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 n 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 n Open source software n MBone Tools (vic, rat, wb/wbd) n Multicast replaced by mirrored unicast n Web administration

Network Support for Communication n 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 n 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 n Other features added to rum –data recording

Web portal n Need for easy reflector administration n Today most common environment with rather standardized and intuitive handling n Not too much fancy features but rather useful ones

Videoconfrence adminisration using web portal n Conference = one or more instances of rum (provides reflector(s) for one or more videoconferencing tools) n Administrator = user who sets up user accounts n User = person who can set up and run one or more conferences

Setting up a conference n User logs in into the conference administration web n 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 n Conference announcement can be found in public part of the administrative web n Conference startup can be manual or scheduled n Conference administrator can browse log file during and after the conference

MBone wbd tool enhancements n wbd used as basis since wb is not available in source code n enhanced security by adding encryption using the same library as other MBone tools rat and vic (UCL Common Multimedia Library - DES and Rijndael encryption)

n displaying using Imlib2 –new formats available for import –zoom –synchronized rotation of image –faster drawing of image n faster network transmission (multiple threads)

wbd - JPEG import

wbd - zoom import

Further mirror develompent n 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

n Development initiated by our group –very secure videoconferencing environment (strong encryption, rekeying during the session etc.)

Conclusions n 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 n System we have developed is in routine use by Czech group participating in EU DataGrid project and by CESNET

n As with all videoconferencing systems input and output audio and video devices must be of reasonable quality to provide users with positive experience n Underlying network must be of sufficient bandwidth to cope with stream multiplication

Acknowledgements n Czech group participating in EU DataGrid project for valuable ideas and patience during testing n Luděk Matyska and Zdeněk Salvet n CESNET Research intent MSM

Thank you for your attention!