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Video Conferencing with NaradaBrokering


Video Conferencing with NaradaBrokering Mark Baker and Rahim Lakhoo Outline Introduction Motivation Technologies: GridSphere, Java Media Framework, NaradaBrokering. – PowerPoint PPT presentation

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Title: Video Conferencing with NaradaBrokering

Video Conferencing with NaradaBrokering
  • Mark Baker and Rahim Lakhoo

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

  • Portsmouth and Readings role in 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 tools based on RDF,
  • Bridging technologies to enable legacy
  • Peer-to-Peer technologies.
  • Portsmouth and Reading are developing JSR-168
    portlets, on the basis that Sakai will consume
    portlets via the WSRP consumer developed within
    the project.
  • 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.

Collaborative Service
  • Motivation
  • Investigate NaradaBrokering that is also
    partially funded by the e-Science programme,
    which other UK Universities and organisations are
  • Add useful tools for the Sakai Demonstrator,
  • To create a chat and video conferencing system
    that work-site users and external users may
    communicate with.
  • To provide the ability to conference with many
    participants, i.e. meetings or teleconferences.
  • Note this work was completed in Jan 2005.

Technologies Choices
  • GridShpere
  • Supports JSR-168 and WebSphere portlets,
  • Provides a portal framework, not just a portal,
    but a development infrastructure.
  • Has an active support and user 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
  • Ability to capture video and compress streams in
    different formats,
  • Supports the Real-Time Protocol.

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
  • GridSphere also supports GridPortlets for
    managing jobs and data on the Grid.
  • GridSphere uses Apache Tomcat as its container
    though it can also use Jetty.

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
  • JMF is available in two formats
  • Performance Pack, for only Linux, Solaris and
  • Includes native libraries for codecs and
    capturing from devices,
  • Platform Independent version
  • Includes partial capability for codecs and no
    video capturing.

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

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.

System Architecture
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.

The Chat Service (2)
The User Interface
The Chat Service (3)
Configuration Interface
An Example System Set-up
The Chat Service (4)
  • Each user has a PortletSession, which hold all
    connection information per a user.
  • The Chat portlet and the NaradaBrokering portlet
    service use PortletSessions for the communication
    of messages and connection information.
  • 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.

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
  • The Userlist portlet provides the video stream
    topics and other details, to initiate the video

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

Video Service (4)
  • There are two JMF applets
  • A transmitting applet which captures a device,
  • A receiving applet which displays a video stream.
  • The transmitting applet captures a users Web-cam
    as RTP data and encapsulates it within the
  • 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
  • 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.

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
  • The portlet services interact with external
    sources, while the portlets only deal with the
    layout and passing of information to the

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 test 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.

NB Chat and Video System Experiment
  • The RTPLinkManager in NaradaBrokering (0.99RC4)
    has hardwired ports, even though there is a
    configuration file.
  • NaradaBrokerings RTP session configuration file
    is not dynamic it requires a broker restart.
  • When many messages are sent to the broker memory
    usage increases and eventually the broker fails.
  • The system suffers from session bloating with
    this portlet and thus consumes a lot of memory.
  • Memory is not reclaimed by the system.
  • JMF has compatibility issues with web-cams and
  • Refreshing the chat room messages automatically
    requires other technologies, such as AJAX and/or
  • Closing the an applets connection is
    problematic needs the whole browser to be

  • 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, with few updates.
  • JSR-168 does not accommodate for the concept of
    portlet services, thus portlets could be very
    large and not easily reusable.
  • NaradaBrokerings RTP support and JMS API needs
    to be extended to improve its capabilities.

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  • Questions?

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