An interconnection device for interconnecting between first and second networks, between which there pass critical data streams having a bandwidth reservation requirement in order to ensure rate and latency constraints, performs, for each critical data stream, the interconnection device: measuring an effective rate of said critical data stream; checking whether said measured effective rate is greater than the sum of a previously reserved bandwidth and a tolerance bandwidth; checking whether said measured effective rate is lower than the previously reserved bandwidth, from which the sum of a margin bandwidth and tolerance bandwidth is deducted; and in the event of positive check, adjusting bandwidth reservation for said critical data stream to a value equal to the sum of the measured effective rate for said critical data stream and the margin bandwidth.