Video conference between Bangkok and Boston

Video conference between Bangkok and Harvard University in Boston.

For the celebration of the 50^th anniversary of the Faculty of Economics, at Thamassat University, was organised an International Conference on the Challenges of Globalization.

The conference was including a speach from Prof. Jeffrey Sachs from Havard University, Boston, USA. In the original setting, the conference would have been using NTU satellite network, but due to the failure of some MPEG2 encoding equipment in Boston, the conference settings had been changed to use NetMeeting over Internet.

At the same time a Real Server was set-up in CSIM to broadcast the even within AIT campus.

A sample of the video conference has been made available through Real System.

Network settings

UBT (ISP from the group Ucom) has been providing an ADSL link between the conference hall and their own facilities. The route to AIT was then using AIT connection to Worldnet (from the group Ucom too).

As the traffic on Worldnet connection to AIT is almost full, the connection had been upgraded 10 800Kbps for the event.

We suspected that the traffic from Ucom group, commercial ISP, may be filtered out by some of the subnet used, so we decided to extend AIT network to the conference hall, using an IP over IP tunnel between AIT and UBT. It is to be noted that IP over IP tunnel had a 24 bytes overhead for each IP packet.

The traffic coming from/going to Harvard University had been pushed in the tunnel using static routes. In the same way the traffic to the Real Server in CSIM has been enforced through static routes.

About 15 minutes after the begining of the conference, some external routes were injected into BGP in Japan. The routing between AIT and Harvard University then changed and AIT became unreachable from Harvard University. As a result, Harvard could still receive the stream coming from Bangkok, but Bangkok could not receive the stream coming from Harvard.

The problem was due to the conjunction of two factors: allowing external routes to modify the original APAN routing, and having static routes to reach the conference hall, such routes lacking adaptativness to BGP changing routing.

Setting for future experiments

For example, APAN request more than one month of delay for proper bandwidth allocation. It is necessary that each of the subnet involved in the routing are informed and helping. Some temporary filters can be set-up to prevent the routing from changing during the event.

Setting up a technical chat channel along the routing used by the event would be a good way to make sure every person involved is aware of the event. As it would be requested that some network engineers are ready to provide immediate help, they would have been informed about the conference.

The second problem could be dealt with by using two ADLS lines, one from the conference hall to the ISP and a second from the ISP to AIT.

This way, a 1Mbps connection would be available at the conference hall (not sharing Worldnet to AIT traffic), and the tunnel would not be necessary, thu taking full advantage of the flexibility of BGP routing. This solution should also increase the security as it would be more easier to set-up a firewall that way than using a tunnel.

Finally, using a tunnel it's not possible to add a static route to tne subnet where the tunnel ends as it would create a recursive routing for the tunnel end. Static routing had to be added for each machine in the subnet, except the tunnel end router. This inconvenient would not appear with two ADSL lines.

Video conference setting

(red=audio, green=video, blue=network)

• Harvard University side was using an omni directional microphone that was catching every noise in the room, including the fan of the computer, and also sending back the echo of what was said in Bangkok;
• No audio tunning could be conducted due to the lack of time: we had no access to the audio system in the conference hall and no time was planned to do tunning with Harvard. We could only test that the sound was getting through, but not adjust the proper levels.

• Pentium II, 400 Mhz, 32MBRam
• Ospray 100
• Windows'NT
• NetMeeting 2.11

PC for Real Encoder

• Pentium II, 400 Mhz, 32 MBRam
• Windows'98

Ethernet hub

ADSL modem

Real Player

VGA to video converter

This converter also offers a x2 zoom to any zone of the screen, this allowed us to display on the screen only the video coming from Harvard and to hide the local video.

Video projector

While image of the teacher does not bring much information to the classroom, it is less disturbing for the students if they can see who is speaking.

Television set

Microphone

Quality of sound is very important as the voice of the teacher will carry most of the information. When most of the audiance is not native English speaking, clear voice is necessary.

Audio mixer

Public addressed audio mixer, with 6 channels: 4 microphones and 2 lines-in, or 2 microphones, one phono input and 3 lines-in. Equalizer function can be a plus, but it needs fine tunning.

Sound system of the conference hall

Camera

Contact: Olivier Nicole

Monday, 01-Nov-1999 13:46:34 +07