1 / 11

Fault-Tolerant Reliable Delivery of Messages in Distributed Publish/Subscribe Systems

This paper discusses the importance of reliable message delivery in distributed publish/subscribe systems, emphasizing fault tolerance, node/link failures, recovery mechanisms, and control over message delivery. It explores the use of repositories and bundles to enhance redundancy and improve communication latencies for better service quality.

ewhitney
Download Presentation

Fault-Tolerant Reliable Delivery of Messages in Distributed Publish/Subscribe Systems

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Fault-Tolerant Reliable Delivery of Messages in Distributed Publish/Subscribe Systems Shrideep Pallickara, Hasan Bulut & Geoffrey Fox Community Grids Lab Indiana University

  2. Reliable Delivery: Desiderata • Cope with node/link failures & unpredictable links • Links may duplicate, garble and lose messages • Many-to-Many reliable delivery across sessions • Support recovery from failures or disconnects • Support replays • Transport-independent • Support exactly-once delivery • Order, duplicate detection • Authorized reliable delivery

  3. Reliable Delivery • One Repository associated with a reliable topic • A Repository can manage multiple reliable topics

  4. Reliable Delivery P2R-Order R2S*-Persistent S2R-ACK R2P-NAK R2S-Rectify S2R-NAK P2R-Retransmit R2P-ACK R2S-Retransmit R2S-Sync Regular Exchange Error Detection Error Correction

  5. Reliable delivery: Advantages • Reliable delivery ONLY for authorized entities • Coexists with entities not interested in reliable delivery • Storage, is not communal, and should be provisioned by the topic owner. • Control Messages are issued over different topics. • Discovery constraints can be imposed e.g. Restrict replays • Different QoS can be associated with control topics. • Require signed acknowledgements (Non-repudiation) • Buffering & Jitter reduction services for replayed messages. • Streams replayed at say 24 fps instead of 500 fps • Easy to maintain audit trails • Track client loss rates, NAKs, disconnects & recoveries • Lends itself naturally for greater redundancy

  6. Repository Redundancy

  7. Repository Redundancy • Multiple repositories constitute a repository bundle • A given repository can be part of multiple bundles • Associate a repository-bundle for a given topic for greater redundancy • Sustain repository failures and downtimes • Fine tune redundancy associated with a bundle • Graceful addition & removal of constituent repositories • Clients leverage network proximity through bundle • By choosing a closer repository, communication latencies are reduced. Retransmissions and recoveries are faster. • Repository with which a client actively interacts with is its steering repository. • Set aside repositories for recovery and replays

  8. Repository Bundle: Publisher P2R-Order Repository P2R-Retransmit P2R-Order P2R-Order R2P-ACK R2P-ACK Publisher R2P-NAK R2P-NAK Repository P2R-Retransmit P2R-Retransmit P2R-Order Repository P2R-Retransmit

  9. Repository Bundle: Subscriber S2R-ACK Repository R2S*-Persistent S2R-ACK R2S*-Persistent S2R-ACK R2S-Rectify Subscriber S2R-NAK R2S-Rectify Repository S2R-NAK R2S-Retransmit R2S-Sync R2S-Retransmit R2S-Sync S2R-ACK Repository

  10. Ongoing Activities • Repository placement schemes • Reduction of publisher & subscriber overheads • Facilitate faster recoveries and error-corrections • Dedicated repositories for use in replays • Current Deployment • eSports System – To facilitate recording, annotation and replays of multimedia stream • Release Schedule • Will be released as part of NaradaBrokering 3.0 in June 2007

More Related