Videoconferencing

(on Windows)

A.J.Flavell,

Glasgow University

Terminology for this talk

Classification by quality:• (Studio quality)• Business class (hardware codecs)• Cheap-and-cheerful (software codecs)

By network technology:• H.320/ISDN (well established technology)• H.323/IP (industry standard for IP)• vic/rat (IETF formats for IP uni- and multicast)

H.320/ISDN

• Long-established technology

• Guaranteed but limited bandwidth

• Point-to-point, or multipoint with ISDN MCU

• Call charges OK inland but...

• Most of our use is studio based (JVCS, DCS), we are unlikely to expand room-based/desktop

• Any data sharing is typically a separate add-on (web or T.120/IP)

H.323/IP

• H.323 is a framework with many options, including audio, video, data sharing

• Point to point, or multipoint with H.323 MCU

• Currently no bandwidth guarantee, but results have usually been good (later maybe QoS).

• Big growth area relevant to us as we will see

• Some gateways to H.320/ISDN

• VRVS gateway is a special case

Vic/rat over IP

• IETF protocols designed for IP - including multicast. Implemented in vic, rat etc.

• Can use inexpensive kit such as webcams

• Multicast use never took off in our community (proprietary streaming formats instead...) (may revisit this topic, but outside of present talk)

• vic/rat inconvenient to use natively in unicast...

• ...but VRVS makes their use more convenient.

H.323 Software Codecs

• NetMeeting audio and video• OpenH323 and derivatives (GnomeMeeting)• CUSeeMe-pro, etc. (no experience)• Uses inexpensive kit (webcam etc.)• Highly Unwelcome by Business-Class MCUs • OK point to point between consenting users• VRVS users would usually also have the vic/rat

option, it would be interesting to get user reactions about which to choose.

Some folk claim NetMeeting is OK!

• The problem is that in a mixed multipoint conference, when there are problems, the site which is causing the problem is usually the last to realise it.

• Audio problems can cause major disruption...

• MCU managers also report cases of MCU hangs due to software codecs: ESnet bans them, and several others strongly discourage.

H.323 Hardware Codecs

PPNCG recommendations are still:• for a group business-class starter kit:

Zydacron OnWAN package (Z353 PCI card) (about £1000)

• for a personal USB-connected unit:Polycom ViaVideo (about £400)

Supported only on Windows OSs!!!

• A useful accessory for many setups is the SoundPoint/PC, a sort-of echo cancelling speakerphone for videoconferencing. We have several, which get used with the Zydacron, with rat/VRVS, and with NetMeeting. (I don’t know about using it with the ViaVideo, which has its own built-in microphone and echo cancelling.) ->

H.323 Hardware Codecs

• Be aware that these devices are dedicated H.323 hardware/software packages. They do not interwork with the normal Windows multimedia software layer e.g webcams, and any interworking with Windows audio is via physical connection to sound card, not within software.

• This can make it inconvenient to run Hardware H.323 and vic/rat on the same PC.

Zydacron OnWAN kit

• The kit is a complete start-up kit• Can be enhanced as needs arise:

– better camera (it accepts normal video sources)– better microphones– document viewer etc.

• Likes to work at high bandwidth (128k, 384k)• Not good at low bandwidth (dial-up etc.)• Includes H.320/ISDN2 if you have an ISDN

line.

H.323: Polycom ViaVideo

• Self-contained USB-connected camera, video and audio codec, echo canceller

• No external video inputs• Intended for use only with built-in microphone

and external speaker(s), or a headset

• So, essentially no scope for enhancement. What you get is what you get (aside from software version upgrades)

• Usable at low bandwidth e.g modem dialup

ViaVideo temporary Gotcha’s

• ViaVideo version 3 is current:– it fails to work with VRVS (under investigation)– there seem to be problems with some RADVision

MCUs (MCU.323)

• ViaVideo version 2.2 does not have these problems:– but version 2.2 doesn’t seem to support application

window sharing under Windows2000.

Usage Aspects of H.323

• H.323 expects “end-points” (i.e clients) to configure to a “gatekeeper”, thus decoupling from details of IP addressing etc.

• End-points must identify themselves properly to the gatekeeper (“E.164 number” &/or alias)

• E.164 number may be formally assigned by a user registration (ESnet), or ad-hoc.

• Point to point calls using IP addressing are usually supported too.

Usage aspects of H.323 (2)

• Some MCUs have an integrated gatekeeper

• Gateways (H.323/IP to H.320/ISDN) may have too

• Or gatekeeper may be separate (different IP)

• Conference traffic may come directly from the MCU or Gateway rather than from the GK; this has impact for your necessary firewall settings

Usage aspects of H.323 (3)

• Take care configuring your own identity into the client station. Vendor menus tend to refer to this “E.164 address” as “phone number” or

• “H.323 extension”.

