ZyXEL Communications P-660H - VERSION 3.40, User Manual

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P-660H/HW/W-T Series User’ Guide
187 Chapter 16 Media Bandwidth Management Advanced Setup
Figure 91 Maximize Bandwidth Usage Example
16.7 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 that has bandwidth borrowing configured, first.
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.
16.7.1 Maximize Bandwidth Usage With Bandwidth Borrowing
If you configure both maximize bandwidth usage (on the interface) and bandwidth borrowing
(on individual child-classes), the Prestige functions as follows.
1
The Prestige sends traffic according to each bandwidth class’s bandwidth budget.
2 The Prestige assigns a parent class’s unused bandwidth to its child-classes that have more
traffic than their budgets and have bandwidth borrowing enabled. The Prestige gives
priority to bandwidth child-classes of higher priority and treats bandwidth classes of the
same priority equally.
3 The Prestige assigns any remaining unused or unbudgeted bandwidth on the interface to
any bandwidth class that requires it. The Prestige gives priority to bandwidth classes of
higher priority and treats bandwidth classes of the same level equally.