A YANG Data Model for Optical Impairment-aware TopologyNokiaDieter.Beller@nokia.comOrangeesther.lerouzic@orange.comNokiaSergio.Belotti@nokia.comggalimbe56@gmail.comHuawei TechnologiesItalo.Busi@huawei.com
Routing
CCAMP Working Group
In order to provision an optical connection through optical
networks, a combination of path continuity, resource availability,
and impairment constraints must be met to determine viable and
optimal paths through the network. The determination of appropriate
paths is known as Impairment-Aware Routing and Wavelength Assignment
(IA-RWA) for WSON, while it is known as Impairment-Aware Routing and
Spectrum Assignment (IA-RSA) for SSON.
This document provides a YANG data model for the impairment-aware TE
topology in optical networks.
In order to provision an optical connection (an optical path)
through a wavelength switched optical networks (WSONs) or spectrum
switched optical networks (SSONs), a combination of path continuity,
resource availability, and impairment constraints must be met to
determine viable and optimal paths through the network. The
determination of appropriate paths is known as Impairment-Aware
Routing and Wavelength Assignment (IA-RWA)
for WSON, while it is known as IA-Routing and Spectrum Assigment
(IA-RSA) for SSON.
This document provides a YANG data model for the impairment-aware
Traffic Engineering (TE) topology in WSONs and SSONs. The YANG model
described in this document is a WSON/SSON technology-specific Yang
model based on the information model developed in
and the two encoding documents
and that developed
protocol independent encodings based on .
The intent of this document is to provide a YANG data model, which
can be utilized by a Multi-Domain Service Coordinator (MDSC) to
collect states of WSON impairment data from the Transport PNCs to
enable impairment-aware optical path computation according to the
ACTN Architecture . The communication
between controllers is done via a NETCONF
or a RESTCONF . Similarly,this model can
also be exported by the MDSC to a Customer Network Controller (CNC),
which can run an offline planning process to map latter the services
in the network.
It is worth noting that optical data plane interoperability is a
complex topic especially in a multi vendor environment and usually
requires joint engineering, which is independent from control plane
and management plane capabilities. The YANG data model defined in
this draft is providing sufficient information to enable optical
impairment aware path computation.
Optical data plane interoperability is outside the scope of this
draft.
This document augments the generic TE topology YANG model defined
in where possible.
This document defines one YANG module: ietf-optical-impairment-
topology () according to the new Network
Management Datastore Architecture .
Refer to , , and
for the key terms used in
this document.
The following terms are defined in and are
not redefined here:
clientserveraugmentdata modeldata node
The following terms are defined in and are
not redefined here:
configuration datastate data
The terminology for describing YANG data models is found in
.
The term ROADM in this document refers to the term "multi-degree
reconfigurable optical add/drop multiplexer (MD-ROADM)" as defined
in . It does not include local optical
transponders, which can be co-located in the same physical device
(managed entity).
The term WDM-node refers to a physical device, which is managed as
a single network element.
The term WDM-TE-node refers to those parts of a WDM-node (physical
device) that are modeled as a TE-node as defined in
, which may include a ROADM and/or multiple
local optical transponders(OTs). Hence, a WDM-TE-node may only
contain OTs.
The term "WDM-TE-network" refers to a set of WDM-TE-nodes as defined
above that are interconnected via TE-links carrying WDM signals.
These TE-links may include optical amplifiers.
The term "add/drop TE-link" refers to a TE-link representing the
media channel between a transceiver's media port of a remote optical
transponder (OT) and an add/drop port of the ROADM in the adjacent
WDM-node. The add/drop TE-link typically carries a single OTSi
signal (modulated optical carrier).
The term "bundled add/drop TE-link" refers to the TE-link bundling
concept as defined in . Multiple component
links, add/drop TE-links in this case, are bundled into a single
bundled add/drop TE-Link.
A simplified graphical representation of the data model is used in
Section 2 of this this document. The meaning of the symbols in
these diagrams is defined in .
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, as shown in
.
