Applicability of Service & Infrastructure Maps (SIMAP) to Transport Networks
draft-busi-nmop-transport-simap-01
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| Document | Type | Active Internet-Draft (individual) | |
|---|---|---|---|
| Authors | Italo Busi , Haomian Zheng , XingZhao , Yunbin Xu | ||
| Last updated | 2026-01-07 | ||
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draft-busi-nmop-transport-simap-01
Network Management Operations I. Busi
Internet-Draft H. Zheng
Intended status: Informational Huawei Technologies
Expires: 11 July 2026 X. Zhao
Y. Xu
CAICT
7 January 2026
Applicability of Service & Infrastructure Maps (SIMAP) to Transport
Networks
draft-busi-nmop-transport-simap-01
Abstract
This document explores the applicability of the Service &
Infrastructure Maps (SIMAP) concepts to transport networks and it
examines the YANG data models defined by the IETF to support the
requirements and use cases for SIMAP applicability to transport
networks.
About This Document
This note is to be removed before publishing as an RFC.
The latest revision of this draft can be found at
https://italobusi.github.io/transport-simap/draft-busi-nmop-
transport-simap.html. Status information for this document may be
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simap/.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. Overview of Key Requirements for Transport SIMAP . . . . . . 3
2.1. Resource and Bandwidth status . . . . . . . . . . . . . . 3
2.2. Delay Measurement . . . . . . . . . . . . . . . . . . . . 3
2.3. Availability . . . . . . . . . . . . . . . . . . . . . . 4
2.4. Real-time Evaluation (Risk?) . . . . . . . . . . . . . . 4
3. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Service Provisioning . . . . . . . . . . . . . . . . . . 4
3.2. Alarm and Incident . . . . . . . . . . . . . . . . . . . 6
3.3. Risk Prediction . . . . . . . . . . . . . . . . . . . . . 6
4. YANG Models Applicability . . . . . . . . . . . . . . . . . . 7
4.1. Planning and Service Provisioning . . . . . . . . . . . . 7
4.2. Alarm and Incident . . . . . . . . . . . . . . . . . . . 7
4.3. Risk Prediction . . . . . . . . . . . . . . . . . . . . . 7
5. Security Considerations . . . . . . . . . . . . . . . . . . . 7
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
7.1. Normative References . . . . . . . . . . . . . . . . . . 7
7.2. Informative References . . . . . . . . . . . . . . . . . 8
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
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1. Introduction
The concept of Service & Infrastructure Maps (SIMAP) is being defined
in [I-D.ietf-nmop-simap-concept] together with a set of SIMP
requirements and use cases.
A transport network is a server-layer network designed to provide
connectivity services for a client-layer network to carry the client
traffic transparently across the server-layer network resources.
A transport network typically utilizes several different transport
technologies such as the Optical Transport Networks (OTN) or
Wavelength Division Multiplexing (WDM).
The concept of SIMAP applies to any type of networks, including but
not being limited to transport networks.
This document complements the definitions in
[I-D.ietf-nmop-simap-concept] providing specific requirements and use
cases for SIMAP applicability to transport networks.
It also examines the YANG data models defined by the IETF to support
these specific requirements and use cases at the northbound interface
of an optical network controller.
1.1. Terminology
The following terms are defined in [I-D.ietf-nmop-simap-concept] and
are not redefined here:
* Service & Infrastructure Maps (SIMAP)
The following terms are defined in [rfc9543] and are not redefined
here:
* Service Level Agreement (SLA)
Editors' Note: should we differentiate between SLA, SLO, SLE and
SLI within this I-D?
2. Overview of Key Requirements for Transport SIMAP
TODO Overview of Key Requirements for Transport SIMAP
2.1. Resource and Bandwidth status
2.2. Delay Measurement
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2.3. Availability
2.4. Real-time Evaluation (Risk?)
3. Use Cases
3.1. Service Provisioning
A transport network provides connectivity services to carry the
client traffic transparently.
In order to allow monetization of the transport network connectivity
services, transport networks are evolving to support connectivity
services with differentiated SLAs.
