Where can I learn about hierarchical class of service?
Hierarchical class of service (HCoS) is the ability to provide CoS functionality as a more granular level (for example, per subscriber rather than per port) by applying traffic schedulers and shapers to a hierarchy of scheduler nodes. Each level of the scheduler hierarchy can be used to treat traffic based on different criteria such as per application, user, VLAN, and physical port.
This allows you to support the requirements of different services / applications, and users on the same physical device and infrastructure.
For more information, please refer to our Hierarchical Class of Service Feature Guide: https://www.juniper.net/techpubs/en_US/junos15.1/information-products/pathway-pages/cos/config-guide-hierarchical-cos.html