Videoconferencing

polycom viavideo

Introduction

GridPP depends upon excellent communications between distributed groups/individuals. We rely upon low-cost IP videoconferencing facilities for operational discussions between multiple users at all levels. We aim to monitor/comply with evolving standards over JANET and use IP videoconferencing and associated application sharing as a working tool.

Industry standard for videoconferencing over IP is H.323. For personal/desktop conferencing we use this both point-to-point and multipoint. The latter requires the use of an MCU (Multipoint Control Unit).

Note that e-Science uses AccessGrid, which uses a different videoconferencing protocol.

Current Practice

(as of April 2003)

  • Users link into a video conference via their windows desktop using a polyspan ViaVideo unit (earlier recommendation was using a Zydacron card)
  • For point-to-point this allows application sharing (also known as data collaboration capability) which works quite well.
  • For multipoint within GridPP in the UK we connect via gatekeeper to an MCU (Multipoint Control Unit) maintained by UCL media resources group, accessed via H.323 from individual offices. Application sharing is possible, but current practice is to rely upon pre-prepared web pages with links to all source material.
  • For International multi-point we link into VRVS using H.323.
  • For multi-point within e-Science in the UK we use Access Grid facilities which are available at each of the e-Science Centre sites. Note that this is a different technology currently requiring booking (and set-up) by your local e-Science centre. Beyond this there are video-conference rooms at most Universities which can be booked through your local Computing Service.
  • A review (and appendix) of multi-site video-conferencing requirements for the UK e-Science Programme provides more detailed information.

    Known Issues

  • Polyspan (and other vendors of hardware video codecs) support only Windows and have no plans to support linux. Users of linux desktops - see notes on Gnomemeeting below, but if a hardware codec is mandated then you'd need access to a Windows PC (for the forseeable future).
  • A reliable backup/second MCU is required in cases where the UCL MCU fails or is already booked.
  • Interworking between Access Grid and an individual polyspan units require a validation process which has not really been tested.
  • Interworking between Access Grid and H.323 might be provided by VRVS. This has has not really been tested.
  • Using a ViaVideo unit with VRVS requires an older version of the software (version 2.2) to be installed.
  • Firewalls may restrict required ports. This may not be under your control, but in general these have been overcome at all sites within the UK (eventually).
  • MCU managers generally forbid use of software codecs such as those in NetMeeting and GnomeMeeting.
  • Netmeeting should also not be used to connect into VRVS.

    • Solutions?

  • We track developments from GnomeMeeting/OpenH323 (Please inform us if you are succesful with linux videoconferencing and we will adopt working solutions here). This is developing into a good software-codec solution on linux.
  • A volunteer site is needed which has sufficient resources to maintain an additional MCU. This role is currently undertaken by Glasgow (with limited resources).
  • Desktop systems with appropriate hardware can be registered on JANET. According to http://www.jvcs.video.ja.net/docs/jvcsip.shtml it appears that desktop systems can be registered for the JVCS (JANET Videoconferencing Service IP): we are trying this now, watch this space (or ask your local JVCS contact person).
  • If the ViaVideo doesn't appeal, there are comments on some other H.323 solutions at the VRVS pages http://vrvs.org/Doc/Hardware/h323_clients.html

    • Contact

  • Any questions, please contact Alan Flavell