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README v1.1.14 2026-08-11

Table of contents

1. General
   1.1 Extract the NED package
   1.2 Install the NED package
       1.2.1 Local install
       1.2.2 System install
   1.3 Configure the NED in NSO
2. Optional debug and trace setup
3. Dependencies
4. Sample device configuration
5. Built in RPC actions
   5.1. rpc clean-package
   5.2. rpc export-package
   5.3. rpc get-modules
   5.4. rpc list-modules
   5.5. rpc list-profiles
   5.6. rpc rebuild-package
   5.7. rpc show-default-local-dir
   5.8. rpc show-loaded-schema
   5.9. rpc xpath-trace-analyzer
   5.7. live-status exec any
   5.8. live-status exec gnoi
6. Built in live-status show
7. Limitations
8. How to report NED issues and feature requests
9. How to rebuild a NED
10. Using the NED for Telemetry
11. Using the NED feature load-native-config

1. General

This document describes the cisco-iosxr_gnmi NED.

This NED can be used together with Cisco IOSXR devices with gNMI support enabled.

It has been successfully tested with the following devices: - Cisco IOSXR version 7.8.2 and 7.10.1

IMPORTANT: This NED is delivered without any of the device YANG models bundled to the NED package.

It is required to download the YANG files separately and rebuild the NED package before the NED is fully operational. See the README-rebuild.md for further information.

The recommended way to do this is by following the steps below:

  1. Install and setup the NED. See chapter 1.1 to 1.3

  2. Download the YANG models. See chapter 1.1 in README-rebuild.md for the recommended method (alternatives are described in README-rebuild.md chapter 2 and 3).

  3. Rebuild the NED. See chapter 1.3 in README-rebuild.md (an alternative with a custom NED-ID is described in README-rebuild.md chapter 4).

  4. Reload the NED in NSO. See chapter 1.4 in README-rebuild.md

Additional README files bundled with this NED package

Common NED Features

Verified target systems

Verified YANG model bundles

1.1 Extract the NED package

It is assumed the NED package ncs-<NSO version>-cisco-iosxr_gnmi-<NED version>.signed.bin has already been downloaded from software.cisco.com.

In this instruction the following example settings will be used:

  • NSO version: 6.0

  • NED version: 1.0.1

  • NED package downloaded to: /tmp/ned-package-store

  1. Extract the NED package and verify its signature:

  2. In case the signature can not be verified (for instance if no internet connection), do as below instead:

  3. The result of the extraction shall be a tar.gz file with the same name as the .bin file:

1.2 Install the NED package

There are two alternative ways to install this NED package. Which one to use depends on how NSO itself is setup.

In the instructions below the following example settings will be used:

  • NSO version: 6.0

  • NED version: 1.0.1

  • NED download directory: /tmp/ned-package-store

  • NSO run time directory: ~/nso-lab-rundir

A prerequisite is to set the environment variable NSO_RUNDIR to point at the NSO run time directory:

IMPORTANT:

This NED is delivered as an “empty” package, i.e without any device YANG models bundled. It must be rebuilt with the device YANG models to become operational.

The procedure to rebuild the empty NED (described in the README-rebuild.md) shall typically be done in a lab environment. For this step a “local install” of the NED shall be used. It is not suitable to use “system install” here since it is intended for production systems only.

Once this NED has been rebuilt with the device YANG and exported to one or many separate tar.gz customized NED packages, a “system installation” can be used on them.

1.2.1 Local install

This section describes how to install a NED package on a locally installed NSO (see "NSO Local Install" in the NSO Installation guide).

It is assumed the NED package has been been unpacked to a tar.gz file as described in 1.1.

  1. Untar the tar.gz file. This creates a new sub-directory named: cisco-iosxr_gnmi-<NED major digit>.<NED minor digit>:

  2. Install the NED into NSO, using the ncs-setup tool:

  3. Open a NSO CLI session and load the new NED package like below:

Alternatively the tar.gz file can be installed directly into NSO. Then skip steps 1 and 2 and do like below instead:

Set the environment variable NED_ROOT_DIR to point at the NSO NED package:

1.2.2 System install

This section describes how to install a NED package on a system installed NSO (see "NSO System Install" in the NSO Installation Guide).

