Administrator Guide

To disable or re-enable DCB on a switch, enter the following commands.
1 Disable DCB.
CONFIGURATION mode
no dcb enable
2 Re-enable DCB.
CONFIGURATION mode
dcb enable
NOTE: Dell Networking OS Behavior: DCB is not supported if you enable link-level flow control on one
or more interfaces.
After you disable DCB, if link-level flow control is not automatically enabled on an interface, to enable flow
control, manually shut down the interface (the shutdown command) and re-enable it (the no shutdown
command).
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.
FC Flex IO Modules 1063