RFC 9093 PROPOSED STANDARD YANG · OPTICAL · NETWORK MANAGEMENT
YANG Layer 0 Types: A YANG Data Model for Layer 0 Types
Shared YANG building blocks for describing optical networks that use fixed and flexible wavelength grids.
RFC EDITOR
Zheng, H., Lee, Y., Guo, A., Lopez, V., and D. King, "A YANG Data Model for Layer 0 Types", RFC 9093, DOI 10.17487/RFC9093, August 2021, <https://www.rfc-editor.org/info/rfc9093>.
BIBTEX
@misc{rfc9093,
series = {Request for Comments},
number = 9093,
howpublished = {RFC 9093},
publisher = {RFC Editor},
doi = {10.17487/RFC9093},
url = {https://www.rfc-editor.org/info/rfc9093},
author = {H. Zheng and Y. Lee and A. Guo and V. Lopez and D. King},
title = {{A YANG Data Model for Layer 0 Types}},
pagetotal = 20,
year = 2021,
month = aug,
} RFC text
Contents
Internet Engineering Task Force (IETF) 郑好棉 (H. Zheng)
Request for Comments: 9093 华为技术有限公司 (Huawei Technologies)
Category: Standards Track Y. Lee
ISSN: 2070-1721 Samsung
A. Guo
Futurewei
V. Lopez
Nokia
D. King
University of Lancaster
August 2021
A YANG Data Model for Layer 0 Types
Abstract
This document defines a collection of common data types and groupings
in the YANG data modeling language. These derived common types and
groupings are intended to be imported by modules that model Layer 0
optical Traffic Engineering (TE) configuration and state capabilities
such as Wavelength Switched Optical Networks (WSONs) and flexi-grid
Dense Wavelength Division Multiplexing (DWDM) networks.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc9093.
Copyright Notice
Copyright (c) 2021 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 Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction
1.1. Terminology and Notations
1.2. Prefix in Data Node Names
2. Layer 0 Types Module Contents
3. YANG Module for Layer 0 Types
4. Security Considerations
5. IANA Considerations
6. References
6.1. Normative References
6.2. Informative References
Acknowledgements
Contributors
Authors' Addresses
1. Introduction
YANG [RFC7950] is a data modeling language used to model
configuration data, state data, Remote Procedure Calls, and
notifications for network management protocols such as the Network
Configuration Protocol (NETCONF) [RFC6241]. The YANG language
supports a small set of built-in data types and provides mechanisms
to derive other types from the built-in types.
This document introduces a collection of common data types derived
from the built-in YANG data types. The derived types and groupings
are designed to be the common types applicable for modeling Traffic
Engineering (TE) features as well as non-TE features (e.g., physical
network configuration aspects) for Layer 0 optical networks in
model(s) defined outside of this document. The applicability of
Layer 0 types specified in this document includes Wavelength Switched
Optical Networks (WSONs) [RFC6163] [ITU-Tg6982] and flexi-grid Dense
Wavelength Division Multiplexing (DWDM) networks [RFC7698]
[ITU-Tg6941].
1.1. Terminology and Notations
Refer to [RFC7446] and [RFC7581] for the key terms used in this
document, and the terminology for describing YANG data models can be
found in [RFC7950].
The YANG data model in this document conforms to the Network
Management Datastore Architecture defined in [RFC8342].
1.2. Prefix in Data Node Names
In this document, names of data nodes and other data model objects
are prefixed using the standard prefix associated with the
corresponding YANG imported modules.
+==========+===================+===========+
| Prefix | YANG module | Reference |
+==========+===================+===========+
| l0-types | ietf-layer0-types | RFC 9093 |
+----------+-------------------+-----------+
Table 1: Data Node Names
The YANG module "ietf-layer0-types" (defined in Section 3) references
[RFC4203], [RFC6163], [RFC6205], [RFC7698], [RFC7699], [RFC8363],
[ITU-Tg6941], and [ITU-Tg6942].
2. Layer 0 Types Module Contents
This document defines a YANG module for common Layer 0 types, ietf-
layer0-types. This module is used for WSON and flexi-grid DWDM
networks. The "ietf-layer0-types" module contains the following YANG
reusable types and groupings:
l0-grid-type:
A base YANG identity for the grid type as defined in [RFC6163] and
[RFC7698].
dwdm-ch-spc-type:
A base YANG identity for the DWDM channel-spacing type as defined
in [RFC6205].
cwdm-ch-spc-type:
A base YANG identity for the Coarse Wavelength Division
Multiplexing (CWDM) channel-spacing type as defined in [RFC6205].
wson-label-start-end:
The WSON label range was defined in [RFC6205], and the generic
topology model defines the label-start/label-end in [RFC8795].
