A method and apparatus for transferring buffer data from a first network node to a second network node during a mobile handover between cells. In order to improve the speed at which buffer data is transferred during a handover, a connection using a congestion control protocol is established between the two nodes prior to the handover. Dummy data is sent over this connection, in order to approach or reach the available data transfer rate, and at the handover, the dummy data is replaced with buffer data.