It is assumed the NED package has been been unpacked to a tar.gz file as described in 1.1.

  1. Do a NSO backup before installing the new NED package:

  2. Start a NSO CLI session and fetch the NED package:

  3. Install the NED package (add the argument replace-existing if a previous version has been loaded):

  4. Load the NED package

1.3 Configure the NED in NSO

This section describes the steps for configuring a device instance using the newly installed NED package.

  • Start a NSO CLI session:

  • Enter configuration mode:

  • Configure a new authentication group (my-group) to be used for this device:

  • Configure a new device instance (example: dev-1):

    IMPORTANT:

    The device-type shall always be set to generic when configuring a device instance to use a 3PY NED. A common mistake is configuring it as netconf, which will cause NSO to use its internal netconf client instead.

Additional configurations

TLS

Set up TLS configurables if needed. The Cisco IOSXR devices typically has at least server certificate authentication enabled by default.

  • Enable TLS

  • Configure Server TLS authentication

Alternative 1: Accept any SSL certificate presented by the device. This is unsafe and should only be used for testing purposes.

Alternative 2: Configure a specific trust manager certificate for the device. Specify the path to the certificate file used by the device.

Enter the multi line content of a PEM formatted CA/server certificate. Including the -----BEGIN CERTIFICATE----- banners etc.

Finish with a -

Use the Unix tool 'openssl' to fetch the PEM certificate from a device:

Optional TLS settings

  • Configure TLS certificate authority overrides

  • Configure the NED for mutual TLS

Enter the multi line content of a PEM formatted client certificate. Including the -----BEGIN CERTIFICATE----- banners etc. Finish with a -d>

Enter the multi line content of a PEM formatted private key. Including the -----BEGIN PRIVATE KEY----- banners etc. Finish with a -d>

  • Configure TLS ciphers to be used for server/client TLS authentication

  • Finally commit the configuration

  • Verify configuration, using a sync-from.

If the sync-from was not successful, check the NED configuration again.

2. Optional debug and trace setup

It is often desirable to see details from when and how the NED interacts with the device(Example: troubleshooting)

This can be achieved by configuring NSO to generate a trace file for the NED. A trace file contains information about all interactions with the device. Messages sent and received as well as debug printouts, depending on the log level configured.

NSO creates one separate trace file for each device instance with tracing enabled. Stored in the following location:

$NSO_RUNDIR/logs/ned-cisco-iosxr_gnmi-gen-1.0-<device name>.trace

Do as follows to enable tracing in one specific device instance in NSO:

  1. Start a NSO CLI session:

  2. Enter configuration mode:

  3. Enable trace raw:

    Alternatively, tracing can be enabled globally affecting all configured device instances:

  4. Configure the log level for printouts to the trace file:

    Alternatively the log level can be set globally affecting all configured device instances using this NED package.

The log level 'info' is used by default and the 'debug' level is the most verbose.

IMPORTANT: Tracing shall be used with caution. This feature does increase the number of IPC messages sent between the NED and NSO. In some cases this can affect the performance in NSO. Hence, tracing should normally be disabled in production systems.

An alternative method for generating printouts from the NED is to enable the Java logging mechanism. This makes the NED print log messages to common NSO Java log file.

$NSO_RUNDIR/logs/ncs-java-vm.log

Do as follows to enable Java logging in the NED

  1. Start a NSO CLI session:

  2. Enter configuration mode:

  3. Enable Java logging with level all from the NED package:

  4. Configure the NED to log to the Java logger

    Alternatively Java logging can be enabled globally affecting all configured device instances using this NED package.

IMPORTANT: Java logging does not use any IPC messages sent to NSO. Consequently, NSO performance is not affected. However, all log printouts from all log enabled devices are saved in one single file. This means that the usability is limited. Typically single device use cases etc.

