Résumé  We consider the problem of broadcasting a large message in
a largescale distributed platform. The message must be sent from a source
node, with the help of the receiving peers which may forward the
message to other peers. In this context, we are interested in
maximizing the throughput (i.e. the maximum streaming rate, once
steady state has been reached). The platform model does not assume
that the topology of the platform is known in advance: we consider an
Internetlike network, with complete potential connectivity.
Furthermore, the model associates to each node local properties
(incoming and outgoing bandwidth), and the goal is to build an overlay
which will be used to perform the broadcast operation. We model
contentions using the bounded multiport model: a processor can be
involved simultaneously in several communications, provided that its
incoming and outgoing bandwidths are not exceeded. It is also
necessary to minimize the number of simultaneous connections that are
opened at a given node (i.e., its outdegree). We also block the possibility
of direct communication between some nodes to model NAT/firewall
restrictions.
