Users Guide

Field Description
Appln Priority TLV
Pkts
QoS dot1p Traffic Classification and Queue
Assignment
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 dot1p priorities in ingress traffic are used at the port or global switch level.
Layer 2 class maps dot1p priorities are used to classify traffic in a class map and apply a service policy to an ingress port to map traffic
to egress queues.
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.
Although the system allows you to change the default dot1p priority-queue assignments, DCB policies applied to an interface may
become invalid if you reconfigure dot1p-queue mapping. If the configured dcb-map 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
Troubleshooting PFC, ETS, and DCBx Operation
In the show interfaces pfc | ets | dcbx output, the DCBx operational status may be down for any of the reasons described in
the following table.
When DCBx is down, the following values display in the show output field for DCBx Oper status:
• PFC DCBx Oper status: Down
• ETS DCBx Oper status: Down
• DCBx Oper status: Disabled.
Reason
Description
Port Shutdown Port is shut down. All other reasons for DCBx inoperation, if any, are ignored.
Data Center Bridging (DCB) 65