1. A discrete multi-tone (DMT) symbol processor for use in a multi-port xDSL communications system, the processor comprising: a first buffer stage for receiving a plurality of DMT symbols to be processed in accordance with a predetermined set of operations so as to extract a plurality of data streams for a plurality of corresponding communications ports; and a first set of hardware based execution units, each of said hardware based execution units being configured to perform a first group of physical layer and/or a transport convergence layer related operations as part of said predetermined set of operations; and a second set of software based execution units, each of said software based execution units also being configured to perform a second group of physical layer and/or a transport convergence layer operation as part of said predetermined set of operations; and said first set of hardware based execution units and said second set of software based execution units being interconnected so as to perform all of said predetermined set of operations for all of said plurality of corresponding communications ports; wherein a plurality of symbols for a plurality of different communications ports are processed simultaneously within the DMT symbol processor.