Reference Guide

In this example, the configured ETS bandwidth allocation and scheduler behavior is as follows:
Unused
bandwidth usage:
Normally, if there is no traffic or unused bandwidth for a priority group, the bandwidth
allocated to the group is distributed to the other priority groups according to the bandwidth
percentage allocated to each group. However, when three priority groups with different
bandwidth allocations are used on an interface:
• If priority group 3 has free bandwidth, it is distributed as follows: 20% of the free
bandwidth to priority group 1 and 30% of the free bandwidth to priority group 2.
• If priority group 1 or 2 has free bandwidth, (20 + 30)% of the free bandwidth is
distributed to priority group 3. Priority groups 1 and 2 retain whatever free bandwidth
remains up to the (20+ 30)%.
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. However, when 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 this 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).
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