• An all too common error is to try to configure the address of the called conference into the client’s own identity. THIS IS FATAL!

Data Sharing

• Data sharing (e.g application windows) is supported by T.120 within H.323, this is a very valuable option for our community.

• Unfortunately, few audio/video MCUs also support T.120, which makes multipoint conferences using data sharing inconvenient to set up (though it’s possible if you work at it!)

• Data sharing typically uses NetMeeting “behind the scenes”: do not confuse this with NetMeeting Audio/Video usage!!

Current Usage

• The situation is complex, so instead of trying to cover everything, I’ve tried to show what is being used - and at the same time introduce you to the facilities which seem relevant to us.

• Something will also be said about future developments: the trend to H.323 will become evident...

Current usage examples

• JVCS studio-based H.320/ISDN

• ESnet DCS Production System H.320/ISDN

• H.323 point to point, no extra resources

• ESnet experimental H.323 MCU, and gateway to the production ISDN system

• UK-based H.323 MCUs (UCL, Glasgow, UKERNA, maybe others?

• VRVS http://www.vrvs.org

JANET ISDN system: JVCS

• The known studio-based ISDN system

• Permanent users must register and be QA tested

• Formal booking system

• Interesting to us because they will add H.323 facilities by Autumn

• But initially, desktop clients will not be accepted. (Group room facilities may be OK)

Scottish vc network SMVCN

• Currently ATM-based, not relevant to HEP, but:

• Procuring replacement H.323-based system to be in place by end of July 2002 and to be effectively the pilot service for the upcoming JVCS H.323 service. Interesting!

• JVCS/SMVCN H.323 service will not permit software-based H.323 codecs

ESnet

ESnet production conferencing services include

• (phone conferencing system)

• ISDN-based videoconferencing system (DCS) with booking system

Their AUP calls for USA site participation in every conference, not unreasonably (but USA-based experiments or US experimenters currently abroad are accepted de facto)

ESnet experimental H.323

• ESnet has for some time been experimenting with H.323, either alone or gatewayed to their production ISDN-based service

• Glasgow CDF, for example, has used this extensively

• Future plans involve integrating H.323 into the production service; a new booking system; multipoint data sharing support; and provision for ad-hoc multipoint conferencing.

ESnet H.323

• Be aware that to use ESnet H.323 you MUST register and be assigned a proper E.164 identity. The previously-assigned temp four-digit addresses are no longer valid: current assignments are six digits beginning with a “2”http://www-staff.es.net/~mikep/

• Anyone trying to connect to a multipoint conference and using a non-valid E.164 identity is liable to be blocked pending manual resolution of the problem.

VRVS, www.vrvs.org

• Original basis is vic/rat• Now provides also an H.323 gateway• User registration procedure is informal• Non-booked coffee rooms for testing etc.• Booking system for proper sessions• Supports data sharing, but does it with vnc• Very popular in the community, but has a reputation,

especially with some casual users, of being complex to set up.

9352 Hosts;5369 Registered Users in 63 Countries 42 (7 I2) Reflectors Annual Growth 2.5X

VRVS continued

• User control is via a web browser page• Works well for most people, but relies heavily on

JavaScript, cookies, Java, application starters: things can turn nasty if any of this isn’t working exactly as expected (due to browser security settings, alternative JVM etc.), so find a browser configuration that works and stick to it.

• Useful user interface “Call someone” for initiating point to point vic/rat

VRVS continued

• Zydacron video receive from VRVS gateway is poor: reason is understood, but impractical to resolve

• Workaround: use the VRVS’s H.323 “Video mode” button to select “Multivideo” mode, i.e this uses vic to display the received video.

Bits and pieces

• This could be a good moment to view the presentations from elsewhere...

Summing up

• Business-class H.323 is giving good results albeit we have to scrape around till now for experimental MCUs we can use

• Pilot/Production H.323 appears to be imminent on ESnet and on SMVCN/JVCS subject to eligibility. “Software codecs need not apply.”

• Data sharing (especially application windows) will be very attractive to our users when it’s straightforward to use.

Summing up (2)

• Business-class H.323 will also gateway to existing H.320/ISDN (both on JVCS and on ESnet), though it’s evident that the move is away from ISDN and towards H.323

• Cheap-and-cheerful is working acceptably for some:– point-to-point H.323 with software codecs

(typically NetMeeting)– vic/rat with VRVS– ? H.323 software codecs with VRVS ?

Conclusion

• It’s already working well, saving a packet on travel costs (and on phone calls)

• It’s about to get better, especially if you are kitted-up for hardware codecs (business-class)

• Data sharing!

Questions, discussion?