



CCAMP Working Group                                           S. Xu, Ed.
Internet-Draft                                                 Y. Hirota
Intended status: Informational                                  Y. Awaji
Expires: 3 September 2026                                           NICT
                                                            2 March 2026


    Problem Statement: Information Sharing of Optical Impairments in
              Monitoring of Multi-Domain All-Optical Paths
           draft-xu-ccamp-impairment-info-sharing-problem-00

Abstract

   In multi-domain all-optical Wavelength Switched Optical Networks
   (WSONs), end-to-end services may traverse multiple administrative
   domains operated by different entities.  Monitoring such services
   requires visibility into optical impairments that accumulate across
   domain boundaries.  However, exchanging impairment-related
   information raises operational, scalability, and confidentiality
   concerns.  Detailed metrics such as attenuation, noise, nonlinear
   effects, and filtering penalties may be necessary for accurate
   performance assessment, yet they can expose sensitive topology,
   equipment, or utilization information.

   This document describes the problem space associated with sharing
   optical impairment information across administrative domains for
   monitoring purposes.  It highlights the need to balance operational
   visibility and confidentiality preservation, and outlines
   considerations for abstraction, information granularity, and trust
   relationships among participating operators.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on 3 September 2026.




Xu, et al.              Expires 3 September 2026                [Page 1]

Internet-Draft     Exchange of Optical Impairment Info        March 2026


Copyright Notice

   Copyright (c) 2026 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.  Code Components
   extracted from this document must include Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Terminology and Notations . . . . . . . . . . . . . . . .   4
     1.2.  Requirements Language . . . . . . . . . . . . . . . . . .   4
   2.  Requirements for Collaborative Cross-Domain Performance Data
           Sharing . . . . . . . . . . . . . . . . . . . . . . . . .   4
     2.1.  Peer Networks and Multi-Domain Optical Path . . . . . . .   4
     2.2.  Signal Degradation  . . . . . . . . . . . . . . . . . . .   5
     2.3.  Requirements for Collaborative Cross-Domain Performance
           Data Sharing  . . . . . . . . . . . . . . . . . . . . . .   5
   3.  Use Cases for Collaborative Cross-Domain Performance Data
           Sharing . . . . . . . . . . . . . . . . . . . . . . . . .   6
     3.1.  Rapid Restoration via Domain-Level Localization . . . . .   6
     3.2.  Quantitative Evidence for SLA Violation Attribution . . .   7
   4.  Problem Statement for Collaborative Cross-Domain Performance
           Data Sharing  . . . . . . . . . . . . . . . . . . . . . .   7
     4.1.  Limited Optical Observability at Domain Boundaries  . . .   7
     4.2.  Confidentiality-Preserving Information Sharing  . . . . .   8
     4.3.  Implications for Solution Design  . . . . . . . . . . . .   9
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  10
     5.1.  Confidentiality . . . . . . . . . . . . . . . . . . . . .  10
     5.2.  Integrity and Authenticity  . . . . . . . . . . . . . . .  10
     5.3.  Trust Model . . . . . . . . . . . . . . . . . . . . . . .  11
     5.4.  Denial-of-Service Considerations  . . . . . . . . . . . .  11
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  11
   7.  Normative References  . . . . . . . . . . . . . . . . . . . .  11
   8.  Informative References  . . . . . . . . . . . . . . . . . . .  12
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  12








Xu, et al.              Expires 3 September 2026                [Page 2]

Internet-Draft     Exchange of Optical Impairment Info        March 2026


1.  Introduction

   To provision an optical connection (hereafter referred to as an
   optical path), [RFC7446] defines an information model to address the
   Routing and Wavelength Assignment (RWA) problem in Wavelength
   Switched Optical Networks (WSONs).  [RFC9094] specifies the
   corresponding YANG data model.  In addition, [RFC6556] addresses
   optical impairments and their impact on signal quality in the context
   of impairment-aware RWA (IA-RWA).  The Internet-Draft [I-D.ietf-
   ccamp-optical-impairment-topology-yang] further extends the YANG data
   modeling of impairment-related topology attributes.  Collectively,
   these works facilitate path computation, provisioning, and validation
   while accounting for optical impairment constraints within a single
   administrative domain.

