Allied Telesis AT-S63 - Manual (Page 143)

AT-S63 Management Software Features Guide
Section II: Advanced Operations 143
Classifiers
Classifiers identify a particular traffic flow, and range from general to
specific. (See Chapter 10, “Classifiers” on page 109 for more information.)
Note that a single classifier should not be used in different flows that will
end up, through traffic classes, assigned to the same policy. A classifier
should only be used once per policy. Traffic is matched in the order of
classifiers. For example, if a flow group has classifiers 1, 3, 2 and 5, that is
the order in which the packets are matched.