Cisco ISE Resources

[David Jam]

Hi friends,
I want to install Cisco ISE 3.4 for Device Administration only. I have about 5000 switches. How many ISE instances should I install for HA (High Availability), and what resources (like RAM, CPU, HDD) in vmware should I allocate to the servers?

Thanks

[Rob Ingram · Accepted solution]

@David Jam you would typically scale ISE based on the number of concurrent active sessions. Once you know roughly how many concurrent active sessions the ISE cluster will need to support, you can follow the ISE sizing guidelines in the ISE Performance and Scale guides below.

https://www.cisco.com/c/en/us/td/docs/security/ise/performance_and_scalability/b_ise_perf_and_scale.html

https://www.ciscolive.com/c/dam/r/ciscolive/emea/docs/2025/pdf/BRKSEC-3234.pdf

You would typically deploy the VM using the OVA which has predefined specs (CPU, Mem, HDD) from the Cisco website - https://software.cisco.com/download/home/283801620/type/283802505/release/3.4.0 based on the specification in the Performance and Scale guides.

[David Jam]

@Rob Ingram thanks for reply. Considering the number of 5000 switches, how do I calculate the number of sessions?

[Rob Ingram]

@David Jam do you know the typical usage? Is it required for just admins logging in to the switches now and then or do you envisage heavy usage of scripts or Network management Systems logging into the devices regularly?

[David Jam]

Yes, for now, I only need it for the admins.

[Rob Ingram]

@David Jam refer to this ISE Device Administration guide, it has a section called "Calculate the Number of Transactions per Second (TPS)" with an example how to calculate the number of transactions per second and how to scale the ISE nodes accordingly.

[David Jam]

Thanls Rob