Developing Collaborative Tools and Services for GridSphere

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Developing Collaborative Tools and Services for
GridSphere

• Mark Baker and Rahim Lakhoo

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Outline

• Introduction
• Motivation
• Technologies
• GridSphere,
• Java Media Framework,
• NaradaBrokering.
• System Architecture
• Experiments
• Issues
• Conclusions

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Introduction

• Portsmouths part of the Sakai VRE project is to
  develop and deploy a number of portlet-based
  tools and services.
• In particular we are looking at
• Collaborative tools based on NaradaBrokering,
• Semantic Web utilities based on RDF,
• Virtualisation using Peer-to-Peer technologies.
• Portsmouth are developing JSR-168 portlets, on
  the basis that Sakai will in the future have some
  means to consume portlets based on this standard.
• In this talk we will recount our experiences
  developing, deploying and testing chat and video
  conferencing services based on NaradaBrokering,
  GridSphere and the Java Media Framework.

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Collaborative Service

• Motivation
• Investigate NaradaBrokering, which is also funded
  by the e-Science programme, which other UK
  Universities and organisations are interested.
• Add useful tools for the Sakai Demonstrator,
• To create a chat and video conferencing system
  that worksite users and external users may
  communicate with.
• To have the ability to conference with many
  participants, i.e. meetings or teleconferences.

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Technologies Choices

• GridShpere
• Supports JSR-168 and WebSphere portlets,
• Provides a portal framework, not just a portal,
• Has an active support community.
• NaradaBrokering
• Unified messaging framework with support for Grid
  and Web Services,
• Software multi-casting with support for different
  transport protocols,
• Supports video conferencing with Global-MMCS.
• Java Media Framework
• Java-based solution for handling time-sensitive
  data,
• Ability to capture video and compress streams in
  different formats,
• Supports the Real-Time Protocol.

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Portals - GridSphere

• The GridSphere framework provides an open-source
  portlet-based Web portal.
• The framework allows developers to manage and
  deploy portlets within the container.
• GridSphere supports JSR-168 and WebSphere-based
  portlets.
• GridSphere also supports GridPortlets for
  managing jobs and data on the Grid.
• GridSphere uses Apache Tomcat as its container.

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Java Media Framework (JMF)

• JMF provides an interface for Java applications
  to interact with media or time sensitive data.
• JMF includes codecs and protocols, such as
• Support for Quick Time movies,
• MP3 playback,
• Video/audio capture,
• Supports the Real Time Protocol (RTP),
• H.263 video conferencing codec (compression
  format).
• JMF is availiable in 2 formats
• Performance Pack, for only Linux, Solaris and
  Windows
• Includes native libraries for codecs and
  capturing from devices,
• Platform Independent version
• Includes partial capability for codecs and no
  video capturing.

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NaradaBrokering

• NaradaBrokering is developed by the Community
  Grids Lab at Indiana University.
• Originally designed to provide software
  multi-casting for real-time collaboration.
• Asynchronous messaging system that is JMS 1.02b
  compliant.
• Publish, subscribe and bind architecture with JMS
  Topics.
• NaradaBrokering supports other capabilities
• Video Conferencing via Global-MMCS,
• Peer-to-Peer with JXTA,
• Grid and Web Services.
• Provides a number of transport protocols
• HTTP/HTTPS, TCP/NIO-TCP and UDP.

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NB Chat and Video Architecture

• The NB Chat and Video System consists of
  portlets, portlet services and Java applets from
  a users perspective
• Chat portlet,
• Video Conferencing portlet,
• NaradaBrokering portlet service,
• Userlist portlet service,
• JMF applet.
• The servers consist of
• NaradaBrokering,
• Apache Tomcat,
• GridSphere,
• Global-MMCS.

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System Architecture
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The Chat Service (1)

• The Chat Service consists of
• A chat portlet,
• A NaradaBrokering portlet service,
• A Userlist portlet service.
• The Chat portlet provides the interface and user
  notification messages.
• The NaradaBrokering portlet service, handles all
  connections and messages to be sent/received for
  all connected users.
• The Userlist portlet service tracks connected
  users and stores user information.

