Addendum

Step Task Command Command Mode
Maximum number of loss less queues
supported on an Ethernet port: 2.
Separate priority values with a comma.
Specify a priority range with a dash, for
example: pfc priority 3,5-7
1. You cannot configure PFC using the pfc
priority command on an interface on
which a DCB map has been applied or
which is already configured for lossless
queues (pfc no-drop queues
command).
Configuring Lossless Queues
DCB also supports the manual configuration of lossless queues on an interface after you disable PFC
mode in a DCB map and apply the map on the interface. The configuration of no-drop queues provides
flexibility for ports on which PFC is not needed but lossless traffic should egress from the interface.
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, take into account:
• By default, no lossless queues are configured on a port.
• A limit of two lossless queues are supported on a port. If the number of lossless queues configured
exceeds the maximum supported limit per port (two), an error message displays. You must
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 displays.
Step Task Command Command Mode
1 Enter INTERFACE Configuration mode. interface
{tengigabitEthernet
slot/port |
fortygigabitEthernet
slot/port}
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 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, see Table 131.
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
pfc no-drop queues
queue-range
INTERFACE
Data Center Bridging (DCB)
535