set dcb cn port-priority alt-pri

Use this command to set the congestion notification alternate priority for the specified port and congestion notification priority.

Syntax

set dcb cn port-priority port-string priority alt-pri alt-priority

Parameters

port-string For a detailed description of possible port-string values, refer to Port String Syntax Used in the CLI in the S-, K-, and 7100 Series Configuration Guide.
priority Specifies a CNPV to which Congestion Notification will be applied on the specified port.
alt-priority The alternate priority a non-congestion controlled flow frame is remapped to when the ingressing frame has the same priority as a CNPV configured for this port.

Defaults

The port-priority alternate priority defaults to 0.

Mode

All command modes.

Usage

When entering any variation of the set dcb cn port-priority command, all options can be specified on a single command line. Options are: choice, alt-pri, defense, and lldp. These commands are detailed separately in this document for purposes of clarity.

The port-priority alternate priority is only used by the port-priority if the port-priority choice is set to admin.

When a frame that belongs to a non-congestion controlled flow ingresses a CNPV configured port with the same priority as the CNPV, the flow priority is remapped to the alternate priority. If frames from a non-congestion controlled flow are allowed to enter a CNPV configured transmit queue and trigger a CNM PDU back to the flows source, the source will not be able to process the CNM PDU and the transmit rate of the flow causing the congestion will not be throttled. This would defeat the purpose of congestion notification.

Up to seven CNPV priorities are configurable on a port. This assures that at least one non-CNPV priority is available on each port as an alternate priority.

Example

This example sets the alternate priority for CNPV 6 for all ports to 3:

System(rw)->set dcb cn port-priority *.*.* 6 choice admin alt-pri 3