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• Guidelines for Configuring Dynamic CoS for Subscriber Access    

• Related Topics
• CoS for Subscriber Access Overview
• Configuring Static Scheduling and Queuing in a Dynamic Profile for Subscriber Access
• Configuring Dynamic Scheduling and Queuing in a Dynamic Profile for Subscriber Access
• For information about static CoS configurations, see the JUNOS Class of Service Configuration Guide the

Guidelines for Configuring Dynamic CoS for Subscriber Access

This topic describes the hardware requirements and guidelines for configuring dynamic CoS in a subscriber access environment.

Hardware Requirements for Dynamic CoS

To configure CoS for dynamic subscriber access, you must have an Enhanced Queuing Distributed Port Controllers (EQ DPC) or the Trio MPC/MIC family of products on the MX Series Ethernet Services Router.

To configure CoS for static PPPoE subscriber interfaces, you must have an IQ2 PIC on the M120 router or M320 router or the Trio MPC/MIC family of products on the MX Series Ethernet Services Router.

To configure hierarchical CoS for static or dynamic PPPoE subscriber interfaces, you must have an IQ2E PIC on the M120 router or M320 router or the Trio MPC/MIC family of products on the MX Series Ethernet Services Router.

Configuration Considerations for Scheduling and Queuing

When configuring scheduling and queuing for subscriber access, consider the following guidelines:

• In the current release, you configure the traffic scheduling and shaping parameters in a traffic-control profile within the dynamic profile. You can configure the scheduler map and schedulers in a dynamic profile or in the [edit class-of-service] hierarchy. You must statically configure the remaining CoS parameters, such as hierarchical scheduling, classifiers, drop profiles, and forwarding classes, in the [edit class-of-service] hierarchy.
• You must enable hierarchical scheduling in the static CLI for the interface referenced in the dynamic profile. If not, the dynamic profile fails.
• You can configure only one traffic-control-profile under a dynamic profile.
• You must define the output-traffic-control-profile that binds the traffic-control profile to the interface within the same dynamic profile as the interface.
• We recommend that you provide different names for the schedulers defined in dynamic profiles that are used for access and services. For example, if there are two dynamic profiles, voice-profile and video-profile, provide unique names for the schedulers defined under those profiles.
• You must use a service dynamic profile with a different profile name for each RADIUS CoA request over the same logical interface.

Configuration Guidelines for Classifiers and Rewrite Rules

When you configure classifiers and rewrite rules for subscriber access, consider the following guidelines:

• To apply classifiers and rewrite rules to a subscriber interface in a dynamic profile, you must configure the rewrite rule and classifier definitions in the static [edit class-of-service] hierarchy and reference them in the dynamic profile.
  • If a static classifier or a rewrite rule definition that is referenced by a dynamic subscriber interface does not exist, the configuration is invalid and the subscriber cannot log in.
  • If a network administrator changes the static classifiers and rewrite rules definitions that is referenced in a dynamic profile with an active subscriber interface logged in, the changes are applied to the active subscriber interface immediately.
  • If a network administrator deletes a classifier or a rewrite rule definition that is referenced by an active dynamic subscriber interface, the system removes the classifier or rewrite rule binding from the interface. The classifier is replaced by the default classifier. If the network administrator adds the removed classifier or rewrite rule to the configuration while the dynamic interface is active, the addition will not take effect until the subscriber logs out and then logs in again.
• IP demux interfaces can only instantiate layer 3 rules (both rewrite rules and classifiers).
  • An IP demux subscriber interface can implicitly inherit a classifier from the underlying interface. If an IP demux interface is created without a classifier and a layer 2 classifier is attached to the underlying interface, the IP demux interface also inherits the layer 2 classifier. The show class-of-service interfaceinterface-name command does not display this attachment.

    Table 1 lists the classification rule configuration for an IP demux subscriber interface with a VLAN underlying interface.

    Table 1: IP Demux Classification Rules

    	IP Demux Interface Classifier Configuration
    	—	Layer 3
    VLAN Underlying Interface Classifier Configuration	Resulting Classifier Configuration
    Layer 2	VLAN layer 2	Demux layer 3
    Layer 3	Default	Demux layer 3

  • An IP demux subscriber interface explicitly inherits layer 2 rewrite rules from the underlying interface if a layer 2 rewrite rule is present. The show class-of-service interfaceinterface-name command displays the attachment.

    Table 2 lists the rewrite rule configuration for an IP demux subscriber interface with a VLAN underlying interface.

    Table 2: IP Demux Rewrite Rules

    	IP Demux Interface Rewrite Rule Configuration
    	—	Layer 3
    VLAN Underlying Interface Rewrite Rule Configuration	Resulting Rewrite Rule Configuration
    Layer 2	VLAN layer 2	VLAN layer 2 and demux layer 3
    Layer 3	Default	Demux layer 3