We used three modes of Deployment of ISE

We used three modes of Deployment of ISE 

1- Monitor Mode

2-  Low-Impact Mode

3-  Closed Mode 

Monitor Mode -->> 

Basically, we used monitor mode to understand the traffic flow of the organization.

we consider below point --

• Will not impact a production network.
• Authentication will be attempted, but denied authentication attempts will be allowed on the network anyway.
• Audit logs can be used to understand what is on the network and what would have failed if policy was being enforced.
• Potential problems can be identified and corrected before transitioning to Low-Impact Mode.

Low-Impact Mode -->>>

Deploys an ACL to every switchport.

• The ACL typically allows basic “Test” services such as DHCP, DNS, AD, 

etc…

• The authentication/authorization takes place and the ACL is replaced, 

in real-time, with a defined ACL based on the authorization result.

• E.g. If user is in Sales AD Group, then grant Sales-ACL.

• This can be and often is the finished product

Closed Mode --->>>

• Only EAP traffic is allowed before authentication.

• E.g. No DHCP, DNS, Etc…

• Most secure option as no traffic is allowed prior to authentication