   However, for an all-optical path spanning multiple administrative
   domains, an information model for monitoring and analyzing
   impairment-induced signal degradation and failures remains an open
   issue.  Optical impairments such as Optical Signal-to-Noise Ratio
   (OSNR), Generalized Signal-to-Noise Ratio (GSNR), nonlinear noise,
   chromatic dispersion (CD), and polarization mode dispersion (PMD) may
   accumulate across domain boundaries and degrade end-to-end service
   performance.  When a receiver detects degraded performance or failure
   of a multi-domain optical path, it is operationally desirable to
   localize the domain(s) that contribute most significantly to the
   degradation and to enable timely corrective actions within the
   responsible domain(s).

   In a multi-domain optical path service, each participating domain may
   contribute to the accumulated degradation along the end-to-end path.
   Effective monitoring therefore requires the exchange of performance-
   related information at domain demarcation points, enabling
   quantitative assessment of each domain's contribution to signal
   degradation.  This introduces the need for an information model that
   (1) supports the sharing of performance-related information among
   relevant domains, and (2) enables analytical methods to assist in
   identifying the domain(s) most likely responsible for observed
   degradation.

   Because such analytical methods depend on the set of information that
   can be exchanged across administrative boundaries, a clear
   understanding of information-sharing requirements and constraints is
   necessary.  Accordingly, this document focuses on the problem
   statement associated with sharing performance-related information
   among domains in multi-domain WSON environments.  The specification
   of a complete information model, including detailed data structures
   and analytical procedures for degradation attribution or failure
   responsibility determination, is outside the scope of this document.



Xu, et al.              Expires 3 September 2026                [Page 3]

Internet-Draft     Exchange of Optical Impairment Info        March 2026


1.1.  Terminology and Notations

   The terminology related to WSON impairments and associated concepts
   used in this document is consistent with
   [I-D.ietf-ccamp-optical-impairment-topology-yang].  Readers are
   referred to that document for definitions of impairment parameters
   and related terms.

1.2.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

2.  Requirements for Collaborative Cross-Domain Performance Data Sharing

2.1.  Peer Networks and Multi-Domain Optical Path

            --------------                       --------------
           |   Domain A   |    -------------    |   Domain C   |
           |              |   |   Domain B  |   |              |
           |  -----       |   |             |   |       -----  |
           | |Src T|-X-->a+-->+b------X--->c+-->+d--X->|R Dst| |
           | |    R|<----h+<--+g<----------f+<--+e<----|T    | |
           |  -----       |   |             |   |       -----  |
            --------------     -------------     --------------

        Figure 1: Peer Networks and a multi-domain all-optical path

   Figure 1 illustrates an example of interconnected multi-domain WSONs
   in the data plane (D-Plane), consisting of Domains A, B, and C under
   different administrative control.  A bidirectional end-to-end optical
   path is provisioned between a source transceiver in Domain A and a
   destination transceiver in Domain C.  The path traverses domain
   border nodes (e.g., nodes a to d in the downstream direction and
   nodes e to h in the upstream direction).

   The provisioned optical path satisfies impairment-related
   constraints, including tolerance thresholds for parameters such as
   OSNR and GSNR.  For simplicity, internal optical nodes, links, and
   control-plane elements are not shown in the figure.  Each domain is
   assumed to operate its own control plane (C-Plane), potentially based
   on the Abstraction and Control of Traffic Engineered Networks (ACTN)
   architecture [RFC8453].  The C-Plane may provide monitoring and
   telemetry capabilities within the administrative domain.




