ZyXEL Communications Prestige 652, User Manual, Page: 239 / 521

Prestige 652 Series User’s Guide
Bandwidth Management 21-7
21.7 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 21.7.1 ).
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.
21.7.1 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.