Transport networks can support connectivity services with different
requirements in terms of bandwidth, delay and availability, or any
combination of them. For examples, some services may have different
bandwidth requirements (e.g., 10G, 100G) or different delay
requirements or different availability requirements. Other services
can have both bandwidth and delay requirements or both delay and
availability requirements.
An optical network controller is able to receive connectivity service
requests with constraints in terms of bandwidth or delay or
availability or any combination of them.
A transport network typically utilizes several different transport
technologies such as the Optical Transport Networks (OTN) or
Wavelength Division Multiplexing (WDM). Therefore the request to
setup a new connectivity service would trigger multi-layer path
computation and setup e.g. to determine whether:
1. an OTN tunnel already exists within the transport network to
carry the new requested connectivity service while meeting the
requested bandwidth, delay and availability requirements: in this
case the optical network controller just configures the
connectivity service on the two devices at the edge of the
selected OTN tunnel;
2. a new OTN tunnel needs to be setup with the transport network and
whether the path of this new OTN tunnel:
a. can re-use existing links or server-layer WDM tunnels: in
this case the optical network controller starts the OTN
tunnel setup procedure (e.g., through GMPLS signalling) and
then configures the connectivity service on the two devices
at the edge of the just set up OTN tunnel;
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b. requires the setup of one ore more new WDM tunnels within the
transport network: in this case the optical network
controller:
i. starts the WDM tunnel setup procedure (e.g., through
GMPLS signalling) for all the new WDM tunnels which
need to be setup;
ii. start the OTN tunnel setup procedure (e.g., through
GMPLS signalling);
iii. configures the connectivity service on the two devices
at the edge of the just set up OTN tunnel.
The WDM path computation performed by the optical controller needs to
have the complete visibility of all the resources within the WDM
layer in order to compute the optimal feasible optical path, taking
into account the characteristics (e.g., optical impairments) of the
ROADM nodes, the capabilities of the transceivers. It also needs to
know the existing OTSi signals within the optical network to
determine the optical impairment impact of the existing OTSi signals
on the optical feasibility of a new OTSi signal and vice versa, i.e.,
the impact of the new OTSi on the existing OTSi signals: see
Section 2.3.1 of [I-D.ietf-ccamp-optical-impairment-topology-yang].
In order to provide the requested level of availability, optical path
computation at any layer (e.g., OTN or WDM) shall be able to compute
SRLG disjoint paths in order to avoid that a single failure would
impact also the backup path.
Manual configuration of SRLG is error-prone because of human errors
and the lack of complete information on how the physical
infrastructure is built (e.g., where the fibers are physically lay
down).
The optical controller can implement advanced algorithms to
automatically detect co-cabling (i.e., fibers which are assembled
within the same cable) as well as co-trenching (i.e., cables which
are lay down on the same trench). These automatic mechanisms can
reduce the errors in provisioning SRLG information thus improving the
provisioning of services with guaranteed availability.
The mechanisms used by the optical controller to detect co-cabling
and co-trenching are implementation specific and outside the scope of
standardization. The Transport SIMAP reports the output of these
mechanisms thought standardized network topology and inventory
models.
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3.2. Alarm and Incident
Alarm and Incident are defined in [I-D.ietf-nmop-terminology].
In transport network an incident can cause alarms or state down on
multiple tunnels and services. For example: - a fiber break will
cause all the WDM tunnels routed through this fiber to go down; - a
WDM tunnel failure will cause all the OTN tunnels routed through it
to go down; - an OTN tunnel failure will cause all the services
(e.g., CBR or Ethernet services) supported by it to go down.
Note that, while usually an OTN tunnel can carry only one service,
there are some cases where multiple services are multiplexed over the
same OTN tunnel.
When an accident occurs in the transport network, Transport SIMAP is
able to report the root alarm/condition (e.g., the fiber break) that
is associated with the incident and all the consequent alarms/
conditions (e.g., WDM tunnels, OTN tunnels and services being down).
This will allow the operator to know which tunnels and services are
impacted by the incident and which is the root cause to be resolved
in order to bring them up again.
By supporting the co-cabling and co-trenching mechanisms, the
Transport SIMAP can also provide a deeper analysis of the incident.