This grouping shows the WSON-specific label-start and label-end
information.
wson-label-hop:
The WSON label range was defined in [RFC6205], and the generic
topology model defines the label-hop in [RFC8795]. This grouping
shows the WSON-specific label-hop information.
l0-label-range-info:
A YANG grouping that defines the Layer 0 label range information
applicable for WSON as defined in [RFC6205]. This grouping is
used in the flexi-grid DWDM by adding more flexi-grid-specific
parameters.
wson-label-step:
A YANG grouping that defines label steps for WSON as defined in
[RFC8776].
flexi-grid-label-start-end:
The flexi-grid label range was defined in [RFC7698], and the
generic topology model defines the label-start/label-end in
[RFC8795]. This grouping shows the flexi-grid-specific label-
start and label-end information.
flexi-grid-label-hop:
The flexi-grid label range was defined in [RFC7698], and the
generic topology model defines the label-hop in [RFC8795]. This
grouping shows the WSON-specific label-hop information.
flexi-grid-label-range-info:
A YANG grouping that defines flexi-grid label range information as
defined in [RFC7698] and [RFC8363].
flexi-grid-label-step:
A YANG grouping that defines flexi-grid label steps as defined in
[RFC8776].
3. YANG Module for Layer 0 Types
<CODE BEGINS> file "ietf-layer0-types@2021-08-13.yang"
module ietf-layer0-types {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-layer0-types";
prefix l0-types;
organization
"IETF CCAMP Working Group";
contact
"WG Web: <https://datatracker.ietf.org/wg/ccamp/>
WG List: <mailto:ccamp@ietf.org>
Editor: Haomian Zheng
<mailto:zhenghaomian@huawei.com>
Editor: Young Lee
<mailto:younglee.tx@gmail.com>
Editor: Aihua Guo
<mailto:aihuaguo.ietf@gmail.com>
Editor: Victor Lopez
<mailto:victor.lopez@nokia.com>
Editor: Daniel King
<mailto:d.king@lancaster.ac.uk>";
description
"This module defines Optical Layer 0 types. This module
provides groupings that can be applicable to Layer 0
Fixed Optical Networks (e.g., CWDM (Coarse Wavelength
Division Multiplexing) and DWDM (Dense Wavelength Division
Multiplexing)) and flexi-grid optical networks.
Copyright (c) 2021 IETF Trust and the persons identified
as authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with
or without modification, is permitted pursuant to, and
subject to the license terms contained in, the Simplified
BSD License set forth in Section 4.c of the IETF Trust's
Legal Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC 9093; see
the RFC itself for full legal notices.";
revision 2021-08-13 {
description
"Initial version";
reference
"RFC 9093: A YANG Data Model for Layer 0 Types";
}
typedef dwdm-n {
type int16;
description
"The given value 'N' is used to determine the nominal central
frequency.
The nominal central frequency, 'f', is defined by:
f = 193100.000 GHz + N x channel spacing (measured in GHz),
where 193100.000 GHz (193.100000 THz) is the ITU-T 'anchor
frequency' for transmission over the DWDM grid, and where
'channel spacing' is defined by the dwdm-ch-spc-type.";
reference
"RFC6205: Generalized Labels for Lambda-Switch-Capable (LSC)
Label Switching Routers,
ITU-T G.694.1 (10/2020): Spectral grids for WDM applications:
DWDM frequency grid";
}
typedef cwdm-n {
type int16;
description
"The given value 'N' is used to determine the nominal central
wavelength.
The nominal central wavelength is defined by:
Wavelength = 1471 nm + N x channel spacing (measured in nm)
where 1471 nm is the conventional 'anchor wavelength' for
transmission over the CWDM grid, and where 'channel spacing'
is defined by the cwdm-ch-spc-type.";
reference
"RFC 6205: Generalized Labels for Lambda-Switch-Capable (LSC)
Label Switching Routers,
ITU-T G.694.2 (12/2003): Spectral grids for WDM applications:
CWDM wavelength grid";
}
typedef flexi-n {
type int16;
description
"The given value 'N' is used to determine the nominal central
frequency.
The nominal central frequency, 'f', is defined by:
f = 193100.000 GHz + N x channel spacing (measured in GHz),
where 193100.000 GHz (193.100000 THz) is the ITU-T 'anchor
frequency' for transmission over the DWDM grid, and where
'channel spacing' is defined by the flexi-ch-spc-type.
