Bandwidth Borrowing; Figure 17-5 Maximize Bandwidth Usage Example - ZyXEL Communications ZyWALL 5 User Manual

R&D requires more bandwidth but only gets its budgeted 2 Mbps because all of the
unbudgeted and unused bandwidth goes to the higher priority sales and marketing classes.
The ZyWALL does not send any traffic that is not defined in the bandwidth filters because all
of the unbudgeted bandwidth goes to the classes that need it.

17.7 Bandwidth Borrowing

Bandwidth borrowing allows a sub-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 sub-class to allow the sub-class to use its parent class's unused
bandwidth. A parent class's unused bandwidth is given to the highest priority sub-class first. The sub-
class can also borrow bandwidth from a higher parent class (grandparent class) if the sub-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 17.7.1).
The total of the bandwidth allotments for sub-classes cannot exceed the bandwidth allotment of their
parent class. The ZyWALL uses the scheduler to divide a parent class's unused bandwidth among the
sub-classes.
17.7.1 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.
Bandwidth Management

Figure 17-5 Maximize Bandwidth Usage Example

ZyWALL 5 Internet Security Appliance
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