Streaming Telemetry Dial-Out Mode
Overview
In OcNOS, dial-out telemetry subscriptions, also known as persistent subscriptions, ensure continuous data streaming, even if the Remote Procedure Call (gRPC) session terminates unexpectedly. With persistent subscriptions, the OcNOS device continuously retries to establish a gRPC connection to the collector server, thus maintaining persistent data streaming.
Feature Characteristics
The dial-out telemetry feature in OcNOS comprises several key aspects ensuring seamless data streaming and connectivity with collector servers:
The described topology outlines a system architecture that utilizes gRPC-based tunneling for persistent streaming telemetry.
Figure 8. Dial-Out Subscription Mode
Here is a detailed explanation of the components and data flow:
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gNMI Client (gRPC Client): The gNMI client, which acts as the gRPC client in this scenario, is responsible for handling telemetry data and connecting to the OcNOS target device. |
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Tunnel Server: The tunnel server, part of the gNMI collector process, listens for incoming gRPC tunnel streams from the gRPC server. |
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gRPC Tunnel Stream: Represents the persistent communication channel established between the tunnel client (OcNOS) and the tunnel server (collector). |
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Tunnel Client: The gRPC tunnel client operates on the OcNOS device and connects to the tunnel server. It manages the tunneling of telemetry data. |
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gRPC Server: Interacts with the tunnel client to establish and manage the tunnel. |
Ensure that the tunnel server is reachable over the network from the tunnel client, and configure both the tunnel client and tunnel server with compatible authentication mechanisms.
Data Flow
The Figure 9 flow chart illustrates streaming telemetry in Dial-out Mode.
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Initialization: When the dial-out command subscription-name is applied successfully, the tunnel client on the OcNOS device initiates a connection to the tunnel server hosted on the collector. |
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Tunnel Establishment: Upon successful connection, the gRPC client and server establish a persistent tunnel stream. This tunnel facilitates the continuous transmission of telemetry data. |
OcNOS supports insecure tunnel connections.
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Telemetry Data Transmission: When telemetry data needs to be transmitted from the OcNOS device, the gNMI client sends a Publish RPC request over the established tunnel. |
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Subscription Configuration: Telemetry commands follow the OpenConfig telemetry model, standardizing the configuration of telemetry subscriptions and related entities. |
Figure 9. Data Flow: Dial-Out Mode
Benefits
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Ensures continuous data streaming even in the event of gRPC session termination, enhancing network monitoring and troubleshooting capabilities. |
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Simplifies configuration and management of telemetry subscriptions using standard OpenConfig models. |
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Facilitates secure and reliable communication between the OcNOS device and the collector server. |
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Enhances interoperability by enabling integration with third-party gRPC client applications like gNMI client, expanding telemetry options for network operators. |
Prerequisites
Before configuring Dial-Out mode, ensure that:
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A supported OcNOS router running a compatible release is required. |
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Access to the management interface of the router is necessary. |