Note that the term 'channel spacing' can be substituted by the
term 'nominal central frequency granularity' defined in
clause 8 of ITU-T G.694.1.";
reference
"RFC 7698: Framework and Requirements for GMPLS-Based Control
of Flexi-Grid Dense Wavelength Division Multiplexing (DWDM)
Networks,
ITU-T G.694.1 (10/2020): Spectral grids for WDM applications:
DWDM frequency grid";
}
typedef flexi-m {
type uint16;
description
"The given value 'M' is used to determine the slot width.
A slot width is defined by:
slot width = M x SWG (measured in GHz),
where SWG is defined by the flexi-slot-width-granularity.";
reference
"RFC 7698: Framework and Requirements for GMPLS-Based Control
of Flexi-Grid Dense Wavelength Division Multiplexing (DWDM)
Networks.
ITU-T G.694.1 (10/2020): Spectral grids for WDM applications:
DWDM frequency grid";
}
identity l0-grid-type {
description
"Layer 0 grid type";
reference
"RFC 6163: Framework for GMPLS and Path Computation Element
(PCE) Control of Wavelength Switched Optical Networks (WSONs),
ITU-T G.694.1 (10/2020): Spectral grids for WDM applications:
DWDM frequency grid,
ITU-T G.694.2 (12/2003): Spectral grids for WDM applications:
CWDM wavelength grid";
}
identity flexi-grid-dwdm {
base l0-grid-type;
description
"Flexi-grid";
reference
"RFC 7698: Framework and Requirements for GMPLS-Based Control
of Flexi-Grid Dense Wavelength Division Multiplexing (DWDM)
Networks,
ITU-T G.694.1 (10/2020): Spectral grids for WDM applications:
DWDM frequency grid";
}
identity wson-grid-dwdm {
base l0-grid-type;
description
"DWDM grid";
reference
"RFC 6163:Framework for GMPLS and Path Computation Element
(PCE) Control of Wavelength Switched Optical Networks (WSONs),
ITU-T G.694.1 (10/2020): Spectral grids for WDM applications:
DWDM frequency grid";
}
identity wson-grid-cwdm {
base l0-grid-type;
description
"CWDM grid";
reference
"RFC 6205: Generalized Labels for Lambda-Switch-Capable (LSC)
Label Switching Routers,
ITU-T G.694.2 (12/2003): Spectral grids for WDM applications:
CWDM wavelength grid";
}
identity dwdm-ch-spc-type {
description
"DWDM channel-spacing type";
reference
"RFC 6205: Generalized Labels for Lambda-Switch-Capable (LSC)
Label Switching Routers,
ITU-T G.694.1 (10/2020): Spectral grids for WDM applications:
DWDM frequency grid";
}
identity dwdm-100ghz {
base dwdm-ch-spc-type;
description
"100 GHz channel spacing";
}
identity dwdm-50ghz {
base dwdm-ch-spc-type;
description
"50 GHz channel spacing";
}
identity dwdm-25ghz {
base dwdm-ch-spc-type;
description
"25 GHz channel spacing";
}
identity dwdm-12p5ghz {
base dwdm-ch-spc-type;
description
"12.5 GHz channel spacing";
}
identity flexi-ch-spc-type {
description
"Flexi-grid channel-spacing type";
reference
"RFC 7698: Framework and Requirements for GMPLS-Based Control
of Flexi-Grid Dense Wavelength Division Multiplexing (DWDM)
Networks,
ITU-T G.694.1 (10/2020): Spectral grids for WDM applications:
DWDM frequency grid";
}
identity flexi-ch-spc-6p25ghz {
base flexi-ch-spc-type;
description
"6.25 GHz channel spacing";
}
identity flexi-slot-width-granularity {
description
"Flexi-grid slot width granularity";
}
identity flexi-swg-12p5ghz {
base flexi-slot-width-granularity;
description
"12.5 GHz slot width granularity";
}
identity cwdm-ch-spc-type {
description
"CWDM channel-spacing type";
reference
"RFC 6205: Generalized Labels for Lambda-Switch-Capable (LSC)
Label Switching Routers,
ITU-T G.694.2 (12/2003): Spectral grids for WDM applications:
CWDM wavelength grid";
}
identity cwdm-20nm {
base cwdm-ch-spc-type;
description
"20nm channel spacing";
}
/* Groupings. */
grouping wson-label-start-end {
description
"The WSON label-start or label-end used to specify WSON label
range.";
choice grid-type {
description
"Label for DWDM or CWDM grid";
case dwdm {
leaf dwdm-n {
when "derived-from-or-self(../../../grid-type,
\"wson-grid-dwdm\")" {
description
"Valid only when grid type is DWDM.";
}
type l0-types:dwdm-n;
description
"The central frequency of DWDM.";
reference
"RFC 6205: Generalized Labels for Lambda-Switch-Capable
