Which node enables Cisco ISE to share contextual information on a device with Cisco Stealth...

The node that enables Cisco ISE to share contextual information on a device with Cisco Stealthwatch is the pXGrid Controller. The pXGrid Controller is a component of the ISE Policy Service Node (PSN) that facilitates the exchange of contextual data between ISE and other security products, such as Stealthwatch, via the Platform Exchange Grid (pxGrid) protocol. The pXGrid Controller acts as a broker that registers, authenticates, and authorizes pxGrid clients, and allows them to publish and subscribe to topics of interest. For example, Stealthwatch can subscribe to the Session Directory topic to obtain user and device information from ISE, and use it to enrich the network flow data and provide better visibility and security analytics. Stealthwatch can also publish topics, such as Rapid Threat Containment (RTC), to allow ISE to take mitigation actions on compromised endpoints, such as quarantine or re-authentication. References:

Cisco Identity Services Engine Administrator Guide, Release 2.4 - Manage Platform Exchange Grid Services [Cisco Identity Services Engine] - Cisco1

Deploying Cisco Stealthwatch 7.x with Cisco ISE 2.4 using pxGrid - Cisco Community2

Stealthwatch — Networking fun3

pxGrid in Depth > Sharing the Context | Cisco Press4