Cisco ISE Policy Services Node (PSN) Redundancy and Load Balancing - Overview

Cisco Identity Services Engine (ISE) is a network access control and policy enforcement platform that helps ensure secure access to network resources. PSN stands for Policy Services Node, which is a component of Cisco ISE responsible for enforcing policy decisions.

Implementing redundancy for PSNs in Cisco ISE is crucial for ensuring high availability and fault tolerance. This is typically done by deploying multiple PSNs in a distributed environment. Here are the steps to set up PSN redundancy:

Design the Redundancy Architecture:

• Decide on the number of PSNs you'll deploy for redundancy. Typically, a minimum of two PSNs is recommended for high availability.
• Consider the physical location and network connectivity of the PSNs to ensure that they are spread out to minimize the risk of a single point of failure.

License ISE for PSN Redundancy:

• Ensure that you have the necessary licenses for PSN redundancy. You'll need licenses for multiple nodes.

In theses series of articles, I want to share with you the techniques and best practices that you can use to ensure high availability for your deployed PSNs. The techniques that I want to write about:

1. Appliance Redundancy (In-Box Redundancy)
2. NIC Bonding (Network Card Redundancy)
3. Node Groups
4. Using Load Balancers Generic Guidelines
5. Load Balancer Fragmentation and Reassembly
6. Load Balancing with URL-Redirect
7. Load Balancing Profiling Services
8. Load Balancing TACACS+
9. Load Balancing Web Requests Using DNS
10. Anycast High Availability for PSNs
11. NAD-based RADIUS Server Redundancy
12. IOS-based RADIUS Server Load Balancing
13. RADIUS Server Reorder on Failure