3. Dependencies

This NED has the following host environment dependencies:

  • Java 1.8 (NSO version < 6.2)

  • Java 17 (NSO version >= 6.2)

  • Gnu Sed

Dependencies for NED recompile:

  • Apache Ant

  • Bash

  • Gnu Sort

  • Gnu awk

  • Grep

  • Python3 (with packages: re, sys, getopt, subprocess, argparse, os, glob)

4. Sample device configuration

The example below has been successfully verified using a Cisco IOSXR VM running version v24.3.1.

5. Built in RPC actions

5.1. rpc clean-package

5.2. rpc export-package

5.3. rpc get-modules

5.4. rpc list-modules

5.5. rpc list-profiles

5.6. rpc rebuild-package

5.7. rpc show-default-local-dir

5.8. rpc show-loaded-schema

5.9. rpc xpath-trace-analyzer

5.7. live-status exec any

exec any get

The NED supports a generic versatile get action which can be used for doing any type of read operation towards a Cisco IOSXR gNMI device.

Mandatory arguments

Optional arguments

Example

5.8. live-status exec gnoi

The gRPC Network Operations Interface (gNOI) defines a set of gRPC-based services for executing operational commands on network devices. The gNOI command interface is supported on IOSXR 7.11.1 and later. Currently limited to the categories system and file. This NED supports a number of gNOI commands that can be executed on a IOSXR target.

exec gnoi system

This container contains all system gNOI commands.

time

Check time on the device

ping

Execute ping on device

Mandatory arguments

Optional arguments

traceroute

Execute traceroute on device.

Mandatory arguments

Optional arguments

killProcess

Kill a process on the device. Either pid or process name must be specified

Mandatory arguments

Optional arguments

reboot

Reboot the device

Optional arguments

cancelReboot

Cancel reboot of the device.

Optional arguments

rebootStatus

Check reboot status on the device.

switchControlProcessor

Switch from the current route processor to the provided route processor.

6. Built in live-status show

The Cisco IOSXR gNMI NED has full support for fetching operational data via the NSO live-status API.

7. Limitations

This NED provides a gNMI client which is gNMI protocol level compliant with Cisco IOS XR for actions like reading data, deploying config and rpc:s.

The gNMI agent running on IOS XR is still very much under continuous development. This includes the behaviour on gNMI protocol level. Hence, some additional adaptions of the NED might be necessary when used with older versions of IOS XR. This can usually be done through the NED settings available for customization or the protocol behaviour.

The NED has been tested using a set of config samples based on customer use cases.

Issues related to deploying config are usually caused by new currently unknown behaviour in the IOS XR gNMI agent for certain config nodes. If this happens further adaptions of the NED are usually necessary. It is encouraged to contact the Cisco NED team for help in any such matter. Create a support case with a description of the issue and the use case.

Cisco IOS XR up to version 7.11.1 has the following limitations directly affecting the NED operation:

  • gNOI file download is supported but broken. Can not be used for YANG model download

  • gNMI telemetry of type STREAM/SAMPLE is sent out in a scattered way. The device is however not able to signal when all fragments for a sample have been transmitted. So NED telemetry gathering feature can not be used.

8. How to report NED issues and feature requests

Issues like bugs and errors shall always be reported to the Cisco NSO NED team through the Cisco Support channel:

The following information is required for the Cisco NSO NED team to be able to investigate an issue:

Do as follows to gather the necessary information needed for your device, here named 'dev-1':

  1. Enable full debug logging in the NED

  2. Configure the NSO to generate a raw trace file from the NED

  3. If the NED already had trace enabled, clear it in order to submit only relevant information

    Do as follows for NSO 6.4 or newer:

    Do as follows for older NSO versions:

  4. Run a compare-config to populate the trace with initial device config

  5. Reproduce the found issue using ncs_cli or your NSO service. Write down each necessary step in a reproduction report.

  6. Gather the reproduction report and a copy of the raw trace file containing data recorded when the issue happened.

  7. Contact the Cisco support and request to open a case. Provide the gathered files together with access details for a device that can be used by the Cisco NSO NED when investigating the issue.

