Telemetry supports NETCONF event notifications where the NETCONF client is configured to receive event notifications from a NETCONF server through a subscription. The NETCONF client must subscribe using a create-subscription request. Currently, only the events from Link Layer Discovery Protocol (LLDP) is supported. These event notifications are sent until either the NETCONF session or the subscription is terminated.

Note	Configuring a sensor group and a subscription is not required for receiving NETCONF notifications. While sensor path and subscription configurations are required for receiving telemetry events, NETCONF create-subscription is required for receiving NETCONF notifications.

This example shows event-driven telemetry fo LLDP configuration data.

1. Create a destination group.

   
   grpc
   port 56782
   address-family ipv4
   !
   telemetry model-driven
   destination-group <destination-udp>
     address-family ipv4 <client-ip>1 port <udp port num>
      encoding self-describing-gpb
      protocol udp
     !
   !
   destination-group <destination-tcp>
     address-family ipv4 <client-ip> port <tcp port num>
      encoding gpb
      protocol tcp
     !
   destination-group <destination-grpc>
     address-family ipv4 <grpc client ip>port <grpc port num>
      encoding self-describing-gpb
      protocol grpc no-tls
   

2. Create a sensor group.

   
   sensor-group <sensor-group-name>
     sensor-path Cisco-IOS-XR-ethernet-lldp-oper:lldp/global-lldp/lldp-info 
     sensor-path Cisco-IOS-XR-ethernet-lldp-oper:lldp/nodes/node/interfaces/interface  
     sensor-path Cisco-IOS-XR-ethernet-lldp-oper:lldp/nodes/node/neighbors/details/detail    
    !
   

3. Create a subscription.

   subscription udp-out
     sensor-group-id <sensor-group-name> sample-interval 0
     destination-id <destination-udp>
   !
   
   subscription <subscription-name>
     sensor-group-id <sensor-group-name> sample-interval 0
     destination-id <destination-tcp>
   
   subscription <subscription-name>
     sensor-group-id <sensor-group-name> sample-interval 0
   !
   netconf-yang agent
   ssh
   !
   

4. Set the notification to stream data when an event occurs.

   
   Router(config-lldp)#timer 12
   Router(config-lldp)#commit
   
   Router(config-lldp)#holdtime 150
   Router (config-lldp)#commit
   
   Router (config-lldp)#exit
   #506
   <?xml version="1.0"?>
   <notification xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0">
    <eventTime>Date-and-Time</eventTime>
    <lldp xmlns="http://cisco.com/ns/yang/Cisco-IOS-XR-ethernet-lldp-oper">
     <global-lldp>
      <lldp-info>
       <chassis-id>000b.1bc9.e700</chassis-id>
       <chassis-id-sub-type>4</chassis-id-sub-type>
       <system-name>ios</system-name>
       <timer>12</timer>
       <hold-time>120</hold-time>
       <re-init>2</re-init>
      </lldp-info>
     </global-lldp>
    </lldp>
   </notification>
   Ready to send a request.
   Paste your request or enter 'get', 'get-config', 'create-sub', or 'bye' to quit):
   

5. Validate response received from NETCONF agent.

   #506
   <?xml version="1.0"?>
   <notification xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0">
    <eventTime>Date-and-Time</eventTime>
    <lldp xmlns="http://cisco.com/ns/yang/Cisco-IOS-XR-ethernet-lldp-oper">
     <global-lldp>
      <lldp-info>
       <chassis-id>000b.1bc9.e700</chassis-id>
       <chassis-id-sub-type>4</chassis-id-sub-type>
       <system-name>ios</system-name>
       <timer>12</timer>
       <hold-time>150</hold-time>
       <re-init>2</re-init>
      </lldp-info>
     </global-lldp>
    </lldp>
   </notification>