Method and apparatus for switching between active and standby switch fabrics with no loss of data

A switching system for a data traffic network. A plurality of line cards provide input and output connections to a plurality of data lines and further are connected to at least two switch fabrics, one of which is designated the active switch fabric and the other designated the standby switch fabric. Data traffic is switched between the plurality of input and output line cards by the active switch fabric. When it is desired to change the active switch fabric assignment, for example due to a fault in the switch fabric, data transmissions into the active switch fabric are terminated and a drain timer is started. When the drain timer times out or the active switch provides an indication that it is empty, the active switch fabric assignment is swapped to the standby switch fabric and data is then switched through the newly assigned active switch fabric.