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dscp (Input Congestion Notification)


Hierarchy Level


Configure a Differentiated Services code point (DSCP) value and apply priority-based flow control (PFC) to packets with that code point.

When this statement is configured, DSCP-based PFC can be invoked for untagged traffic by matching specified 6-bit DSCP values in the Layer 3 IP header of incoming packets instead of an IEEE 802.1p priority in the Layer 2 VLAN header. Additional configuration parameters associate configured DSCP values with a PFC priority to use in the Layer 2 pause frames sent to peers when the link becomes congested.

DSCP-based PFC can be used to support Remote Direct Memory Access (RDMA) over converged Ethernet version 2 (RoCEv2).

To enable DSCP-based PFC:

  • Use this statement to define a congestion notification profile to enable PFC on traffic specified by a DSCP value.

  • Use the [edit class-of-service forwarding-classes class class-name] pfc-priority statement to map a lossless forwarding class to a PFC priority value to use in the PFC pause frames.

  • Use the [edit class-of-service classifiers] dscp statement to set up a DSCP classifier for the desired DSCP value and forwarding class mapped to a PFC priority above.

The remaining statements are explained separately. Search for a statement in CLI Explorer or click a linked statement in the Syntax section 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 17.4R1.