If the traffic congestion is on PORT B , Egress DROP is on PORT A or C, as the PFC is not enabled on
PORT B.
Refer the following configuration for queue to dot1p mapping:
Dell(conf)#do show qos dot1p-queue-mapping
Dot1p Priority : 0 1 2 3 4 5 6 7 -> On ingress interfaces[Port A and
C] we used the PFC on priority level.
Queue : 0 0 0 1 2 3 3 3 -> On Egress interface[Port B] we
used no-drop queues.
Lossless traffic egresses out the no-drop queues. Ingress 802.1p traffic from PFC-enabled peers is
automatically mapped to the no-drop egress queues.
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.
Step Task Command Command Mode
1 Enter INTERFACE Configuration mode. interface
{tengigabitEthernet
slot/port /subport
| fortygigabitEthernet
slot/port}
CONFIGURATION
2Open a DCB map and enter DCB map
configuration mode. dcb-map name INTERFACE
3Disable PFC. no pfc mode on DCB MAP
4Return to interface configuration mode. exit DCB MAP
5Apply the DCB map, created to disable the
PFC operation, on the interface dcb-map {name |
default}
INTERFACE
6Configure 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.
pfc no-drop
queuesqueue-range
INTERFACE
Data Center Bridging (DCB) 259