ZyXEL Communications 650 Series Manuel D’Utilisation

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Prestige 650 Series User’s Guide 
Bandwidth Management 
 
20-7 
20.7 Bandwidth Borrowing 
Bandwidth borrowing allows a child-class to borrow unused bandwidth from its parent class, whereas 
maximize bandwidth usage allows bandwidth classes to borrow any unused or unbudgeted bandwidth on the 
whole interface. 
Enable bandwidth borrowing on a child-class to allow the child-class to use its parent class’s unused 
bandwidth. A parent class’s unused bandwidth is given to the highest priority child-class first. The child-class 
can also borrow bandwidth from a higher parent class (grandparent class) if the child-class’s parent class is 
also configured to borrow bandwidth from its parent class. This can go on for as many levels as are 
configured to borrow bandwidth from their parent class (see section 20.7.1).  
The total of the bandwidth allotments for child-classes cannot exceed the bandwidth allotment of their parent 
class. The Prestige uses the scheduler to divide a parent class’s unused bandwidth among the child-classes.  
20.7.1 Bandwidth Borrowing Example 
Here is an example of bandwidth management with classes configured for bandwidth borrowing. The classes 
are set up based on departments and individuals within certain departments.