Android around the clockAuthors :

Lior NarkisMaxim Chepurnyak

Supervisor:Ittay Eyal

Agenda Motivation Project Goals CTP algorithm Application top-level Main modules overview

Clock synchronization Membership Playback command dispatch Media Player control GUI

Design environment Milestones

Motivation Android based smart-phones are very

common nowadays. These phones are used by many also as a media device.

We want to let a group of two or more of these phones, play the same song at the same time.

The playback can be controlled by any of group member.

Project goals Creating a distributed Android application

which will play a song on different devices all together.

The application will manage the group membership by supporting joining and leaving.

The application will keep all the group members clocks synchronized to each other.

The application will ensure global ordering of users’ commands.

Classless Time Protocol A network clock synchronization

protocol Based on Omer Gurewitz’s work

published in IEEE/ACM TRANSACTIONS ON NETWORKING, VOL. 14, NO. 4, AUGUST 2006

Improvement to NTP

Application top-level

• The diagram is neither complete nor final

Clock synchronization module

Implements CTP. Provides a synchronized clock for other

modules. Provides a level of confidence

parameter indicating the CTP quality.

Clock synchronization module – class diagram

Clock synchronization module – sequence diagram for NTP packet life-cycle

Membership module Maintaining a list of active

members(“alive” messages). Support joining and leaving(avoiding

partitions and livelocks). Provides the members list to the rest of

the modules.

Playback command dispatch(PCD) module Broadcasts commands list sent by the

MPC to all group members(including itself).

Delivers commands list to the MPC if no later commands list was delivered before.

Media player control(MPC) module Drives the Android media player. Receives commands from the GUI and

sends those to the PCD. Receives commands lists delivered by

the PCD. Processing the commands list.

GUI module Simple. Provides joining and leaving a group. Provides basic playback operations.

Design Environment The following tools/packages will be used:

Eclipse JRE 7+ JDK 1.7+ Android SDK tools for eclipse Paradigm UML plugin for eclipse – community

edition The project will be written in Java, using Android

libraries, and will be checked on the Android emulator and real Android smart-phones.

Milestones Completion of mid semester report. Basic clock synchronization module Basic membership module Basic PCD module Basic MPC module Basic GUI module Basic app