Randomized and Changing Media Access Control (MAC) Addresses: Context, Network Impacts, and Use Cases

To limit the privacy issues created by the association between a device, its traffic, its location, and its user in IEEE 802 networks, client vendors and client OS vendors have started implementing Media Access Control (MAC) address randomization. This technology is particularly important in Wi-Fi networks (defined in IEEE 802.11) due to the over-the-air medium and device mobility. When such randomization happens, some in-network states may break, which may affect network connectivity and user experience. At the same time, devices may continue using other stable identifiers, defeating the purpose of MAC address randomization. This document lists various network environments and a range of network services that may be affected by such randomization. This document then examines settings where the user experience may be affected by in-network state disruption. Last, this document examines some existing frameworks that maintain user privacy while preserving user quality of experience and network operation efficiency.