Quality Of Service (Qos); Chapter 10 Quality Of Service (Qos); Qos Overview; What You Can Do In This Chapter - ZyXEL Communications EX5501-B0 User Manual

Quality of Service (QoS)

10.1 QoS Overview

Quality of Service (QoS) refers to both a network's ability to deliver data with minimum delay, and the
networking methods used to control the use of bandwidth. Without QoS, all traffic data is equally likely
to be dropped when the network is congested. This can cause a reduction in network performance and
make the network inadequate for time-critical applications such as video-on-demand.
Configure QoS on the Zyxel Device to group and prioritize application traffic and fine-tune network
performance. Setting up QoS involves these steps:
Configure classifiers to sort traffic into different flows.
1
Assign priority and define actions to be performed for a classified traffic flow.
2
The Zyxel Device assigns each packet a priority and then queues the packet accordingly. Packets
assigned a high priority are processed more quickly than those with low priority if there is congestion,
allowing time-sensitive applications to flow more smoothly. Time-sensitive applications include both
those that require a low level of latency (delay) and a low level of jitter (variations in delay) such as
Voice over IP (VoIP) or Internet gaming, and those for which jitter alone is a problem such as Internet
radio or streaming video. There are eight priority levels, with 1 having the highest priority.
This chapter contains information about configuring QoS and editing classifiers.

10.1.1 What You Can Do in this Chapter

• The General screen lets you enable or disable QoS and set the upstream bandwidth
page 154).
• The Queue Setup screen lets you configure QoS queue assignment
• The Classification Setup screen lets you add, edit or delete QoS classifiers
• The Shaper Setup screen limits outgoing traffic transmission rate on the selected interface
10.6 on page
• The Policer Setup screen lets you control incoming traffic transmission rate and bursts
page 163).

10.2 What You Need to Know

The following terms and concepts may help as you read through this chapter.
162).
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H A P T E R
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(Section 10.3 on
(Section 10.4 on page 155).
(Section 10.5 on page
(Section
(Section 10.7 on
158).