A method of processing frames received at a sending port of a switching
device for communication to a destination port includes storing in the
switching device an offset value, a comparator value, and an expectant
value; comparing information located at a position in a frame determined
by the offset value with the comparator value to obtain an outcome; and
processing the frame with the outcome. Processing the frame may include
communicating the frame to a destination port or setting the priority of
the frame. The offset and comparator values may be part of a filter that
also includes an anchor value from which the offset value is measured and
a mask value that masks the frame information before comparison with the
comparator value. Where there are a multiple of filters in the switching
device, the method may include combining the filter outcomes to obtain a
filter group outcome; and processing the frame with the group outcome.
Combining the filter outcomes may include logically combining their
outcomes. The method may also include merging the outcome with frame
forwarding information from another source; and processing the frame with
the merged outcome. Apparatus in accordance with the invention practices
these methods.