Reference Guide

Data Center Bridging (DCB) | 319
Using PFC and ETS to Manage Converged Ethernet Traffic in a Switch
Stack
Figure 13-16 shows how to apply the DCB map (ipc_san_lan) configured in Figure 13-15 on all ports in a
switch stack.
Figure 13-16. PFC and ETS Configuration in a Switch Stack: Example
Hierarchical Scheduling in ETS Configuration
ETS supports up to three levels of hierarchical scheduling. For example, you can apply ETS configurations
in a DCB map with the following settings:
• Priority group 1 assigns traffic to one priority queue with 20% of the link bandwidth and strict-priority
scheduling.
• Priority group 2 assigns traffic to one priority queue with 30% of the link bandwidth.
• Priority group 3 assigns traffic to two priority queues with 50% of the link bandwidth and
strict-priority scheduling.
When you configure strict-priority groups:
• If two priority groups have strict-priority scheduling, traffic assigned from the priority group with the
higher priority-queue number is scheduled first.
• If three priority groups are used and two groups have strict-priority scheduling (such as groups 1 and 3
in the example), the strict priority group whose traffic is mapped to one queue takes precedence over
the strict priority group whose traffic is mapped to two queues.
Therefore, in the example, scheduling traffic to priority group 1 (mapped to one strict-priority queue) takes
precedence over scheduling traffic to priority group 3 (mapped to two strict-priority queues).
On the stack master, apply DCB map on all port on stack ports:
Dell(conf)# dcb-map stack-unit all stack-ports all ipc_san_lan