIC), which provides centralized policy management and automation. The physical and virtual network fabric follows a leaf-spine topology, with leaf switches connecting to endpoints and spine switches routing between leaves. Policy objects—tenants, application network profiles, endpoint groups, and contracts—define connectivity and security, while the fabric enforces these policies across the data plane.

ACIs support multi-tenant isolation, integration with virtualization platforms and cloud services, and scalable deployment across data centers. They leverage VXLAN for network virtualization and BGP EVPN for routing, enabling large-scale, policy-driven connectivity. The approach emphasizes centralized visibility, rapid application provisioning, and consistent enforcement of security and QoS policies.

Adoption and considerations: ACI has been deployed in many enterprises and service providers seeking automated, application-centric networks. However, deployments can involve substantial upfront cost and expertise, potential vendor lock-in, and complexity during design and migration. Some organizations adopt hybrid or open SDN approaches as alternatives or supplements.

See also: Software-defined networking; Cisco ACI; VXLAN; BGP EVPN; data center fabric.