(LSC) Label Switching Routers";
}
}
case cwdm {
leaf cwdm-n {
when "derived-from-or-self(../../../grid-type,
\"wson-grid-cwdm\")" {
description
"Valid only when grid type is CWDM.";
}
type l0-types:cwdm-n;
description
"Channel wavelength computing input.";
reference
"RFC 6205: Generalized Labels for Lambda-Switch-Capable
(LSC) Label Switching Routers";
}
}
}
reference
"RFC 6205: Generalized Labels for Lambda-Switch-Capable (LSC)
Label Switching Routers";
}
grouping wson-label-hop {
description
"Generic label-hop information for WSON";
choice grid-type {
description
"Label for DWDM or CWDM grid";
case dwdm {
choice single-or-super-channel {
description
"single or super channel";
case single {
leaf dwdm-n {
type l0-types:dwdm-n;
description
"The given value 'N' is used to determine the
nominal central frequency.";
}
}
case super {
leaf-list subcarrier-dwdm-n {
type l0-types:dwdm-n;
description
"The given values 'N' are used to determine the
nominal central frequency for each subcarrier
channel.";
reference
"ITU-T Recommendation G.694.1: Spectral grids for
WDM applications: DWDM frequency grid";
}
}
}
}
case cwdm {
leaf cwdm-n {
type l0-types:cwdm-n;
description
"The given value 'N' is used to determine the nominal
central wavelength.";
reference
"RFC 6205: Generalized Labels for Lambda-Switch-Capable
(LSC) Label Switching Routers";
}
}
}
reference
"RFC 6205: Generalized Labels for Lambda-Switch-Capable (LSC)
Label Switching Routers";
}
grouping l0-label-range-info {
description
"Information about Layer 0 label range.";
leaf grid-type {
type identityref {
base l0-grid-type;
}
description
"Grid type";
}
leaf priority {
type uint8;
description
"Priority in Interface Switching Capability Descriptor
(ISCD).";
reference
"RFC 4203: OSPF Extensions in Support of Generalized
Multi-Protocol Label Switching (GMPLS)";
}
reference
"RFC 6205: Generalized Labels for Lambda-Switch-Capable (LSC)
Label Switching Routers";
}
grouping wson-label-step {
description
"Label step information for WSON";
choice l0-grid-type {
description
"Grid type: DWDM, CWDM, etc.";
case dwdm {
leaf wson-dwdm-channel-spacing {
when "derived-from-or-self(../../grid-type,
\"wson-grid-dwdm\")" {
description
"Valid only when grid type is DWDM.";
}
type identityref {
base dwdm-ch-spc-type;
}
description
"Label-step is the channel spacing (GHz), e.g., 100.000,
50.000, 25.000, or 12.500 GHz for DWDM.";
reference
"RFC 6205: Generalized Labels for Lambda-Switch-Capable
(LSC) Label Switching Routers";
}
}
case cwdm {
leaf wson-cwdm-channel-spacing {
when "derived-from-or-self(../../grid-type,
\"wson-grid-cwdm\")" {
description
"Valid only when grid type is CWDM.";
}
type identityref {
base cwdm-ch-spc-type;
}
description
"Label-step is the channel spacing (nm), i.e., 20 nm
for CWDM, which is the only value defined for CWDM.";
reference
"RFC 6205: Generalized Labels for Lambda-Switch-Capable
(LSC) Label Switching Routers";
}
}
}
reference
"RFC 6205: Generalized Labels for Lambda-Switch-Capable (LSC)
Label Switching Routers,
ITU-T G.694.2 (12/2003): Spectral grids for WDM applications:
CWDM wavelength grid";
}
grouping flexi-grid-label-start-end {
description
"The flexi-grid label-start or label-end used to specify
flexi-grid label range.";
leaf flexi-n {
type l0-types:flexi-n;
description
"The given value 'N' is used to determine the nominal
central frequency.";
}
reference
"RFC 7698: Framework and Requirements for GMPLS-Based Control
of Flexi-Grid Dense Wavelength Division Multiplexing (DWDM)
Networks";
}
grouping flexi-grid-frequency-slot {
description
"Flexi-grid frequency slot grouping.";
uses flexi-grid-label-start-end;
leaf flexi-m {
type l0-types:flexi-m;
description
"The given value 'M' is used to determine the slot width.";
}
reference
"RFC 7698: Framework and Requirements for GMPLS-Based Control
of Flexi-Grid Dense Wavelength Division Multiplexing (DWDM)
Networks";
}
grouping flexi-grid-label-hop {
description
"Generic label-hop information for flexi-grid";
choice single-or-super-channel {
