Settings for wireless networks can also be configured using Group policy. Windows Vista enhances security when joining a domain over a wireless network. It can use "Single Sign On" to use the same credentials to join a wireless network as well as the domain housed within the network. In this case, the same RADIUS server is used for both PEAP authentication for joining the network and MS-CHAP v2 authentication to log into the domain. A bootstrap wireless profile can also be created on the wireless client, which first authenticates the computer to the wireless network and joins the network. At this stage, the machine still does not have any access to the domain resources. The machine will run a script, stored either on the system or on USB thumb drive, which authenticates it to the domain. Authentication can be done either by using username and password combination or security certificates from a Public key infrastructure (PKI) vendor such as VeriSign. Windows Vista features "Windows Connect Now" which supports setting up a wireless network using several methods supported in the Wi-Fi Protected Setup standard. It implements a native code API, Web Services for Devices (WSDAPI) to support Devices Profile for Web Services (DPWS) and also a managed code implementation in WCF. DPWS enables simpler device discoverability like UPnP and describes available services to those clients. "Function Discovery" is a new technology that serves as an abstraction layer between applications and devices, allowing applications to discover devices by referencing the device's function, rather than by its bus type or the nature of its connection. "Plug and Play Extensions (PnP-X)" allow network-connected devices to appear as local devices inside Windows connected physically. UPnP support has also been enhanced to include integration with "PnP-X" and "Function Discovery". Windows Vista's networking stack also uses several performance optimizations, which allow higher throughput by allowing faster recovery from packet losses, when using a high packet loss environment such as wireless networks. Windows Vista uses the "NewReno" () algorithm which allows a sender to send more data while retrying in case it receives a partial acknowledgement, which is acknowledgement from the receiver for only a part of data that has been received. It also uses Selective Acknowledgements (SACK) to reduce the amount of data to be retransmitted in case a portion of the data sent was not received correctly, and Forward RTO-Recovery (F-RTO) to prevent unnecessary retransmission of TCP segments when round trip time increases.