Juniper Networks EX2500 - Manual (Page 67)

QoS Overview „ 53
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 53
„ Using ACL Filters on page 54
„ Using Storm Control Filters on page 61
„ Using DSCP Values to Provide QoS on page 62
„ Using 802.1p Priority to Provide QoS on page 65
„ Queuing and Scheduling on page 66
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 54 shows the basic QoS model used by the switch.