Juniper Networks EX2500 manual Quality of Service, QoS Overview

Chapter 5

Quality of Service

Quality of Service features allow you to allocate network resources to mission-critical applications at the expense of applications that are less sensitive to such factors as time delays or network congestion. You can configure your network to prioritize specific types of traffic, ensuring that each type receives the appropriate Quality of Service (QoS) level.

The following topics are discussed in this chapter:

„QoS Overview on page 51

„Using ACL Filters on page 52

„Using Storm Control Filters on page 59

„Using DSCP Values to Provide QoS on page 60

„Using 802.1p Priority to Provide QoS on page 63

„Queuing and Scheduling on page 64

QoS Overview

QoS helps you allocate guaranteed bandwidth to the critical applications, and limit bandwidth for less critical applications. Applications such as video and voice must have a certain amount of bandwidth to work correctly; using QoS, you can provide that bandwidth when necessary. Also, you can put a high priority on applications that are sensitive to timing out or that cannot tolerate delay, by assigning their traffic to a high-priority queue.

By assigning QoS levels to traffic flows on your network, you can ensure that network resources are allocated where they are needed most. QoS features allow you to prioritize network traffic, thereby providing better service for selected applications.

Figure 11 on page 52 shows the basic QoS model used by the switch.

QoS Overview „ 51