Requests for new features and extensions of the NED are handled by the Cisco NSO NED team when applicable. Such requests shall also go through the Cisco support channel.

The following information is required for feature requests and extensions:

  1. A detailed use case description, with details like:

    • Data of interest

    • The kind of operations to be used on the data. Like: 'read', 'create', 'update', 'delete' and the order of the operation

    • Device APIs involved in the operations (For example: REST URLs and payloads)

    • Device documentation describing the operations involved

  2. Run sync-from # devices device dev-1 sync-from (if relevant)

  3. Attach the raw trace to the ticket (if relevant)

  4. Access to a device that can be used by the Cisco NSO NED team for testing and verification of the new feature. This usually means that both read and write permissions are required. Pseudo access via tools like Webex, Zoom etc is not acceptable. However, it is ok with access through VPNs, jump servers etc.

9. How to rebuild a NED

Check the README-rebuild.md file, chapter 1.3, for more information.

10. Using the NED for Telemetry

Introduction

This NED supports subscribing to telemetry events using the telemetry feature introduced in NSO 6.7. With this capability, NSO can act as a telemetry subscriber towards managed devices, enabling powerful automation patterns at the service layer — such as feedback loops that provision configuration on a device and then automatically react when that configuration becomes active.

Prerequisites

  • The NED is used together with NSO 6.7 or newer.

  • The managed device supports gNMI Telemetry. This is true for all recent versions of IOS XR.

Restrictions

The NSO telemetry feature is designed to assist with provisioning — for example, by receiving automatic notifications when a provisioned configuration becomes active. It is generally not intended for high-frequency telemetry data reception.

The Cisco IOS XR platform also has some telemetry-related limitations:

  • Subscriptions can only be made for events related to operational data. Changes to configuration do not currently trigger telemetry events. This restriction applies to all IOS XR versions up to at least 25.4.1.

  • The on-change subscription type is supported only for certain parts of the IOS XR YANG schemas. The periodic subscription type is supported across the entire IOS XR schema.

For full details, refer to the IOS XR documentation.

Background: gNMI Telemetry

gNMI (gRPC Network Management Interface) is a network management protocol developed by the OpenConfig working group. It uses gRPC as the transport layer and Protocol Buffers for message encoding, providing a high-performance, modern alternative to traditional management interfaces like NETCONF and SNMP.

A central feature of gNMI is its Subscribe RPC, which allows a client to establish long-lived telemetry subscriptions towards a device. Instead of repeatedly polling the device for state, the client opens a subscription stream and the device pushes updates as they occur or at defined intervals.

gNMI supports three subscription modes:

Mode
Behavior

ON_CHANGE

The device sends an update only when the value of a subscribed path changes. Ideal for configuration state, protocol status, and other data where changes are discrete events. Not all paths on a device may support this mode.

SAMPLE (Periodic)

The device sends a snapshot of the subscribed data at a fixed interval. Suitable for counters, statistics, and any data that changes frequently and continuously.

TARGET_DEFINED

The device chooses the most appropriate mode (on-change or periodic) for each path based on its own internal classification. This mode offers flexibility but means the behavior may vary across paths and device platforms. Currently not supported by the NSO telemetry feature.

Key characteristics of gNMI telemetry include:

  • Path-based subscriptions — Subscriptions target specific paths in the device's YANG schema, giving precise control over what data is streamed.

  • Efficient transport — gRPC provides HTTP/2-based streaming with low overhead, making it well suited for high-frequency telemetry data.

  • Structured encoding — Updates are encoded using Protocol Buffers or JSON, ensuring a compact and well-defined message format.

  • Initial synchronization — When a subscription is established, the device can send a full snapshot of the current state before switching to incremental updates, ensuring the subscriber starts with a known baseline.

  • Heartbeat intervals — A heartbeat can be configured to let the device send periodic keep-alive messages even when no data has changed, allowing the subscriber to detect a silent connection failure.

  • Redundancy suppression — The device can be instructed to suppress updates that carry the same value as the previously sent update, reducing unnecessary traffic.

