ZyWALL 5/35/70 Series User’s Guide

25.8 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 25.8.1 on page 403).

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.

25.8.1 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.

Refer to the product specifications in the appendix to see how many class levels you can configure on your ZyWALL.

Table 140 Bandwidth Borrowing Example

BANDWIDTH CLASSES AND BANDWIDTH BORROWING SETTINGS

Root Class:

Administration: Borrowing

 

 

 

Enabled

 

 

 

 

 

 

 

Sales: Borrowing Disabled

Sales USA: Borrowing

Bill: Borrowing Enabled

 

 

Enabled

 

 

 

Amy: Borrowing Disabled

 

 

 

 

 

 

 

 

 

Sales Asia: Borrowing

Tina: Borrowing Enabled

 

 

Disabled

 

 

 

Fred: Borrowing Disabled

 

 

 

 

 

 

 

 

Marketing: Borrowing

 

 

 

Enabled

 

 

 

Research: Borrowing

Software: Borrowing

 

 

Enabled

Enabled

 

 

 

Hardware: Borrowing

 

 

 

Enabled

 

•The Bill class can borrow unused bandwidth from the Sales USA class because the Bill class has bandwidth borrowing enabled.

•The Bill class can also borrow unused bandwidth from the Sales class because the Sales USA class also has bandwidth borrowing enabled.

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Chapter 25 Bandwidth Management