Users Guide

Step Task Command Command Mode
already configured for lossless queues (pfc no-
drop queues command).
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.
Table 16. Configuring PFC without a DCB Map
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.
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 4 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.
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Data Center Bridging (DCB)