Install Guide

For the dot1p-queue assignments, refer to the dot1p Priority-Queue Assignment table.
The maximum number of lossless queues globally supported on the switch is two.
The range is from 0 to 7. Separate the queue values with a comma; specify a priority range with a dash; for example, pfc
no-drop queues 1,7 or pfc no-drop queues 2-7.
The default: No lossless queues are configured.
3. Configure to drop the unknown unicast packets flooding on lossless priorities.
CONFIGURATION mode
pfc-nodrop-priority l2-dlf drop
4. View the packets drop count corresponding to the priority.
EXEC mode
EXEC Privilege mode
show hardware pfc-nodrop-priority l2-dlf drops stack-unit stack-unit-number port-set
port-pipe
DellEMC#show hardware pfc-nodrop-priority l2-dlf drops stack-unit 0 port-set 0
---------------------------------------------------
Priority DropCount
---------------------------------------------------
0 0
1 0
2 0
3 0
4 0
5 0
6 0
7 0
To clear the drop statistics, use the clear hardware pfc-nodrop-priority l2-dlf drops stack-unit
stack-unit-number port-set port-pipe command.
NOTE: Dell EMC Networking OS Behavior: By default, no lossless queues are configured on a port.
A limit of two lossless queues is supported on a port. If the amount of priority traffic that you configure to be paused exceeds
the two lossless queues, an error message displays.
It is the user responsibility to have symmetric PFC configurations on the interfaces involved in a particular PFC-enabled
traffic-flow to obtain lossless behavior.
Configuring PFC in a DCB Map
A switch supports the use of a DCB map in which you configure priority-based flow control (PFC) setting. To configure PFC
parameters, you must apply a DCB map on an interface.
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.
When traffic congestion occurs, PFC sends a pause frame to a peer device with the CoS priority values of the traffic that
needs to be stopped. DCBx provides the link-level exchange of PFC parameters between peer devices. PFC allows network
administrators to create zero-loss links for SAN traffic that requires no-drop service, while at the same time retaining packet-
drop congestion management for LAN traffic.
On a switch, PFC is enabled by default on Ethernet ports (pfc mode on command). You can configure PFC parameters
using a DCB map or the pfc priority command in Interface configuration mode. For more information, see Configuring
Priority-Based Flow Control.
As soon as you apply a DCB map with PFC enabled on an interface, DCBx starts exchanging information with a peer. The
IEEE802.1Qbb, CEE and CINIEEE802.1Qbb and CEE versions of PFC TLV are supported. DCBx also validates PFC configurations
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Data Center Bridging (DCB)