What is a subscription, and how does subscription work in the Octopus graph topology?
A subscription allows time-limited access to a catalog of content, such as all episodes of a particular television series or all issues of a particular online magazine. A subscription is represented as a Link between a User Node and a Subscription Node. The Link has a specified expiration. For example, it may only be valid for 30 days. After a Link has expired, it can no longer be used to provide access to the content subscribed to.