ZyXEL Communications 70 Series User Manual

ZyWALL 5/35/70 Series User’s Guide

Chapter 25 Bandwidth Management

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• The Bill class cannot borrow unused bandwidth from the Root class because the Sales 

class has bandwidth borrowing disabled.

• The Amy class cannot borrow unused bandwidth from the Sales USA class because the 

Amy class has bandwidth borrowing disabled.

• The Research Software and Hardware classes can both borrow unused bandwidth from 

the Research class because the Research Software and Hardware classes both have 
bandwidth borrowing enabled. 

• The Research Software and Hardware classes can also borrow unused bandwidth from 

the Root class because the Research class also has bandwidth borrowing enabled. 

If you configure both maximize bandwidth usage (on the interface) and bandwidth borrowing 
(on individual sub-classes), the ZyWALL functions as follows.

1 The ZyWALL sends traffic according to each bandwidth class’s bandwidth budget.

2 The ZyWALL assigns a parent class’s unused bandwidth to its sub-classes that have more 

traffic than their budgets and have bandwidth borrowing enabled. The ZyWALL gives 
priority to sub-classes of higher priority and treats classes of the same priority equally.

3 The ZyWALL assigns any remaining unused or unbudgeted bandwidth on the interface to 

any class that requires it. The ZyWALL gives priority to classes of higher priority and 
treats classes of the same level equally.

4 If the bandwidth requirements of all of the traffic classes are met and there is still some 

unbudgeted bandwidth, the ZyWALL assigns it to traffic that does not match any of the 
classes.

Click ADVANCED, BW MGMT to open the Summary screen. 

Enable bandwidth management on an interface and set the maximum allowed bandwidth for 
that interface.