Extreme Networks Summit 300-48, Software User'S Manual

Page: 121 / 198

Summit 300-48 Switch Software User Guide 121
11
Quality of Service (QoS)
This chapter describes the following topics:
• Overview of Policy-Based Quality of Service on page 121
• Applications and Types of QoS on page 122
• Configuring QoS for a Port or VLAN on page 123
• Traffic Groupings on page 124
— MAC-Based Traffic Groupings on page 125
— Explicit Class of Service (802.1p and DiffServ) Traffic Groupings on page 126
— Physical and Logical Groupings on page 130
• Verifying Configuration and Performance on page 131
• Modifying a QoS Configuration on page 132
• Traffic Rate-Limiting on page 132
Policy-based Quality of Service (QoS) is a feature of ExtremeWare and the Extreme switch architecture
that allows you to specify different service levels for traffic traversing the switch. Policy-based QoS is an
effective control mechanism for networks that have heterogeneous traffic patterns. Using Policy-based
QoS, you can specify the service level that a particular traffic type receives.
Overview of Policy-Based Quality of Service
Policy-based QoS allows you to protect bandwidth for important categories of applications or
specifically limit the bandwidth associated with less critical traffic. For example, if voice–over-IP traffic
requires a reserved amount of bandwidth to function properly, using QoS, you can reserve sufficient
bandwidth critical to this type of application. Other applications deemed less critical can be limited so
as to not consume excessive bandwidth. The switch contains separate hardware queues on every
physical port. Each hardware queue can be programmed by ExtremeWare with bandwidth limitation
and prioritization parameters. The bandwidth limitation and prioritization parameters that modify the
forwarding behavior of the switch affect how the switch transmits traffic for a given hardware queue on
a physical port.