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

implements such service model by performing the dynamic bandwidth allocation algorithms
described in Chapter 5. Finally, in Section 3.3, we present the signalling messages used to
assure the interaction between network elements.
3.1 Service Model
We propose a service model that, first, provides a quantitative per-flow bandwidth guar-
antee and then exploits the unused bandwidth individuated periodically in the network to
propose short-term guaranteed extra-bandwidth to users who are willing to pay more to
get a higher bandwidth.
In this process, different weights can be assigned to network users to allocate extra-
bandwidth with different priorities; such weights can be set statically offline, based on the
service contract proposed to the user, or can be adapted online based, for example, on the
user bandwidth utility function.
Our proposed service model is therefore characterized by:
• A quantitative bandwidth guarantee, expressed through the specification of user’s
subscribed rate.
• Short-term guaranteed extra-bandwidth: the network is monitored online to indi-
viduate unused bandwidth that is allocated touserswhocanexploitittotransmit
extra-traffic for the duration specified in the contract. The contract duration depends
on the user request and can span on several consecutive update intervals.
• A weight that expresses how each user shares network resources with other users in
the extra-bandwidth assignment procedure.
Throughout this thesis, we assume for simplicity that the duration of such contracts
is minimal (i.e. equal to one bandwidth update interval); this allows us to derive upper
bounds to the performance that can be achieved by our proposed architecture.
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