Simple Service Discovery Protocol
| application | SSDP | ||||
| transport | UDP | ||||
| Internet | IP ( IPv4 , IPv6 ) | ||||
| Network access | Ethernet |
Token bus |
Token ring |
FDDI | ... |
The Simple Service Discovery Protocol ( SSDP ) is a network protocol that is used to search for UPnP devices in the network. SSDP usually uses port 1900 UDP . The company Microsoft has it along with their operating system Microsoft Windows ME introduced.
On the UPnP side you can read:
“As soon as a UPnP device has an IP address, it must report its existence in the network to the control points. This is done via UDP using the multicast address 239.255.255.250:1900 on the basis of the SSDP protocol. Control points can also search for UPnP devices on the network. In both cases, the "discovery message" only contains the most important information about the device and its services, such as the device name, device type and a URL for a precise description of the device. "
Package structure
An SSDP packet is an HTTP request with the "NOTIFY" (or "M-SEARCH") method, which is sent via UDP. The HTTP body is empty, the HTTP header must still be terminated with a blank line. UPnP specific attributes are set in the HTTP header:
- NTS (Notification Sub Type) has the value "ssdp: alive" to log in or "ssdp: byebye" to log off a device.
- NT (Notification Type) determines the properties of the device.
- USN (Unique Service Name) contains a unique ID of the device.
- LOCATION contains a URL for the description (Description)
Example:
NOTIFY * HTTP/1.1 SERVER: Linux/2.6.15.2 UPnP/1.0 Mediaserver/1.0 CACHE-CONTROL: max-age=1800 LOCATION: http://192.168.0.10:8080/description.xml NTS: ssdp:alive NT: urn:schemas-upnp-org:service:ConnectionManager:1 USN: uuid:550e8400-e29b-11d4-a716-446655440000::urn:schemas-upnp-org:service:ConnectionManager:1 HOST: 239.255.255.250:1900
Multicast addresses
The multicast addresses available for the SSDP protocol are:
| IP version | address | Area |
|---|---|---|
| IP V4 | 239.255.255.250 | site-local |
| IP V6 | FF02 :: C | link-local |
| IP V6 | FF05 :: C | site-local |
| IP V6 | FF08 :: C | organization-local |
| IP V6 | FF0E :: C | global |
See also
Web links
- IETF draft revision 3
- http://www.upnp.org/specs/arch/UPnP-arch-DeviceArchitecture-v1.1.pdf
- Simple Service Discovery Protocol (SSDP) in MSDN