Addendum

Step Task Command Command Mode
1
Create a DCB map to specify PFC and ETS
settings for groups of dot1p priorities.
dcb-map name CONFIGURATION
2
Configure the PFC setting (on or off) and the
ETS bandwidth percentage allocated to traffic
in each priority group or whether priority
group traffic should be handled with strict
priority scheduling. The sum of all allocated
bandwidth percentages 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.
Restriction: You can enable PFC on a
maximum of two priority queues.
Repeat this step to configure PFC and ETS
traffic handling for each priority group; for
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
priority-group group_num
{bandwidth percentage |
strict-priority} pfc {on |
off}
DCB MAP
3
Specify the priority group ID number to handle
VLAN traffic for each dot1p class-of-service: 0
through 7. Leave a space between each
priority group number. For example: priority-
pgid 0 0 0 1 2 4 4 4 Where dot1p priorities 0,
1, and 2 are mapped to priority group 0; dot1p
priority 3 is mapped to priority group 1; dot1p
priority 4 is mapped to priority group 2; dot1p
priorities 5, 6, and 7 are mapped to priority
group 4.
All priorities that map to the same egress
queue must be in the same priority group.
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
DCB MAP
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 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.
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