Chainsaw: Eliminating Trees From Overlay Multicast Vinay Pai Kapil - PowerPoint PPT Presentation

Chainsaw Problem Statement Chainsaw: Eliminating Trees From Overlay Multicast Vinay Pai Kapil Kumar Karthik Tamilmani Vinay Sambamurthy Alexander E. Mohr { vinay,kkumar,tamilman,vsmurthy,amohr } @cs.stonybrook.edu Department of Computer Science Stony Brook University International Workshop on Peer-to-Peer Systems 2005 Pai, Kumar, Tamilmani, Sambamurthy, Mohr Chainsaw: Eliminating Trees From Overlay Multicast

Chainsaw Problem Statement Problem Statement Problem Statement Design an overlay multicast system that: Delivers high bandwidth Supports a large number of simultaneous users Incurs little or no packet loss Minimizes duplication of data Is robust to large-scale node failure Pai, Kumar, Tamilmani, Sambamurthy, Mohr Chainsaw: Eliminating Trees From Overlay Multicast

Introduction Trees System Description Various Solutions Experimental Results Splitstream Future Work Bullet Conclusion Other Traditional Approach: Multicast Trees Shortcoming of Trees Rigid structure Pai, Kumar, Tamilmani, Sambamurthy, Mohr Chainsaw: Eliminating Trees From Overlay Multicast

Introduction Trees System Description Various Solutions Experimental Results Splitstream Future Work Bullet Conclusion Other Traditional Approach: Multicast Trees Shortcoming of Trees Rigid structure Unfair sharing of load Leaf nodes don’t upload! Pai, Kumar, Tamilmani, Sambamurthy, Mohr Chainsaw: Eliminating Trees From Overlay Multicast

Introduction Trees System Description Various Solutions Experimental Results Splitstream Future Work Bullet Conclusion Other Traditional Approach: Multicast Trees Shortcoming of Trees Rigid structure Unfair sharing of load Error propagation Pai, Kumar, Tamilmani, Sambamurthy, Mohr Chainsaw: Eliminating Trees From Overlay Multicast

Introduction Trees System Description Various Solutions Experimental Results Splitstream Future Work Bullet Conclusion Other Solutions Splitstream Bullet Chainsaw More Trees! Tree overlaid with Get rid of the trees mesh Pai, Kumar, Tamilmani, Sambamurthy, Mohr Chainsaw: Eliminating Trees From Overlay Multicast

Introduction Trees System Description Various Solutions Experimental Results Splitstream Future Work Bullet Conclusion Other Splitstream Splitstream: Multiple Trees A node is interior in at most one tree Improves fairness Pai, Kumar, Tamilmani, Sambamurthy, Mohr Chainsaw: Eliminating Trees From Overlay Multicast

Introduction Trees System Description Various Solutions Experimental Results Splitstream Future Work Bullet Conclusion Other Splitstream Splitstream: Multiple Trees A node is interior in at most one tree Improves fairness Limitation Only partially mitigates effect of packet loss/node failure Pai, Kumar, Tamilmani, Sambamurthy, Mohr Chainsaw: Eliminating Trees From Overlay Multicast

Introduction Trees System Description Various Solutions Experimental Results Splitstream Future Work Bullet Conclusion Other Bullet Bullet: Tree+Mesh Most data sent over the tree Missing packets recovered using mesh Improves performance vs. pure tree Pai, Kumar, Tamilmani, Sambamurthy, Mohr Chainsaw: Eliminating Trees From Overlay Multicast

Introduction Trees System Description Various Solutions Experimental Results Splitstream Future Work Bullet Conclusion Other Bullet Bullet: Tree+Mesh Most data sent over the tree Missing packets recovered using mesh Improves performance vs. pure tree Limitation Does not fully address the issue of fairness—leaf nodes still likely to upload very little Pai, Kumar, Tamilmani, Sambamurthy, Mohr Chainsaw: Eliminating Trees From Overlay Multicast

Introduction Trees System Description Various Solutions Experimental Results Splitstream Future Work Bullet Conclusion Other Other BitTorrent: Mesh-based file sharing File sharing not overlay multicast! But is similar to our approach Others Gossip-based protocols End System Multicast TMesh Pai, Kumar, Tamilmani, Sambamurthy, Mohr Chainsaw: Eliminating Trees From Overlay Multicast

Introduction System Architecture System Description State Maintenance Experimental Results Protocol Future Work Request Strategy Conclusion Network Structure Random Graph Structure C Nodes are connected randomly B with some average degree D Seed node S injects new data S into the network A F E Pai, Kumar, Tamilmani, Sambamurthy, Mohr Chainsaw: Eliminating Trees From Overlay Multicast

