RADIUS Attribute for Persistent Device Identity in MAC-Randomized Environments

This document defines a new RADIUS attribute, Persistent-Device-Id, that enables Network Access Control (NAC) systems to maintain a stable device identity across Media Access Control (MAC) address changes. Modern operating systems randomize MAC addresses by default, disrupting RADIUS-based authentication, authorization, and accounting workflows that rely on the Calling-Station-Id attribute as a persistent device identifier. The Persistent-Device-Id attribute carries a Globally Unique Identifier (GUID) in RADIUS Access-Accept and Accounting-Request messages, providing a stable correlation key for device profiling, policy enforcement, and regulatory compliance. This document specifies the attribute format, assignment procedures, and usage guidelines for RADIUS clients and servers..