Bwm (Bandwidth Management); Overview; What You Can Do In This Chapter; What You Need To Know - ZyXEL Communications USG40 User Manual

24.1 Overview

Bandwidth management provides a convenient way to manage the use of various services on the
network. It manages general protocols (for example, HTTP and FTP) and applies traffic prioritization
to enhance the performance of delay-sensitive applications like voice and video.

24.1.1 What You Can Do in this Chapter

Use the BWM screens (see
through the ZyWALL/USG, and it identifies the conditions that refine the bandwidth control.

24.1.2 What You Need to Know

When you allow a service, you can restrict the bandwidth it uses. It controls TCP and UDP traffic.
Use policy routes to manage other types of traffic (like ICMP).
Note: Bandwidth management in policy routes has priority over TCP and UDP traffic
policies.
If you want to use a service, make sure both the security policy allow the service's packets to go
through the ZyWALL/USG.
Note: The ZyWALL/USG checks security policies before it checks bandwidth management
rules for traffic going through the ZyWALL/USG.
Bandwidth management examines every TCP and UDP connection passing through the ZyWALL/
USG. Then, you can specify, by port, whether or not the ZyWALL/USG continues to route the
connection.
DiffServ and DSCP Marking
QoS is used to prioritize source-to-destination traffic flows. All packets in the same flow are given
the same priority. CoS (class of service) is a way of managing traffic in a network by grouping
similar types of traffic together and treating each type as a class. You can use CoS to give different
priorities to different packet types.
DiffServ (Differentiated Services) is a class of service (CoS) model that marks packets so that they
receive specific per-hop treatment at DiffServ-compliant network devices along the route based on
the application types and traffic flow. Packets are marked with DiffServ Code Points (DSCPs)
indicating the level of service desired. This allows the intermediary DiffServ-compliant network
devices to handle the packets differently depending on the code points without the need to
C

BWM (Bandwidth Management)

Section 24.2 on page
ZyWALL/USG Series User's Guide
407
HAPTER
411) to control bandwidth for services passing
2 4