Reference Guide

Step Task Command Command Mode
4
Return to interface configuration mode.
exit
DCB MAP
5
Apply the DCB map, created to disable the PFC
operation, on the interface
dcb-map {name | default}
INTERFACE
6
Configure the port queues that still function as no-
drop queues for lossless traffic. For the dot1p-queue
assignments.
The maximum number of lossless queues globally
supported on a port is 2.
You cannot configure PFC no-drop queues on an
interface on which a DCB map with PFC enabled has
been applied, or which is already configured for PFC
using the pfc priority command.
Range: 0-3. Separate queue values with a comma;
specify a priority range with a dash; for example: pfc
no-drop queues 1,3 or pfc no-drop queues 2-3
Default: No lossless queues are configured.
pfc no-drop
queuesqueue-range
INTERFACE
Data Center Bridging: Default Configuration
Before you configure PFC and ETS on a switch see the priority group setting taken into account the following default settings:
DCB is enabled.
PFC and ETS are globally enabled by default.
The default dot1p priority-queue assignments are applied as follows:
Dell(conf)#do show qos dot1p-queue-mapping
Dot1p Priority : 0 1 2 3 4 5 6 7
Queue : 2 0 1 3 4 5 6 7
Dell(conf)#
NOTE: In Egress queue assignment (8 queues in S6000 and Z9500, 4 against in S5000 and S4810.
PFC is not applied on specific dot1p priorities.
ETS: Equal bandwidth is assigned to each port queue and each dot1p priority in a priority group.
To configure PFC and ETS parameters on an S6000 interface, you must specify the PFC mode, the ETS bandwidth allocation
for a priority group, and the 802.1p priority-to-priority group mapping in a DCB map. No default PFC and ETS settings are
applied to Ethernet interfaces.
Configuring PFC and ETS in a DCB Map
A Z9500 switch supports the use of a DCB map in which you configure priority-based flow control (PFC) and enhanced
transmission selection (ETS) settings. To configure PFC and ETS parameters, you must apply a DCB map on a Z9500 interface.
This functionality is supported on the Z9500 platform.
PFC Configuration Notes
PFC provides flow control based on the 802.1p priorities in a converged Ethernet traffic that is received on an interface and is
enabled by default when you enable DCB. As an enhancement to the existing Ethernet pause functionality, PFC stops traffic
transmission for specified priorities (CoS values) without impacting other priority classes. Different traffic types are assigned to
different priority classes.
Data Center Bridging (DCB)
209