ZyXEL Communications P-661H Series, User Manual, Page: 237 / 383

P-661H/HW Series User’s Guide
Chapter 15 Bandwidth Management 237
15.5.2 Fairness-based Scheduler
The ZyXEL Device divides bandwidth equally among bandwidth classes when using the
fairness-based scheduler; thus preventing one bandwidth class from using all of the interface’s
bandwidth.
15.6 Maximize Bandwidth Usage
The maximize bandwidth usage option (see Figure 136 on page 240 ) allows the ZyXEL
Device to divide up any available bandwidth on the interface (including unallocated
bandwidth and any allocated bandwidth that a class is not using) among the bandwidth classes
that require more bandwidth.
When you enable maximize bandwidth usage, the ZyXEL Device first makes sure that each
bandwidth class gets up to its bandwidth allotment. Next, the ZyXEL Device divides up an
interface’s available bandwidth (bandwidth that is unbudgeted or unused by the classes)
depending on how many bandwidth classes require more bandwidth and on their priority
levels. When only one class requires more bandwidth, the ZyXEL Device gives extra
bandwidth to that class.
When multiple classes require more bandwidth, the ZyXEL Device gives the highest priority
classes the available bandwidth first (as much as they require, if there is enough available
bandwidth), and then to lower priority classes if there is still bandwidth available. The ZyXEL
Device distributes the available bandwidth equally among classes with the same priority level.
15.6.1 Reserving Bandwidth for Non-Bandwidth Class Traffic
Do the following three steps to configure the ZyXEL Device to allow bandwidth for traffic
that is not defined in a bandwidth filter.
1
Leave some of the interface’s bandwidth unbudgeted.
2 Do not enable the interface’s Maximize Bandwidth Usage option.
3
Do not enable bandwidth borrowing on the child-classes that have the root class as their
parent (see
Section 15.8 on page 241 ).