Dell PowerEdge FN I/O Module Configuration Guide 9.10(0.0)

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QoS dot1p Traffic Classification and Queue Assignment

The following section describes QoS dot1P traffic classification and assignments.

DCB supports PFC, ETS, and DCBx to handle converged Ethernet traffic that is assigned to an egress queue according to the following QoS methods:

Honor dot1p	You can honor dot1p priorities in ingress traffic at the port or global switch level (refer to Default dot1p to Queue Mapping) using the `service-class dynamic dot1p` command in INTERFACE configuration mode (refer to Honoring dot1p Values on Ingress Packets ).
Layer 2 class maps	You can use dot1p priorities to classify traffic in a class map and apply a service policy to an ingress port to map traffic to egress queues (refer to Policy-Based QoS Configurations).

NOTE: Dell Networking does not recommend mapping all ingress traffic to a single queue when using PFC and ETS. However, Dell Networking does recommend using Ingress traffic classification using the service-class dynamic dot1p command (honor dot1p) on all DCB-enabled interfaces. If you use L2 class maps to map dot1p priority traffic to egress queues, take into account the default dot1p-queue assignments in the following table and the maximum number of two lossless queues supported on a port (refer to Configuring Lossless Queues).
Although the system allows you to change the default dot1p priority-queue assignments (refer to Setting dot1p Priorities for Incoming Traffic ), DCB policies applied to an interface may become invalid if you reconfigure dot1p-queue mapping. If the configured DCB policy remains valid, the change in the dot1p-queue assignment is allowed. For DCB ETS enabled interfaces, traffic destined to queue that is not mapped to any dot1p priority are dropped.

dot1p Value in the Incoming Frame	Egress Queue Assignment
0	0
1	0
2	0
3	1
4	2
5	3
6	3
7	3

NOTE: If you reconfigure the global dot1p-queue mapping, an automatic re-election of the DCBX configuration source port is performed (refer to Configuration Source Election ).