Prefix YANG module Referenceoptical-imp-topoietf-optical-impairment-topology[RFCXXXX]l0-typesietf-layer0-typesnwietf-networkntietf-network-topologytetietf-te-topology
[Editor's note: The RFC Editor will replace XXXX with the number
assigned to the RFC once this draft becomes an RFC.]
shows the control plane architecture.
||
| ||
| +------------------------+
| | OPTICAL |
+---------+ | | DOMAIN | +---------+
| Device | | | CONTROLLER | | Device |
| config. | | +------------------------+ | config. |
+---------+ v // || \\ +---------+
______|______ // || \\ ______|______
/ OT \ // || \\ / OT \
| +--------+ |// __--__ \\| +--------+ |
| |Vend. A |--|----+ ( ) +----|--| Vend. A| |
| +--------+ | | ~-( )-~ | | +--------+ |
| +--------+ | +---/ \---+ | +--------+ |
| |Vend. B |--|--+ / \ +--|--| Vend. B| |
| +--------+ | +---( OLS Segment )---+ | +--------+ |
| +--------+ | +---( )---+ | +--------+ |
| |Vend. C |--|--+ \ / +--|--| Vend. C| |
| +--------+ | +---\ /---+ | +--------+ |
| +--------+ | | ~-( )-~ | | +--------+ |
| |Vend. D |--|----+ (__ __) +----|--| Vend. D| |
| +--------+ | -- | +--------+ |
\_____________/ \_____________/
^ ^
| |
| |
Scope of [I-D.ietf-ccamp-dwdm-if-param-yang]
]]>
The topology model developed in this document is an abstracted
topology YANG model that can be used at the interfaces between the
MDSC and the Optical Domain Controller (aka MPI) and between the
Optical Domain Controller and the Optical Device (aka SBI) in
.
It is not intended to support a detailed low-level DWDM interface
model. DWDM interface model is supported by the models presented in
.
This section provides the description of the optical transport
network reference architecture and its relevant components to
support optical impairment-aware path computation.
shows the reference architecture.
<--------->
OMS MCG = TE-link
<-------------------------------->
BA: Booster Amplifier (or egress amplifier)
PA: Pre-Amplifier (or ingress amplifier)
ILA: In-Line Amplifier
MCG: Media Channel Group
]]>
BA (WDM-node 1) is the egress Amplifier and PA (WDM-node 2) is the
ingress amplifier for the OMS Media Channel Group (MCG) in the
direction from left to right in .
According to , a Media Channel Group (MCG)
represents "a unidirectional point-to-point management/control
abstraction that represents a set of one or more media channels that
are co-routed. A media channel group (MCG) is bounded by a pair of
media ports."
According to , an
OTS Media Channel Group (MCG) represents a topological construct
between two adjacent amplifiers, such as:
defines an OMS MCG as "The topological
relationship between the media port on a filter or coupler where a
set of media channels are aggregated and the media port on a filter
or coupler where one or more media channel is added to or removed
from that aggregate. All of the media channels that are represented
by the OMS MCG must be carried over the same serial concatenation of
OTS MCGs and amplifiers."
An OMS MCG originates at the ROADM in the source WDM-node and
terminates at the ROADM in the destination WDM-node traversing the
Booster Amplifier (BA) and the Pre-Amplifier (PA) in the WDM-nodes
as well as the In-Line Amplifiers (ILAs) between the two WDM-nodes.
An OMS MCG can be decomposed into a sequence of OTS MCGs and
amplifiers.
An OMS MCG traverses a sequence of elements such as BA, fiber
section, ILA, PA, and concentrated loss wherever there is an
insertion loss caused for example by a fiber connector.
In TE-topology terms, the OMS MCG is modeled as a WDM TE-link
interconnecting two WDM-TE-nodes. A network controller can retrieve
the optical impairment data for all the WDM TE-link elements defined
in the layer-0 topology YANG model.
The optical impairments related to the link between remote optical
transponders, located in a different WDM-TE-node (an IP router with
integrated optical transponders for example), can also be modeled
as a WDM TE-link using the same optical impairments as those defined
for a WDM TE-link between WDM-TE-nodes (OMS MCG). In this scenario,
the node containing the remote optical transponders can be
considered as WDM-TE-node with termination capability only and no
switching capabilities.
A WDM TE-link is terminated on both ends by a link termination point
(LTP) as defined in .
