Peer to peer
Download as PPT, PDF1 like651 views
This document discusses peer-to-peer systems as a way to build distributed systems and applications that are self-managing. It introduces DKS, a peer-to-peer middleware that provides routing, directory, and messaging services. DKS allows for automatic management including adding/removing resources, handling crashes, and load balancing. Some potential applications built using DKS are discussed, including a peer-to-peer web server, backup system, and file system. Structured peer-to-peer systems aim to overcome inefficiencies of earlier unstructured systems through self-organization and fault tolerance.
Peer to peer
- 1. Peer-to-Peer System Raviteja Adusumalli ali@sics.se 1
- 2. Definition • What is a distributed system? ”You know you have a distributed system when the crash of a computer you have never heard of stops you from getting any work done.” Leslie Lamport We counteract this definition! ali@sics.se 2
- 3. Distributed Systems • Example of distributed systems: – File systems Frequently, an organization – Web servers stores all its files on a centralized distributed file server – Mail servers If it fails, no one can access their – Databases files The central mail server crashes, no one can read their Webb servers often become email! overloaded and fail ali@sics.se 3
- 4. Our effort • Build on an 30-year old idea • Arpanet, the precursor of Internet, was built for: – Military survivability • If some part stops working, the rest should continue to function • Internet has been quite successful so far… – No fail-stop yet • But the effort stopped here… ali@sics.se 4
- 5. Peer-to-Peer System • We want to build – Services – Servers – Applications • That are self-managed • Achieved by peer-to-peer techniques! ali@sics.se 5
- 6. Peer-to-Peer Middleware • After several years of research – Built a middleware: DKS • Provides: – Routing services – Directory services – Name-based messaging (multicast/publish/subscribe) ali@sics.se 6
- 7. Peer-to-Peer System • DKS is self-managing • Automatic managent: – Adding servers/resources – Removing servers/resources – Crash of servers/resources – Load balancing of data/nodes – Security ali@sics.se 7
- 8. Peer-to-Peer? • How is it different from: – KaZaa – Napster – Gnutella – Skype • These are so called unstructured p2p systems – Limited applicability (file sharing) – Inefficient (wastes bandwidth) • Our focus is on structured p2p systems – Chord/CAN/Pastry (USA) – DKS/P-Grid (Europe) ali@sics.se 8
- 9. What can we do with DKS? • Three concrete applications: – P2P Web server – P2P Backup – P2P File system ali@sics.se 9
- 10. P2P Web • Works like an Publish your web pages ordinary web server • Differences: – It is distributed – Automatic data Gets stored on the DKSStore a copy here replication 15 0 Store it here 1 – Load-balancing 14 15 1 2 of users 13 13 3 4 12 4 • Too much load 5 – Add another 11 5 server Store a new copy here 10 6 9 7 8 ali@sics.se 10
- 11. P2P Backup • Initialization – Install a client on your computer – Decide on amount of space to share – Choose files for backup • Regular backup – Data is encrypted – Always accessible ali@sics.se 11
- 12. Conclusion • Structured Peer-to-Peer system – Self-organizing • Automatic fault-tolerance • Automatic addition of nodes/resources • Automatic removal of nodes/resources • Automatic load-balancing • Many interesting applications – File systems – Backup – Web – M.m. • Cost-saving for companies – Save money on administration ali@sics.se 12