{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

HW3FailureDetectionConsensusPeerToPeer-solution

HW3FailureDetectionConsensusPeerToPeer-solution - Homework...

Info icon This preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Homework 3 (Failure Detection, Consensus, Peer to Peer, Routing, Distributed Object) 100 Points CS425/ECE 428 Distributed Systems, Fall 2009, Instructor: Klara Nahrstedt Out: Thursday, October 15, Due Date : Thursday, October 29 Instructions: (1) Please, hand in hardcopy solutions that are typed (you may use your favorite word processor). We will not accept handwritten solutions. Figures and equations (if any) may be drawn by hand. (2) Please, start each problem on a fresh sheet and type your name at the top of each sheet. (3) Homework will be due at the beginning of class on the day of the deadline. Relevant Reading for this Homework: Chapter 3 Problem 1: Failure Detection (20 Points) Centralized heart-beating and ring heart-beating may not detect simultaneous multiple failures of processes, while all-to-all heart-beating is too expensive (in terms of messages sent per time unit). Suppose, in an asynchronous system that initially has N processes, you are given that at most N/4 processes may crash. (a) Design an efficient failure detector algorithm for this system. Your failure detector should satisfy completeness. Either give pseudo-code for your algorithm, or explain it using a figure. (b) How many failure detector messages are sent by your algorithm if no failures occur? (c) Calculate the best-case and worst-case detection times for your failure detector (hint: These are likely to occur with 1 and N/4 simultaneous failures respectively.) Solutions: ( a) Ring-heart-beating can be modified to design a fault detector that can detect simultaneous failures, where at most N/4 simultaneous failures can occur. Processes form a ring, ordered using
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern