Need to break the Monolithic MCU into small pieces ( service )
Introduce a common AV signaling protocol to interoperate different AV collaboration endpoints
Floor control application level QoS policy Different role Capability QoS XML specification For example, a role named <panel-member> It demands the delay stream -> panel-member is within 20ms.
Each audio package is independent of others. Therefore, each package in the audio stream takes almost the same amount of time to route. This results in very small amount of jitter. In addition, the latency values for the first participant is almost always the same independent of the number of participants in the meeting. Since there are multiple video packages in a frame, upcoming packages wait the earlier ones in the frame. Therefore, even the latency values of the first participant increases as the number of participants increase in the meeting. Similarly, the jitter increases as the number of participants increase in the meeting. One broker can support at most 400 participants. Although the broker is saturated when there are 1000 participants.
Going through multiple brokers does not introduce considerable overhead. Scalability of the system can be increased almost linearly by adding new brokers.
Global Multimedia Collaboration System Wenjun Wu Indiana University Bloomington IN 47401 [email_address] http:// www.globalmmcs.org
XGSP Web Service MCU Architecture Gateways convert to uniform XGSP Messaging High Performance (RTP) and XML/SOAP and .. Use Multiple Media servers to scale to many codecs and many versions of audio/video mixing NB Scales as distributed Web Services NaradaBrokering SIP H323 Access Grid Native XGSP Admire Media Servers Filters Session Server XGSP-based Control NaradaBrokering All Messaging
Test results showed that the broker network can scale well for both single large size meetings and multiple smaller size meetings.
In large size meetings, the capacity of the broker network is increased with respect to the capacity of the added brokers.
In multiple smaller size meetings, the distribution of users among brokers are important. Inter-broker stream exchange can reduce the scalability. Few users should not be scattered around the broker network.
In wide area networks, this videoconferencing system provides many benefits with distributed broker architecture: bandwidth savings, latency savings, and better quality services.
In summary, thousands of concurrent users can easily be supported in distributed broker settings.
media services computation overhead 90% while 4, 23fps stream producers are running Real Streaming Producer 70% while 50 image grabbers are running Image Grabber 94% while 4 video mixers ( 4-way mixing ) are running Video Mixing 46% while 20 audio mixers ( six active speakers ) are running Audio Mixing Computation Overhead Media Services
Improved JMF Performance Fraction of CPU used versus number of received streams The CIF-size video sequence from a 30-second movie with a lot of motions is streamed to the clients. Each stream is encoded in H.261, and has average bandwidth of 400Kbps and 20 fps. 34% - 35% 62% - 63% 40% - 41% 8 31% - 32% 58% - 59% 35% - 36% 7 27% - 28% 51% - 52% 32% - 33% 6 23% -24% 46% - 47% 26% - 27% 5 17% - 18% 40% - 41% 23% - 24% 4 15% - 16% 33% - 34 % 17% - 18% 3 9% - 10% 24% - 25 % 13% - 14% 2 6% - 7% 15% - 16 % 8% - 9% 1 Fast JMF Client Old JMF Client VIC