Xu, et al.              Expires 3 September 2026                [Page 4]

Internet-Draft     Exchange of Optical Impairment Info        March 2026


2.2.  Signal Degradation

   Signal degradation along a multi-domain optical path may result from
   accumulated optical impairments, such as additional noise introduced
   by optical amplifiers.  Such impairments propagate along the path and
   may accumulate at the receiving endpoint.  As illustrated in
   Figure 1, OSNR degradation may occur at specific locations within
   Domains A and B along the downstream direction.  The impairment
   contributions from multiple domains accumulate and may result in
   significant end-to-end signal degradation.  Furthermore, noise
   introduced in upstream domains may be further amplified by optical
   amplifiers in downstream domains, potentially increasing its impact
   on the final OSNR observed at the receiver [ZYSKIND2016].

   For illustration purposes, Figure 1 and this document explain
   degradation and failure in the downstream direction only.  Similar
   impairment scenarios may occur in the upstream direction or in both
   directions.

2.3.  Requirements for Collaborative Cross-Domain Performance Data
      Sharing

   At the receiving endpoint, a service failure may be declared when
   accumulated impairment causes the observed OSNR or GSNR to exceed the
   configured tolerance threshold.  In some cases, analysis of the
   received signal may provide indications of localized loss or optical
   power variation along the optical path.  For example, Digital
   Longitudinal Monitoring (DLM) techniques [SASAI2024] may assist in
   estimating impairment distribution along the path.  An alarm
   notification that includes such monitoring information may be
   generated and delivered to the controller of the destination domain
   (e.g., Domain C).

   While DLM-based information may help identify abnormal optical power
   variation, it is generally insufficient to determine the detailed
   contribution of each administrative domain to the observed OSNR
   degradation.  Accurate attribution may require additional impairment-
   related parameters, such as amplifier noise figures or other domain-
   specific characteristics, which are not locally available to the
   destination domain controller.  Without such information,
   quantitative assessment of domain-level responsibility remains
   challenging.









Xu, et al.              Expires 3 September 2026                [Page 5]

Internet-Draft     Exchange of Optical Impairment Info        March 2026


   Accordingly, collaborative mechanisms for sharing performance-related
   information among the relevant administrative domains (e.g., Domains
   A through C) are necessary to support degradation analysis of multi-
   domain optical paths.  Such information exchange is intended to
   assist in identifying the domain(s) that most significantly
   contribute to observed impairment and to facilitate appropriate
   operational response.

   These considerations motivate the need for controlled and
   interoperable exchange of impairment-related information across
   administrative boundaries.

3.  Use Cases for Collaborative Cross-Domain Performance Data Sharing

   By exchanging the minimum necessary performance-related information
   for a degraded or failed multi-domain optical path (e.g., information
   obtained via monitoring, telemetry, and analysis systems),
   participating administrative domains can perform coordinated and
   quantitative analysis of impairment contributions.  Such analysis may
   assist in identifying and localizing the domain(s) that contribute
   most significantly to the observed degradation.  The following
   subsections describe representative use cases.

3.1.  Rapid Restoration via Domain-Level Localization

   When service degradation or failure is detected, a straightforward
   restoration approach is to provision a new end-to-end multi-domain
   optical path.  For example, the controller in the destination domain
   (e.g., Domain C) may initiate end-to-end reprovisioning across all
   traversed domains.

   Alternatively, if the affected administrative domain(s) can be
   identified through collaborative impairment analysis, restoration
   actions may be confined to the responsible domain(s).  In this case,
   local reoptimization or reprovisioning between the relevant border
   nodes (e.g., within Domain B) may be sufficient, provided that
   wavelength continuity and impairment constraints are satisfied.
   Compared to full end-to-end reprovisioning, domain-local restoration
   may reduce operational cost and restoration time by limiting the
   scope of reconfiguration to the affected administrative domain.











Xu, et al.              Expires 3 September 2026                [Page 6]

Internet-Draft     Exchange of Optical Impairment Info        March 2026


3.2.  Quantitative Evidence for SLA Violation Attribution

   Coordinated quantitative analysis of impairment contributions across
   domains may provide a common and verifiable basis for assessing
   service performance.  Such analysis can assist stakeholders in
   determining whether a Service Level Agreement (SLA) violation has
   occurred and in identifying the administrative domain(s) primarily
   responsible for the degradation.