description
"single or super channel";
case single {
uses flexi-grid-frequency-slot;
}
case super {
list subcarrier-flexi-n {
key "flexi-n";
uses flexi-grid-frequency-slot;
description
"List of subcarrier channels for flexi-grid super
channel.";
}
}
}
reference
"RFC 7698: Framework and Requirements for GMPLS-Based Control
of Flexi-Grid Dense Wavelength Division Multiplexing (DWDM)
Networks";
}
grouping flexi-grid-label-range-info {
description
"Flexi-grid-specific label range related information";
uses l0-label-range-info;
container flexi-grid {
description
"flexi-grid definition";
leaf slot-width-granularity {
type identityref {
base flexi-slot-width-granularity;
}
default "flexi-swg-12p5ghz";
description
"Minimum space between slot widths. Default is 12.500
GHz.";
reference
"RFC 7698: Framework and Requirements for GMPLS-Based
Control of Flexi-Grid Dense Wavelength Division
Multiplexing (DWDM) Networks";
}
leaf min-slot-width-factor {
type uint16 {
range "1..max";
}
default "1";
description
"A multiplier of the slot width granularity, indicating
the minimum slot width supported by an optical port.
Minimum slot width is calculated by:
Minimum slot width (GHz) =
min-slot-width-factor * slot-width-granularity.";
reference
"RFC 8363: GMPLS OSPF-TE Extensions in Support of Flexi-
Grid Dense Wavelength Division Multiplexing (DWDM)
Networks";
}
leaf max-slot-width-factor {
type uint16 {
range "1..max";
}
must '. >= ../min-slot-width-factor' {
error-message
"Maximum slot width must be greater than or equal to
minimum slot width.";
}
description
"A multiplier of the slot width granularity, indicating
the maximum slot width supported by an optical port.
Maximum slot width is calculated by:
Maximum slot width (GHz) =
max-slot-width-factor * slot-width-granularity
If specified, maximum slot width must be greater than or
equal to minimum slot width. If not specified, maximum
slot width is equal to minimum slot width.";
reference
"RFC 8363: GMPLS OSPF-TE Extensions in Support of Flexi-
Grid Dense Wavelength Division Multiplexing (DWDM)
Networks";
}
}
}
grouping flexi-grid-label-step {
description
"Label step information for flexi-grid";
leaf flexi-grid-channel-spacing {
type identityref {
base flexi-ch-spc-type;
}
default "flexi-ch-spc-6p25ghz";
description
"Label-step is the nominal central frequency granularity
(GHz), e.g., 6.25 GHz.";
reference
"RFC 7699: Generalized Labels for the Flexi-Grid in Lambda
Switch Capable (LSC) Label Switching Routers";
}
leaf flexi-n-step {
type uint8;
description
"This attribute defines the multiplier for the supported
values of 'N'.
For example, given a grid with a nominal central frequency
granularity of 6.25 GHz, the granularity of the supported
values of the nominal central frequency could be 12.5 GHz.
In this case, the values of flexi-n should be even and this
constraint is reported by setting the flexi-n-step to 2.
This attribute is also known as central frequency
granularity in RFC 8363.";
reference
"RFC 8363: GMPLS OSPF-TE Extensions in Support of Flexi-Grid
Dense Wavelength Division Multiplexing (DWDM) Networks";
}
}
}
<CODE ENDS>
4. Security Considerations
The YANG module specified in this document defines a schema for data
that is designed to be accessed via network management protocols such
as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer
is the secure transport layer, and the mandatory-to-implement secure
transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer
is HTTPS, and the mandatory-to-implement secure transport is TLS
[RFC8446].
The Network Configuration Access Control Model (NACM) [RFC8341]
provides the means to restrict access for particular NETCONF or
RESTCONF users to a preconfigured subset of all available NETCONF or
RESTCONF protocol operations and content. The NETCONF protocol over
Secure Shell (SSH) specification [RFC6242] describes a method for
invoking and running NETCONF within a Secure Shell (SSH) session as
an SSH subsystem.
The objects in this YANG module are common data types and groupings.
