Global Qos Parameter Instance Overview; Qos Parameters For Interfaces Overview - Juniper JUNOSE SOFTWARE FOR E SERIES 11.3.X - QUALITY OF SERVICE CONFIGURATION GUIDE 2010-09-22 Configuration Manual

JunosE 11.3.x Quality of Service Configuration Guide

Global QoS Parameter Instance Overview

QoS Parameters for Interfaces Overview

226
Shared-shaping rate
Scheduler weight
In the following example, a parameter instance is created in Global Configuration mode.
host1(config)#qos-parameter max-subscriber-bandwidth 8000000
When you create a parameter instance in Global Configuration mode, the value that you
set for a rate becomes the default value for the router. We recommend that you create
a global default value for a parameter instance to provide a minimal level of service by
default for the router.
When you attach a parameter instance to an interface in Interface Configuration mode,
the default value for the chassis overrides the default value for the router. When attached
to subinterfaces, parameter instances override both interface and global configurations.
In the following example, a parameter instance is created on a Fast Ethernet interface
in Interface Configuration mode.
host1(config)#interface fastEthernet 9/0.2
host1(config-if)#qos-parameter max-subscriber-bandwidth 8000000
Parameter instances have hierarchical scope. The scope of a parameter instance is the
set of logical interfaces stacked above the interface upon which you create it. Any interface
stacked above the instance that is one of the controlled-interface types that are
configured in the parameter definition can have its nodes or queues controlled by that
instance. For example, a parameter named max-sub-bw might have logical interface
types of IP and l2tp-session; therefore, it controls rates only for nodes and queues
associated with those interface types.
For example, the scope of a parameter instance at a S-VLAN can be all VLANs stacked
above that particular S-VLAN. Scopes can overlap, for example, if a parameter instance
is created for both an S-VLAN and a VLAN. The most specific instance overrides the other
instances.
However, you cannot configure QoS parameter instances to downreference through the
interface stack. For example, you cannot create a parameter instance with an interface
type of ATM VP on an ATM1483 subinterface.
When you attach the parameter instance to an interface, it provides a default subscriber
bandwidth for terminated and tunneled subscribers that terminate over that interface.
To set parameter instances for a subscriber, a parameter instance is attached to a
subscriber interface such as a vlan or atm-vc. The QoS administrator defines the available
subscriber-interface types in the parameter definition. The parameter instance overrides
the QoS profile attachment lower down the interface stack, providing a subscriber-specific
value.
You can attach QoS profiles and QoS parameters to a logical interface in either order. If
a scheduler profile calls for a parameter and no parameter instance is defined, the system
Copyright © 2010, Juniper Networks, Inc.