1. Directory Server System Software Laboratory

3. Source Stream Service Description File (XML) Stream Description File (XML) Stream (Simple Service) Description File (XML) Service Authoring Tool Query/Get Service Description File (XML) Publish New services Publish UI Query/Get Publish New streams

4. Service XML file NTHU student canteen live CAM test This service contains a live video stream of a video camera set up in the student canteen of National Tsing Hua University John Camera One

5. Current Progress An centralized XML database (eXist) for storing/indexing service files. JAVA Query and Publish interface using XQuery to perform publish and query requests

6. Decentralized XML DB design To perform the index/query of XML files in decentralized manner. Each peer in the system stores some portion of the service XML files collection. Structured P2P overlay Routing XQuery in the system

7. Treeguides as tries in a peer service titledescriptionauthor catagory app name streamlayout dimension Ma r teo y tin k [1,2,3,4] [1,2][2,3,4][1,2,3][3,4] [1,2,3,4] [1] [2,3][4] [2] [1] [2,3] [1,3] [2]

8. Basic Flow Peer Join  As most structured p2p system  Generate Peer ID -> participate in the system -> shift some data from other peers Publish  Generate service XML file (Service authoring tool)->hash the document and send to the peer responsible for it->route update message to other nodes

9. Basic Flow (cont’d) Query  Route the query message generated from one peer to the peer containing the desired data. (by looking up the tries of treeguides in the peers along the path)

10. To-Dos Many detail aspects of the system, like replication, error recovery,…,etc.