Links between WDM nodes in optical transport networks are typically
bidirectional.
Generally, they have different impairments in the two directions and
hence they have to be modeled as a pair of two unidirectional
TE-links following the modeling approach.
Unlike TE-links, which are unidirectional, the LTPs on either end
of the TE-link pair forming the bidirectional link, are
bidirectional as described in
and the
pair of unidirectional links are connected to the same bidirectional
LTP on either end of the link pair.
The OTSi is defined in ITU-T Recommendation G.959.1, section 3.2.4
as "Optical signal that is placed within a
network media channel for transport across the optical network. This
may consist of a single modulated optical carrier or a group of
modulated optical carriers or subcarriers."
The YANG model defined below assumes that
a single OTSi consists of a single modulated optical carrier. This
single modulated optical carrier conveys digital information.
Characteristics of the OTSi signal are modulation scheme (e.g. QPSK,
8-QAM, 16-QAM, etc.), baud rate (measure of the symbol rate), pulse
shaping (e.g. raised cosine - complying with the Nyquist inter
symbol interference criterion), etc.
Path computation needs to know the existing OTSi signals for each
OMS link in the topology 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. For determining the optical feasibility of
the new OTSi, it is necessary to know the OTSi properties like
carrier frequency, baud rate, and signal power for all existing
OTSi signals on each OMS link.
Additionally, it is necessary for each WDM-TE-node in the network to
know the OTSi signals that are added to or dropped from an WDM
TE-link (OMS MCG)link as well as the optical power of these OTSi
signals to check whether the WDM-TE-node's optical power constraints
are met.
The optical impairment-aware topology YANG model below defines the
OTSi properties needed for optical impairment-aware path computation
including the spectrum occupied by each OTSi signal. The model also
defines a pointer (leafref) from the OTSi to the transceiver module
terminating the OTSi signal.
The OTSi signals in the YANG model are described by augmenting the
network and each OTSi signal is uniquely identified by its
otsi-carrier-id, which is unique within the scope the OTSiG [see
below] the OTSi belongs to.
The OTSiG is defined in ITU-T Recommendation G.807
as a "set of optical tributary signals (OTSi)
that supports a single digital client".
Hence, the OTSiG is an electrical signal that is carried by one or
more OTSi's. The relationship between the OTSiG and the the OTSi's
is described in , section 10.2.
The YANG model below supports both cases: the single OTSi case
where the OTSiG contains a single OTSi (see ,
Figure 10-2) and the multiple OTSi case where the OTSiG consists of
more than one OTSi (see , Figure 10-3).
From a layer 0 topology YANG model perspective, the OTSiG is a
logical construct that associates the OTSi's, which belong to the
same OTSiG. The typical application of an OTSiG consisting of more
than one OTSi is inverse multiplexing. Constraints exist for the
OTSi's belonging to the same OTSiG such as: (i) all OTSi's must be
co-routed over the same optical fibers and nodes and (ii) the
differential delay between the different OTSi's may not exceed a
certain limit. Example: a 400Gbps client signal may be carried by 4
OTSi's where each OTSi carries 100Gbps of client traffic.
All OTSiGs are described in the YANG model by augmenting the network
and each OTSiG is uniquely identified by its otsi-group-id, which is
unique within the network. Each OTSiG also contains a list of the
OTSi signals belonging to the OTSiG.
defines a "media channel" as "A media
association that represents both the topology (i.e., the path
through the media) and the resource (i.e., frequency slot or
effective frequency slot) that it occupies." In this document,
the term "channel" is occasionally used to indicate the resource
of an MC (i.e., frequency slot or effective frequency slot),
without representing topology.
In this document, an end-to-end MC is defined as a type of MC,
which is formed by the serial concatenation of all the MCs from
source Transceiver media ports to destination transceiver media
ports.
This end-to-end MC is defined across all the ROADM nodes along the
end-to-end optical path with the same nominal central frequency n
and frequency slot of width m, which represents the effective
frequency slot of the end-to-end MC.
