Administrator Guide

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
4 Clear the queue disable state, when the queue is disabled
during the pfc storm detection
DellEMC(conf-storm-
control-pcf)# storm-
control pfc in queue-
drop-state clear
INTERFACE
Priority-Based Flow Control Using Dynamic Buffer
Method
In a data center network, priority-based flow control (PFC) manages large bursts of one traffic type in multiprotocol links so that it does
not affect other traffic types and no frames are lost due to congestion. When PFC detects congestion on a queue for a specified priority,
it sends a pause frame for the 802.1p priority traffic to the transmitting device.
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Data Center Bridging (DCB)