Deployment Guide

When configuring lossless queues on a port interface, consider the following points:
● By default, no lossless queues are configured on a port.
● A limit of two lossless queues is supported on a port. If the number of lossless queues configured exceeds the maximum
supported limit per port (two), an error message is displayed. Reconfigure the value to a smaller number of queues.
● If you configure lossless queues on an interface that already has a DCB map with PFC enabled (pfc on), an error message is
displayed.
Table 18. Configuring Lossless Queues on a Port Interface
Step Task Command Command Mode
1 Enter INTERFACE Configuration mode.
interface interface-type
CONFIGURATION
2
Open a DCB map and enter DCB map configuration
mode.
dcb-map name
INTERFACE
3
Disable PFC.
no pfc mode on
DCB MAP
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
Configuring PFC Asymmetric
The interface is designed to honor incoming pause frames (lossy and lossless) on all priorities. However, the interface will only
generate pause frames on priorities that are configured to be lossless (typically priorities 3 and 4). Any received pause frames
are reflected in the appropriate counters, and PFC watchdog accounts for pause frames on all priorities.
Table 19. Configuring PFC Assymetric
Step Task Command Command Mode
1 Enter interface configuration mode on an Ethernet
port.
DellEMC#interface
interface-type
CONFIGURATION
2 Enable pfc asymmetric on interface.
DellEMC(conf-if-
fo-1/1/1)#pfc asymmetric
INTERFACE
3 Configure pfc storm control to disable the queue if the
pfc storm is detected
DellEMC(conf-if-
fo-1/1/1)#storm-control
pfc in queue-drop
INTERFACE
Data Center Bridging (DCB) 249