A local pre-transfer agent, that can be run on a local computer including RAM, one central processing unit, and one interface communicating with a data exchange network connected to the RAM by a communication bus. The agent includes a first function establishing a first predictive value of the data transmission or reception bandwidth limit from configuration data on the memory, a second function establishing a second predictive value of bandwidth limit from configuration data of the processing unit, a third function establishing a third predictive value of bandwidth limit from bus configuration data, a fourth function establishing a fourth predictive value of bandwidth limit from configuration data of the communication interface, and a hardware diagnostic function invoking each one these functions and establishing, from the resulting predictive values, a bandwidth reference value in accordance with predefined comparison rules for said predictive values.