18.104.22.168 Discovering a Cloud
To discover nodes on the same link, a node uses the Simple Service Discovery Protocol (SSDP) (as specified in [UPNPARCH1], section 1) to discover other nearby nodes that are already in the cloud. If there are no other nodes in the cloud of interest that exist on the node's link, then the discovering node uses a seed server to find some. To discover some nodes in the Global PNRP cloud, the discovering node contacts one of two well-known seed servers whose addresses are resolved via a Domain Name System (DNS) lookup. To discover some nodes in a Site cloud, the discovering node obtains the name or address of a seed server via some other method (for example, manual configuration, or supplied by an application).