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Two-Way Video Transmission
The following graphs represent the packet inter-arrival time and lengths captured by Computer 1 and Computer 2 transmitting video data via the web cameras simultaneously. Two flows of traffic occur for each web camera: data from the computer transmitting video and the ACK replies from the computer receiving. As a result, four flows of traffic are identified.
Inter-packet Arrival Results
Figure 3.1: Data Packet Flow
Figure 3.2: Data Packet Flow
Figure 3.3: ACK Packet Flow
Figure 3.4: ACK Packet Flow
Figure 3.1 has been cropped to show a close-up of the 67.2% of packets with an inter-arrival time of 0.25msec or less. In Figure 3.2, the corresponding cumulative graph, this results in the large initial jump to over 67%. Figures 3.3 and 3.4 show that ACKs from Computer 2 were distributed over 100msec to 200msec with less than 1% frequency and just under 2% of packets arrived with less than 0.25msec inter-arrival time.
Figure 3.5: Data Packet Flow
Figure 3.6: Data Packet Flow
Figure 3.7: ACK Packet Flow
Figure 3.8: ACK Packet Flow
We can see from Figures 3.5 to 3.8 that data sent from Computer 2 resulted in similar inter-packet arrival times as occured from Computer 1 (Figures 3.1 to 3.4). 68.5% of packets sent by Computer 2 had an inter-arrival time of less than or equal to 0.25msec. ACK replies from Computer 1 were once again spread over a 100msec to 200msec inter-arrival time distribution with less than 1% frequency. 9.4% of ACK packets from Computer 1 had an inter-arrival time of less than 0.25msec.
Packet Length Results
Figure 3.9: Data Packet Flow
Figure 3.10: Data Packet Flow
Figure 3.11: ACK Packet Flow
Over 32% of packet sent by Computer 1 were 52bytes long, with a further 35% being 1500bytes long as seen in Figures 3.9 and 3.10. We can see in Figure 3.11 that Computer 2 replied with 46byte ACK packets.
Figure 3.12: Data Packet Flow
Figure 3.13: Data Packet Flow
Figure 3.14: ACK Packet Flow
Once again, with Computer 2 transmissing video data this time, large peaks at 52bytes and 1500bytes occured. Over 31% of packets sent by Computer 2 were 52bytes long and just under 38% were 1500bytes long. As seen in Figure 3.14, Computer 1 replied to the web camera data with 46bytes ACK packets.
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Last Updated: Monday 28-Jun-2004 10:00:12 AEST URL: Maintained by: Ana Pavlicic apavlicic@groupwise.swin.edu.au Authorised by: Grenville Armitage garmitage@swin.edu.au