class (Forwarding Classes)
Syntax for QFX Series and OCX Series Routers
class {
class-name {
pfc-priority pfc-priority;
queue-num queue-number <no-loss>;
}
}
Syntax for M120, M320, MX Series routers, T Series routers, and EX Series switches
class {
class-name {
queue-num queue-number ;
priority (high | low) ;
}
}
Hierarchy Level
[edit class-of-service forwarding-classes]
Description
On M120 , M320, MX Series routers, T Series routers and EX Series switches only, 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.
On systems that do not use the ELS CLI, if you are using
Junos OS Release 12.2, use the default forwarding-class-to-queue mapping
for the lossless fcoe and no-loss forwarding
classes. If you explicitly configure the lossless forwarding classes,
the traffic mapped to those forwarding classes is treated as lossy
(best effort) traffic and does not receive lossless
treatment.
On systems that do not use the ELS CLI, if you are using
Junos OS Release 12.3 or later, the default configuration is the same
as the default configuration for Junos OS Release 12.2, and the default
behavior is the same (the fcoe and no-loss forwarding
classes receive lossless treatment). However, if you explicitly configure
lossless forwarding classes, you can configure up to six lossless
forwarding classes by specifying the no-loss option. If
you do not specify the no-loss option in an explicit forwarding
class configuration, the forwarding class is lossy. For example, if
you explicitly configure the fcoe forwarding class and
you do not include the no-loss option, the fcoe forwarding class is lossy, not lossless.
Options
class-name—Name of the forwarding class.
queue-number—Output queue
number.
Range: 0 through 7. Some T Series router PICs are restricted to 0 through 3.
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.