Administrator Guide

• 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.
Step Task Command Command Mode
1 Enter INTERFACE Conguration mode.
interface{tengigabitEther
net slot/port |
fortygigabitEthernet slot/
port}
CONFIGURATION
2
Open a DCB map and enter DCB map conguration
mode.
dcb-map name
INTERFACE
3
Disable PFC.
no pfc mode on
DCB MAP
4
Return to interface conguration mode.
exit
DCB MAP
5
Apply the DCB map, created to disable the PFC
operation, on the interface
dcb-map {name | default}
INTERFACE
6
Congure the port queues that still function as no-drop
queues for lossless trac.
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.
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.
pfc no-drop
queuesqueue-range
INTERFACE
Data Center Bridging Exchange Protocol (DCBx)
The data center bridging exchange (DCBx) protocol is disabled by default on any switch on which PFC or ETS are enabled.
DCBx allows a switch to automatically discover DCB-enabled peers and exchange conguration information. PFC and ETS use DCBx
to exchange and negotiate parameters with peer devices. DCBx capabilities include:
• Discovery of DCB capabilities on peer-device connections.
• Determination of possible mismatch in DCB conguration on a peer link.
• Conguration of a peer device over a DCB link.
DCBx requires the link layer discovery protocol (LLDP) to provide the path to exchange DCB parameters with peer devices.
Exchanged parameters are sent in organizationally specic TLVs in LLDP data units. For more information, refer to Link Layer
Discovery Protocol (LLDP). The following LLDP TLVs are supported for DCB parameter exchange:
PFC parameters
PFC Conguration TLV and Application Priority Conguration TLV.
ETS parameters ETS Conguration TLV and ETS Recommendation TLV.
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Data Center Bridging (DCB)