Users Guide

• If you configure lossless queues on an interface that already has a DCB map with PFC enabled (pfc on),
an error message is displayed.
Table 16. Configuring Lossless Queues on a Port Interface
Step Task Command Command Mode
1 Enter INTERFACE Configuration mode.
interface
{tengigabitEthernet
slot/port /subport
| 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 the 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.
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
Priority-Based Flow Control Using
Dynamic Buffer Method
In a data center network, priority-based flow control (PFC) manages large bursts of one traffic type in
multiprotocol links so that it does not affect other traffic types and no frames are lost due to congestion.
When PFC detects congestion on a queue for a specified priority, it sends a pause frame for the 802.1p
priority traffic to the transmitting device.
Data Center Bridging (DCB) 269