Abstract: A request for transfer of data over a network is processed to obtain current values of network parameters such as aggregate network processing overhead and effective network bandwidth. In response to receipt of a data transfer request, the maximum size transport unit which can be sent over the network without packet loss is determined. The full maximum size transport unit is then sent over the network from, for example, a client to a server, in order to provide a measure of full size transport time. Similarly, a half size transport unit is sent over the network to provide a measure of half size transfer time. The fall and half size transfer times are then used to compute current values for the network processing overhead and effective network bandwidth parameters. The current values are processed to determine an internal buffer size to be allocated for use in receiving data transferred over the network in response to the request.