seamless roaming and auto-configuration. Windows XP's Wireless Zero Configuration service supports automatic wireless network configuration with re-authentication when necessary thus providing seamless roaming capability and setting the preferred order of connections. In the absence of a wireless access point, Windows XP can set up an ad hoc wireless network. There is native support for WPA and WPA2 authentication in infrastructure networks with the latest service packs and/or updates applied. Windows XP includes a Wireless Network Setup Wizard which supports the Windows Connect Now: USB Flash Drive (WCN-UFD) method to ease setting up the wireless network for inexperienced users. Windows XP can connect to hotspots created using Wireless Provisioning Services. Internet Connection Sharing In Windows XP, Internet Connection Sharing is integrated with UPnP, allowing remote discovery and control of the ICS host. It has a Quality of Service Packet Scheduler component. When an ICS client is on a relatively fast network and the ICS host is connected to the internet through a slow link, Windows may incorrectly calculate the optimal TCP receive window size based on the speed of the link between the client and the ICS host, potentially affecting traffic from the sender adversely. The ICS QoS component sets the TCP receive window size to the same as it would be if the receiver were directly connected to the slow link. Internet Connection Sharing also includes a local DNS resolver in Windows XP to provide name resolution for all network clients on the home network, including non-Windows-based network devices. ICS is also location-aware, that is, when connected to a domain, the computer can have a Group Policy to restrict the use of ICS but when at home, ICS can be enabled. Quality of Service for modems and remote access When multiple applications are accessing the internet simultaneously without any QoS and the connection isn't fast enough, the TCP receive window size is set to the full window of data in transit that the first application uses in the connection until a steady state is reached. Subsequent connections made by other applications will take much longer to reach an optimal window size and the transmission rate of the second or third application will always be lower than that of the application that established the connection first. On such slow links, the QoS component in Windows XP automatically enables a Deficit round robin scheduling scheme, which creates a separate queue for each