15-1Contivity 221 VPN Switch User’s GuideChapter 15UPnPThis chapter introduces the Universal Plug and Play feature.15.1 Universal Plug and Play OverviewUniversal Plug and Play (UPnP) is a distributed, open networking standard that uses TCP/IP forsimple peer-to-peer network connectivity between devices. A UPnP device can dynamically join anetwork, obtain an IP address, convey its capabilities and learn about other devices on thenetwork. In turn, a device can leave a network smoothly and automatically when it is no longer inuse.15.1.1 How Do I Know If I'm Using UPnP?UPnP hardware is identified as an icon in the Network Connections folder (Windows XP). EachUPnP compatible device installed on your network will appear as a separate icon. Selecting theicon of a UPnP device will allow you to access the information and properties of that device.15.1.2 NAT TraversalUPnP NAT traversal automates the process of allowing an application to operate through NAT.UPnP network devices can automatically configure network addressing, announce their presencein the network to other UPnP devices and enable exchange of simple product and servicedescriptions. NAT traversal allows the following:¾ Dynamic port mapping¾ Learning public IP addresses¾ Assigning lease times to mappingsWindows Messenger is an example of an application that supports NAT traversal and UPnP.See the SUA/NAT chapter for further information about NAT.