An end-to-end MC can carry a single OTSi, or multiple OTSi signals
belonging to the same OTSiG.
defines a "network media channel (NMC)"
as "a type of media channel that is formed by the serial
concatenation of all media channels between the media port of a
modulator and the media port of a demodulator". The modulator and
demodulator are integral functions of a transceiver and their media
ports do not necessarily coincide with the media port of the
transceiver, which is associated with the transceiver's physical
optical port. Due to this difference, the end-to-end MC is defined
above and is used in this document.
In section , the term "end-to-end MC path" is
used to describe the topological aspect of the end-to-end MC, i.e.,
the path through the media (see: ,
section 7.1.2). This is in line with the TE path defined in
, section 3.9, where the TE path is defined
as "an ordered list of TE links and/or TE nodes on the TE topology
graph" interconnecting a pair of tunnel termination points (TTPs).
]]>
The frequency slot of the MC is defined by the n value defining the
central frequency of the MC and the m value that defines the width
of the MC following the flexible grid definition in
. In this model, the effective frequency
slot as defined in is equal to the frequency
slot of this MC. It is also assumed that ROADM devices
can switch MCs.
For various reasons (e.g. differential delay), it is preferred to
use a single MC for all OTSi's of the same OTSiG. It may however not
always be possible to find a single MC for carrying all OTSi's of an
OTSiG due to spectrum occupation along the OTSiG path.
ITU-T [G.807] defines the Media Channel Group MCG as
"A unidirectional point to point management/control abstraction
that represents a set of one or more media channels that are
co-routed."
The YANG model below assumes
that the MCG is a logical grouping of one or more MCs that are used
to to carry all OTSi's belonging to the same OTSiG.
The MCG can be considered as an association of MCs without defining
a hierarchy where each MC is defined by its (n,m) value pair. An MCG
consists of more than one MC when no single MC can be found from
source to destination that is wide enough to accommodate all OTSi's
(modulated carriers) that belong to the same OTSiG. In such a case
the set of OTSi's belonging to a single OTSiG have to be split
across 2 or more MCs.
The MCG is relevant for path computation because all end-to-end MCs
belonging to the same MCG have to be co-routed, i.e., have to follow
the same path. Additional constraints may exist (e.g. differential
delay).
Optical amplifiers are used in WDM networks for amplifying the
optical signal in the optical domain without any optical to
electrical and electrical to optical conversion. Three
main optical amplifier technologies are existing today:
Erbium Doped Fiber Amplifiers (EDFAs)
Raman Amplifiers
Semiconductor Optical Amplifiers (SOAs)
In today's WDM networks EDFAs and Raman amplifiers are widely used.
Raman amplifiers have become attractive due to their large spectral
gain bandwidth, which can be quite flat, with similar or even lower
noise figures compared to EDFAs. On the other hand, Raman amplifiers
consume more power and are usually more expensive than EDFAs.
Raman amplifiers are distributed amplifiers where an optical pump
signal is injected typically in opposite direction to the optical
signal that is amplified (backward pump, counter-propagating pump
light). Injecting the optical pump signal in the same direction is
also possible (forward pump, co-propagating pump light).
For optical amplifiers, the YANG model defines Raman pump light
attributes describing the direction (raman-direction) with respect
to the signal that is amplified and optical frequency and power for
the pump light source(s) contained in the raman-pump list. These
Raman amplifier-specific attributes are optional as they are only
applicable to Raman amplifiers. For determining the optical
amplifier type, i.e., to figure out whether an optical amplifier is
a Raman amplifier, the type-variety attribute is used.
Due to the distributed nature of the Raman amplifier it is difficult
to clearly separate the amplifier from the fiber span into which the
pump signal is injected. From a topology modeling perspective, the
Raman amplifier is modeled as two OMS line elements:
a passive fiber element accounting for the fiber loss only
and not the resulting loss including the Raman gain
an amplifier element providing all optical amplifier properties
(gain, tilt, etc.). On the OMS-link, the amplifier element is
placed where the pump is located and the geolocation information
also indicates the location of the pump.
Amplifiers can be classified according to their location along the
TE-link (OMS MCG). There are three basic amplifier types: In-Line
Amplifiers (ILAs), Pre-Amplifiers and Booster Amplifiers. ILAs are
separate physical devices while Pre-Amplifiers and Booster
Amplifiers are integral elements of a WDM-node. From a data modeling
perspective, node-internal details should not be modeled and should
be abstracted as much as possible. For Pre-Amplifiers and Booster
Amplifiers, however, a different approach has been taken and they
are modeled as TE-link elements as they have the same optical
impairments as ILAs.
