Changing application environments are creating new demands on the IT infrastructure that supports them. With application workloads deployed across a mix of virtualized and nonvirtualized server and storage infrastructure, you require a network infrastructure that provides consistent connectivity, security, and visibility across a range of bare-metal, virtualized, and cloud computing environments. For example:

- Application instances are created dynamically, so provisioning, modification, and removal of application network connectivity also need to be dynamic.
- Business units demand accelerated application deployments, so IT departments must provide a shared IT infrastructure that addresses time-to-market needs and provides a positive return on investment (ROI).
- When organizations deploy a mix of custom, open-source, and off-the-shelf commercial applications, IT departments must manage security and quality of service (QoS) for environments that support multitenancy.
- Applications are transitioning to a less monolithic, scale-out, multinode model. The IT infrastructure that supports this model must scale with the speed of business and support both 1, 10, 25, 40, 50 and 100 Gigabit Ethernet connectivity.

The Cisco Nexus® 9000 Series Switches include both modular and fixed-port switches that overcome these challenges with flexible, agile, low-cost Cisco® Application Centric Infrastructure (Cisco ACI™).

The modular Cisco Nexus 9504, 9508, and 9516 Switches (Figure 1) are Cisco ACI spine devices enabled by nonblocking 100 and 40 Gigabit Ethernet line cards, supervisors, system controllers, and power supplies.