We are exploring the possibility of configuring QOS policies for the main interface, which has multiple sub-interfaces. I want to know if a common policy applied on the main interface will be applicable to the subinterfaces too. This makes all layer 2 connections under the interface subject to the QoS policy. Each class within the policy will operate on the aggregate class traffic across all the layer 2 connections. If the Qos policy is at the full interface rate then a single tier policy can be applied directly to the main interface. If the required speed is less than the interface then a hierarchical policy can be applied. In the output direction and parent policy and a child policy are constructed. The child policy matched on each of the Qos classed and provided the necessary treatment. The parent policy is applied to the main interface. IT matched on the default class (i.e. all traffic), applied a shaper to limit the output bandwidth and also is where the child policy is applied. In the inbound direction the same structure is repeated except in this case the parent policy used a policer rather than a shaper.