ILAs may have a variable optical attenuator on the ingress side
(in-voa attribute) allowing to control the input power of the WDM
signal (OMS MCG) entering the gain stage of the ILA. It may also
have a variable optical attenuator on the egress side, which allows
to control the optical power of the WDM output signal (OMS MCG) of
the ILA. The actual-gain attribute reflects the gain of the ILA gain
stage and does not include the attenuation of the in-voa and/or
out-voa.
ILAs are placed at locations where the optical amplification of the
WDM signal is required on the TE-link (OMS MCG) between two
WDM-TE-nodes nodes.
Geolocation information is already defined for TE nodes in
and is also beneficial for ILAs. Therefore,
the same geolocation container has been added to the amplifier
element on an OMS link containing altitude, latitude, and longitude
as optional attributes.
One modeling consideration of the ROADM internal is to model power
parameter through the ROADM, factoring the output power from the
Pre-Amplifier minus the ROADM power loss would give the input power
to the Booster Amplifier. In other words, Power_in (@ ROADM Booster)
= Power_out (@ ROADM Pre-Amplifier) - Power_loss (@ ROADM
WSS/Filter).
[Editor's note: The relationship between the transponder and the
OTSi in the YANG model described in
needs further clarification and refinement.]
A Transponder is the element that sends and receives the optical
signal from a DWDM network. A transponder can comprise one or more
transceivers. A transceiver represents a transmitter/receiver
(Tx/Rx) pair as defined in ITU-T Recommendation G.698.2
. In addition to the transceiver, which is
terminating an OTSi signal, a transponder typically provides
additional layer 1 functionality like for example aggregation
(multiplexing) of client layer signals, which is outside the scope
of this document addressing layer 0 aspects of transponders.
The termination of an OTSi signal by a transceiver is modeled as a
function of the tunnel termination point (TTP) as defined in
.
Due to the fact that optical transport services (TE tunnels) are
typically bidirectional, a TTP is also modeled as a bidirectional
entity like the LTP described above. Moreover, a TTP can terminate
one or several OTSiG signals (tunnels) as described in
and each
OTSiG consists of one or multiple OTSi signals as described in
.
Therefore, a TTP may be associated with multiple transceivers.
A transponder is typically characterized by its data/symbol rate
and the maximum distance the signal can travel. Other transponder
properties are: carrier frequency for the optical channels,
output power per channel, measured input power, modulation scheme,
FEC, etc.
From a path computation perspective, the selection of the compatible
configuration of the source and the destination transceivers is an
important factor for optical signals to traverse through the DWDM
network.
The YANG model defines three different approaches to describe the
transceiver capabilities (called "modes") that are needed to
determine optical signal compatibility:
Standard ModesOrganizational ModesExplicit Modes
A standard mode is related to an optical specification developed
by an SDO organization. Currently, the "Standard Modes" can only
be referred to ITU-T G.698.2 since G.698.2
is the only specification defining "Standard Modes" today.
Nothing is precluding, however, to consider other specifications
provided by any other SDO in the Standard Mode context as soon as
such sepcifications will be available. An application code as
defined in ITU-T G.698.2 is representing
a standard ITU-T G.698.2 optical interface specification towards
the realization of transversely compatible DWDM systems.
Two transceivers supporting the same application code and a line
system matching the constraints, defined in ITU-T G.698.2, for that
application code will interoperate. As the characteristics are
encoded in the application code, the YANG model in this document
only defines a string, which represents that application code.
Organizations like operator groups, industry fora, or equipment
vendors can define their own optical interface specifications and
make use of transceiver capabilities going beyond existing
standards.
An organizational mode is identified by the organization-identifier
attribute defining the scope and an operational-mode that is
meaningful within the scope of the organization. Hence, the two
attributes must always be considered together. It is the
responsibility of the organization to assign operational modes and
to ensure that operational modes are unique and unambiguous within
the scope of the organization.
