1. Networking Support for Collaborative Virtual Reality Projects in National, European and International Context TERENA Conference 2004 Rhodes, Greece 7-10 June, 2004 Eva Pless, Ferdinand Hommes Fraunhofer Institute for Media Communication

2. 2 Context of work - Projects Networking support of Virtual Reality projects  ProViT -Digital product development with virtually cooperating teams -German national project between five Fraunhofer Institutes -http://www.provit.net/  DHX -Digital artistic and ecological heritage exchange -European IST project with Belgian, German, Greek, Italian partners -Korea as Asian partner -http://www.eurasian-dhx.org/

3. 3 Context of work – Virtual reality system Avango – Virtual Environment Framework  Object-oriented framework for Virtual Reality applications  Based on SGI Performer  Focus on high-end, real-time, virtual environments like CAVE, i-CONE and responsive workbench  Binding to Scheme language  Supports distributed applications  Distribution based on Maestro/Ensemble API  Data transmission via IP/UDP unicast and multicast

4. 4 Focus of networking support Support of distributed applications  Transmission of model data  Exchange of synchronization and control data  Live streaming Interaction and communication model

5. 5 Focus of networking support Support of remote collaboration  Audio/video conferencing -Personal communication -Transmission of screen pictures  Remote computer control -Transmission of slides KIST Screen Fraunhofer IMK Screen

6. 6 Networking issues -Data exchange via IPv4 Internet connectivity -IP unicast and multicast connectivity required by applications -Multicast services not provided by some service providers involved ProViT multicast tunnelDHX topology

7. 7 Advanced networking issues QoS trials between European partners  GÉANT network offers Premium IP (PIP) service  Link to University of Crete totally overloaded  Several NOCs had to be contacted  Package overhead of 25 % has to be considered

8. 8 Advanced networking issues IPv6 connectivity to Korea via TEIN link  Dedicated 5 Mbps connection with low traffic  Tunnelling of IPv6 over IPv4 within Germany  Tunnelling of IPv4 over IPv6 as not all applications support IPv6

9. 9 Networking tools -Monitoring  nsl, iptraf  Multi Router Traffic Grapher (MRTG) -Reachability and routing  ping  trace, mtrace -Package capturing  ethereal -Service providers provide multicast beacons, looking glasses and interface graphs  Problem: restricted access

10. 10 Performance measurement -Tools  NetIQ Qcheck and Chariot, iperf -Type of measurements  Throughput  Response time  Streaming emulation -Jitter, data loss -Problems  Results depend on network and workstation configuration  Changes of the network configuration und usage Results from DHX response time tests (ms)

11. 11 Networking experience – security and firewall -Private network protection  Opening of the firewall for agreed addresses -Problem: each address change has to be discussed with all partners  Opening special ports -Problem: overhead in application configuration  Positioning of gateways outside the firewall -Problem: Security policies of companies -Virtual Private Networks  Different service providers, different technologies -Restriction of multicast traffic in private networks  Avoidance of overload by multicast traffic  Restricted multicast group access not yet available

12. 12 End-user Problems -Restricted access bandwidth of private networks (financial restrictions) -Missing multicast know-how -Responsibility of application developer and networking personal -Missing interest in networking of application developers Traffic graph February 2003: Link to the University of Crete incoming from UOC outgoing to UOC

13. 13 Benefits and problems in European and international context -Research networks offer more services than commercial networks -Research networks are better prepared to fulfil advanced requirements of end-users -Living networks are dynamically adapted to changing necessities and technological progress -If problems arise, a number of different administrative units has to be addressed to solve them -Tools are needed that help non-expert users to see the state of the network at a glance

14. 14 Conclusion -Virtual interaction and collaboration will be important topics in the next years -Research networks will be the first that offer advanced services (Grid, Bandwidth on Demand, Quality of Service, Advanced multicast features) -Security issues have to be considered that do not restrict collaboration -In distributed projects all partners should plan the engagement of networking specialists -NOCs should provide tools to allow end-to-end network analysis and performance monitoring