Th`ese de Doctorat de l'université Paris VI Pierre et Marie Curie Mlle ...

utility function proposed in [14], Uk(x) =a · log(b + x), where a ≥ 0and0≤ b ≤ 1.
In this scenario, we assume that all users have the same utility function considering
a =0.5 andb = 1 (see Figure 7.2).
Utility
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.5log(1+x)
0
0 1 2 3 4 5
Bandwidth (Mb/s)
Figure 7.2: Utility of an elastic application as a function of bandwidth
Note that a realistic characterization of network applications is outside the scope of
this thesis. The specification of the utility function allows us exclusively to gauge the
extra network revenue that can derive from the deployment of our proposed bandwidth
allocation algorithms.
Figures 7.3 and 7.4 show, respectively, the average total load accepted in the network
and the corresponding total extra-revenue as a function of the average total load offered
to the network.
It can be observed that the best performance is achieved by the Optimum Bandwidth
Allocation, OBA, and Iterative Dynamic Bandwidth Allocation, IDBA. This is mainly due
to the fact that we considered the same utility function for all users, as we will show in
the following. SDBA achieves lower performance, but it still outperforms static bandwidth
allocation both in terms of total accepted load and network revenue.
The maximum network extra-revenue is achieved when the average Off time of Expo-
nential sources is equal to 80 s, corresponding to an offered load approximately equal to
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