   By enabling objective attribution based on shared performance data,
   collaborative analysis may reduce ambiguity in responsibility
   determination during multi-domain degradation or failure events.

   These use cases illustrate the operational value of collaborative
   cross-domain performance data sharing.  In particular, they highlight
   the need for mechanisms that support controlled information exchange
   among administrative domains to facilitate degradation localization
   and responsibility attribution in multi-domain WSON deployments.

4.  Problem Statement for Collaborative Cross-Domain Performance Data
    Sharing

   The use cases described in Section 3 illustrate the operational value
   of collaborative cross-domain performance analysis.  However,
   realizing these use cases in practice requires careful consideration
   of architectural and policy constraints that affect cross-domain
   information exchange.  This section examines these constraints and
   defines the associated problem space.  In particular, limited optical
   observability at domain boundaries and confidentiality restrictions
   on detailed intra-domain information significantly affect the scope
   and granularity of shareable data.

   The following subsections examine these constraints and their
   implications for collaborative cross-domain performance analysis.

4.1.  Limited Optical Observability at Domain Boundaries

   In optical transport networks, signals are transmitted as continuous
   optical waveforms without protocol headers or discrete packet
   structures that can be inspected at intermediate nodes.  As a result,
   intrinsic observability of end-to-end optical paths is limited,
   particularly at administrative domain boundaries where signals
   traverse border nodes transparently.

   At domain border nodes, monitoring devices MAY be deployed at ingress
   and/or egress ports to observe signal quality parameters associated
   with multi-domain optical paths.  When such devices are deployed,
   consistent telemetry capabilities and data representations are



Xu, et al.              Expires 3 September 2026                [Page 7]

Internet-Draft     Exchange of Optical Impairment Info        March 2026


   desirable to enable meaningful cross-domain analysis.  In the absence
   of standardized telemetry definitions and formats, implementations
   from different vendors may expose heterogeneous metrics, thereby
   complicating correlation and interpretation across domains.

   In some deployments, monitoring devices may not be installed at
   border nodes due to cost, operational, or architectural
   considerations.  In such cases, impairment-related information at
   domain boundaries may need to be derived through estimation performed
   by the domain controller.  Estimation typically relies on intra-
   domain monitoring and telemetry data and on impairment models
   maintained within the administrative domain.

   However, estimation accuracy and update frequency may be constrained
   by computational complexity, particularly in large-scale WSON
   environments.  Operators may therefore balance estimation precision
   against processing overhead and reporting frequency.  Consequently,
   boundary observability may be limited in terms of both measurement
   accuracy and temporal resolution.  This limitation constitutes a
   fundamental constraint on the availability and reliability of cross-
   domain performance data.

4.2.  Confidentiality-Preserving Information Sharing

   Accurate degradation analysis within a single-domain WSON requires
   detailed physical-layer, operational, and topological information.
   Such information typically includes per-span loss, amplifier gain and
   noise figure, launch and receive power levels, OSNR, CD, PMD,
   nonlinear impairment estimates, spectrum occupancy, filter narrowing
   effects, and ROADM configuration states.  Real-time performance
   indicators, such as pre-/post-FEC BER, Q-factor, and optical power
   drift, are also necessary to assess signal quality evolution.
   Furthermore, precise topology knowledge, including fiber routes, span
   lengths, amplifier placement, protection status, and recent
   configuration changes, is essential to localize degradation within
   the domain.















Xu, et al.              Expires 3 September 2026                [Page 8]

Internet-Draft     Exchange of Optical Impairment Info        March 2026


   While this level of visibility is required for accurate intra-domain
   diagnosis, much of the information is considered confidential and
   cannot be disclosed across administrative boundaries.  Detailed
   topology data may reveal internal network design, vendor selection,
   or infrastructure investment strategy.  Precise OSNR margins,
   nonlinear penalty estimates, and utilization levels may expose
   engineering margins, residual capacity, or congestion conditions.
   Even certain performance trends or spectrum usage information could
   enable external inference of traffic load, protection mechanisms, or
   commercial priorities.  As a result, unrestricted sharing of raw
   performance data is typically infeasible in multi-operator
   environments.

