Reference Guide

Data Center Bridging (DCB) | 295
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 quality of service (QoS) methods:
• Honor dot1p: Using the
service-class dynamic dot1p command in INTERFACE configuration mode, you
can honor dot1p priorities in ingress traffic at the port or global switch level (refer to Default dot1p to
Queue Mapping).
• 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).
Set PFC buffering on the DCB stack unit.
dcb stack-unit all
pfc-buffering
pfc-ports 64
pfc-queues 2
CONFIGURATION
Note: Save the configuration and reboot the system to save the pfc buffering configuration changes.
FTOS Behavior:
DCB is not supported if you enable link-level flow control on one or more interfaces (refer to Ethernet
Pause Frames on page 470).
Important: of two
Note: Dell Force10 does not recommend mapping all ingress traffic to a single queue when using PFC
and ETS. Ingress traffic classification using the service-class dynamic dot1p command (honor dot1p) is
recommended 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 Table 13-1 and the maximum
number of two lossless queues supported on a port (refer to Configuring Lossless Queues).
Although FTOS allows you to change the default dot1p priority-queue assignments (refer to Set dot1p
Priorities for Incoming Traffic), DCB policies applied to an interface may become invalid if dot1p-queue
mapping is reconfigured. If the configured DCB policy remains valid, the change in the dot1p-queue
assignment is allowed.
Task Command Command Mode