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Hierarchy Level


Configure the class-of-service (CoS) queue threshold by percentage.


This feature is only available when you enable subscriber management. For more information on enabling subscriber management, see Configuring Junos OS Enhanced Subscriber Management.

This CoS resource monitoring feature bases admission decisions only on queues. Other CoS resources are not part of this criteria. This feature does not support throttling for subscribers arriving on pseudo-wire, logical tunnel, or redundant logical tunnel devices. The feature is supported on the following hardware:

  • MX240, MX480, and MX960 routers

  • MPC2E legacy, MPC2E-NG, MPC3E-NG, MPC5E, and MPC7E line cards



High-threshold percentage for CoS queue utilization per scheduler. When CoS queue utilization on a given FPC reaches that FPC's configured threshold level, further subscriber logins on that FPC are not allowed. This resource monitoring mechanism provides adjustable safety margins to proactively avoid completely exhausting each FPC's available CoS queue resources. Starting in Junos OS Release 19.4R1, you can specify a value of 0, which means that no subscribers are throttled based on CoS queue throttling.

  • Range: 0 through 90

  • Default: 100

Required Privilege Level

system—To view this statement in the configuration.

system-control—To add this statement to the configuration.

Release Information

Statement introduced in Junos OS Release 17.4R1.