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, consider the following points:
• 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 is displayed. You must re-
configure 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{tengigabitE
thernet slot/port |
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.
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
1048 FC Flex IO Modules