By leveraging gNMI telemetry through this NED, NSO gains a real-time, event-driven view of device state — a foundation for building closed-loop automation and reactive service logic.

How It Works

NSO does not have native support for parsing gNMI messages. Instead, this NED transforms received gNMI telemetry messages into a corresponding YANG-Push format that NSO can parse and process. This translation is transparent to the service layer — services interact with the telemetry data using the same NSO APIs regardless of whether the underlying protocol is gNMI or YANG-Push.

Configuring a Telemetry Subscription

Telemetry subscriptions are configured under each device's telemetry container:

You can set up one or more subscriptions per device. Each subscription must specify, at a minimum, a subscription mode (periodic or on-change) and a set of paths (in XPath format) pointing to the locations of interest in the device schema.

General Subscription Settings

The telemetry subscription model in NSO is designed around YANG-Push concepts. When using a gNMI NED, some of these settings are not applicable since gNMI uses its own subscription semantics. The table below indicates which settings are used and which are not relevant for gNMI-based subscriptions.

Setting
Description

name

Subscription name (used as the list key).

local-user

The NSO user whose authentication credentials are used when connecting to the device for the telemetry session.

datastore

Not used for gNMI NEDs.

xpaths

XPath filter pointing to the paths of interest in the device schema.

subtree

Not used for gNMI NEDs.

periodic

Enables periodic (SAMPLE) mode. The device sends a full snapshot of data under the subscribed path at regular intervals.

periodic/period

Update interval in centiseconds. Mandatory when using periodic mode.

periodic/anchor-time

Not used for gNMI NEDs.

on-change

Enables on-change (ON_CHANGE) mode. The device sends an update only when a node under the subscribed path has changed. Note that on-change may only be supported for certain parts of the device schema.

on-change/dampening-period

Not used for gNMI NEDs.

on-change/sync-on-start

Not used for gNMI NEDs.

on-change/excluded-change

Not used for gNMI NEDs.

reconnect-interval

How often (in seconds) to retry a failed subscription. Default: 60.

setting

A list of key/value pairs for NED-specific settings (see below).

NED-Specific Settings

The following settings are configured in the setting list. Because this list accepts arbitrary key/value string pairs, it is important that both keys and values are spelled exactly as shown below.

Key
Description

allow-aggregation

When set to true, the NED signals to the device that it is allowed to aggregate multiple subscription updates into a single gNMI message. This can improve efficiency when many paths are changing simultaneously but may increase message latency. Default: false.

config-only

When set to true, the telemetry subscription delivers configuration updates only. This option requires the device to support the gNMI extension ConfigSubscription. Default: false.

force-raw

When set to true, yang-push, or gnmi, the NED delivers telemetry events to NSO as raw, unparsed messages instead of model-driven data. By default, telemetry events are parsed by NSO and populated into a synthetic transaction, which allows services to perform standard operations such as diff iteration using the Maagic API. In some cases it may be preferable to receive the raw data and handle parsing in the service itself. When raw mode is active, the data is made available at: /devices/device/<name>/telemetry/subscription/<name>/raw-telemetry. Valid values: true or yang-push — the events are first transformed to YANG-Push format by the NED before they are passed to NSO as raw data. gnmi — the events are passed as raw JSON-serialized gNMI messages to NSO. Disabled by default.

gather-updates

Some gNMI devices send periodic telemetry events as an array of smaller messages, each typically containing an snapshot of a single node. These arrays can contain a large number of messages. When set to true, the NED gathers and consolidates such array-based gNMI update messages before forwarding the event to NSO. This can help reduce the number of synthetic transactions created in NSO. Default: false.

heartbeat-interval

Heartbeat interval in centiseconds. When set, the device is requested to send periodic heartbeat messages even when no data has changed. This allows the NED to detect a silent connection failure and trigger a reconnection. Disabled by default.

rate-limit-drop-log-interval

Controls how often dropped telemetry events are logged when rate limiting is active. Default: 50.

rate-limit-period

Rate-limit period in centiseconds. When set, the NED ensures that telemetry messages are not forwarded to NSO more frequently than this interval. This is intended as a safeguard against excessively high-frequency updates (e.g., from a misbehaving device). Disabled by default.

suppress-redundant

When set to true, the NED instructs the device to suppress updates that carry the same value as the previously sent update. This reduces unnecessary traffic for paths whose values remain stable over time. Default: false.

updates-only

When set to true, the device is instructed to skip the initial synchronization snapshot and only send subsequent updates. This is useful when the subscriber does not need the full current state at subscription startup. Default: false.

