Stateful Smart Filters

Smart filters allow to apply filters to subscriptions for datastore updates that are based on object values. Smart filters facilitate service assurance and network automation because they allow client applications to focus on "outliers" and conditions of interest have the biggest operational significance or that signify exceptions.

Smart Filters for Push Updates will provide for the following features:

• Support for smart filter extensions to YANG-Push subscriptions. The targeted model takes a "base" YANG-Push subscription and subjects updates to an additional filtering stage that is based on object values.
• Support for refined on-change update semantics that allow for a distinction of whether object values were omitted or included because the object was created or deleted, or because the object's value fell inside or outside filter range.
• Support for object updates as long as object values meet filter condition
• Support for selected stateful filters, e.g.:
  • A generalized "threshold crossing alert" filters, or filters that provide an update only when an object's value passes a filter for the first time, and not again until the object's value passes a counter filter
  • A "recent high water mark" filter sends an update to an object only if its new value is greater than the last value that had been previously reported.

The draft problem statement can be found here: draft-clemm-netconf-push-smart-filters-ps