Exam 300-435 topic 1 question 35 discussion

both period, and xpath-filter are mandatory.

even though it is mentioned as mandatory, period, is not used for on-change subscription which is mentioned in the same document

While <yp:subscription-id> is important for managing subscriptions, it is not typically required to be specified by the client when initially establishing the subscription. Instead, it is usually generated and returned by the server upon successful creation of the subscription.

I am going to go with xpathFilter as for On Chamge , the period is replaced by another value

the xpath tag specifies the par of the YANG tree the client is subcription to.

YANG-Push YANG-push is the subscription and push mechanism for YANG databases. YANG-push subscriptions are defined using a data model. Using YANG-push, subscriber applications can request a continuous, customized stream of updates from YANG databases. The YANG-push encompasses all data in the configuration and operational databases that is described by the YANG model installed on a device. You must provide a filter for data, as subscription to all data is not supported. 'You must provide a filter for data' https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/prog/configuration/167/b_167_programmability_cg/model_driven_telemetry.html

Answer is C, a unique subscription ID is required. The subscription ID is used to identify the subscription and is included in all YANG-push notifications sent by the device.

The stream, xpath-filter, and period fields in the RPC are mandatory.<rpc message-id="101" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"> <establish-subscription xmlns="urn:ietf:params:xml:ns:yang:ietf-event-notifications" xmlns:yp="urn:ietf:params:xml:ns:yang:ietf-yang-push"> <stream>yp:yang-push</stream> <yp:xpath-filter>/mdt-oper:mdt-oper-data/mdt-subscriptions</yp:xpath-filter> <yp:period>1000</yp:period> </establish-subscription> </rpc> https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/prog/configuration/167/b_167_programmability_cg/model_driven_telemetry.html

The stream, xpath-filter, and period fields in the RPC are mandatory. https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/prog/configuration/167/b_167_programmability_cg/model_driven_telemetry.html