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2. Configure the PFC setting (on or off) and the ETS bandwidth percentage allocated to traffic in each priority group, or
whether the priority group traffic should be handled with strict priority scheduling. You can enable PFC on a maximum of
two priority queues on an interface. Enabling PFC for dot1p priorities makes the corresponding port queue lossless. The
sum of all allocated bandwidth percentages in all groups in the DCB map must be 100%. Strict-priority traffic is serviced
first. Afterwards, 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.
DCB MAP mode
priority-group group_num {bandwidth percentage | strict-priority} pfc {on | off}
Example:
priority-group 0 bandwidth 60 pfc off
priority-group 1 bandwidth 20 pfc on
priority-group 2 bandwidth 20 pfc on
priority-group 4 strict-priority pfc off
Repeat this step to configure PFC and ETS traffic handling for each priority group.
3. Specify the dot1p priority-to-priority group mapping for each priority. Priority-group range: 0 to 7.
DCB MAP mode
priority-pgid dot1p0_group_num dot1p1_group_num dot1p2_group_num dot1p3_group_num
dot1p4_group_num dot1p5_group_num dot1p6_group_num dot1p7_group_num
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
To apply a DCB map to an Ethernet port, follow these steps:
1. Enter interface configuration mode on an Ethernet port.
CONFIGURATION mode
interfacetengigabitEthernet slot/port
2. Apply the DCB map on the Ethernet port to configure it with the PFC and ETS settings in the map.
INTERFACE mode
FC Flex IO Modules
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