Two transceivers can be interconnected, if they have at least one
(organization-identifier, operational-mode) pair in common and if
the supported carrier frequency and power attributes have a matching
range. This is a necessary condition for path computation in the
context of organizational modes.
An operational mode is a transceiver preset (a configuration with
well-defined parameter values) subsuming several transceiver
properties defined by the optical interface specification - these
properties are not provided for an operational mode and are
therefore not defined in the YANG model. Examples of these
properties are:
FEC typeModulation schemeEncoding (mapping of bit patterns (code words) to symbols in the
constellation diagram)Baud rate (symbol rate)Carrier bandwidth (typically measured in GHz)
The major reason for these transceiver presets is the fact that the
attribute values typically cannot be configured independently and
are therefore advertised as supported operational mode capabilities.
It is the responsibility of the organization to assign operational
modes and to ensure that operational modes are unique and not
ambiguous within the scope of the organization.
In addition to the transceiver properties subsumed by the
operational mode, optical power and carrier frequency related
properties are modeled separately, i.e., outside of the operational
mode. This modeling approach allows transponders using different
transceiver variants (e.g. optical modules) with slightly different
power and/or frequency range properties to interoperate without
defining separate operational modes. Different optical modules
(pluggables) from different suppliers typically have slightly
different input and output power ranges or may have slightly
different carrier frequency tuning ranges.
The received channel power and the received total power are two
parameters that can be measured by the receiver and can be provided
by the transceiver in order to allow a controller to determine the
expected performance of the end-to-end service taking into account
the optical impairments along the path.
An organization may define the operational modes to include the
optical power and carrier frequency related properties following the
application code approach as defined in ITU-T Recommendation G.698.2
. In such a case, the explicit optical power
and carrier frequency related optional attributes shall be omitted
in order to avoid redundant information in the description of the
transceiver capabilities. If these attributes are provided in
addition to the operational modes including these attribute values
implicitly, the parameter values provided explicitly replace the
implicit values and take precedence. This shall, however, only be
an done in exceptional cases and shall be avoided whenever possible.
In case an implicitly given range is extended utilizing the explicit
optional attributes, a path computation policy rule may be applied
to select a value preferably from the range defined implicitly and
to only select a value from the extended range if no path can be
found for values in the implicitly defined range. Path computation
policy is outside the scope of this topology YANG model.
In summary, the optical power and carrier frequency related
attributes shall either be described implicitly by the operational
mode following the definition provided by that organization or shall
be described explicitly when the optical power and carrier frequency
related properties are not included in the operational mode
definition.
The explicit mode allows to encode, explicitly, any subset of
parameters e.g., FEC type, Modulation type, etc, to enable a
controller entity to check for interoperability by means outside
of this draft. It shall be noted that using the explicit encoding
does not guarantee interoperability between two transceivers even
in case of identical parameter definitions. The explicit mode
shall therefore be used with care, but it could be useful when no
common Application Codes or Organizational Modes exist or the
constraints of common Application Codes or Organizational Modes
cannot be met by the line system.
The YANG model described in defines the
optical transceiver properties. They are divided between:
Optical transceiver capabilities, describing how it can be
configuredCurrent transceiver setting, indicating how it is currently
configured
The transceiver capabilities are described by the set of modes the
transceiver is supporting. Each mode MUST follow only one of the
three mode options defined above (choice in the YANG model). The
YANG model allows to describe the transceiver capabilities by mixing
different modes. A transceiver may support some ITU-T application
codes and in addition some organizational or explicit modes.
A transceiver mode description comprises the following properties:
Supported transmitter tuning range with min/max nominal carrier
frequency [f_tx_min, f_tx_max]Supported transmitter tunability describing the transmitter's
frequency fine tuning steps (the minimum distance between two
adjacent carrier frequencies in GHz)Supported transmitter power range [p_tx-min, p_tx_max]Supported receiver channel power range [p_rx-min, p_rx_max]Supported maximum total power, rx power for all channels fed
into the receiver
These optical transceiver properties are explicitly defined in the
model for explicit and organizational modes, while they are
implicitly defined for the application codes (see ITU-T G698.2
).