No object in this module can be read or written to. These
definitions can be imported and used by other Layer 0 specific
modules. It is critical to consider how imported definitions will be
utilized and accessible via RPC operations, as the resultant schema
will have data nodes that can be writable, or readable, and will have
a significant effect on the network operations if used incorrectly or
maliciously. All of these considerations belong in the document that
defines the modules that import from this YANG module. Therefore, it
is important to manage access to resultant data nodes that are
considered sensitive or vulnerable in some network environments.
The security considerations spelled out in the YANG 1.1 specification
[RFC7950] apply for this document as well.
5. IANA Considerations
IANA has assigned new URIs from the "IETF XML Registry" [RFC3688] as
follows:
URI: urn:ietf:params:xml:ns:yang:ietf-layer0-types
Registrant Contact: The IESG
XML: N/A; the requested URI is an XML namespace.
This document registers the following YANG module in the "YANG Module
Names" registry [RFC7950].
Name: ietf-layer0-types
Namespace: urn:ietf:params:xml:ns:yang:ietf-layer0-types
Prefix: l0-types
Reference: RFC 9093
6. References
6.1. Normative References
[ITU-Tg6982]
ITU-T, "Amplified multichannel dense wavelength division
multiplexing applications with single channel optical
interfaces", ITU-T Recommendation G.698.2, November 2018.
[RFC4203] Kompella, K., Ed. and Y. Rekhter, Ed., "OSPF Extensions in
Support of Generalized Multi-Protocol Label Switching
(GMPLS)", RFC 4203, DOI 10.17487/RFC4203, October 2005,
<https://www.rfc-editor.org/info/rfc4203>.
[RFC6163] Lee, Y., Ed., Bernstein, G., Ed., and W. Imajuku,
"Framework for GMPLS and Path Computation Element (PCE)
Control of Wavelength Switched Optical Networks (WSONs)",
RFC 6163, DOI 10.17487/RFC6163, April 2011,
<https://www.rfc-editor.org/info/rfc6163>.
[RFC6205] Otani, T., Ed. and D. Li, Ed., "Generalized Labels for
Lambda-Switch-Capable (LSC) Label Switching Routers",
RFC 6205, DOI 10.17487/RFC6205, March 2011,
<https://www.rfc-editor.org/info/rfc6205>.
[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
and A. Bierman, Ed., "Network Configuration Protocol
(NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
<https://www.rfc-editor.org/info/rfc6241>.
[RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure
Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011,
<https://www.rfc-editor.org/info/rfc6242>.
[RFC7698] Gonzalez de Dios, O., Ed., Casellas, R., Ed., Zhang, F.,
Fu, X., Ceccarelli, D., and I. Hussain, "Framework and
Requirements for GMPLS-Based Control of Flexi-Grid Dense
Wavelength Division Multiplexing (DWDM) Networks",
RFC 7698, DOI 10.17487/RFC7698, November 2015,
<https://www.rfc-editor.org/info/rfc7698>.
[RFC7699] Farrel, A., King, D., Li, Y., and F. Zhang, "Generalized
Labels for the Flexi-Grid in Lambda Switch Capable (LSC)
Label Switching Routers", RFC 7699, DOI 10.17487/RFC7699,
November 2015, <https://www.rfc-editor.org/info/rfc7699>.
[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
RFC 7950, DOI 10.17487/RFC7950, August 2016,
<https://www.rfc-editor.org/info/rfc7950>.
[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<https://www.rfc-editor.org/info/rfc8040>.
[RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration
Access Control Model", STD 91, RFC 8341,
DOI 10.17487/RFC8341, March 2018,
<https://www.rfc-editor.org/info/rfc8341>.
[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>.
[RFC8363] Zhang, X., Zheng, H., Casellas, R., Gonzalez de Dios, O.,
and D. Ceccarelli, "GMPLS OSPF-TE Extensions in Support of
Flexi-Grid Dense Wavelength Division Multiplexing (DWDM)
Networks", RFC 8363, DOI 10.17487/RFC8363, May 2018,
<https://www.rfc-editor.org/info/rfc8363>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>.
[RFC8776] Saad, T., Gandhi, R., Liu, X., Beeram, V., and I. Bryskin,
"Common YANG Data Types for Traffic Engineering",
RFC 8776, DOI 10.17487/RFC8776, June 2020,
<https://www.rfc-editor.org/info/rfc8776>.
