Chapter 17 Bandwidth Management; Bandwidth Management Overview; Bandwidth Classes And Filters; Proportional Bandwidth Allocation - ZyXEL Communications ZyWALL 5 User Manual

This chapter describes the functions and configuration of bandwidth management.

17.1 Bandwidth Management Overview

Bandwidth management allows you to allocate an interface's outgoing capacity to specific types of
traffic. It can also help you make sure that the ZyWALL forwards certain types of traffic (especially
real-time applications) with minimum delay. With the use of real-time applications such as Voice-
over-IP (VoIP) increasing, the requirement for bandwidth allocation is also increasing.
Bandwidth management addresses questions such as:
•
Who gets how much access to specific applications?
•
What priority level should you give to each type of traffic?
•
Which traffic must have guaranteed delivery?
•
How much bandwidth should be allotted to guarantee delivery?
Bandwidth management also allows you to configure the allowed output for an interface to match
what the network can handle. This helps reduce delays and dropped packets at the next routing device.
For example, you can set the WAN interface speed to 1000kbps if the broadband device connected to
the WAN port has an upstream speed of 1000kbps. All configuration screens display measurements in
kbps (kilobits per second), but this User's Guide also uses Mbps (megabits per second) for brevity's
sake.

17.2 Bandwidth Classes and Filters

Use bandwidth classes and sub-classes to allocate specific amounts of bandwidth capacity (bandwidth
budgets). Configure a bandwidth filter to define a bandwidth class (or sub-class) based on a specific
application and/or subnet. Use the Class Setup tab (see section 17.9.1) to set up a bandwidth class's
name, bandwidth allotment, and bandwidth filter. You can configure up to one bandwidth filter per
bandwidth class. You can also configure bandwidth classes without bandwidth filters. However, it is
recommended that you configure sub-classes with filters for any classes that you configure without
filters. The ZyWALL leaves the bandwidth budget allocated and unused for a class that does not have
a filter itself or sub-classes with filters. View your configured bandwidth classes and sub-classes in the
Class Setup tab (see section 17.9 for details).
The total of the configured bandwidth budgets for sub-classes cannot exceed the configured bandwidth
budget speed of the parent class.

17.3 Proportional Bandwidth Allocation

Bandwidth management allows you to define how much bandwidth each class gets; however, the
actual bandwidth allotted to each class decreases or increases in proportion to actual available
bandwidth.
Bandwidth Management
ZyWALL 5 Internet Security Appliance
Bandwidth Management
Chapter 17
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