The set of optical impairment limits, e.g., min OSNR, max PMD,
max CD, max PDL, Q-factor limit, are explicitly defined for the
explicit modes while they are defined implicitly for the
application codes and organizational modes.
It is possible that the set of parameter values defined for an
explicit mode may also be represented in form of an organizational
mode or one or more application codes. The "supported-mode"
container may provide two different lists with pointers to
application codes and organizational modes, respectively.
The current transponder configuration describes the properties of
the OTSi transmitted or received by the transceiver attached to a
specific transponder port.
Each OTSi has the following three pointer attributes modeled as
leafrefs:
Pointer to the transponder instance containing the transceiver
terminating the OTSiPointer to the transceiver instance terminating the OTSiPointer to the currently configured transceiver mode
Additionally, the OTSi is described by the following frequency and
optical power related attributes:
current carrier-frequencycurrently transmitted channel powercurrently received channel powercurrently received total power
Optical transponders are usually used to terminate a layer 0 tunnel
(layer 0 service) in the WDM layer. If, however, no optical path can
be found from the source transponder to the destination transponder
that is optically feasible due to the optical impairments, one or
more 3R regenerators are needed for regenerating the optical signal
in intermediate nodes. The term "3R" regenerator means:
reamplification, reshaping, retiming. As described in
, Appendix IV, a 3R regenerator terminates the
OTSi and generates a new OTSi. Depending on the 3R regenerator
capabilities, it can provide functions such as carrier frequency
translation (carrier-frequency), changes in the modulation scheme
(modulation-type) and FEC (FEC-type) while passing through the
digital signal except the FEC (the FEC is processed and errors are
corrected).
The 3R regeneration compound function is illustrated in section 10.1
of , and sections 10.3 and 10.4 provide
examples of a ROADM architecture and a photonic cross-connect
architecture including 3R regenerators.
Based on the provided functionality, 3R regenerators are considered
as topological layer 0 entities because they are needed for layer 0
path computation in case the optical impairments make it impossible
to find an optically feasible end-to-end path from the source
transponder to the destination transponder without 3R regeneration.
When an end-to-end path includes one or more 3R regenerators, the
corresponding layer 0 tunnel is subdivided into 2 or more segments
between the source transponder and the destination transponder
terminating the layer 0 tunnel.
3R regenerators are usually realized by a pair of optical
transponders, which are described in
above. If a pair of optical transponders is used to perform a 3R
regeneratator function, two different configurations are possible
involving the pair of optical transceivers of the two optical
transponders:
The two transponders can be operated in a back-to-back
configuration where the transceiver of each optical transponder
receives and transmits the optical signal from/to the same segment
of the end-to-end tunnel. This means that each transceiver is
operated in a bi-directional mode.
| Receiver |---|Sig. |--->|Sig. |---| Transmitter |--->
|-------------+ | | | | +-------------|
<---| Transmitter |---|Proc.|<---|Proc.|---| Receiver |<---
|-------------+ +-----| |-----+ +-------------|
| | | |
+-----------------------+ +-----------------------+
Sig. Proc. = Signal Processing
]]>
The two transponders can be operated in a configuration where each
transponder performs the 3R regeneration function in one direction,
one in forward direction (from source to destination) and the other
in the reverse direction. In this configuration, the transceiver of
each optical transponder receives the signal from one segment and
transmits the regenerated optical signal into the adjacent segment.
This configuration is also called cross-regeneration and each
transceiver is operated in an uni-directional mode.
Implemantations may support the change of the carrier frequency
where the receiver may operate at a different optical frequency
as the transmitter. The transceiver mode is a property of the
transceiver and is applied to the transmitter and the receiver.