[RFC8795] Liu, X., Bryskin, I., Beeram, V., Saad, T., Shah, H., and
O. Gonzalez de Dios, "YANG Data Model for Traffic
Engineering (TE) Topologies", RFC 8795,
DOI 10.17487/RFC8795, August 2020,
<https://www.rfc-editor.org/info/rfc8795>.
6.2. Informative References
[ITU-Tg6941]
ITU-T, "Spectral grids for WDM applications: DWDM
frequency grid", ITU-T Recommendation G.694.1, October
2020.
[ITU-Tg6942]
ITU-T, "Spectral grids for WDM applications: CWDM
wavelength grid", ITU-T Recommendation G.694.2, December
2003.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/info/rfc3688>.
[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 10.17487/RFC7446, February 2015,
<https://www.rfc-editor.org/info/rfc7446>.
[RFC7581] Bernstein, G., Ed., Lee, Y., Ed., Li, D., Imajuku, W., and
J. Han, "Routing and Wavelength Assignment Information
Encoding for Wavelength Switched Optical Networks",
RFC 7581, DOI 10.17487/RFC7581, June 2015,
<https://www.rfc-editor.org/info/rfc7581>.
Acknowledgements
The authors and the working group give their sincere thanks to Robert
Wilton for the YANG doctor review and Tom Petch for his comments
during the model and document development.
Contributors
Dhruv Dhody
Huawei
Email: dhruv.ietf@gmail.com
Bin Yeong Yoon
ETRI
Email: byyun@etri.re.kr
Ricard Vilalta
CTTC
Email: ricard.vilalta@cttc.es
Italo Busi
Huawei
Email: Italo.Busi@huawei.com
Authors' Addresses
Haomian Zheng
Huawei Technologies
H1, Huawei Xiliu Beipo Village, Songshan Lake
Dongguan
Guangdong, 523808
China
Email: zhenghaomian@huawei.com
Additional contact information:
郑好棉
中国
523808
广东 东莞
松山湖华为溪流背坡村H1
华为技术有限公司
Young Lee
Samsung
South Korea
Email: younglee.tx@gmail.com
Aihua Guo
Futurewei
Email: aihuaguo.ietf@gmail.com
Victor Lopez
Nokia
Email: victor.lopez@nokia.com
Daniel King
University of Lancaster
Email: d.king@lancaster.ac.uk
AI ELI5
On this page
PROBLEMEach YANG model of a Layer 0 optical network would need the same definitions of grids, channel spacings and label ranges.
MECHANISMThe RFC defines the module ietf-layer0-types, a set of derived types, identities and groupings for WSON and flexi-grid DWDM networks, meant to be imported by other modules.
WHY IT MATTERSLayer 0 models can reuse one agreed vocabulary. The module defines no readable or writable data nodes of its own.
§1Purpose and Scope
YANG (RFC 7950) is a data modeling language for configuration data, state data, remote procedure calls and notifications, used with protocols such as NETCONF (RFC 6241). It has a small set of built-in types and lets authors derive more.
This RFC introduces common types and groupings derived from the built-in ones. They are meant for modeling Traffic Engineering (TE) and non-TE features of Layer 0 optical networks, in models defined outside this document. They apply to Wavelength Switched Optical Networks (WSONs) and flexi-grid Dense Wavelength Division Multiplexing (DWDM) networks. The module conforms to the Network Management Datastore Architecture (RFC 8342).
Many people need to describe the same kind of light-based network. This document writes down the common words once, so everyone can use them.
§2Module Contents
The module is named ietf-layer0-types and uses the prefix l0-types. The RFC lists these reusable pieces:
l0-grid-type: a base identity for the grid type.dwdm-ch-spc-typeandcwdm-ch-spc-type: base identities for DWDM and Coarse Wavelength Division Multiplexing (CWDM) channel spacing.- Groupings for WSON:
wson-label-start-end,wson-label-hopandwson-label-step, plusl0-label-range-infofor the label range. - Groupings for flexi-grid:
flexi-grid-label-start-end,flexi-grid-label-hop,flexi-grid-label-range-infoandflexi-grid-label-step.
The label groupings supply the WSON-specific or flexi-grid-specific parts of the label-start, label-end and label-hop information that the generic topology model (RFC 8795) defines.
The module is a parts shelf. Some parts say which kind of grid you have, some say how far apart the colors are, and some describe a range of colors.
§3Grids, Channel Spacing and Slot Widths
A grid is the set of allowed positions for optical channels. The module defines three grid identities derived from l0-grid-type: wson-grid-dwdm, wson-grid-cwdm and flexi-grid-dwdm.
