Policy Evaluation - Alcatel-Lucent 7705 Configuration Manual

Route Policy Configuration Overview

Policy Evaluation

Routing policy statements can consist of one or several entries. The entries specify the
matching criteria. A label is compared to the first entry in the policy statement. If it matches,
the specified entry action is taken, either accepted or rejected. If the action is to accept or
reject the label, that action is taken and the evaluation of the label ends.
If the label does not match the first entry, the label is compared to the next entry (if more than
one is configured) in the policy statement. If there is a match with the second entry, the
specified action is taken. If the action is to accept or reject the label, that action is taken and
the evaluation of the label ends, and so on.
Each route policy statement can have a default-action clause defined. If a default action is
defined for one or more of the configured route policies, the default action should be handled
in the following ways.
Route policies can also match a given route policy entry and continue to search for other
entries within either the same route policy or the next route policy by specifying the
next-entry or next-policy option in the entry's action command. Policies can be
constructed to support multiple states to the evaluation and setting of various route attributes.
Figure 15
Figure 16
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• The process stops when the first complete match is found and executes the action
defined in the entry.
• If the packet does not match any of the entries, the system executes the default action
specified in the policy statement.
shows an example of the route policy process.
and Figure 17 show the next-policy and next-entry route policy processes.
7705 SAR OS Router Configuration Guide