Use this command to configure a default congestion notification alternate priority on all ports for the specified CNPV.
| cnpv | Specifies a CNPV that the specified alternate priority is applied to. |
| alt-priority alt-priority | Specifies a non-CNPV alternate priority for the specified CNPV. Default value is 0. |
The alternate priority defaults to 0.
All command modes.
The congestion notification alternate priority is a non-CNPV. CNPVs are configured using set dcb cn priority. At least one 802.1p priority on a port must be a non-CNPV. Any non-CNPV can be used as a congestion notification alternate priority. A non-CNPV value should never be assigned to a transmit queue that contains a CNPV.
When a packet ingresses a congestion notification domain edge port with the same priority as a CNPV configured on the edge port, the priority of the ingressing packet must be remapped to an alternate priority. Should a non-congestion notification packet trigger congestion in a CNPV queue, the source for this packet will not know what to do with the CNM PDU it receives back from the congestion point. The remapping of the priority to a non-CNPV value at the congestion notification domain edge guards against this possibility.
The CNPV alternate priority value configured using this command is only used by a port-priority if the port-priority choice set using set dcb cn port-priority choice is default and the CNPV choice set using set dcb cn priority choice is admin.
If the port-priority choice is default and the CNPV choice is auto, or the port-priority choice is auto, the auto alternate priority is used. The auto alternate priority is the next lowest available non-CNPV priority relative to the CNPV. If there are no lower non-CNPVs, the next higher non-CNPV priority is used.
This example sets for CNPV 4, the port-priority choice on all ports to default, the CNPV choice to admin, and priority 3 as the alternate priority:
System(rw)->set dcb cn port-priority *.*.* 4 choice default System(rw)->set dcb cn priority 4 choice admin System(rw)->set dcb cn priority 4 alt-pri 3
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