Reference 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.
Step Task Command Command Mode
1 Enter INTERFACE Configuration mode.
interface{tengigabitE
thernet 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 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.
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
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 configuration
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 configuration on a peer link.
• Configuration 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 specific 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:
Data Center Bridging (DCB)
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