Model-driven management interfaces

SR OS supports two classes of management interfaces:

• Classic management interfaces

  • SNMP

  • classic CLI

• Model-driven management interfaces

  • Model-Driven CLI (MD-CLI)

  • NETCONF

  • gRPC (gNMI and gNOI)

Unless otherwise indicated, the term ‟CLI” in the SR OS user documentation refers to the classic CLI. The classic CLI has been supported in SR OS from the initial introduction of SR OS. For more information about classic CLI commands, see the 7450 ESS, 7750 SR, 7950 XRS, and VSR Classic CLI Command Reference Guide.

The MD-CLI is a model-driven CLI introduced in SR OS Release 16.0.R1. For more information about MD-CLI commands, see the 7450 ESS, 7750 SR, 7950 XRS, and VSR MD-CLI User Guide and the 7450 ESS, 7750 SR, 7950 XRS, and VSR MD-CLI Command Reference Guide.

Model-driven management interfaces are based on a common infrastructure that uses YANG models as the core definition for configuration, state, and operational actions. All model-driven interfaces take the same common underlying YANG modules and render them for the particular management interface.

The model-driven interfaces are similar to the classic CLI interfaces with the following notable differences.

• The classic and model-driven configuration formats are incompatible; the system automatically converts the classic configuration to the model-driven format when the management interface configuration mode is changed to model-driven.

• Some classic CLI branches have been moved, renamed, or reorganized in the SR OS YANG modules.

• Many elements use strict references in model-driven interfaces instead of the loose references used in the classic CLI and SNMP. For more information, see Loose references to IDs and String routing policy validation.

• Many elements use string names as keys in model-driven interfaces instead of the numerical identifiers used in the classic CLI and SNMP. See String names as keys for more information.

• The classic CLI shutdown command has been replaced with admin-state in model-driven interfaces.

• The classic CLI commands with multiple parameters have been separated into individual leafs in model-driven interfaces.

• The model-driven interfaces make extensive use of Boolean values (true and false) for configuration settings.

• The default configuration handling is as follows.

  • In classic configuration mode, the default handling is similar to RFC 6243 ‟trim” mode. Configuration values are not reported if they are equal to the default value, even if the user explicitly configured the value.

  • In model-driven configuration mode, the system operates with ‟explicit” default handling. Users can set a leaf to the same value as the default and the system displays it as part of the configuration. This handling is similar to RFC 6243 ‟explicit” mode.

  • In mixed configuration mode, the system uses ‟explicit” default handling but it is not persistent. Explicitly configured default values are not preserved during a high-availability CPM switchover or a reboot. Nokia recommends deleting the leaf instead of setting any leaf explicitly to its default value in mixed configuration mode.

• A newly created routing instance, group, or EBGP neighbor in a model-driven interface applies the secure default behavior to reject all routes. Using the ebgp-default-reject-policy command to implement this is compliant with RFC 8212. Nokia recommends configuring import and export policies that express the intended routing instead of using the insecure default behavior. For more information about RFC behavior, see the 7450 ESS, 7750 SR, 7950 XRS, and VSR Unicast Routing Protocols Guide.