Reference Guide

Configuring PFC without a DCB Map
In a network topology that uses the default ETS bandwidth allocation (assigns equal bandwidth to each priority), you can also
enable PFC for specific dot1p-priorities on individual interfaces without using a DCB map. This type of DCB configuration is
useful on interfaces that require PFC for lossless traffic, but do not transmit converged Ethernet traffic.
Step Task Command Command Mode
1 Enter interface configuration mode on an Ethernet
port.
interface
{tengigabitEthernet slot/
port |
fortygigabitEthernet slot/
port}
CONFIGURATION
2 Enable PFC on specified priorities. Range: 0-7.
Default: None.
Maximum number of lossless queues supported on
an Ethernet port: 2.
Separate priority values with a comma. Specify a
priority range with a dash, for example: pfc priority
3,5-7
1. You cannot configure PFC using the pfc
priority command on an interface on which a
DCB map has been applied or which is already
configured for lossless queues (pfc no-drop
queues command).
pfc priority priority-
range
INTERFACE
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
{tengigabitEthernet
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
208 Data Center Bridging (DCB)