Configuring a Route-Filter

Procedure

• Configure a route-filter using the paragraph editing mode.
  1. Run the edit xpl route-filter route-filter-name command to enter the route-filter paragraph editing interface view.
  2. Press i to enter the text editing mode.
     

     Sets or route-filters can be configured only in the text editing mode. If you exit from the text editing mode, you can perform shortcut key operations only.

  3. Configure a start clause in the format of xpl route-filter route-filter-name($var1,$var2,...) for a route-filter. The parameters are optional and can be used in condition or action clauses.
  4. Configure a matching condition in the format of if+condition clause+then and connect the conditions with the Boolean operator NOT, AND, or OR. For details about condition clauses, see Condition Clauses.
     

     Route-filters can have only action clauses and can also be empty (configured with only a start clause and an end clause). In this case, the default action refuse is used. If an empty route-filter is specified in another route-filter using a call clause, the empty route-filter does not take effect.

  5. Configure an action clause. For details about action clauses, see Action Clauses.
     

     • Multiple action clauses can be configured if they do not conflict with each other.
     • Action clauses (excluding approve, refuse, finish, call route-filter route-filter-name, and break) must follow apply.

  6. (Optional) Configure elseif+condition clause+then to filter the routes that fail to match the conditions specified in the if clause and specify an action clause for the elseif clause. You can configure multiple elseif clauses to filter the routes that fail to meet the previous matching rule or configure an else clause to match the routes that fail to meet all the previous matching rules. Each if, elseif, or else clause must be followed by an action clause.
  7. Configure a conclusive condition clause (endif).
     

     Steps 2 to 5 describe how to configure an if condition branch. One route-filter can have multiple if condition branches, which can be configured in two modes, and both the two modes can be used in the same route-filter.

     • One if condition branch is followed by another.
     • The if+condition clause+then or elseif+condition clause+then is followed by another if condition branch. Such a configuration further filters the routes that match if+condition clause+then or elseif+condition clause+then against the second if condition branch.

     Regardless of the configuration mode, route filtering continues until finish, break, refuse, or the last if condition branch is implemented.

  8. Configure a conclusive clause (end-filter) for the route-filter.
  9. Press Esc to exit from the text editing mode.
  10. Press :wq and Enter to save the configurations and exit from the global variable set paragraph editing interface view.
      

      A message is displayed for you to confirm whether to commit the configurations when you attempt to exit from the global variable set paragraph editing interface view. To commit the configurations, press Y.

      To exit from the global variable set paragraph editing interface view without saving the configurations, press :q! and Enter.

• Configure a route-filter using the line editing mode.
  1. Run the system-view command to enter the system view.
  2. Run the xpl route-filter route-filter-name command to enter the route-filter view.
  3. Run the if [ not ] condition-clause [ { and | or } [ not ] condition-clause ] ^* then command to configure matching rules for the route-filter.
     

     Route-filters can have only action clauses and can also be empty (only configured with xpl route-filter and end-filter). In this case, the default action refuse is used. If an empty route-filter is specified in another route-filter using a call clause, the empty route-filter does not take effect.

  4. Configure an action using any of the following commands for the routes that meet matching rules:
     • apply action-clause: sets a route attribute for the routes that meet matching rules.
     • approve: further filters the routes that meet the matching rules of the current if condition branch against the next if condition branch.
     • refuse: denies routes that meet matching rules.
     • finish: completes route filtering and allows the routes that meet matching rules to match the route-filter.
     • call route-filter route-filter-name: further matches the routes that meet the matching rules of the current route-filter against the specified route-filter.
     • break: enables the device to exit from the current route-filter. If the current route-filter is referenced by a parent route-filter, the device keeps implementing remaining condition and action clauses of the parent route-filter.
     

     Multiple action clauses can be configured if they do not conflict with each other.

  5. Run the elseif [ not ] condition-clause [ { and | or } [ not ] condition-clause ] ^* then command to filter the routes that fail to meet the rules specified in the if command and specify an action for the routes. You can run the elseif command multiple times to filter the routes that fail to meet the previous matching rules or run the else command to match the routes that fail to meet all the previous matching rules.
  6. Run the endif command to conclude the configuration of the current if condition branch.
     

     An if condition branch is the part from if to endif. One route-filter can have multiple if condition branches, which can be configured in two modes, and the two modes can be used in the same route-filter.

     • One if condition branch is followed by another.
     • The if or elseif clause of one if condition branch is followed by another if condition branch. Such a configuration further filters the routes that match the if or elseif clause against the second if condition branch.

     Regardless of the configuration mode, route filtering continues until finish, break, refuse, or the last if condition branch is implemented.

  7. Run the end-filter command to conclude the configuration of the route-filter.
  8. Run the commit command to commit the configuration.