Packet Forwarding Engine sensor support with INITIAL_SYNC on JTI

You can use Junos telemetry interface (JTI) and gRPC Network Management Interface (gNMI) services to export Packet Forwarding Engine statistics from devices to an outside collector using gNMI submode INITIAL_SYNC. When an external collector sends a subscription request for a sensor with INITIAL_SYNC (gnmi-submode 2), the host sends all supported target leaves (fields) under that resource path at least once to the collector with the current value. This is valuable because:

• The collector has a complete view of the current state of every field on the device for that sensor path.
• Event-driven data (ON_CHANGE) is received by the collector at least once before the next event is seen. In this way, the collector is aware of the data state before the next event happens.
• Packet Forwarding Engine sensors that contain zero counter values (zero-suppressed) that normally do not show up in streamed data are sent, ensuring that all fields from each line card (also referred to

as source) are known to the collector.

INITIAL_SYNC submode requires that at least one copy to be sent to the collector; however, sending more than one is acceptable.

INITIAL_SYNC submode is supported for the following sensors:

• Sensor for CPU (ukernel) memory (resource path /junos/system/linecard/cpu/memory/)
• Sensor for firewall filter statistics (resource path /junos/system/linecard/firewall/)
• Sensor for physical interface traffic (resource path /junos/system/linecard/interface/)
• Sensor for logical interface traffic (resource path /junos/system/linecard/interface/logical/usage/)
• Sensor for physical interface queue traffic (resource path /junos/system/linecard/interface/ queue/)
• Sensor for physical interface traffic except queue statistics (resource path /junos/system/linecard/ interface/traffic/)
• Sensor for NPU memory (resource path /junos/system/linecard/npu/memory/)
• Sensor for NPU utilization (resource path /junos/system/linecard/npu/utilization/)
• Sensor for packet statistics (resource path /junos/system/linecard/packet/usage/)
• Sensor for software-polled queue-monitoring statistics (resource path /junos/system/linecard/ qmon-sw/)