A computer-implemented method for routing a bursty data flow comprising a series of one or more data packets over a converged network comprising a plurality of communication networks, the bursty data flow consisting of a sequence of phases of high data transmission rate followed by low or zero data transmission rate, the method comprising, for each of the series of data packets in turn: selecting which one of the plurality of communication networks to transmit that data packet over by: i) obtaining flow statistics indicating a current flow state of the bursty data flow; ii) performing a classification of the current flow state of the bursty data flow by selecting from a list of flow states in dependence on the flow statistics, the list of flow states comprising a start-up phase and an established phase; and iii) selecting the one of the plurality of communication networks in accordance with a bursty bonding policy which mandates selection of the one of the plurality of communication networks in dependence on said classification, wherein the bursty bonding policy is configured to result in transmission of the bursty data flow: over a first set of two or more of the plurality of networks while the current flow state is classified as start-up phase, and over a second set of the plurality of networks while the current flow state is classified as established phase, wherein the second set is smaller than the first set; then initiating transmission of the data packet over the one of the plurality of communication networks selected in step iii). selecting which one of the plurality of communication networks to transmit that data packet over by: i) obtaining flow statistics indicating a current flow state of the bursty data flow; ii) performing a classification of the current flow state of the bursty data flow by selecting from a list of flow states in dependence on the flow statistics, the list of flow states comprising a start-up phase and an established phase; and iii) selecting the one of the plurality of communication networks in accordance with a bursty bonding policy which mandates selection of the one of the plurality of communication networks in dependence on said classification, wherein the bursty bonding policy is configured to result in transmission of the bursty data flow: over a first set of two or more of the plurality of networks while the current flow state is classified as start-up phase, and over a second set of the plurality of networks while the current flow state is classified as established phase, wherein the second set is smaller than the first set; then i) obtaining flow statistics indicating a current flow state of the bursty data flow; ii) performing a classification of the current flow state of the bursty data flow by selecting from a list of flow states in dependence on the flow statistics, the list of flow states comprising a start-up phase and an established phase; and iii) selecting the one of the plurality of communication networks in accordance with a bursty bonding policy which mandates selection of the one of the plurality of communication networks in dependence on said classification, wherein the bursty bonding policy is configured to result in transmission of the bursty data flow: over a first set of two or more of the plurality of networks while the current flow state is classified as start-up phase, and over a second set of the plurality of networks while the current flow state is classified as established phase, wherein the second set is smaller than the first set; then over a first set of two or more of the plurality of networks while the current flow state is classified as start-up phase, and over a second set of the plurality of networks while the current flow state is classified as established phase, wherein the second set is smaller than the first set; then initiating transmission of the data packet over the one of the plurality of communication networks selected in step iii).