Extreme Networks ExtremeWare 7.3.0, Command Reference Manual

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ExtremeWare Software 7.3.0 Command Reference Guide 379
7
QoS Commands
This chapter describes the following commands:
• Commands for configuring Quality of Service (QoS) profiles
• Commands creating traffic groupings and assigning the groups to QoS profiles
• Commands for configuring, enabling and disabling explicit class-of-service traffic groupings (802.1p
and Diffserv)
• Commands for configuring, enabling and disabling Random Early Detection (RED)
• Commands for configuring traffic grouping priorities
• Commands for verifying configuration and performance
• Commands for enabling and disabling the Dynamic Link Context System (DLCS)
This chapter does not describe the additional ingress and egress QoS capabilities available on the High
Density Gigabit Ethernet
“3”
series I/O modules. For more information and a full description of the
“3”
series I/O module command set, see Chapter 26.
Qualify of Service (QoS) is a feature of ExtremeWare that allows you to specify different service levels
for outbound and inbound traffic. QoS is an effective control mechanism for networks that have
heterogeneous traffic patterns. Using QoS, you can specify the service that a traffic type receives.
Policy-based QoS allows you to protect bandwidth for important categories of applications or
specifically limit the bandwidth associated with less critical traffic. The switch contains separate
hardware queues on every physical port. Each hardware queue is programmed by ExtremeWare with
bandwidth management and prioritization parameters, defined as a QoS profile. The bandwidth
management 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. Up to eight physical
queues per port are available.
Policy-based QoS can be configured to perform per-port Random Early Detection (RED). Using this
capability, the switch detects when traffic is filling up in any of the eight hardware queues, and
performs a random discard on subsequent packets, based on the configured RED drop-probability.
Instead of dropping sessions during times when the queue depth is exceeded, RED causes the switch to
lower session throughput.
To configure QoS, you define how your switch responds to different categories of traffic by creating and
configuring QoS profiles. The service that a particular type of traffic receives is determined by assigning
a QoS profile to a traffic grouping or classification. The building blocks are defined as follows:
• QoS profile —Defines bandwidth and prioritization parameters.