ZyXEL Communications ZyXEL ZyWALL 35 - Manual (Page 323)

ZyWALL 35 User’s Guide
Chapter 19 Bandwidth Management 321
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H A P T E R
19
Bandwidth Management
This chapter describes the functions and configuration of bandwidth management.
19.1 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.
19.2 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 the Bandwidth
Manager Class Configuration section ) 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 the Configuring Class Setup section ) for
details).