France Telecom

Christophe Mangin

Michel Servel

Pierre Boyer

Olivier Dugeon

Data flows generated in accordance with a connected mode protocol and formatted in packets in accordance with a non-connected mode protocol are transmitted via an ATM network. A set of virtual circuits of the ATM network is assigned in advance to each pair of access points of the ATM network, without allocating transmission rate resources to them. When an access point receives a request, formulated in accordance with the connected mode protocol, to establish a connection between a source address and a destination address accessible via another access point of the ATM network, an available virtual circuit is selected from the set assigned to this pair of access points and a resource management cell containing a request to activate the virtual circuit is transmitted on the selected virtual circuit. When this cell is received by a node of the ATM network located on the selected virtual circuit, a transmission rate resource is allocated, if it is available, to the selected virtual circuit.

Method of transmitting data flows over an ATM network and device for implementing the method

Bit rate reservation is effected with the aid of a reservation cell containing a requested bit rate transmitted from a calling terminal to a called terminal via switching nodes of an asynchronous network. At each node, a bit rate increase request is at least partially satisfied even if the difference between the requested bit rate and the current bit rate is greater than the bit rate available at the node. The node replaces the requested bit rate in the reservation cell by a new bit rate lower than the latter so that the called terminal receives the lower new adopted bit rate by the nodes. An acknowledgement cell retransmitted with this lower new bit rate by the called terminal renders uniform the adopted bit rate at all the nodes. If no acknowledgement cell has been received after a predetermined time-delay the nodes revert to their initial state, with the current bit rate preceding the bit rate reservation.

Growing community of inventors

Breal Sous Monfort, France

Christophe Mangin