HP-UX IPQoS A.01.00 Programmer's Guide (October 2005)

Using the HP-UX IPQoS API
Filter Objects
Chapter 2 31
A completely overlapping (superset) filter prevents any traffic from matching the other filter
and effectively renders the other filter completely ineffective. A partial overlap (intersection)
renders the other function partially ineffective. An HP-UX IPQoS configuration with
overlapping filters is not recommended. Filters should be redefined to avoid having complete
or partial overlap conditions.
The HP-UX IPQoS API has a function IpqosCheckFilterOverlap() to assist with checking
for these cases. Refer to the IpqosOverlapFilter (3c) manpage for more detailed information on
how to check for overlapping filters.