Cisco Identity Services Engine (ISE) is a network access control (NAC) product. It decides who and what may connect to a network, based on identity and context. ISE discovers and profiles managed and unmanaged devices, including IoT and OT endpoints, across wired, wireless, VPN and cloud environments. It applies segmentation and least-privilege policies and can automatically quarantine risky endpoints. Through pxGrid and open APIs it shares context with Cisco products and third-party tools. You run ISE on Cisco Secure Network Server appliances, as a virtual machine on supported hypervisors, or in supported cloud environments.
Cisco is a publicly listed company headquartered in San Jose, California, so ISE is a US product and is not open source. Because the organisation operates the software itself, on its own premises or in a cloud environment it selects, it decides where policy and endpoint data are kept. For a European organisation it remains relevant that the software and licences come from a US vendor, which matters when assessing exposure to US legislation such as the CLOUD Act.