Reference Guide

Afterwards, you can configure either the peak rates or the committed rates. The bandwidth allocated to other priority
groups is made available and allocated according to the specified percentages. If a priority group does not use its allocated
bandwidth, the unused bandwidth is made available to other priority groups.
● Repeat the above procedure to configure PFC and ETS traffic handling for each priority group
● Specify the dot1p priority-to-priority group mapping for each priority. The priority group range is from 0 to 7. All priorities
that map to the same queue must be in the same priority group.
Leave a space between each priority group number. For example: priority-pgid 0 0 0 1 2 4 4 4 in which priority group 0
maps to dot1p priorities 0, 1, and 2; priority group 1 maps to dot1p priority 3; priority group 2 maps to dot1p priority 4; priority
group 4 maps to dot1p priorities 5, 6, and 7.
Important Points to Remember
● If you remove a dot1p priority-to-priority group mapping from a DCB map (no priority pgid command), the PFC and
ETS parameters revert to their default values on the interfaces on which the DCB map is applied. By default, PFC is not
applied on specific 802.1p priorities; ETS assigns equal bandwidth to each 802.1p priority.
As a result, PFC and lossless port queues are disabled on 802.1p priorities, and all priorities are mapped to the same priority
queue and equally share the port bandwidth.
● To change the ETS bandwidth allocation configured for a priority group in a DCB map, do not modify the existing DCB map
configuration. Instead, first create a new DCB map with the desired PFC and ETS settings, and apply the new map to the
interfaces to override the previous DCB map settings. Then, delete the original dot1p priority-priority group mapping.
If you delete the dot1p priority-priority group mapping (no priority pgid command) before you apply the new DCB
map, the default PFC and ETS parameters are applied on the interfaces. This change may create a DCB mismatch with peer
DCB devices and interrupt network operation.
Applying a DCB Map on a Port
When you apply a DCB map with PFC enabled on a switch interface, a memory buffer for PFC-enabled priority traffic is
automatically allocated. The buffer size is allocated according to the number of PFC-enabled priorities in the assigned map.
To apply a DCB map to an Ethernet port, follow these steps:
Step
Task Command Command Mode
1
Enter interface configuration mode on an Ethernet
port.
interface
{tengigabitEthernet slot/
port |
fortygigabitEthernet slot/
port}
CONFIGURATION
2
Apply the DCB map on the Ethernet port to configure it
with the PFC and ETS settings in the map; for example:
Dell# interface tengigabitEthernet 1/1
Dell(config-if-te-1/1)# dcb-map SAN_A_dcb_map1
Repeat Steps 1 and 2 to apply a DCB map to more than
one port.
You cannot apply a DCB map on an interface that has
been already configured for PFC using thepfc
priority command or which is already configured for
lossless queues (pfc no-drop queues command).
dcb-map name
INTERFACE
Data Center Bridging (DCB) 207