TITRE Adaptive Packet Video Streaming Over IP Networks - LaBRI

BEGIN
Initialize the classification process.
S = {AVO 1 , AVO 2 , …, AVO n } // Set of Audio-Visual Object
For each AVO i in S do
Begin
Calculate the Label l of the AVO i using the classification / mapping process
Mark each packet resulting from the stream of the AVO i with the label l
End
END
Figure 5-2: Generalization of DVMA using the classification model
One drawback of DVMA is its static behavior, i.e. the selection of the marking algorithm is
known by advance and can not dynamically change according to network state variations. The
solution of this problem will be presented later.
Second, the lack of flexibility since the MPEG-4 applications cannot express their needs in
terms of particular processing of particular media stream i.e. due to a poor interaction between
MPEG-4 applications and network delivery services. This is why we have developed the
classification layer that allows building cross-layer QoS architecture by mapping from application
level QoS to network QoS.
In order to prove our algorithm we have conducted an intensive experiment using both
simulation and real testbed with Diffserv capabilities. We present in next Section 5.5 the results
obtained.
5.3 An Adaptive IP QoS Matching Model
5.3.1 Static vs. Dynamic Policy-Driven Decision
In the Diffserv architecture, a particular traffic receives a predefined treatment based on
predefined policies. This treatment is interpreted as a particular PHB [128], [129]. This task is done
by the TC (Traffic Control) function, which assigns the correct DSCP [127] for the client’s traffic
according to it SLA (Service Level Agreement). Recall that each client defines it requirements and
these are translated into SLAs. The allocation of resources (QoS) still static and can lead to
bandwidth wasting and starving clients.
To receive a particular treatment, the user must specify it profile TSpec (Traffic Specification).
TSpec specifies the temporal properties of a traffic stream selected by a classifier. It provides rules
for determining whether a particular packet is in profile or out of profile. The Meter uses a Token
Bucket to control user traffic. The following is a non-exhaustive list of potential profile parameters:
• Peak rate p in bits per sec (bps)
• Token bucket rate r (bps),
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