5.1. Enabling supplementary and optional repositories
As product subscriptions are attached to systems, the system gains access to content repositories that are identified in the system’s certificate. Content repositories are based on the product and on the content delivery network (CDN) that are defined in the rhsm.conf file.
A subscription may include access to optional content repositories in addition to the default repositories that are automatically enabled on the system. These optional repositories must be enabled before the packages in them can be installed even if the system has the appropriate subscriptions for the products in those repositories.
The optional and supplementary channels are named