Ad-Hoc Networks: Routing and Transport Protocol Issues
ŠT—v
Ad hoc networks are made of wireless mobile nodes which do not
rely on any preexisting wired infrastructure. These types of networks
are characterized by two main topology problems: first their topology
may change frequently, secondly nodes may join and leave the network
at any time. Moreover, any node in the network can be both a router
and an end host offering services. These aspects of ad-hoc networks
led to the introduction of new routing protocols. Some of the old
protocols for wired networks have been adapted and some new ones have
been introduced. In addition, transport protocols must be adapted to
these new types of networks. Congestion and flow control mechanisms,
robustness and reliability mechanisms of transport protocols such as
TCP must be redesigned. In this presentation, we give a description of
ad-hoc networks and their uses and also the new design problems they
introduce. We shall present some routing protocols and the TCP
protocol for these new networks and then give some research
contributions in relation to transport issues. Finally, ad-hoc
networks make it possible to introduce new types of services and
applications such as "awareness based" applications. We shall
therefore discuss some issues related to the design of middleware for
these services.