Prior to SP3, the 802.1x service for XP is the Wireless Zero Configuration Service. This service handles the 802.1x needs for both wired and wireless connections. This has been problematic since not everyone uses wired 802.1x. Also, because the wired 802.1x engine listens passively for EAP Identity traffic, we are not fully compliant with the IEEE spec, which state the client should initiate authentication by sending an EAPOL-Start frame.
With SP3, we have separated the wireless service from the wired service and created a new Dot3Svc (Wired AutoConfig). This service is set as a manual start as opposed to being automatic. The default behavior of the Dot3Svc is now compliant with the IEEE specification.