1. The LUCeS Conferencing
Tool
Enhancing the Collaboration
Experience
Adrian Fish a.fish@lancaster.ac.uk
Miguel Gonzalez m.gonzalez@lancaster.ac.uk
LUCeS (Lancaster University Centre for e-Science)
2. Table of Contents
• Background
• The Conferencing Tool and Some Use
Cases
• Work in Progress
• Technical Stuff
4. Sakai
(In a nutshell …)
• Sakai is open source software designed
primarily to provide online learning
environments for universities and colleges
• It provides lots of default functionality, like
group resource sharing, textual chat,
discussion boards, course authoring and
assessment tools.
• It is an application framework in that it
provides services to programmers who want to
add new functionality. The units of
functionality in the case of Sakai are called
tools
5. The VRE Demonstrator
Project (in a nutshell …)
• The project will provide a suite of useful tools hosted in
a Sakai ‘portal’. It will give tangible demonstrations of
the benefit of such tools for distributed scientific teams.
• Users of the demonstrator will get all of Sakai’s
collaboration tools plus our conferencing tool and
happiness prevails! In theory of course …
• The VRE Demonstrator project is funded by the JISC.
The project is a collaborative effort between 4 UK
institutions, Lancaster, CCLRC Daresbury, Oxford and
Portsmouth
7. Overview
• Delivered as a Java applet, via a web
browser
• Offers powerful functionality such as
video conferencing, shared desktop,
whiteboard, etc from one simple user
interface
• Completely free and open source
• Does not require exotic (expensive)
hardware to run successfully
8. Conferencing Tool
Components
• Conferencing – Create and participate in
audio and video conferences
• Whiteboard – A many-to-many drawing tool
• Shared Desktop – A one-to-many desktop
sharing tool
• Chat – A basic group chat
• MovieCaster – Broadcast a .mpeg,.mov or
.avi movie from your PC to the others in the
conference
10. Whiteboard
• The whiteboard allows a group of worksite
users to collaboratively draw and manipulate
shapes on a canvas
• All participants receive the shapes from every
other participant
• Can be used with the video tool to build
freehand diagrams as a team, work on
mathematical formulae, etc.
• Drops straight into Sakai with minimal
configuration
• Uses the ConferencingService (more about
that later) to route the shape modifications to
whiteboard participants
12. Shared Desktop
• Allows Sakai users to broadcast JPEG images
of their desktop to a select group of fellow
worksite users
• Network friendly. Only the area of screen that
has changed is sent to subscribers
• When used in conjunction with the audio tool
you have a powerful tool for document editing
or collaborative software development
• Only the producer needs to have installed the
software visible in the display being broadcast
-all that is being sent is a stream of JPEGs
13. Shared Desktop Use Cases
• A team wants to work on a document
together. As one types the others watch, and
can discuss the changes using the audio tool.
This could be a Word document, a Java source
file in Eclipse, Photoshop …
• A tutor demonstrates some software to her
students. She uses the software whilst talking
about her actions. The students watch, listen
and can ask questions via the audio tool
16. Conferencing
• Gives Sakai worksite users the ability to
start, and participate in, full multi-way
audio and video conferences from within
the Sakai environment
• The audio tool adds value to the other
tools in the suite - it is hard ‘doing’ textual
chat whilst using a whiteboard!
20. Whiteboard WiP
• Broadcast mode: One participant is
designated the broadcaster, the rest are
viewers. This will satisfy the well known
scenario of a teacher in a classroom.
• Saving Drawings: Each participant will
be able to save the drawing, in its
current state, to the Sakai resources
tool. In broadcast mode only the
broadcaster will be able to do this
21. Conferencing WiP
• Floor Control: Both turn based or
moderator controlled floor control
• AG Integration: A protocol bridge to
VIC/RAT to allow AGN session
participants to join Sakai hosted
sessions
22. Shared Desktop WiP
• Document Handoff: Participants can
take turns editing (and broadcasting) a
document by passing the document file
between themselves
• Whiteboard Integration: This will allow
operations such as taking a still of the
desktop into a whiteboard session for
annotation purposes
23. Conference Recording
• We are currently working on a
mechanism for recording the entire
conference.
• The messages from every component
are recorded, the video, whiteboard,
shared desktop and chat.
• When you playback a conference
everything occurs in the same sequence
as during the live conference
24. Encryption
• We are currently working on a
mechanism for the generation and
distribution of a synchronous key for
conference encryption
• Each conferencing tool instance
requests the conference key over a SSL
encrypted link, then uses that key to
encrypt any further network traffic.
26. MessagingService
• A Spring component that allows tool clients to
create new channels with specified users
• Drops into Sakai using a standard maven build
• Is currently used by the whiteboard and
shared desktop tools, but is generic enough to
be easily used for others
• Comes with a Sakai tool base class that
handles all of the interaction with the
messaging service. This can be specialised into
your tool by implementing a few simple
methods
27. Shared Desktop
• Uses the ConferencingService to send JPEG
desktop snapshots to channel subscribers
• Screen is broken into a set of tiles, designed
to fit into a 64KB datagram packet. At 32bpp
colour depth, this equates to a 128 pixel
square tile per datagram
• Only the tiles that have changed are sent; this
should hopefully reduce bandwidth
requirements
• One-to-many. The user that creates the
channel becomes the publisher and their
screen is grabbed, split and broadcast to the
other channel users.
28. Whiteboard
• Shape modifications are encoded inside
UDP packets
• The packet is sent to the conferencing
service, which then sends it on to all
the channel subscribers
• Subscribers extract the modification
instruction and duplicate it on their
whiteboard instance
29. ConferencingService
• The conferencing service is a Spring
component that drops into Sakai and needs
minimal configuration
• It sets up four datagram sockets and routes
RTP packets received on these sockets to the
relevant conference object
• Implements a software multicast algorithm
and delivers all the received datagrams to all
conference subscribers
• Has message distribution capabilities for lower
throughput applications like the whiteboard
and chat components
31. Audio/Video Conferencing
• Both audio and video conferences are controlled from
one Sakai tool
• Both use JMF on the client and the conferencing service
on the server (Sakai)
• The conferencing service is a software multicasting
system and follows the well known publish/subscribe
model for users joining conferences
• It needs four ports open on the Sakai host machine, two
for audio’s data and control (RTP and RTCP) packets
and two for the video. The service dispatches the
packets to the correct conference object for forwarding
to subscribers
32. About the Developers
• We work for the Centre for e-Science
(LUCeS) at Lancaster University in the UK
• We are currently funded, under the Sakai
VRE Demonstrator project and have been
focusing on developing advanced
collaboration tools that extend and
complement the standard ‘out of the box’
tool set that comes with Sakai
33. The LUCeS Conferencing
Tool
Enhancing the Collaboration
Experience
Adrian Fish a.fish@lancaster.ac.uk
Miguel Gonzalez m.gonzalez@lancaster.ac.uk
LUCeS (Lancaster University Centre for e-Science)
