Dependability within Dependability within Peer- -to to- -Peer - - PowerPoint PPT Presentation
Dependability within Dependability within Peer- -to to- -Peer Systems Peer Systems Peer James Walkerdine Walkerdine James Lee Melville Lee Melville Ian Sommerville Sommerville Ian Lancaster University, UK Lancaster University, UK
Lancaster University, UK Lancaster University, UK
– – Identify dependability issues within P2P applications Identify dependability issues within P2P applications – – Develop a methodology for dependable P2P application Develop a methodology for dependable P2P application development (with tool support) development (with tool support) – – Develop reference architectures for P2P applications Develop reference architectures for P2P applications
– – Network evolution Network evolution – – Legacy versions Legacy versions – – Fault tolerance Fault tolerance – – Connection bandwidth Connection bandwidth – – Intermittent peer connectivity Intermittent peer connectivity – – Peer discovery Peer discovery – – Peer addressing Peer addressing – – Load balancing Load balancing
– – Scalability Scalability – – Survivability Survivability – – Maintainability Maintainability – – Manageability Manageability – – Repairability Repairability – – Trust Trust
– – Responsibility, accountability and reputation Responsibility, accountability and reputation – – Data integrity Data integrity – – Adaptability Adaptability
Decentralised (a) Direct Communication (b) (c) (f) (g) Semi-centralised
Structured indirect communication Un- structured indirect communication
(d) Single centralised
index server
(e) Computational model
(no autonomy) Computational model (with autonomy) Multiple server node model
– – No single point of failure No single point of failure
Help tackle system survivability survivability and and fault tolerance fault tolerance
– – Difficult to control/monitor the system Difficult to control/monitor the system
Can hinder system management management and and maintainability maintainability
– – Freeform network structure Freeform network structure
System can easily adapt adapt and and evolve evolve
Can hinder system scalability scalability and and responsiveness responsiveness
Un
communication
– – Better suited for controlling and monitoring a system Better suited for controlling and monitoring a system
Help where safety safety, , maintainability maintainability or
manageability are are important important
Server peer can help support trust trust and and accountability accountability techniques techniques
Server peer can aid in system responsiveness responsiveness particularly particularly with with peer discovery peer discovery
– – Single point of failure Single point of failure
Can hinder a systems fault tolerance fault tolerance and and survivability survivability
Single centralised index server