Channels are located by an integer. For DWDM, the nominal central frequency is f = 193100.000 GHz + N x channel spacing, where 193100.000 GHz is the ITU-T anchor frequency. For CWDM, the wavelength is 1471 nm + N x channel spacing. Flexi-grid uses the same frequency anchor with a value flexi-n, and a second integer flexi-m sets the slot width as M x SWG in GHz, where SWG is the slot width granularity.
Channel spacings are identities. DWDM has dwdm-100ghz, dwdm-50ghz, dwdm-25ghz and dwdm-12p5ghz. CWDM has cwdm-20nm, the only CWDM value defined. Flexi-grid has flexi-ch-spc-6p25ghz, and its slot width granularity is flexi-swg-12p5ghz.
Think of a piano. The grid says which keys exist, the spacing says how far apart they are, and a number says which key you mean. Flexi-grid lets you press several neighboring keys together as one wide note.
- dwdm-100ghzDWDM — 100 GHz channel spacing.
- dwdm-50ghzDWDM — 50 GHz channel spacing.
- dwdm-25ghzDWDM — 25 GHz channel spacing.
- dwdm-12p5ghzDWDM — 12.5 GHz channel spacing.
- cwdm-20nmCWDM — 20 nm channel spacing, the only CWDM value defined.
- flexi-ch-spc-6p25ghzFlexi-grid — 6.25 GHz channel spacing.
- flexi-swg-12p5ghzFlexi-grid — 12.5 GHz slot width granularity.
§4Label Ranges, Hops and Steps
The groupings use YANG choice statements so a model can describe a DWDM or CWDM label for WSON. In a label hop, a DWDM channel is either a single channel with one dwdm-n or a super channel with a list of subcarrier values. A when condition makes a DWDM or CWDM leaf valid only when the grid type matches.
For flexi-grid, flexi-grid-frequency-slot combines flexi-n and flexi-m. A flexi-grid label range adds a container with slot-width-granularity (default 12.500 GHz), min-slot-width-factor (default 1) and max-slot-width-factor. The maximum must be greater than or equal to the minimum, and if it is not given it equals the minimum. Slot widths are the factor times the granularity.
These pieces let you say 'a stretch of colors from here to there', 'the exact colors used on one hop', and 'how big each step is'. A wide flexi-grid slot is just a minimum and maximum number of small steps.
§5IANA Registrations
IANA has registered the XML namespace URI urn:ietf:params:xml:ns:yang:ietf-layer0-types in the IETF XML Registry, with the IESG as registrant contact. It also registered the YANG module ietf-layer0-types in the YANG Module Names registry, with prefix l0-types and this document as the reference. The module's revision is dated 2021-08-13 and is described as the initial version.
The module was added to the official lists under its own name so nobody else uses it by mistake.
§6Security Considerations
YANG data is accessed through protocols such as NETCONF or RESTCONF. NETCONF's mandatory-to-implement secure transport is Secure Shell (SSH), and RESTCONF's is TLS. The Network Configuration Access Control Model (NACM) can restrict which users may use which operations and content.
This module defines only common types and groupings, so no object in it can be read or written. The risk comes from modules that import it: the resulting schema may have writable or readable data nodes that matter to network operations if misused. The RFC says those considerations belong in the importing documents, and that access to sensitive nodes should be managed. The security considerations of YANG 1.1 also apply.
This box of parts is harmless by itself. Whoever builds something with the parts has to think about who may touch the finished thing.
§7References
[RFC7950]RFC 7950Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", RFC 7950, August 2016.August 2016[RFC6241]RFC 6241Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., and A. Bierman, Ed., "Network Configuration Protocol (NETCONF)", RFC 6241, June 2011.June 2011[RFC6163]RFC 6163Lee, Y., Ed., Bernstein, G., Ed., and W. Imajuku, "Framework for GMPLS and Path Computation Element (PCE) Control of Wavelength Switched Optical Networks (WSONs)", RFC 6163, April 2011.April 2011[RFC6205]RFC 6205Otani, T., Ed. and D. Li, Ed., "Generalized Labels for Lambda-Switch-Capable (LSC) Label Switching Routers", RFC 6205, March 2011.March 2011[RFC7698]RFC 7698Gonzalez de Dios, O., Ed., et al., "Framework and Requirements for GMPLS-Based Control of Flexi-Grid Dense Wavelength Division Multiplexing (DWDM) Networks", RFC 7698, November 2015.November 2015[RFC8342]RFC 8342Bjorklund, M., et al., "Network Management Datastore Architecture (NMDA)", RFC 8342, March 2018.March 2018