1. N ETWORKed M EDIA L AB. D EPT. OF I NFO. & C OMM., K-JIST Scalable Overlay Network for Peer-to-Peer File Sharing Park, Chanmo Networked Media Lab. Kwang-Ju Institute of Science and Technology (KJIST) KOREA cmpark@netmedia.kjist.ac.kr

2. N ETWORKed M EDIA L AB. D EPT. OF I NFO. & C OMM., K-JIST 2/18Contents  Overview oPeer-to-Peer Computing and Core Operations  Challenges in P2P File Sharing  Structured Overlay Network Support for P2P oGood and Bad  Existing Overlay Network Approaches  Initial Thoughts on Scalable Overlay Network  Conclusions

3. N ETWORKed M EDIA L AB. D EPT. OF I NFO. & C OMM., K-JIST 3/18 Peer-to-Peer Computing of the Internet2 Collaboration Distributed computing and resources Intelligent agents Edge Services create and administer collaboration areas access to the freshest data move data closer to the point at which it is actually consumed act as a network caching mechanism help businesses with large-scale computer processing needs using idle CPU cycle and disk space allow computing networks to dynamically work together using intelligent agents.

4. N ETWORKed M EDIA L AB. D EPT. OF I NFO. & C OMM., K-JIST 4/18 Core Operations of P2P  Identity Operation oRefers to the name and credentials that identify an entity  Discovery Operation oFind out peers, services, or resources  Authentication Operation oVerify identity (person or machine)  Authorization Operation oAllow the verified entity permission for specific actions and/or access  Function Operation oApplication specific actions

5. N ETWORKed M EDIA L AB. D EPT. OF I NFO. & C OMM., K-JIST 5/18 Challenges in Scalable P2P File Sharing  Flooding & Loop Path In Discovery Operation oresults in many duplicated packet. oIncrease the network traffics  Reducing large number of Discovery operations  A new topology such as structured overlay network should be considered 1 2 2 2 3 3 3 3 4 4 Loop 4 Flooding

6. N ETWORKed M EDIA L AB. D EPT. OF I NFO. & C OMM., K-JIST 6/18 Structured Overlay Network Support for P2P Good and Bad  Good omay reduce duplicated packets omay remove loop in message forwarding  Bad oshould maintain redundant link in overlay network oNetwork partitioning

7. N ETWORKed M EDIA L AB. D EPT. OF I NFO. & C OMM., K-JIST 7/18 Existing Overlay Network Approaches  AMRoute.  ScatterCast  End System Multicast  ALMI 19982002200120001999 2001.3 ALMI 1998.8 AMRoute 1999.7 Scattercast 2001.7 End System Multicast 1989 IP Multicast

8. N ETWORKed M EDIA L AB. D EPT. OF I NFO. & C OMM., K-JIST 8/18AMRoute  Goal : Robust IP Multicast in mobile ad hoc network  Concept oDynamic logical cores  Selected by core resolution algorithm  creates the mesh of a group  creates the user-multicast tree oUser-multicast trees  create a bi-directional, share tree for data distribution with group members  Low scalability oElecting a Logical core

9. N ETWORKed M EDIA L AB. D EPT. OF I NFO. & C OMM., K-JIST 9/18ScatterCast  Goal: partitioning a heterogeneous set of session participants into disjoint data groups  Concept oSCX(ScatterCast proXy)s  organize themselves into an overlay network of unicast connections (mesh)  build data distribution tree on the top of this overlay structure (tree) ousing native IP Multicast Client SCX Client Multicast Group Unicast Connection The Internet

10. N ETWORKed M EDIA L AB. D EPT. OF I NFO. & C OMM., K-JIST 10/18 End System Multicast  Goal : overlay network efficiency  Concept oconstruct and maintain the mesh using distributed algorithm oImproving mesh quality by probing each others oconstruct tree based on distance vector, latency  Not scalable due to probing each nodes R1R2 A B C D 1 2 25 1 1 R1R2 A B C D 1 2 25 1 1

11. N ETWORKed M EDIA L AB. D EPT. OF I NFO. & C OMM., K-JIST 11/18 ALMI (An Application Level Multicast Infrastructure)  Goal: support of multicast groups of small size  Concept oNode of a session are connected via a virtual multicast tree oTree is formed as a minimum spanning tree by session controller Session Controller handle member registration maintain multicast tree Virtual Multicast Tree RRT monitoring Parent Child

12. N ETWORKed M EDIA L AB. D EPT. OF I NFO. & C OMM., K-JIST 12/18 From Existing Approaches  Mesh-first Topology oAMRoute, ScatterCast, End System Multicast ois suitable for multimedia multicast  Data delivery path is constructed over mesh oIf no RPs  Not scalable  Not suitable for P2P File Sharing  Existing Approaches finally construct only one data delivery path oMesh topology is proper for failure recovery oIn the case of P2P File Sharing, Network efficiency is not issue oFor Scalability, Tree-first can be considered as possible as can

13. N ETWORKed M EDIA L AB. D EPT. OF I NFO. & C OMM., K-JIST 13/18 Initial Thoughts on Scalable Overlay Network for Peer-to-Peer File Sharing  Challenges are reducing duplications and preventing loop  Node Grouping (Tree) oFor reducing duplications oFlooding Messages are forced to sent to limited scoped nodes by grouping  Shift from Undetermined path to Determined path oFor Loop Avoidance oTree is constructed at first and maintained

14. N ETWORKed M EDIA L AB. D EPT. OF I NFO. & C OMM., K-JIST 14/18 Initial Thoughts on Scalable Overlay Network for Peer-to-Peer File Sharing(2)  we construct tree for grouping nodes  tree oIs a scope of message flooding oIs a shared tree oIs a data path along which all message are sent  Single Data Path within a tree oLoop avoidance oMessages are sent to parent and child nodes except of received node.

15. N ETWORKed M EDIA L AB. D EPT. OF I NFO. & C OMM., K-JIST 15/18 Initial Thoughts on Scalable Overlay Network for Peer-to-Peer File Sharing(3)  In case of Exchanging messages between trees oNew connection type (such as a InterTreeConnection) is introduced to distinguish link within a tree from link between trees o These types of connections are determined when a new tree is created oNew tree is created when limited number of nodes is reached oThese type messages are used when a node connected to other tree sends messages.

16. N ETWORKed M EDIA L AB. D EPT. OF I NFO. & C OMM., K-JIST 16/18Conclusion  We show Problems of Unstructured P2P oFlooding oLooping  Overview the existing Overlay Network  Our Initial Thoughts on Scalable Structured Overlay Network oGrouping into a tree for reducing duplicated messages oa shared data path for loop avoidance  Future Works oConsider proper group size and Recovery mechanism from failure oImplement our thoughts

17. N ETWORKed M EDIA L AB. D EPT. OF I NFO. & C OMM., K-JIST 17/18 Thanks!