Problem Statement: YANG Modeling for Protocol Buffer Based Network APIs
draft-ali-opsawg-yang-protobuf-problem-statement-00

Network Working Group                                             Z. Ali
Internet-Draft                                             Cisco Systems
Intended status: Informational                               6 July 2026
Expires: 7 January 2027

Problem Statement: YANG Modeling for Protocol Buffer Based Network APIs
          draft-ali-opsawg-yang-protobuf-problem-statement-00

Abstract

   Network devices increasingly expose management, telemetry, and
   dynamic service interfaces using gRPC and Protocol Buffers.  Many of
   these interfaces carry ephemeral or runtime state that is not
   intended to be stored as persistent configuration.  At the same time,
   the IETF has standardized YANG as the primary data modeling language
   for network management and operations.  This document describes the
   problem space and identifies questions for the IETF community
   regarding the role of YANG in defining interoperable Protocol Buffer
   based APIs.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Existing IETF Work  . . . . . . . . . . . . . . . . . . . . .   2
     2.1.  YANG Data Modeling  . . . . . . . . . . . . . . . . . . .   2
     2.2.  RFC 8342 and Ephemeral State  . . . . . . . . . . . . . .   3
   3.  Industry Practice . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Existing Tooling  . . . . . . . . . . . . . . . . . . . . . .   3
   5.  Problem Statement . . . . . . . . . . . . . . . . . . . . . .   3
   6.  Discussion Topics for the IETF  . . . . . . . . . . . . . . .   3
   7.  Potential Direction . . . . . . . . . . . . . . . . . . . . .   4
   8.  Next Steps  . . . . . . . . . . . . . . . . . . . . . . . . .   4
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   10. IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   11. Normative References  . . . . . . . . . . . . . . . . . . . .   4
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   4

1.  Introduction

   The networking industry has broadly adopted gRPC and Protocol Buffers
   for communication between network devices, controllers, orchestration
   systems, and operational applications.  Many deployed implementations
   expose information that is transient in nature and exists only for
   the lifetime of a process, service, session, or device runtime.

   Although the IETF has standardized YANG as the primary network
   management modeling language, there is currently no common IETF
   guidance describing how YANG models should be represented within
   Protocol Buffer schemas used by gRPC APIs.  As a result, vendors
   often develop independent protobuf definitions despite representing
   similar information.

2.  Existing IETF Work

2.1.  YANG Data Modeling

   YANG provides a standardized framework for modeling configuration and
   operational state.  These models provide a common vocabulary and
   semantics that can potentially be reused across management protocols
   and API technologies.

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2.2.  RFC 8342 and Ephemeral State

   RFC 8342 defines the Network Management Datastore Architecture
   (NMDA).  While Appendix B provides an example of an Ephemeral Dynamic
   Configuration Datastore, many currently deployed gRPC and Protocol
   Buffer APIs are not implementing the architecture described therein.
   Instead, vendors are exposing runtime information through
   implementation-specific protobuf schemas.

3.  Industry Practice

   Many network vendors have adopted gRPC and Protocol Buffers.  While
   the underlying information may correspond to concepts already modeled
   in YANG, the protobuf schema definitions are frequently vendor-
   specific, leading to challenges such as divergent semantics and the
   inability to reuse existing YANG standardization work.

4.  Existing Tooling

   Tools already exist that can derive Protocol Buffer schemas from YANG
   models, demonstrating that technical conversion is feasible.
   However, different tools may generate different protobuf structures
   from the same YANG model, meaning tooling alone does not guarantee
   interoperability.

5.  Problem Statement

   There is currently no IETF framework that answers the following
   questions:

   *  Should YANG serve as the authoritative information model for gRPC
      APIs?

   *  How should ephemeral and dynamic state be modeled?

   *  How should operational state be represented?

6.  Discussion Topics for the IETF

   This document seeks discussion on the following topics:

   *  Is there sufficient industry interest to standardize YANG-based
      protobuf modeling?

   *  Does RFC 8342 adequately address current deployment requirements
      for ephemeral and dynamic state?

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   *  Should the IETF define a standardized mapping between YANG and
      Protocol Buffers?

   *  Should generated protobuf schemas become a standardized artifact
      derived from YANG models?

7.  Potential Direction

   One possible direction is for the IETF to define a framework in which
   YANG remains the authoritative information model, and Protocol Buffer
   schemas are generated using standardized rules to preserve consistent
   semantics across implementations.

8.  Next Steps

   The authors believe that a focused discussion involving operators,
   vendors, protocol designers, and implementers would help determine
   whether there is sufficient interest to pursue future standardization
   work.

9.  Security Considerations

   None.

10.  IANA Considerations

   None.

11.  Normative References

   [RFC8342]  Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
              and R. Wilton, "Network Management Datastore Architecture
              (NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018,
              <https://www.rfc-editor.org/info/rfc8342>.

Author's Address

   Zafar Ali
   Cisco Systems
   Email: zali@cisco.com

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