1. Web Services Basics stateless services: –simple request response state-dependent service: –each service is maintaining a state Services Service Broker Service Requestor Service Provider Deploy Bind Find SOAP WSDL UDDI

2. Service Description message spec (WSDL) process annotation (choreographies) semantic annotation (RDF,OWL-S,…) Service Level Agreements (SLAs) extension to Quality of Service (QoS) issues Who is providing annotations and why? complexity of descriptions automated generation vs. re-usage vs. manual editing

3. Querying different meta data require different query mechanisms combined query support required performance –complexity of the approach affects response time/usability –aim: least complex formalization –the easier the approach the less the computational complexity –“indexing” approaches needed