Introduction System Architecture System Description State Maintenance Experimental Results Protocol Future Work Request Strategy Conclusion Network Structure Random Graph Structure N Nodes are connected randomly C with some average degree B Seed node S injects new data D S into the network A New node N joins the system F E Pai, Kumar, Tamilmani, Sambamurthy, Mohr Chainsaw: Eliminating Trees From Overlay Multicast

Introduction System Architecture System Description State Maintenance Experimental Results Protocol Future Work Request Strategy Conclusion Network Structure Random Graph Structure N Nodes are connected randomly C with some average degree B Seed node S injects new data into the network D S A New node N joins the system F N picks a random set of nodes E to connect to Pai, Kumar, Tamilmani, Sambamurthy, Mohr Chainsaw: Eliminating Trees From Overlay Multicast

Introduction System Architecture System Description State Maintenance Experimental Results Protocol Future Work Request Strategy Conclusion Packet Stream Packet Stream Stream is broken up into packets 5 6 7 8 9 10 11 Packets are assigned ... ... sequence number Assume (for this talk) that packets are all equal in size Pai, Kumar, Tamilmani, Sambamurthy, Mohr Chainsaw: Eliminating Trees From Overlay Multicast

Introduction System Architecture System Description State Maintenance Experimental Results Protocol Future Work Request Strategy Conclusion Packet Stream Windows Attempt to download packets within Window of Interest 5 6 7 8 9 10 11 ... ... Packets that don’t arrive Window of interest before they “fall off the Window of availability edge” are considered lost Windows advance Offer neighbors packets over time within Window of Availability Pai, Kumar, Tamilmani, Sambamurthy, Mohr Chainsaw: Eliminating Trees From Overlay Multicast

Introduction System Architecture System Description State Maintenance Experimental Results Protocol Future Work Request Strategy Conclusion State Maintained State Only local state is maintained! List of neighbors Packets available at each neighbor List of potential neighbors (to replace dead ones) Pai, Kumar, Tamilmani, Sambamurthy, Mohr Chainsaw: Eliminating Trees From Overlay Multicast

Introduction System Architecture System Description State Maintenance Experimental Results Protocol Future Work Request Strategy Conclusion Protocol Request-Response Protocol Node A gets a new packet and informs node B A NOTIFY D C B Pai, Kumar, Tamilmani, Sambamurthy, Mohr Chainsaw: Eliminating Trees From Overlay Multicast

Introduction System Architecture System Description State Maintenance Experimental Results Protocol Future Work Request Strategy Conclusion Protocol Request-Response Protocol Node A gets a new packet and informs node B Node B makes a list of packet it is A interested in REQUEST D Node B picks from the list to C request B Pai, Kumar, Tamilmani, Sambamurthy, Mohr Chainsaw: Eliminating Trees From Overlay Multicast

Introduction System Architecture System Description State Maintenance Experimental Results Protocol Future Work Request Strategy Conclusion Protocol Request-Response Protocol Node A gets a new packet and informs node B Node B makes a list of packet it is A interested in PACKET Node B picks from the list to D C request B Node A responds by sending the packet Pai, Kumar, Tamilmani, Sambamurthy, Mohr Chainsaw: Eliminating Trees From Overlay Multicast

Introduction System Architecture System Description State Maintenance Experimental Results Protocol Future Work Request Strategy Conclusion Protocol Request-Response Protocol Node A gets a new packet and informs node B Node B makes a list of packet it is A interested in D Node B picks from the list to C request B NOTIFY NOTIFY Node A responds by sending the packet Node B informs its other neighbors C and D Pai, Kumar, Tamilmani, Sambamurthy, Mohr Chainsaw: Eliminating Trees From Overlay Multicast

Introduction System Architecture System Description State Maintenance Experimental Results Protocol Future Work Request Strategy Conclusion Request Strategy Which packet to request? Question: Given the list of packets a neighbor has that you’re interested in, which do you request? Pai, Kumar, Tamilmani, Sambamurthy, Mohr Chainsaw: Eliminating Trees From Overlay Multicast

Introduction System Architecture System Description State Maintenance Experimental Results Protocol Future Work Request Strategy Conclusion Request Strategy Which packet to request? Question: Given the list of packets a neighbor has that you’re interested in, which do you request? Potential Choices: Random Some packets may not get picked from the seed for a long time Pai, Kumar, Tamilmani, Sambamurthy, Mohr Chainsaw: Eliminating Trees From Overlay Multicast