Concept Guide

You cannot apply a DCB map on an interface that has been already congured for PFC using thepfc priority command or which

is already congured for lossless queues (pfc no-drop queues command).

Dell# interface tengigabitEthernet 0/0

Dell(config-if-te-0/0)# dcb-map SAN_A_dcb_map1

Repeat Steps 1 and 2 to apply a DCB map to more than one port.

Conguring 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 specic dot1p-priorities on individual interfaces without using a DCB map. This type of DCB conguration is useful on interfaces that

require PFC for lossless trac, but do not transmit converged Ethernet trac.

1 Enter interface conguration mode on an Ethernet port.

CONFIGURATION mode

interface {tengigabitEthernet slot/

port

| fortygigabitEthernet slot/

port

}

2 Enable PFC on specied priorities. Range: 0-7. Default: None.

INTERFACE mode

pfc priority priority-range

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

You cannot congure PFC using the pfc priority command on an interface on which a DCB map has been applied or which is

already congured for lossless queues (pfc no-drop queues command).

Conguring Lossless Queues

DCB also supports the manual conguration of lossless queues on an interface after you disable PFC mode in a DCB map and apply the

map on the interface. The conguration of no-drop queues provides exibility for ports on which PFC is not needed, but lossless trac

should egress from the interface.

Lossless trac egresses out the no-drop queues. Ingress 802.1p trac from PFC-enabled peers is automatically mapped to the no-drop

egress queues.

When conguring lossless queues on a port interface, consider the following points:

• By default, no lossless queues are congured on a port.

• 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.

1 Enter INTERFACE Conguration mode.

CONFIGURATION mode

interface {tengigabitEthernet slot/port |fortygigabitEthernet slot/port}

2 Open a DCB map and enter DCB map conguration mode.

Data Center Bridging (DCB)