Chapter 19 Bandwidth Management

2Do not enable the interface’s Maximize Bandwidth Usage option.

3Do not enable bandwidth borrowing on the sub-classes that have the root class as their parent (see Section 19.8 on page 355).

19.7.5Maximize Bandwidth Usage Example

Here is an example of a ZyWALL that has maximize bandwidth usage enabled on an interface. The following table shows each bandwidth class’s bandwidth budget. The classes are set up based on subnets. The interface is set to 10240 kbps. Each subnet is allocated 2048 kbps. The unbudgeted 2048 kbps allows traffic not defined in any of the bandwidth filters to go out when you do not select the maximize bandwidth option.

Table 103 Maximize Bandwidth Usage Example

BANDWIDTH CLASSES AND ALLOTMENTS

Root Class: 10240 kbps

Administration: 2048 kbps

 

 

 

Sales: 2048 kbps

 

 

 

Marketing: 2048 kbps

 

 

 

Research: 2048 kbps

 

 

The ZyWALL divides up the unbudgeted 2048 kbps among the classes that require more bandwidth. If the administration department only uses 1024 kbps of the budgeted 2048 kbps, the ZyWALL also divides the remaining 1024 kbps among the classes that require more bandwidth. Therefore, the ZyWALL divides a total of 3072 kbps of unbudgeted and unused bandwidth among the classes that require more bandwidth.

19.7.5.1 Priority-based Allotment of Unused and Unbudgeted Bandwidth

The following table shows the priorities of the bandwidth classes and the amount of bandwidth that each class gets.

Table 104 Priority-based Allotment of Unused and Unbudgeted Bandwidth Example

BANDWIDTH CLASSES, PRIORITIES AND ALLOTMENTS

Root Class: 10240 kbps

Administration: Priority 4, 1024 kbps

 

 

 

Sales: Priority 6, 3584 kbps

 

 

 

Marketing: Priority 6, 3584 kbps

 

 

 

Research: Priority 5, 2048 kbps

 

 

Suppose that all of the classes except for the administration class need more bandwidth.

•Each class gets up to its budgeted bandwidth. The administration class only uses 1024 kbps of its budgeted 2048 kbps.

•The sales and marketing are first to get extra bandwidth because they have the highest priority (6). If they each require 1536 kbps or more of extra bandwidth, the ZyWALL divides the total 3072 kbps total of unbudgeted and unused bandwidth equally between the sales and marketing departments (1536 kbps extra to each for a total of 3584 kbps for each) because they both have the highest priority level.

•Research requires more bandwidth but only gets its budgeted 2048 kbps because all of the unbudgeted and unused bandwidth goes to the higher priority sales and marketing classes.

354

 

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