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Video Conferencing with NaradaBrokering

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					Video Conferencing with
NaradaBrokering

Mark Baker and Rahim Lakhoo




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          Outline
          • Introduction
          • Motivation
          • Technologies:
               – GridSphere,
               – Java Media Framework,
               – NaradaBrokering.
          • System Architecture
          • Experiments
          • Issues
          • Conclusions
13 July 2006                             2
      Introduction
      • Portsmouth and Reading’s 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 applications,
         – 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,
13 July 2006 GridSphere and the Java Media Framework.             3
          Collaborative Service
          • Motivation:
               – Investigate NaradaBrokering that is also
                 partially 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 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.

13 July 2006                                                     4
          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 data,
               – Ability to capture video and compress streams in different
                 formats,
               – Supports the Real-Time Protocol.
13 July 2006                                                              5
          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 – though it can also use Jetty.

13 July 2006                                            6
          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 available in two 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.

13 July 2006                                                                        7
          NaradaBrokering
         • NaradaBrokering is developed by the Community Grids
           Lab at Indiana University.
         • Originally designed to provide software multi-casting
           for real-time collaborative systems.
         • 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.

13 July 2006                                                   8
          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.

13 July 2006                                                   9
               System Architecture




13 July 2006                         10
          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.


13 July 2006                                                   11
          The Chat Service (2)




                     The User Interface



13 July 2006                              12
          The Chat Service (3)




                     Configuration Interface



13 July 2006                                   13
               An Example System Set-up
                                                                                          N a ra d a B r o k e r in g , B r o k e r
                                                                                                         c lo u d




                                                                                                                                                  P o r tle t S e s s io n

                                                                            B ro k e r S e rv e r                                       J M S T o p ic C o n n e c tio n O b je c t
                                                                                                                                      J M S P u b lis h e rs S e s s io n O b je c t
                                                                                                                                      J M S S u b s c r ib e r S e s s io n O b je c t
                                  N a ra d a B r o k e r                                                                                 J M S T o p ic P u b lis h er O b je c t
                                                                                                                                        J M S T o p ic S u b s c r ib e r O b je c t
                                    C h at
                                  T o p ic N                                                                                                  JM S T o p ic U s e r n a m e
                                                                                                                                                J M S T o p ic S tr in g
                                                                                                                                         J M S C o n n e c tio n P ro p e r tie s
                                                                                                                                       J M S T e x t M e s s a g e s R e c e iv e d
                                                                                                                                         J M S T e x t M e s s a g es t o S e n d
                                   T om c at                                                                                                   C o n n e c tio n S ta t u s
                                  C o n ta in e r

                                               G r id s p h e r e

                                                                                                      S e s s io n
                                                                 S e s s io n                          in fo - 3
                                                                  in fo - 2

                                                                                N a r a d a B ro k e r in g
                                                                                        S e r v ic e
                                                                                                           S e s s io n
                                                                    S e s s io n
                                                                                                            in fo - 4
                                                                     in fo - 1




                C hat        V id e o


                                                                                                                                         C h at           V id e o
                    C lie n t 1

                                                                                                          C h at           V id e o
                                                                                                                                                C lie n t 4
                                                    C hat              V id e o
13 July 2006                                                                                                      C lie n t 3
                                                                                                                                                                                         14
                                                           C lie n t 2
          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.




13 July 2006                                                    15
          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.

13 July 2006                                            16
          The Video Service (2)




               The Video Camera Subscription Interface




13 July 2006                                             17
          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.

13 July 2006                                             18
          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
        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.

13 July 2006                                                    19
          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.


13 July 2006                                            20
          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.

13 July 2006                                                  21
          NB Chat and Video System Experiment




13 July 2006                                    22
          Issues
      • The RTPLinkManager in NaradaBrokering (0.99RC4) has
        ‘hardwired’ ports, even though there is a configuration file.
      • NaradaBrokering’s 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 Linux.
      • Refreshing the chat room messages automatically requires
        other technologies, such as AJAX and/or JavaScript.
      • Closing the an applet’s connection is problematic; needs the
        whole browser to be shutdown.

13 July 2006                                                       23
          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, with few updates.
          • JSR-168 does not accommodate for the
            concept of portlet services, thus portlets
            could be very large and not easily reusable.
          • NaradaBrokering’s RTP support and JMS
            API needs to be extended to improve its
            capabilities.
13 July 2006                                               24
          References
          • http://www.gridpshere.org
          • http://www.naradabrokering.org
          • http://java.sun.com/products/java-media/jmf/
          • http://www.globalmmcs.org/
          • http://java.sun.com/products/java-
            media/jmf/2.1.1/guide/JMFArchitecture.html
          • http://www.javaworld.com/javaworld/jw-08-
            2003/jw-0801-portlet.html
          • http://www-
            128.ibm.com/developerworks/websphere/library
            /techarticles/0312_hepper/hepper.html

13 July 2006                                               25
Questions?

       http://dsg.port.ac.uk
       http://acet.rdg.ac.uk


                                         QuickTime™ and a
                               TIFF (Uncompressed) decompressor
                                  are needed to see this picture.

				
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