In a network (10) providing a service to a client of a terminal (T1) and comprising at lease first and second session border controllers (A, B), at least one identical address (@Ain) is allocated to the first and second session border controllers. A router (Ra) connects the terminal (T1) to the first session border controller (A) and is capable of dynamically managing a routing table indicating at least first and second routes for the address. A message transmitted from the terminal to the network is received at the first session border controller when the router selects the first route and at the second session border controller when the router selects the second route.