For example, if a cable breaks, Transport SIMAP can report the cable
break as the root cause for the consequent alarms reporting fiber
breaks.
[I-D.ietf-nmop-network-incident-yang] provide also more details about
incident management.
3.3. Risk Prediction
Related with protection and restoration. Current approach is
based on the monitoring of the status of the connection (SF or SD)
triggering re-routing. SF is mainly related to loss of
continuity. What about latency degradation?
Provide more enhanced SD definitions (latency)
When a connectivity service with availability requirements is
requested, the optical controller can decide to configure some
resiliency (e.g., protection or restoration) mechanisms within the
network to recover the service traffic in case a failure or a
degradation occur.
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Transport SIMAP reports the configuration of the mechanism as well as
its status.
In particular, after a failure or a degradation occurs, the service
resiliency mechanism may be in a state which will not allow the
transport network to recover any additional failure (for example, the
1+1 protection mechanism is not able to recover from the failure of
the secondary path after the primary path has failed and the traffic
has switched to the secondary path).
Based on the status of the resiliency mechanism reported by Transport
SIMAP, the customer may request to reconfigure the service
availability requirements (e.g., from 1+1 to always-1+1) or do
nothing.
More discussion to be done based on the availability monetization
description
4. YANG Models Applicability
TODO YANG Models Applicability
4.1. Planning and Service Provisioning
TODO Evaluate: OTN/WDM/ETH topology, Tunnel, client-signal, path
computation models. Planning maybe a gap or Inventory (location) is
sufficient
4.2. Alarm and Incident
TODO Evaluate: RFC8632, Incident models
4.3. Risk Prediction
TODO Evaluate: performance monitoring models
5. Security Considerations
TODO Security
6. IANA Considerations
This document has no IANA actions.
7. References
7.1. Normative References
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[I-D.ietf-nmop-simap-concept]
Havel, O., Claise, B., de Dios, O. G., and T. Graf,
"SIMAP: Concept, Requirements, and Use Cases", Work in
Progress, Internet-Draft, draft-ietf-nmop-simap-concept-
07, 18 October 2025,
<https://datatracker.ietf.org/doc/html/draft-ietf-nmop-
simap-concept-07>.
[rfc9543] Farrel, A., Ed., Drake, J., Ed., Rokui, R., Homma, S.,
Makhijani, K., Contreras, L., and J. Tantsura, "A
Framework for Network Slices in Networks Built from IETF
Technologies", RFC 9543, DOI 10.17487/RFC9543, March 2024,
<https://www.rfc-editor.org/rfc/rfc9543>.
7.2. Informative References
[I-D.ietf-ccamp-optical-impairment-topology-yang]
Beller, D., 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-20, 10 October
2025, <https://datatracker.ietf.org/doc/html/draft-ietf-
ccamp-optical-impairment-topology-yang-20>.
[I-D.ietf-nmop-network-incident-yang]
Hu, T., Contreras, L. M., Wu, Q., Davis, N., and C. Feng,
"A YANG Data Model for Network Incident Management", Work
in Progress, Internet-Draft, draft-ietf-nmop-network-
incident-yang-07, 3 January 2026,
<https://datatracker.ietf.org/doc/html/draft-ietf-nmop-
network-incident-yang-07>.
[I-D.ietf-nmop-terminology]
Davis, N., Farrel, A., Graf, T., Wu, Q., and C. Yu, "Some
Key Terms for Network Fault and Problem Management", Work
in Progress, Internet-Draft, draft-ietf-nmop-terminology-
23, 18 August 2025,
<https://datatracker.ietf.org/doc/html/draft-ietf-nmop-
terminology-23>.
Acknowledgments
TODO Acknowledgments
Authors' Addresses
Italo Busi
Huawei Technologies
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Email: italo.busi@huawei.com
Haomian Zheng
Huawei Technologies
H1, Huawei Xiliu Beipo Village, Songshan Lake
Dongguan
Guangdong, 523808
China
Email: zhenghaomian@huawei.com
Xing Zhao
CAICT
China
Email: zhaoxing@caict.ac.cn
Yunbin Xu
CAICT
Email: xuyunbin@caict.ac.cn
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