Streaming Telemetry

Overview

Streaming telemetry allows users to monitor network health by efficiently streaming operational data of interest from OcNOS routers. This structured data is transmitted to remote management systems for proactive network monitoring and understanding CPU and memory usage in managed devices for troubleshooting.

A machine learning (ML) database can be created with telemetry data to establish a baseline for normal network operation and predict or mitigate network issues.

Feature Characteristics

In OcNOS various gRPC Network Management Interface (gNMI) Subscription Modes, Telemetry Modes, and Encoding Types are supported, providing efficient network management capabilities.

gNMI Subscription Modes

Streaming Telemetry Dial-In Mode: In this mode, the collector initiates a connection to the target device (OcNOS) and subscribes to receive telemetry data from OcNOS devices.

Streaming Telemetry Dial-Out Mode (Persistent Subscriptions): In this mode, the target (OcNOS) initiates the gRPC tunnel connection to the collector. Once the connection is established, the collector invokes the “Publish" RPC on the target. Subscriptions configured on the target are then streamed on that connection at the specified sample interval. These subscriptions remain active on OcNOS devices as long as the corresponding configuration on the target exists. If the gRPC tunnel connection is interrupted or the target reboots, the gNMI server on the target re-establishes the connection to the gNMI collector, ensuring continued streaming.

Streaming Telemetry Modes

Stream Mode: Enables continuous and real-time transmission of telemetry data from OcNOS devices to the monitoring system. The stream mode applies to both the dial-in and dial-out gNMI subscription modes.

Poll Mode: Poll mode subscriptions allow for on-demand data retrieval through a long-lived RPC. Subscribers initiate this mode by sending a Subscribe request message, followed by sending an empty Poll message to receive the desired data.

The system supports Poll mode only in Dial-in subscription mode.

Once Mode: In Once mode subscription, the OcNOS device responds to a subscribe request with a one-time data retrieval, similar to a get request. Upon receiving the Once mode subscribe request, the device sends back the subscribe response for all subscriptions in the list and terminates the RPC.

The system supports Once mode only in Dial-in subscription mode.

gNMI In-Band Support

OcNOS supports streaming telemetry data transmission across multiple VRF Virtual Routing and Forwarding instances, enabling users to manage data for up to four VRFs simultaneously. If users do not define a VRF, the system automatically allows streaming telemetry in the default VRF.

This improves efficiency and monitoring capabilities within the network.

Encoding Types

Protocol Buffers (protobuf): Offers a compact binary serialization format for efficient encoding and transmission of structured telemetry data. Protobuf is optimized for performance and bandwidth efficiency.

JavaScript Object Notation (JSON): Provides a human-readable data interchange format commonly used for telemetry data representation. JSON encoding facilitates interoperability and ease of integration with various applications and tools. It adheres to the JSON specification outlined in RFC7159, employing relevant quoting. Consequently, string values are quoted while number values remain unquoted.

JSON-IETF: This variant of JSON encoding adheres to the IETF standards, ensuring consistency and compatibility with industry specifications. JSON_IETF encoded data conforms the rules outlined in RFC7951 for JSON serialization.

OcNOS supports the protobuf, JSON, and JSON-IETF encoding types for both the dial-in and dial-out gNMI subscription modes.