Table 2: Dial-in and Dial-Out Model-Driven Telemetry Data Source Specifications Sources of telemetry data in a subscription are specified by the use of a stream and a filter. The term stream refers to a related set of events. RFC 5277 defines an event stream as a set of event notifications matching some forwarding criteria. Normally, the set of events from a stream are filtered. Different filter types are used for different stream types. Cisco IOS XE supports two streams: yang-push and yang-notif-native . Update Notifications As part of a subscription, you can specify when data is required. However this is stream-dependent.
Some streams support making data available only when there a change happens, or after an event within the stream. Other streams make data available when there is a change or at a defined time period. The result of the when specification is a series of update notifications that carry the telemetry data of interest. How the data is sent is dependent on the protocol used for the connection between the publisher and the receiver. Subscription Identifiers Subscriptions are identified by a 32-bit positive integer value. The IDs for configured subscriptions is set by the controller, and for dynamic subscriptions is set by the publisher.
Controllers must limit the values they use for configured subscriptions in the range 0 to 2147483647 to avoid collisions with the dynamic subscriptions created on the publisher. The dynamic subscription ID space is global, meaning that the subscription IDs for independently-created dynamic subscriptions do not overlap. Subscription Management Any form of management operation can be used to create, delete, and modify configured subscriptions. This includes both CLIs and network protocol management operations. All subscriptions, both configured and dynamic, can be displayed using show commands and network protocol management operations.
Model-Driven Telemetry Data Source Specifications Dial-In (Dynamic) Dial-Out (Static or Configured) Telemetry updates are sent to the initiator or subscriber. Telemetry updates are sent to the specified receiver or collector. Life of the subscription is tied to the connection (session) that created it, and over which telemetry updates are sent. No change is observed in the running configuration. Subscription is created as part of the running configuration; it remains as the device configuration till the configuration is removed. Dial-in subscriptions need to be reinitiated after a reload, because established connections or sessions are killed during stateful switchover.
Dial-out subscriptions are created as part of the device configuration, and they automatically reconnect to the receiver after a stateful switchover. Subscription ID is dynamically generated upon successful establishment of a subscription. Subscription ID is fixed and configured on the device as part of the configuration. Model-Driven Telemetry 7