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class (Forwarding Classes)

Syntax for QFX Series Routers

Syntax for MX Series routers and EX Series switches

Hierarchy Level


Specify the output transmission queue to which to map all input from an associated forwarding class.

This statement enables you to configure up to 16 forwarding classes with multiple forwarding classes mapped to single queues. If you want to configure up to eight forwarding classes with one-to-one mapping to output queues, use the queue statement instead of the class statement at the [edit class-of-service forwarding-classes] hierarchy level.

Map one or more forwarding classes to a single queue. Also, when configuring DSCP-based PFC, map a forwarding class to a PFC priority value to use in pause frames when traffic on a DSCP value becomes congested (see Configuring DSCP-based PFC for Layer 3 Untagged Traffic for details).

You can map unicast forwarding classes to a unicast queue (0 through 7) and multidestination forwarding classes to a multicast queue (8 through 11). The queue to which you map a forwarding class determines if the forwarding class is a unicast or multicast forwarding class.


class-name—Name of the forwarding class.

queue-number—Output queue number.

  • Range: 0 through 7.

The remaining statements are explained separately. See CLI Explorer for details.

Required Privilege Level

interface—To view this statement in the configuration.interface-control—To add this statement to the configuration.

Release Information

Statement introduced in Junos OS Release 8.1.

No-loss option introduced in Junos OS Release 12.3 for the QFX Series.

PFC-priority statement introduced in Junos OS Release 17.4R1 for the QFX Series.