A wireless mesh network system comprising: - at least two border routers (200, 200a, 200b) configured to connect nodes in the wireless mesh network to an external network, and wherein a border router device (200, 200a, 200b) comprises: - a first controller configured to determine a beacon-interval; - a scheduler configured to determine a beacon-transmission time moment for sending a beacon packet periodically after each beacon-interval; - a first transceiver configured to transmit the beacon packet on a communication channel at the beacon-transmission time moment; and the border router device (200, 200a, 200b) being characterized in that: the first controller is further configured to determine the beacon-interval based on an available capacity of the border router, wherein the available capacity is related to an actual traffic load of the border router, the actual traffic load comprises reception of data packets with the border router as a destination in the wireless mesh network coming from the nodes in the wireless mesh network either via a direct link or via multi-hop relaying, transmission of data packets from the border router to the nodes in the wireless mesh network either via a direct link or via multi-hop relaying, and internal processing of said data packets; and wherein the higher the actual traffic load the lower the available capacity, and hence the longer the beacon-interval; - at least one node, and wherein the node comprises: - a second transceiver configured to monitor a communication channel; - a second controller; and the node characterized in that - the second controller is configured to derive estimated beacon-intervals of at least two border routers, and to select one border router that has the shortest estimated beacon-interval out of the at least two border routers as the forwarding border router, with the forwarding border router as a destination in the wireless mesh network. - at least two border routers (200, 200a, 200b) configured to connect nodes in the wireless mesh network to an external network, and wherein a border router device (200, 200a, 200b) comprises: - a first controller configured to determine a beacon-interval; - a scheduler configured to determine a beacon-transmission time moment for sending a beacon packet periodically after each beacon-interval; - a first transceiver configured to transmit the beacon packet on a communication channel at the beacon-transmission time moment; and the border router device (200, 200a, 200b) being characterized in that: the first controller is further configured to determine the beacon-interval based on an available capacity of the border router, wherein the available capacity is related to an actual traffic load of the border router, the actual traffic load comprises reception of data packets with the border router as a destination in the wireless mesh network coming from the nodes in the wireless mesh network either via a direct link or via multi-hop relaying, transmission of data packets from the border router to the nodes in the wireless mesh network either via a direct link or via multi-hop relaying, and internal processing of said data packets; and wherein the higher the actual traffic load the lower the available capacity, and hence the longer the beacon-interval; - a first controller configured to determine a beacon-interval; - a scheduler configured to determine a beacon-transmission time moment for sending a beacon packet periodically after each beacon-interval; - a first transceiver configured to transmit the beacon packet on a communication channel at the beacon-transmission time moment; and the border router device (200, 200a, 200b) being characterized in that: the first controller is further configured to determine the beacon-interval based on an available capacity of the border router, wherein the available capacity is related to an actual traffic load of the border router, the actual traffic load comprises reception of data packets with the border router as a destination in the wireless mesh network coming from the nodes in the wireless mesh network either via a direct link or via multi-hop relaying, transmission of data packets from the border router to the nodes in the wireless mesh network either via a direct link or via multi-hop relaying, and internal processing of said data packets; and wherein the higher the actual traffic load the lower the available capacity, and hence the longer the beacon-interval; - at least one node, and wherein the node comprises: - a second transceiver configured to monitor a communication channel; - a second controller; and the node characterized in that - the second controller is configured to derive estimated beacon-intervals of at least two border routers, and to select one border router that has the shortest estimated beacon-interval out of the at least two border routers as the forwarding border router, with the forwarding border router as a destination in the wireless mesh network. - a second transceiver configured to monitor a communication channel; - a second controller; and - the second controller is configured to derive estimated beacon-intervals of at least two border routers, and to select one border router that has the shortest estimated beacon-interval out of the at least two border routers as the forwarding border router, with the forwarding border router as a destination in the wireless mesh network.