1 / 13

Distributed Computing:

Fault-Tolerant. Distributed Computing:. Atomic Broadcast. Outline. Why distributed computing? Atomic Broadcast The atom system Relevance for e-textiles What’s next? Q&A. Why Distributed Computing?. Spread and balance the computational weight of applications Solve bigger problems

Download Presentation

Distributed Computing:

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 Distributed Computing: Atomic Broadcast

  2. Outline • Why distributed computing? • Atomic Broadcast • The atom system • Relevance for e-textiles • What’s next? • Q&A

  3. Why Distributed Computing? • Spread and balance the computational weight of applications • Solve bigger problems • Deal with problems locally instead of centralizing all the data

  4. Example • Space filtering vs. raw consensus • Acoustic Beam Forming: master collects information from slaves and decides according to the relevance of data • Consensus: no master, all processes decide upon one common value

  5. Atomic Broadcast: Definition (1) • Atomic Broadcast = the same set of messages is delivered by all the processes in the same order • Consensus = all processes decide upon one common value among those proposed

  6. Atomic Broadcast: Definition (2) • Validity: If a correct process broadcasts a message m it will eventually receive it • Uniform agreement: If a process delivers a message m then every correct process will deliver it • Uniform integrity: Every message m is delivered at most once and only if it was reliably broadcasted by sender(m) • Total order: If 2 correct processes p and q deliver 2 messages m and m’ then p delivers m before m’ iff q delivers m before m’

  7. Atomic Broadcast: Bad News • Impossibly to achieve in a totally asynchronous system [Fisher, Lynch, Patterson 85]

  8. Atomic Broadcast: Good News • Can be done using unreliable failure detectors • Based on a Consensus algorithm described in [Chandra, Toueg 96]

  9. Atom • Open source Atomic Broadcast system

  10. Producer Atom A-broadcast AB task1 FD suspect transmission do_Consensus R-broadcast start AB task 3 One_run start do_decide cancel AB task 2 RB A-deliver Consumer FD trust

  11. Relevance to E-textiles • Synchronization of data • Coordination of decisions and actions • Light-weight process • Buffer sizes can be predicted

  12. What’s Next? • Scalability is a problem for classic fault-tolerant distributed algorithms • Bimodal Multicast[Ken Birman, Mark Hayden, Oznur Ozkasap, Zhen Xiao, Mihai Budiu, Yaron Minsky – 1998] • Gossip protocol • Relaxes the “strong” reliability guarantees replacing them with probabilistic guarantees • Converges to “strong” reliability in the absence of failures • Scalable with steady throughput

  13. Questions …

More Related