An access node such as an OLT or DSLAM for use in a communications network. The access node performs a plurality of functions using in a number of function modules, each divided into one or more sub-modules. The status of the sub-modules is controlled by a controlled by a controller that reviews load statistics and other inputs and determines whether the configuration of the function module should be changed. If so, individual sub-modules are powered down, clock-gated, or returned to operational status. A traffic dispatcher positioned before each function module distributes the data traffic to available sub-modules for processing, after which it is aggregated by a traffic aggregator and passed on to the next stage. A number of circuit boards may be used, each containing only one or two function modules. The boards are connected by short, high-speed serial lines, which may have multiple links whose status may also be controlled.