Simple Service Discovery Protocol (SSDP) The SSDP protocol can discover Plug & Play devices, with uPnP (Universal Plug and Play). SSDP uses unicast and multicast adress (239.255.255.250). SSDP is HTTP like protocol and work with NOTIFY and M-SEARCH methods. SSDP can be used over IPv4 and IPv6. History IETF Draft Revision 3 IETF Draft Revision 2 Protocol dependencies SSDP uses UDP transport protoco