Allied Telesis AT-S63 User Manual

Page of 514
Chapter 10: Classifiers
118
Section II: Advanced Operations
Guidelines
Follow these guidelines when creating a classifier:
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Each classifier represents a separate traffic flow.
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The variables within a classifier are linked by AND. The more variables 
defined within a classifier, the more specific it becomes in terms of the 
flow it defines. For instance, specifying both a source IP address and a 
TCP destination port within the same classifier defines a traffic flow 
that relates to IP packets containing both the designated source IP 
address and TCP destination port. However, there are some 
restrictions on combining variables in the same classifier. For the 
restrictions, refer to “Classifier Criteria” on page 113.
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The same classifier can be applied to both ACLs and QoS policies.
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You can apply the same classifier to more than one ACL or QoS 
policy.
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A classifier without any defined variables applies to all packets.
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You cannot create two classifiers that have the same settings. There 
can be only one classifier for any given type of traffic flow.
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A classifier can have a maximum of eight defined criteria, not including 
the classifier ID number and the description.
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The switch can store up to 256 classifiers. However, the maximum 
number of classifiers that you can assign to active access control lists 
and QoS policies at any one time will be from 14 to 127. The number 
depends on several factors, such as the number of ports to which the 
classifiers are assigned and the types of criteria defined in the 
classifiers.
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You cannot modify a classifier if it belongs to an ACL or QoS policy 
assigned to a port. You must remove the port assignments from the 
ACL or policy and reassign them after modifying the classifier.
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You cannot delete a classifier if it belongs to an ACL or QoS policy. 
You must remove a classifier from its ACLs and QoS policies before 
you can delete it.