MAC address can exist in different VLANs. In bridged networks (Layer 2), we know that for a given VLAN the MAC address is used as a unique identifier, and this same General Considerations on Bridged Networks Is possible to have duplicate MAC addresses. This behavior is handled on the device side, but on rare occasion it Two different clients can have the same MAC address. If the client device clears the SSID by forgetting the network and then rejoins the same SSID, the client receives the sameĪ client device can have a maximum MAC address equal to the number of SSIDs in the network.ĭuplication of MAC addresses is possible. If the client rejoins the same SSID, the client receives the same MAC address that it had previously. The first time the client device joins the SSID, a new random

The following bullets provide clarifying information about MAC randomization's impact on client devices:įor an end user device, the MAC address per SSID is maintained. For example, in 32:8c:27:26:72:34 the 2 in the first octet reveals this is a random MAC address. The b1īit determines if the MAC address is globallly or locally administered, and the b0 bit determines if the MAC address is aĪccording to the IEEE, to qualify as a random MAC address, the first octet (in hexadecimal notation) must end with a 2, 6,Ī, or E. Components include octets, bits, the OUI, and the NIC. Structural Elements of a MAC Addressįigure 1 displays the structural elements of a MAC address.

For a MAC address to be considered a random MAC address, the MAC address must be locallyĪdministered (the b1 bit set as 1) and be a unicast address (the b0 bit set as 0).įigure 1. How the b0 bit identifies whether the MAC address is unicast or multicast and how the b1 bit identifies if the MAC address In Figure 1, you can see the 48-bit structure of a MAC address. The following diagram provides the foundational groundwork This generation of MAC randomization follows rules set by the IEEE.

Mac address vendor codes.