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The Chat Service (2)
The User Interface
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The Chat Service (3)
Configuration Interface
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The Chat Service (3)

• The Chat portlet forwards messages to be sent via
  PortletSessions, to the NaradaBrokering portlet
  service.
• The Chat portlet also extracts messages received,
  via the users session.
• The NaradaBrokering portlet service uses the
  PortletSession to extract any connection objects
  and messages.
• Messages are sent by the NaradaBrokering portlet
  service to a JMS Chat topic on the broker.
• Each user has an associated asynchronous
  MesaageListener, which stores any received
  messages inside their PortletSession.
• Each user has a PortletSession, which hold all
  connection information per a user.

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An Example System Set-up
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The Video Service (1)

• The Video Service consists of
• A Video Conferencing portlet,
• JMF Applets,
• A Userlist portlet service.
• The Video Conferencing portlet displays a list of
  available cameras and loads the relevant JMF
  applet.
• The Userlist portlet provides the video stream
  topics and other details, to initiate the video
  conference.

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The Video Service (2)
The Video Camera Subscription Interface
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The Video Service (3)

• Users may publish a web-cam or subscribe to other
  registered web-cams.
• The video conferencing portlet gathers user
  information from the Userlist portlet service, to
  display a list of any available cameras.
• The video conferencing portlet generates an
  Applet tag with the connection details.
• The Applet then connects to a broker to
  initialise a video conference.

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Video Service (4)

• There are 2 JMF Applets
• A transmitting Applet which captures a device,
• A receiving Applet which displays a video stream.
• The transmitting applet captures a users Webcam
  as RTP data and encapsulates it within the
  NaradaRTPConnector.
• The receiving applet uses the NaradaRTPConnector
  to extract the video stream and plays it with a
  JMF player.
• This means that only one UDP port is required to
  be open on the broker for users to use the video
  conferencing.
• The chat facility also only requires one TCP port
  on the broker.
• This is unlike VRVS or Access Grid which requires
  a range of ports to be open.

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Chat and Video Services

• The presentation layers are separated from the
  logic an MVC design pattern.
• All inter-portlet communications are undertaken
  with either PortletSessions or via portlet
  services.
• The portlet services interact with external
  sources, while the portlets only deal with the
  layout and passing of information to the
  services.

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NB Chat and Video System Experiment

• The Chat and Video Portlet was tested with four
  cameras and five users.
• Each participant was connected to the chat room
  and four cameras where published.
• All participants subscribed to all four cameras.
• To stress the system all participants subscribed
  multiple times to all four cameras.
• The limitations of the number of subscriptions
  each user could make, was only limited by their
  system resources.
• The maximum obtained was 18 subscriptions with
  one published camera, by a single user.
• The broker and GridSphere consistently utilised
  500 MBytes of memory, peaking to 643 MBytes.
• The server only had 768 MBytes!

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NB Chat and Video System Experiment
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Issues

• The RTPLinkManager in NaradaBrokering has
  hardwired ports, even though theres a
  configuration file.
• NaradaBrokerings RTP session configuration file
  is not dynamicrequires broker restart.
• When many messages are sent to the broker memory
  usage increases.
• GridSphere suffers from session bloating in this
  portlet and also consumes a lot of memory.
• Memory is not reclaimed by the system.
• JMF has compatibility issues with web-cams and
  Linux.
• Refreshing the chat room messages automatically
  requires other technologies, such as AJAX and/or
  JavaScript.
• Closing the Applets connection is problematic
  needs the whole browser to be killed.

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Conclusions

• As proof of concept the system does work, however
  some of the technologies and standards need to
  mature.
• Installing JMF is still problematic for platforms
  other than Windows and seems to be a dormant
  project.
• JSR-168 does not accommodate for the concept of
  portlet services, thus portlets could be very
  large and not easilyreusable.
• NaradaBrokerings RTP support and JMS API needs
  to be extended to improve its capabilities.

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References

• http//www.javaworld.com/javaworld/jw-08-2003/jw-0
  801-portlet.html
• http//www.naradabrokering.org
• http//www.gridpshere.org
• http//www-128.ibm.com/developerworks/websphere/li
  brary/techarticles/0312_hepper/hepper.html
• http//java.sun.com/products/java-media/jmf/
• http//java.sun.com/products/java-media/jmf/2.1.1/
  guide/JMFArchitecture.html

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• Questions?