Users Guide

Conguring Lossless Queues
DCB also supports the manual conguration of lossless queues on an interface after you disable PFC mode in a DCB map and apply
the map on the interface. The conguration of no-drop queues provides exibility for ports on which PFC is not needed, but lossless
trac should egress from the interface.
Lossless trac egresses out the no-drop queues. Ingress 802.1p trac from PFC-enabled peers is automatically mapped to the no-
drop egress queues.
When conguring lossless queues on a port interface, consider the following points:
• By default, no lossless queues are congured on a port.
• A limit of two lossless queues are supported on a port. If the number of lossless queues congured exceeds the maximum
supported limit per port (two), an error message is displayed. You must re-congure the value to a smaller number of queues.
• If you congure lossless queues on an interface that already has a DCB map with PFC enabled (pfc on), an error message is
displayed.
1. Enter INTERFACE Conguration mode.
CONFIGURATION mode
interface {tengigabitEthernet slot/port |fortygigabitEthernet slot/port}
2. Open a DCB map and enter DCB map conguration mode.
INTERFACE mode
dcb-map name
3. Disable PFC.
DCB MAP mode
no pfc mode on
4. Return to interface conguration mode.
DCB MAP mode
exit
5. Apply the DCB map, created to disable the PFC operation, on the interface.
INTERFACE mode
dcb-map {name | default}
6. Congure the port queues that still function as no-drop queues for lossless trac. 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 congured.
INTERFACE mode
pfc no-drop queuesqueue-range
The maximum number of lossless queues globally supported on a port is 2.
You cannot congure PFC no-drop queues on an interface on which a DCB map with PFC enabled has been applied, or which
is already congured for PFC using the pfc priority command.
Data Center Bridging (DCB)
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