Limitations on CoS for Aggregated Interfaces

There are some restrictions when you configure CoS on aggregated Ethernet and SONET/SDH interfaces:

• Chassis scheduling, described in Applying Scheduler Maps to Chassis-Level Queues, is not supported on aggregated interfaces, because a chassis scheduler applies to the entire PIC and not just to one interface.

• An aggregated interface is a pseudo-interface. Therefore, CoS queues are not associated with the aggregated interface. Instead, CoS queues are associated with the member link interfaces of the aggregated interface.

• When you apply CoS parameters to the aggregated interface, they are applied to the CoS queues of the member link interfaces. You do not, however, apply CoS classifiers and rewrite rules directly to the member link interfaces.

• You cannot apply a scheduler map to a member link of an aggregate interface.

• Rate-based CoS components such as scheduler, shaper, and policer are not supported on mixed rate aggregated Ethernet links. However, the default CoS settings are supported by default on the mixed rate aggregated Ethernet links.

• Ingress queuing is not supported on aggregated interfaces.

When the scheduler map of the aggregate interface has schedulers configured for absolute transmit rate, the scheduler for the member link interfaces is scaled to the speed of each member link interface. Each member link interface has an automatic scheduler map that is not visible in the CLI. This scheduler map is allocated when the member link is added to the aggregate interface and is deleted when the member link is removed from the aggregate interface.

• If you configure the scheduler transmit rate of the aggregate interface as an absolute rate, the software uses the following formula to scale the transmit rate of each member link:

• If you configure the scheduler transmit rate of the aggregate interface as a percentage, the software uses the following formula to scale the transmit rate of each member link:

The total configured percent is the sum of the configured transmit rate of all schedulers in terms of percentage of the total speed of the aggregate interface.

• All the other parameters for the schedulers, including priority, drop profile, and buffer size, are copied without change from the scheduler of the aggregated interface to the member link interfaces.

• The configuration related to the logical interfaces, including classifiers and rewrite rules, is copied from the aggregated logical interface configuration to the member link logical interfaces.

• For the scheduler map applied to an aggregated interface, if you configure a transmission rate in absolute terms, then the traffic of all the member link interfaces might be affected if any of the member link interfaces go up or down.

When applying CoS configurations to bundles, you must apply the CoS configuration directly to the bundle, not to the physical ports that are part of the bundle. The device may give you a false commit if you apply a CoS configuration directly to a physical port that is part of a bundle. This limitation applies if you attempt to configure a physical port that is already a member of a bundle or if you attempt to add a physical port to a bundle that already has a CoS configuration applied to it.

If you want to add a physical port to a bundle that already has a CoS configuration, you must:

1. Remove the CoS configuration from the port.

2. Commit your changes on the device.

3. Add the port to the bundle. The CoS configurations that are present on the bundle will be applied to the port you are adding to the bundle.

4. Commit you changes on the device.

In addition, if you want to remove a physical port from a bundle and ensure the physical port has the appropriate CoS configurations, you must:

1. Remove the port from the bundle.

2. Commit your changes on the device.

3. Apply the applicable CoS configuration to the port.

4. Commit your changes on the device.