Administrator Guide

Creating a DCB Map
Configure the priority-based flow control (PFC) and enhanced traffic selection (ETS) settings in a DCB map
before you apply them on downstream server-facing ports on an Aggregator.
1 Create a DCB map to specify PFC and ETS settings for groups of dot1p priorities.
CONFIGURATION mode
dcb-map name
2 Configure the PFC setting (on or off) and the ETS bandwidth percentage allocated to traffic in each
priority group. Configure whether the priority group traffic should be handled with strict-priority
scheduling. The sum of all allocated bandwidth percentages must be 100 percent. Strict-priority traffic is
serviced first. Afterward, 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
onpriority-group 2 bandwidth 20 pfc on priority-group 4 strict-priority pfc off
DCB MAP mode
priority-group group_num {bandwidth percentage | strict-priority} pfc {on | off}
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.
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
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, create a new DCB map with the desired PFC and ETS
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