   Consequently, collaborative cross-domain degradation localization
   must operate under confidentiality constraints.  Information exchange
   therefore relies on abstraction and aggregation mechanisms, as
   described in [RFC7926].  Abstraction represents an administrative
   domain using simplified virtual nodes or abstract links, exposing
   only selected high-level attributes rather than detailed internal
   state.  Aggregation further compresses multiple metrics into
   summarized health indicators or impairment classes.  In the event of
   degradation, each domain performs internal analysis locally and
   exports only abstracted status indicators or alarm summaries to the
   relevant administrative domains.

   While this approach preserves confidentiality and supports
   scalability, it inherently reduces diagnostic granularity.  Cross-
   domain fault localization therefore becomes a distributed inference
   process under partial visibility, rather than a direct measurement
   problem with complete information.

4.3.  Implications for Solution Design

   The constraints described in Sections 4.1 and 4.2 have direct
   implications for any mechanism intended to support collaborative
   cross-domain performance data sharing.

   First, limited observability at domain boundaries implies that
   solutions cannot assume uniform availability of precise measurement
   data.  Mechanisms SHOULD accommodate heterogeneous telemetry
   capabilities and varying levels of measurement accuracy across
   administrative domains.  In some cases, derived or estimated
   information may need to be used in place of direct measurements.

   Second, confidentiality requirements restrict the scope and
   granularity of information that can be exchanged.  Solutions
   therefore need to support abstraction and aggregation of impairment-
   related data, allowing domains to expose only the minimum necessary



Xu, et al.              Expires 3 September 2026                [Page 9]

Internet-Draft     Exchange of Optical Impairment Info        March 2026


   information required for cross-domain correlation.  The exchanged
   information SHOULD avoid revealing detailed internal topology,
   vendor-specific characteristics, or sensitive operational parameters.

   Third, because degradation localization under partial visibility
   becomes a distributed inference problem, solution designs need to
   consider correlation logic that operates on abstracted indicators
   rather than raw physical-layer data.  This may involve standardized
   health indicators, impairment classes, or summarized performance
   metrics suitable for inter-domain exchange.

   In summary, collaborative cross-domain performance analysis in multi-
   domain WSON environments must operate under constrained observability
   and confidentiality-preserving abstraction.  These constraints define
   the boundaries within which interoperable and scalable information-
   sharing mechanisms can be developed.

5.  Security Considerations

   Collaborative cross-domain performance data sharing introduces
   security considerations related to confidentiality, integrity,
   authenticity, and trust among administrative domains.

5.1.  Confidentiality

   Impairment-related information may reveal sensitive details regarding
   internal topology, equipment characteristics, engineering margins, or
   operational status.  Unauthorized disclosure of such information
   could expose infrastructure design choices, residual capacity, or
   commercial strategy.

   Mechanisms supporting cross-domain information exchange SHOULD ensure
   that only the minimum necessary abstracted information is shared.
   Confidentiality protection SHOULD include appropriate access control,
   policy enforcement, and, where applicable, encryption of inter-domain
   communications.

5.2.  Integrity and Authenticity

   Incorrect or manipulated performance data may lead to improper fault
   localization, incorrect responsibility attribution, or unnecessary
   restoration actions.  Therefore, exchanged information MUST be
   protected against unauthorized modification in transit.

   Inter-domain communication mechanisms SHOULD support integrity
   protection and mutual authentication between participating
   administrative domains.  The receiving entity SHOULD be able to
   verify the origin and integrity of impairment-related reports.



