Scalable Overlay Network for PeertoPeer File Sharing Park

Scalable Overlay Network for Peerto-Peer File Sharing Park, Chanmo Networked Media Lab. Kwang-Ju Institute of Science and Technology (KJIST) KOREA cmpark@netmedia. kjist. ac. kr NETWORKed MEDIA LAB. DEPT. OF INFO. & COMM. , K-JIST /18

2 Contents q Overview o Peer-to-Peer Computing and Core Operations q Challenges in P 2 P File Sharing q Structured Overlay Network Support for P 2 P o Good and Bad q Existing Overlay Network Approaches q Initial Thoughts on Scalable Overlay Network q Conclusions NETWORKed MEDIA LAB. DEPT. OF INFO. & COMM. , K-JIST

3 Peer-to-Peer Computing of the Internet 2 • create and administer collaboration areas • access to the freshest data Collaboration • help businesses with large-scale computer processing needs using idle CPU cycle and disk space Edge Services • move data closer to the point at which it is actually consumed • act as a network caching mechanism Distributed computing and resources Intelligent agents • allow computing networks to dynamically work together using intelligent agents. NETWORKed MEDIA LAB. DEPT. OF INFO. & COMM. , K-JIST

4 Core Operations of P 2 P q Identity Operation o Refers to the name and credentials that identify an entity q Discovery Operation o Find out peers, services, or resources q Authentication Operation o Verify identity (person or machine) q Authorization Operation o Allow the verified entity permission for specific actions and/or access q Function Operation o Application specific actions NETWORKed MEDIA LAB. DEPT. OF INFO. & COMM. , K-JIST

5 Challenges in Scalable P 2 P File Sharing Flooding 1 2 4 3 Loop 2 2 3 Loop 4 Loop 3 3 Loop 4 q Flooding & Loop Path In Discovery Operation o results in many duplicated packet. o Increase the network traffics q Reducing large number of Discovery operations q A new topology such as structured overlay network should be considered NETWORKed MEDIA LAB. DEPT. OF INFO. & COMM. , K-JIST

Structured Overlay Network Support for P 2 P Good and Bad q Good o may reduce duplicated packets o may remove loop in message forwarding q Bad o should maintain redundant link in overlay network o Network partitioning NETWORKed MEDIA LAB. DEPT. OF INFO. & COMM. , K-JIST 6

7 Existing Overlay Network Approaches q AMRoute. q Scatter. Cast q End System Multicast q ALMI 1998 1999 1998. 8 AMRoute 2000 1999. 7 Scattercast 2001 2002 2001. 3 ALMI 1989 IP Multicast 2001. 7 End System Multicast NETWORKed MEDIA LAB. DEPT. OF INFO. & COMM. , K-JIST

8 AMRoute q Goal : Robust IP Multicast in mobile ad hoc network q Concept o Dynamic logical cores § Selected by core resolution algorithm § creates the mesh of a group § creates the user-multicast tree o User-multicast trees § create a bi-directional, share tree for data distribution with group members q Low scalability o Electing a Logical core NETWORKed MEDIA LAB. DEPT. OF INFO. & COMM. , K-JIST

9 Scatter. Cast q Goal: partitioning a heterogeneous set of session participants into disjoint data groups q Concept o SCX(Scatter. Cast pro. Xy)s § organize themselves into an overlay network of unicast connections (mesh) § build data distribution tree on the top of this overlay structure (tree) o using native IP Multicast The Internet SCX Unicast Connection Client SCX Multicast Group Client NETWORKed MEDIA LAB. DEPT. OF INFO. & COMM. , K-JIST

10 End System Multicast q Goal : overlay network efficiency q Concept o construct and maintain the mesh using distributed algorithm o Improving mesh quality by probing each others o construct tree based on distance vector, latency q Not scalable due to probing each nodes A B 1 R 1 25 R 2 2 NETWORKed MEDIA LAB. DEPT. OF INFO. & COMM. , K-JIST 1 1 C D A B 1 2 R 1 25 R 2 1 1 C D

11 ALMI (An Application Level Multicast Infrastructure) q Goal: support of multicast groups of small size q Concept o Node of a session are connected via a virtual multicast tree o Tree is formed as a minimum spanning tree by session controller • handle member registration Session Controller • maintain multicast tree RRT monitoring Parent Virtual Multicast Tree Child NETWORKed MEDIA LAB. DEPT. OF INFO. & COMM. , K-JIST

12 From Existing Approaches q Mesh-first Topology o AMRoute, Scatter. Cast, End System Multicast o is suitable for multimedia multicast § Data delivery path is constructed over mesh o If no RPs § Not scalable § Not suitable for P 2 P File Sharing q Existing Approaches finally construct only one data delivery path o Mesh topology is proper for failure recovery o In the case of P 2 P File Sharing, Network efficiency is not issue o For Scalability, Tree-first can be considered as possible as can NETWORKed MEDIA LAB. DEPT. OF INFO. & COMM. , K-JIST

Initial Thoughts on Scalable Overlay Network for Peer-to-Peer File Sharing q Challenges are reducing duplications and preventing loop q Node Grouping (Tree) o For reducing duplications o Flooding Messages are forced to sent to limited scoped nodes by grouping q Shift from Undetermined path to Determined path o For Loop Avoidance o Tree is constructed at first and maintained NETWORKed MEDIA LAB. DEPT. OF INFO. & COMM. , K-JIST 13

14 Initial Thoughts on Scalable Overlay Network for Peer-to-Peer File Sharing(2) q we construct tree for grouping nodes q tree o Is a scope of message flooding o Is a shared tree o Is a data path along which all message are sent q Single Data Path within a tree o Loop avoidance o Messages are sent to parent and child nodes except of received node. NETWORKed MEDIA LAB. DEPT. OF INFO. & COMM. , K-JIST

Initial Thoughts on Scalable Overlay Network for Peer-to-Peer File Sharing(3) q In case of Exchanging messages between trees o New connection type (such as a Inter. Tree. Connection) 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 o New tree is created when limited number of nodes is reached o These type messages are used when a node connected to other tree sends messages. NETWORKed MEDIA LAB. DEPT. OF INFO. & COMM. , K-JIST 15

16 Conclusion q We show Problems of Unstructured P 2 P o Flooding o Looping q Overview the existing Overlay Network q Our Initial Thoughts on Scalable Structured Overlay Network o Grouping into a tree for reducing duplicated messages o a shared data path for loop avoidance q Future Works o Consider proper group size and Recovery mechanism from failure o Implement our thoughts NETWORKed MEDIA LAB. DEPT. OF INFO. & COMM. , K-JIST

17 Thank s! NETWORKed MEDIA LAB. DEPT. OF INFO. & COMM. , K-JIST