Differences Between Per-Unit Scheduling and Shared Scheduling
Shared scheduling allows you to allocate separate
pools of shared resources to subsets of logical interfaces belonging
to the same physical port.
Per-unit scheduling enables one set of output queues
for each logical interface configured under the physical interface.
An unconfigured logical interface (in the context of CoS) is a logical interface that you configure
at the [edit interfaces interface-name unit logical-unit-number] hierarchy level, but do not
configure at the [edit class-of-service interfaces interface-name unit logical-unit-number] hierarchy level.
The differences between per-unit scheduling and
shared-scheduling are as follows:
With per-unit scheduling, an unconfigured logical interface
receives its own set of output queues.
With shared scheduling, an unconfigured logical interface
receives its own set of output queues only if there is some configuration
for that logical interface at the [edit class-of-service interfaces interface-name unit logical-unit-number] hierarchy level.
When you configure shared scheduling, you can include
the shared-instance statement with the traffic-control profile.
The shared-instance statement is not supported with per-unit
scheduling.
When you configure shared scheduling, a dedicated scheduler
is assigned to a logical interface on the output direction only, if
you configure one or more of the following: a scheduler map, a shaping-rate,
a guaranteed rate, or a traffic-control profile. All the other logical
interfaces use the same set of queues in the output direction. Similarly,
a dedicated scheduler is assigned to a logical interface on the input
direction only, if you configure one or more of the following: an
input scheduler map, an input shaping rate, or an input traffic-control
profile. All other logical interfaces use the same set of queues in
the input direction.
