What is the purpose of a 'Quarantine VLAN' in Cisco ISE?

The purpose of a 'Quarantine VLAN' in Cisco ISE is to isolate non-compliant devices pending remediation. This concept plays a critical role in network security and compliance management. When a device connects to the network and fails to meet predefined security policies or compliance requirements, it is placed in the Quarantine VLAN. This VLAN acts as a containment area where the device can be monitored and analyzed without being able to access sensitive resources or the broader network.

By isolating these non-compliant devices, administrators can ensure that potential security threats are mitigated while allowing remediation steps to be taken, such as updates, patches, or configuration changes. Once the device complies with the necessary security policies, it can be moved out of the Quarantine VLAN and back into the normal operational VLAN, thus restoring its access to the network.

The other options do not accurately describe the functionality of a Quarantine VLAN within Cisco ISE. While restricting access, providing open access, or offering backup services are important aspects of network management, they do not capture the specific purpose of isolating and managing the compliance status of non-compliant devices.