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README v2.2.4 2025-03-07

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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 live-status actions
6. Built in live-status show
7. Limitations
8. How to report NED issues and feature requests
9. How to rebuild a NED
10. Configure the NED to use ssh multi factor authentication
11. How to configure additional config warning exceptions
12. How to execute configuration commands on a SFR device (not recommended)
13. NED Secrets - Securing your Secrets

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1. General

This document describes the sfr-nbe300 NED.

The NED was tested on target devices with OS version R1.2.7 and R.1.5.5. If the device is not one of the devices mentioned above, then some of the commands will be treated similar to the R1.5.5 device type. Between the 2 firmware versions there are slightly differences like:

  1. deleting a parameter. Example:

    • "version" under "router rip" section is deleted as "no version no-version" on R1.2.7 and is deleted as "no version" on R1.5.5.

  2. different commands with the same meaning. Example:

    • "bind telnet acl 10" is a valid command on R1.2.7 device and the correspondent command on R1.5.5 is:

The NED connects to the device CLI using SSH. Configuration is done by sending native CLI commands to the device through the communication channel.

Additional README files bundled with this NED package

Common NED Features

Verified target systems

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1.1 Extract the NED package

It is assumed the NED package ncs-<NSO version>-sfr-nbe300-<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:

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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:

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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:sfr-nbe300-<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:

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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

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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):

  • If configured protocol is ssh, do fetch the host keys now:

  • Finally commit the configuration

  • Verify configuration, using a sync-from.

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

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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-sfr-nbe300-cli-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.

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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)

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4. Sample device configuration

Example of configuring an "interface gigabitethernet":

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5. Built in live-status actions

The NED includes support for operational SFR commands and the following action can be used: devices device live-status exec any.

Examples:

  1. show version

  2. show uptime

In order to execute multiple commands, these must be separated by " ; ". Please note that a white space must exist before and after the ;. This applies to both 'exec' and 'live-status exec any' actions.

Example:

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6. Built in live-status show

NONE

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7. Limitations

NONE

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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.

    In addition to this, it helps if you can show how it should work by manually logging into the device using SSH/TELNET and type the relevant commands showing a successful operation.

  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. Set the config on the real device including all existing dependent config and run sync-from to show it in the trace.

  2. Run sync-from # devices device dev-1 sync-from

  3. Attach the raw trace to the ticket

  4. List the config you want implemented in the same syntax as shown on the device

  5. SSH/TELNET 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 as long as we can connect to the NED via SSH/TELNET.

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9. How to rebuild a NED

To rebuild the NED do as follows:

When the NED has been successfully rebuilt, it is necessary to reload the package into NSO.

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10. Configure the NED to use ssh multi factor authentication

This NED supports multi factor authentication (MFA) using the ssh authentication method 'keyboard-interactive'.

Some additional steps are required to enable the MFA support:

  1. Verify that your NSO version supports MFA. This is configurable as additional settings in the authentication group used by the device instance.

    Enter a NSO CLI and enter the following and do tab completion:

    If 'mfa' is displayed in the output like above, NSO has MFA support enabled. In case MFA is not supported it is necessary to upgrade NSO before proceeding.

  2. Implement the authenticator executable. The MFA feature relies on an external executable to take care of the client part of the multi factor authentication. The NED will automatically call this executable for each challenge presented by the ssh server and expects to get a proper response in return.

    The executable can be a simple shell script or a program implemented in any programming language.

    The required behaviour is like this:

    • read one line from stdin The line passed from the NED will be a semi colon separated string containing the following info:

      The elements for device name, user, password and opaque corresponds to what has been configured in NSO. The ssh server name, instruction and prompt are given by the ssh server during the authentication step.

      Each individual element in the semi colon separated list is Base64 encoded.

    • Extract the challenge based on the contents above.

    • Print a response matching the challenge to stdout and exit with code 0

    • In case a matching response can not be given do exit with code 2

    Below is a simple example of an MFA authenticator implemented in Python3:

  3. Configure the authentication group used by the device instance to enable MFA. There are two configurables available:

    • executable The path to the external multi factor authentication executable (mandatory).

    • opaque Opaque data that will passed as a cookie element to the executable (optional).

  4. Try connecting to the device.

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10.1 Trouble shooting

In case of connection problems the following steps can help for debugging:

Enable the NED trace in debug level:

Try connect again

Inspect the generated trace file.

Verify that the ssh client is using the external authenticator executable:

Verify that the executable is called with the challenges presented by the ssh server:

Check for any errors reported by the NED when calling the executable

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11. How to configure additional config warning exceptions

In some situations, when configuring a particular command, the NED will treat the replies coming after, as an error if they are not part of known replies:

Even if the above replies are received, the command is taken into account, so we must ignore those replies. If more similar replies are encountered, the NED list of known harmless replies must be updated. However, the user can get the same result by configuring the sfr-nbe300 write config-warning ned-setting. The config-warning list key is a regular expression with a warning that should be ignored.

For example, supposing that the last reply ("PIN .* No modification on key.") was not part of the known exception list inside NED.

User can add a new warning as below:

Another regex examples are:

  • This second regex can be used when a "pin" is set under the "controller cellular 0" and the device replies with:

    After every modification, user must issue the commit command:

    Note that in order for the warning exception to take effect, the ned-settings must be read again by disconnect and connect commands.

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12. How to execute configuration commands on a SFR device (not recommended)

Configuration commands can be executed using actions. They can be accessed using the exec prefix.

NOTE:

  • please be aware that when using these actions, the NED's CDB (configuration database) and the target device's configuration will not be in sync anymore. Therefore, a "sync-from" command is required when further configuration will be sent via NED. Also, if some configuration fails when is being executed by the exec action, there will be no rollback mechanism.

Examples:

  1. unset apn and pin

  1. set apn and pin

In order to execute multiple commands, these must be separated by spaces and a ; like this: " ; ".

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13. NED Secrets - Securing your Secrets

Naturally, for security reasons, NSO in general has no way of encrypting/decrypting passwords with the secret key on the device. This means that if nothing is done about this we will become out of sync once we write secrets to the device.

In order to avoid becoming out of sync the NED reads back these elements immediately after set and stores the encrypted value(s) in a special 'secrets' table in oper data. Later on, when config is read from the device, the NED replaces all cached encrypted values with their plaintext values; effectively avoiding all config diffs in this area. If the values are changed on the device, the new encrypted value will not match the cached pair and no replacement will take place. This is desired, since out of band changes should be detected.

--- Handling auto-encryption

Let us say that we have password-encryption on and we want to write a new value for the 'sip-authentication' element to our device:

this will be automatically encrypted by the device as below:

But the secrets management will store this new encrypted value in our 'secrets' table:

which means that compare-config or sync-from will not show any changes and will not result in any updates to CDB.

In case encrypted values are present at sync-from, and the 'sip-authentication' element was not created through ncs_cli, meaning there is no corresponding element set in the 'secrets' table in oper data, then the rollback operation will be performed using the following command: encrypted sip-authentication 7tIVZ+GABbpVtikPJ0yuIJNFsSRQsAwTzOCVJSpe4IE=. This is to preserve the value set before for the 'sip-authentication' element.

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