Examples

The following examples show how to configure telemetry subscriptions through the NSO CLI.

Example 1: On-Change Subscription with Rate Limiting

This subscription monitors the interfaces subtree and applies a rate limiter to prevent excessive updates.

Example 2: Periodic Subscription with Raw Delivery

This subscription polls the interfaces subtree every 10 seconds (1000 centiseconds) and delivers the data as raw gNMI messages.

Using Telemetry in Service Applications

This section provides an overview of how telemetry can be integrated into service applications to assist with provisioning and monitoring. For full details, refer to the NSO documentation.

Toolkit Components

The service developer's toolkit for working with telemetry consists of two main components:

  1. Synthetic Telemetry Transactions

    • For model-driven telemetry events, NSO fully populates the received data into a synthetic transaction. This means you can use standard NSO API operations — such as diff iteration and the Python Maagic API — to inspect and react to the data.

    • For raw telemetry events, the unparsed data can be read from the synthetic transaction at: /devices/device/<name>/telemetry/subscription/<name>/raw-telemetry

  2. Telemetry Kickers

    • The telemetry-kicker (configured under /kickers) lets you trigger an action whenever a telemetry event is received that matches a selector expression. This is the primary mechanism for wiring telemetry events into your service logic.

Together, these components enable patterns such as:

  • Feedback-loop provisioning — Push configuration to a device, then automatically detect when it has taken effect.

  • Alarm propagation — React to operational state changes on the device and propagate them northbound.

Example: Feedback-Loop Based BGP Provisioning

The following example demonstrates a simple service application that provisions a BGP neighbor on a device and uses telemetry to detect when that neighbor reaches the ESTABLISHED state. When the telemetry event is received, the service automatically updates an operational leaf, which in turn can notify northbound systems (for instance, via a northbound YANG-Push subscription from NSO).

Service YANG Model

Service Python Module

How It Works

  1. When the service is created, it configures a telemetry kicker and an on-change telemetry subscription targeting the BGP group on the device.

  2. As the device detects a change in the subscribed BGP group, it pushes an update to NSO via gNMI, which the NED translates into YANG-Push format.

  3. The telemetry kicker fires and invokes the handle-autonomous-bgp-notification action.

  4. The action inspects the synthetic transaction to check whether the BGP neighbor has reached the ESTABLISHED state.

  5. If so, the action removes the subscription and kicker (cleanup) and sets the service's operational-state leaf to ESTABLISHED.

  6. Northbound systems subscribed to NSO can then be notified of this state change automatically.

11. Using the NED feature load-native-config

This NED has support for the load-native-config feature, meaning that you can load config directly from a file formatted in native device format. Since it is a gNMI NED it is required that the file is formatted as a gNMI SetRequest message, as specified here: https://github.com/openconfig/reference/blob/master/rpc/gnmi/gnmi-specification.md#341-the-setrequest-message

A gNMI SetRequest message is using a JSON structure containing three lists with the self explained names update, replace and delete. Each entry in the update and replace lists is a modify and/or create operation, represented by a gNMI path and a payload element. The latter is a JSON formatted string itself (in cleartext) describing the elements to be modified.

Each entry in the delete list is a delete operation represented by a gNMI path.

Optionally each gNMI SetRequest message can contain a prefix which is a gNMI path that will be prepended to all operations in the update, replace and delete lists.

Below is an example of a valid JSON structure that can be used for the load-native-commands feature.

The NSO command commit dry-run outformat native is an easy way to generate valid JSON snippets that can be used with the load-native-command feauture.

Example:

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