Xu, et al.              Expires 3 September 2026               [Page 10]

Internet-Draft     Exchange of Optical Impairment Info        March 2026


5.3.  Trust Model

   Collaborative degradation analysis relies on trust relationships
   between administrative domains.  Because fault localization under
   partial visibility becomes a distributed inference process,
   inaccurate or incomplete information from one domain may affect
   overall analysis accuracy.

   Solution designs SHOULD clearly define trust assumptions, including:
   (1) The level of confidence in abstracted indicators, (2) The scope
   of shared data, and (3) The authority responsible for coordination
   and correlation.

   In environments involving multiple operators, contractual and policy
   agreements may complement technical safeguards to establish
   accountability and acceptable information-sharing boundaries.

5.4.  Denial-of-Service Considerations

   Frequent telemetry exchanges or large volumes of impairment data may
   increase control-plane processing load.  Mechanisms SHOULD consider
   rate limiting, aggregation, and filtering to mitigate potential
   resource exhaustion or signaling overload.

6.  IANA Considerations

   TBD

7.  Normative References

   [I-D.ietf-ccamp-optical-impairment-topology-yang]
              Beller, D., Ed., Le Rouzic, E., Belotti, S., Galimberti,
              G., and I. Busi, "A YANG Data Model for Optical
              Impairment-aware Topology", Work in Progress, Internet-
              Draft, draft-ietf-ccamp-optical-impairment-topology-yang-
              23, February 2026, <https://datatracker.ietf.org/doc/
              draft-ietf-ccamp-optical-impairment-topology-yang/>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC6556]  Lee, Y., Ed., Bernstein, G., Ed., Li, D., and G.
              Martinelli, "A Framework for the Control of Wavelength
              Switched Optical Networks (WSONs) with Impairments",
              RFC 6556, DOI DOI 10.17487/RFC6566, March 2012,
              <https://www.rfc-editor.org/info/rfc6556>.



Xu, et al.              Expires 3 September 2026               [Page 11]

Internet-Draft     Exchange of Optical Impairment Info        March 2026


   [RFC7446]  Lee, Y., Ed., Bernstein, G., Ed., Li, D., and W. Imajuku,
              "Routing and Wavelength Assignment Information Model for
              Wavelength Switched Optical Networks", RFC 7446,
              DOI 110.17487/RFC7446, February 2015,
              <https://www.rfc-editor.org/info/rfc7446>.

   [RFC7926]  Farrel, A., Ed., Drake, J., Bitar, N., Swallow, G.,
              Ceccarelli, D., and X. Zhang, "Problem Statement and
              Architecture for Information Exchange between
              Interconnected Traffic-Engineered Networks", RFC 7926,
              DOI DOI 10.17487/RFC7926, July 2016,
              <https://www.rfc-editor.org/info/rfc7926>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC9094]  Zheng, H., Lee, Y., Guo, A., Lopez, V., and D. King, "A
              YANG Data Model for Wavelength Switched Optical Networks",
              RFC 9094, DOI DOI 10.17487/RFC9094, August 2021,
              <https://www.rfc-editor.org/info/rfc9094>.

8.  Informative References

   [SASAI2024]
              Sasai, T., Takahashi, M., Nakamura, M., Yamazaki, E., and
              Y. Kisaka, "Linear Least Squares Estimation of Fiber-
              longitudinal Optical Power Profile", Journal of Lightwave
              Technology vol. 42, no. 6, pp. 1955–1965, 2024.

   [ZYSKIND2016]
              Zyskind, J., "Optically Amplified WDM Networks",
              Publisher Academic Press, 2016.

Authors' Addresses

   Sugang Xu (editor)
   NICT
   Email: xsg@nict.go.jp


   Yusuke Hirota
   NICT
   Email: hirota.yusuke@nict.go.jp


   Yoshinari Awaji
   NICT



Xu, et al.              Expires 3 September 2026               [Page 12]

Internet-Draft     Exchange of Optical Impairment Info        March 2026


   Email: yossy@nict.go.jp


















































Xu, et al.              Expires 3 September 2026               [Page 13]
