TITRE Adaptive Packet Video Streaming Over IP Networks - LaBRI

mechanism associated with the Drop Tail Queues. Therefore, all video packets are dropped with an
equal probability and regardless to their relevance.
Figure 5-15 shows the end-to-end IP packet transmission delay (IPTD) for the IP best effort.
IPTD variations are correlated with the queue size and the packets loss. The more the queue is on
congestion; the more the delay to reach the destination is increased for a particular packet.
With IP Diffserv, DVMA is activated. The core router queue size is shown in Figure 5-13, and
the video packets loss in Figure 5-16.
FTP and CBR traffics are marked using TSWTCM, whereas, MPEG-4 video is marked
according to the proposed DVMA algorithm.
We notice that packets are dropped according to their priority score. Less important packets
are dropped first to maintain a low queue size. Consequently, MPEG-4 main video stream is
preserved and encounter limited packet loss probability.
Similarly, router queue size is smaller in the IP Diffserv domain than with the IP Best Effort.
The early congestion detection algorithm implemented in Diffserv router queue explains this fact.
This result to a lower utilization of the queue capacity. The performance can be improved by better
tuning the minThreshold and maxThreshold in a situation of multiple shared RED queues.
Finally, Figure 5-17 presents the end-to-end packet transmission delay with IP Diffserv model.
Performance measurements of the Diffserv model are better than with Best Effort. The mean
packet delay is about 0,1s with the best effort, and only about 0.05 when using Diffserv AF PHB.
Figure 5-12: The MPEG-4 elementary stream bit rates
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