A method of establishing a data transfer connection between a device (101, 105) and another device using a basic protocol having a multipath extension that allows for the data transfer connection to use several different paths (304, 305) in parallel, the method involving an intermediate device that carries out: - a reception step in which the intermediate device receives a connection request from the device, the connection request comprising: - an indication that the device is capable of handling the multipath extension; - a destination field that specifies an address of the intermediate device; - a field (500, 600) other than the destination field that comprises an address (504, 604) of the other device with which the data transfer connection is to be established; - a determination step (204, 206) in which the intermediate device determines whether the other device is capable of handling the multipath extension, or not; and wherein the determination step (204, 206) further comprises a delegated connection request step in which the intermediate device issues a delegated connection request that is targeted to the other device; the delegated connection request comprising a destination address field that specifies the address of the other device; - a connection establishment step in which the intermediate device establishes the data transfer connection in accordance with the multipath extension if the other device is capable of handling the multipath extension and, if not, in which the intermediate device establishes the data transfer connection as a concatenation of two data transfer connection portions: - a multipath-enabled data transfer connection portion between the device and the intermediate device in accordance with the multipath extension; and - a basic data transfer connection portion between the intermediate device and the other device in accordance with the basic protocol. - a reception step in which the intermediate device receives a connection request from the device, the connection request comprising: - an indication that the device is capable of handling the multipath extension; - a destination field that specifies an address of the intermediate device; - a field (500, 600) other than the destination field that comprises an address (504, 604) of the other device with which the data transfer connection is to be established; - an indication that the device is capable of handling the multipath extension; - a destination field that specifies an address of the intermediate device; - a field (500, 600) other than the destination field that comprises an address (504, 604) of the other device with which the data transfer connection is to be established; - a determination step (204, 206) in which the intermediate device determines whether the other device is capable of handling the multipath extension, or not; and wherein the determination step (204, 206) further comprises a delegated connection request step in which the intermediate device issues a delegated connection request that is targeted to the other device; the delegated connection request comprising a destination address field that specifies the address of the other device; - a connection establishment step in which the intermediate device establishes the data transfer connection in accordance with the multipath extension if the other device is capable of handling the multipath extension and, if not, in which the intermediate device establishes the data transfer connection as a concatenation of two data transfer connection portions: - a multipath-enabled data transfer connection portion between the device and the intermediate device in accordance with the multipath extension; and - a basic data transfer connection portion between the intermediate device and the other device in accordance with the basic protocol. - a multipath-enabled data transfer connection portion between the device and the intermediate device in accordance with the multipath extension; and - a basic data transfer connection portion between the intermediate device and the other device in accordance with the basic protocol.