Cisco ISE's log retention is determined by the available disk space. Additionally, Cisco ISE supports IPv6 downloadable ACLs, making these two statements true.

Cisco ACS was integrated into Cisco ISE between the releases 2.0 and 2.3. This integration aimed to consolidate network security functions, incorporating ACS's functionality into ISE to offer a unified solution for network access control.

The use cases involving the highest level of implementation complexity in Cisco ISE are typically Software-defined access and Software-defined segmentation. These solutions require comprehensive planning, configurations, and often involve the integration of various technologies and policies within an organization's infrastructure.

For network devices like printers that do not support a supplicant, Cisco ISE handles authentication using MAC Authentication Bypass (MAB). MAB allows devices to be authenticated based on their MAC address rather than requiring 802.1X credentials or web-based logins, which are not feasible for such devices.

SD-Access and ACI Fabric share similarities in that they both use overlays to abstract the physical network, which simplifies network design and operation. They also both utilize Virtual Network IDs (VNIDs) to segment the network logically, allowing for isolation and multi-tenancy within the network. Finally, they both use group policies to manage and apply policies to groups of users or devices dynamically based on their attributes, enhancing security and manageability.