Service discovery protocols are network protocols which allow automatic detection of devices and services offered by these devices on a computer network.

Service discovery is an essential ingredient of the Semantic Web

Semantic Web

The Semantic Web is a collaborative movement led by the World Wide Web Consortium that promotes common formats for data on the World Wide Web. By encouraging the inclusion of semantic content in web pages, the Semantic Web aims at converting the current web of unstructured documents into a "web of...

, since the future Web must allow software agents to make use of one another's services without the need for continuous user intervention.

There are many service discovery protocols, including:

• DNS Service Discovery (DNS-SD), part of Apple's Bonjour
  Bonjour (software)
  In computing, Bonjour is Apple Inc.'s trade name for its implementation of Zeroconf, a group of technologies that includes service discovery, address assignment, and name resolution...
  
   technology
• Service Location Protocol
  Service Location Protocol
  The Service Location Protocol is a service discovery protocol that allows computers and other devices to find services in a local area network without prior configuration. SLP has been designed to scale from small, unmanaged networks to large enterprise networks...
  
   (SLP)
• Simple Service Discovery Protocol
  Simple Service Discovery Protocol
  The Simple Service Discovery Protocol is a network protocol based on the Internet Protocol Suite for advertisement and discovery of network services and presence information...
  
   (SSDP) as used in Universal Plug and Play
  Universal Plug and Play
  Universal Plug and Play is a set of networking protocols for primarily residential networks without enterprise class devices that permits networked devices, such as personal computers, printers, Internet gateways, Wi-Fi access points and mobile devices to seamlessly discover each other's presence...
  
   (UPnP)
• Universal Description Discovery and Integration
  Universal Description Discovery and Integration
  Universal Description, Discovery and Integration is a platform-independent, Extensible Markup Language -based registry for businesses worldwide to list themselves on the Internet and a mechanism to register and locate web service applications...
  
   (UDDI) for web service
  Web service
  A Web service is a method of communication between two electronic devices over the web.The W3C defines a "Web service" as "a software system designed to support interoperable machine-to-machine interaction over a network". It has an interface described in a machine-processable format...
  
  s
• Jini
  Jini
  Jini , also called Apache River, is a network architecture for the construction of distributed systems in the form of modular co-operating services.Originally developed by Sun, Jini was released under an open source license...
  
   for Java
  Java (programming language)
  Java is a programming language originally developed by James Gosling at Sun Microsystems and released in 1995 as a core component of Sun Microsystems' Java platform. The language derives much of its syntax from C and C++ but has a simpler object model and fewer low-level facilities...
  
   objects.
• Bluetooth
  Bluetooth
  Bluetooth is a proprietary open wireless technology standard for exchanging data over short distances from fixed and mobile devices, creating personal area networks with high levels of security...
  
   Service Discovery Protocol (SDP)
• Salutation
  Salutation (computing)
  Salutation in computing is a technique for service discovery and service management.-See also:* Service Location Protocol* Zero Configuration Networking * OSGi Alliance* Jini* Universal Plug and Play * Bluetooth-References:*Golden G...
  
  
• XMPP
  Extensible Messaging and Presence Protocol
  Extensible Messaging and Presence Protocol is an open-standard communications protocol for message-oriented middleware based on XML . The protocol was originally named Jabber, and was developed by the Jabber open-source community in 1999 for near-real-time, extensible instant messaging , presence...
  
   Service Discovery (XEP-0030)
• WS-Discovery (Web Services Dynamic Discovery)
• Internet Storage Name Service (iSNS)
• Web Proxy Autodiscovery Protocol
  Web Proxy Autodiscovery Protocol
  The Web Proxy Auto-Discovery Protocol is a method used by clients to locate a URL of a configuration file using DHCP and/or DNS discovery methods. Once detection and download of the configuration file is complete it can be executed to determine the proxy for a specified URL...
  
   (WPAD)
• Dynamic Host Configuration Protocol
  Dynamic Host Configuration Protocol
  The Dynamic Host Configuration Protocol is a network configuration protocol for hosts on Internet Protocol networks. Computers that are connected to IP networks must be configured before they can communicate with other hosts. The most essential information needed is an IP address, and a default...
  
   (DHCP)
• XRDS (eXtensible Resource Descriptor Sequence)
  XRDS
  XRDS is an XML format for discovery of metadata about a resource – in particular discovery of services associated with the resource, a process known as service discovery...
  
   used by XRI, OpenID
  OpenID
  OpenID is an open standard that describes how users can be authenticated in a decentralized manner, eliminating the need for services to provide their own ad hoc systems and allowing users to consolidate their digital identities...
  
  , OAuth
  OAuth
  OAuth is an open standard for authorization. It allows users to share their private resources stored on one site with another site without having to hand out their credentials, typically username and password.OAuth allows users to hand out tokens instead of credentials to their data hosted by a...
  
  , etc.

Service Discovery Protocol (SDP) should not be confused with Session Description Protocol

Session Description Protocol

The Session Description Protocol is a format for describing streaming media initialization parameters. The IETF published the original specification as an IETF Proposed Standard in April 1998, and subsequently published a revised specification as an IETF Proposed Standard as RFC 4566 in July...

(SDP), which is intended for describing multimedia sessions for the purposes of session announcement, session invitation, and other forms of multimedia session initiation.

External Links

• Service Discovery S-Cube Knowledge Model