Transcript Teleconferencing support for small groups

Teleconferencing support for
small groups
Eva Hladká*‡, Petr Holub*†‡,
Jiří Denemark*‡
*Faculty
of Informatics Masaryk University Brno, CZ
†Institute of Computer Science Masaryk University Brno, CZ
‡CESNET z.s.p.o, CZ
Introduction

Target environment:
– multitude of small groups with all active
members
– no special network services needed (e.g.
multicast)
– diverse computer system platforms
– users from computer science community
– to provide reasonable security
– new features to be easily added
Our Choice
Open source software
 MBone Tools (vic, rat, wb/wbd)
 Multicast replaced by mirrored unicast
 Web administration

Network Support for
Communication

UDP Packet Reflector - “rum”
– similar to simple H.323 MCU
– initial version: just UDP packet reflecting
– services transferred from network level
(multicast) to application level (mirror):
=> easy modification
=> worse scalability and efficiency
Reflector
reflector
Multicast
Enhancing reflector

Security features added to “rum”
– IP address restrictions
– AA based on username/password
– activity logging
– merge of MCU functions and basic
gatekeeper functions in terms of H.323

Other features added to “rum”
– data recording
Web portal
Need for easy reflector administration
 Today most common environment with
rather standardized and intuitive
handling
 Not too much fancy features but rather
useful ones

Videoconfrence adminisration
using web portal

Conference = one or more instances of
“rum” (provides reflector(s) for one or
more videoconferencing tools)
 Administrator = user who sets up user
accounts
 User = person who can set up and run
one or more conferences
Setting up a conference
User logs in into the conference
administration web
 Set up features required for the
conference

– mirrors and their parameters (ports,
logging features, description, etc.)
mirrors can be organized into groups
– allowed/denied IP addresses
– allowed users
Running the conference
Conference announcement can be
found in public part of the
administrative web
 Conference startup can be manual or
scheduled
 Conference administrator can browse
log file during and after the conference

MBone wbd tool
enhancements

wbd used as basis since wb is not
available in source code
 enhanced security by adding encryption
using the same library as other MBone
tools rat and vic (UCL Common
Multimedia Library - DES and Rijndael
encryption)

displaying using Imlib2
– new formats available for import
– zoom
– synchronized rotation of image
– faster drawing of image

faster network transmission (multiple
threads)
wbd - JPEG import
wbd - zoom import
Further mirror develompent

Further development effort by our
group
– improving scalability: tunneling
– passing through firewalls: “Enhanced UDP
packet reflector for unfriendly
environments”
– 3D projection: stream synchronization
– publishing information about mirrors in
LDAP

Development initiated by our group
– very secure videoconferencing environment
(strong encryption, rekeying during the
session etc.)
Conclusions

Development was motivated by two
factors:
– instability and unavailability of multicast in
many of networks of today
– videoconferencing needs of several small
groups on Masaryk university and CESNET

System we have developed is in routine
use by Czech group participating in EU
DataGrid project and by CESNET
As with all videoconferencing systems
input and output audio and video
devices must be of reasonable quality
to provide users with positive
experience
 Underlying network must be of
sufficient bandwidth to cope with
stream multiplication

Acknowledgements
Czech group participating in EU
DataGrid project for valuable ideas and
patience during testing
 Luděk Matyska and Zdeněk Salvet
 CESNET Research intent
MSM000000001

Thank you for your attention!