Therefore, the transceiver mode is the same for the two segments
on the two sides of the 3R regenaretor realised by two transceivers
operated in the uni-directional mode.
| Receiver |---|Sig. --+ | |
|-------------+ | | | |
<---| Transmitter |---|Proc.<-+ | |
|-------------+ +---------+ |
| |
+-----------------------------+
3R in forward direction
Optical Transponder 2
+-----------------------------+
| Transceiver |
|-------------+ +---------+ |
--->| Receiver |---|Sig. --+ | |
|-------------+ | | | |
<---| Transmitter |---|Proc.<-+ | |
|-------------+ +---------+ |
| |
+-----------------------------+
3R in reverse direction
Sig. Proc. = Signal Processing
]]>
Due to the fact that 3R regenerators are composed of an optical
transponder pair, the capability whether an optical transponder can
be used as a 3R regenerator is is added to the transponder
capabilities. Hence, no additional entity is required for describing
3R regenerators in the TE-topology YANG model. The optical
transponder capabilities regarding the 3R regenerator function are
described by the following two YANG model attributes:
supported-termination-typesupported-3r-mode
The supported-termination-type attribute describes whether the
optical transponder can be used as tunnel terminating transponder
only, as 3R regenerator only, or whether it can support both
functions. The supported-3r-mode attribute describes the
configuration of the transponder pair forming the 3R regenerator
as described above.
More text to be added here!
WSS separates the incoming light input spectrally as well as
spatially, then chooses the wavelength that is of interest by
deflecting it from the original optical path and then couple it to
another optical fibre port. WSS/Filter is internal to ROADM. So this
document does not model the inside of ROADM.
There are various optical fiber types defined by ITU-T. There are
several fiber-level parameters that need to be factored in, such as,
fiber-type, length, loss coefficient, pmd, connectors (in/out).
ITU-T G.652 defines Standard Singlemode Fiber; G.654 Cutoff Shifted
Fiber; G.655 Non-Zero Dispersion Shifted Fiber; G.656 Non-Zero
Dispersion for Wideband Optical Transport; G.657 Bend-Insensitive
Fiber. There may be other fiber-types that need to be considered.
The WDM-node architectures in today's dense wavelength division
multiplexing (DWDM) networks can be categorized as follows:
Integrated WDM-node architecture with local optical transponders
Integrated WDM-node architecture with local optical transponders
and single channel add/drop ports for remote optical transponders
Disaggregated WDM-node architecture where the WDM-TE-node is
composed of degree, add/drop, and optical transponder subsystems
handled as separate WDM-nodes
The TE topology YANG model augmentations including optical
impairments for DWDM networks defined below intend to cover all the
3 categories of WDM-node architectures listed above. In the case
of a disaggregated WDM-node architecture, it is assumed that the
optical domain controller already performs some form of abstraction
and presents the WDM-TE-node representing the disaggregated WDM-node
in the same way as an integrated WDM-TE-node with local optical
transponders if the optical transponder subsystems and the add/drop
subsystems are collocated (short fiber links not imposing any
significant optical impairments).
The different WDM-node architectures are briefly described and
illustrated in the following subsections.
[Editor's note: The modeling of remote optical transponders located
for example in the client device with a single channel link between
the OT and the add/drop port of the WDM-TE-node requires further
investigations and will be addressed in a future revision of this
document.]
and below show
the typical architecture of an integrated WDM-node, which contains
the optical transponders as an integral part of the WDM-node. Such
an integrated WDM-node provides DWDM interfaces as external
interfaces for interconnecting the device with its neighboring
WDM-node (see OMS MCG above). The number of these interfaces denote
also the degree of the WDM-node. A degree 3 WDM-node for example has
3 DWDM links that interconnect the WDM-node with 3 neighboring
WDM-nodes. Additionally, the WDM-node provides client interfaces for
interconnecting the WDM-node with client devices such as IP routers
or Ethernet switches. These client interfaces are the client
interfaces of the integrated optical transponders.
below shows the extreme case where all
optical transponders are not integral parts of the WDM-node but are
separate devices that are connected to the add/drop ports of the
WDM-node. If the optical transponders and the WDM-node are
collocated and if short single channel fiber links are used to
interconnect the optical transponders with an add/drop port of the
WDM-node, the optical domain controller may present these optical
transponders in the same way as local optical transponders. If,
however, the optical impairments of the single channel fiber link
between the optical transponder and the add/drop port of the
WDM-node cannot be neglected, it is necessary to represent the
fiber link with its optical impairments in the topology model This
also implies that the optical transponders belong to a separate
TE-node.
[Editor's note: this requires further study].
Recently, some DWDM network operators started demanding WDM
subsystems from their vendors. An example is the OpenROADM project
where multiple operators and vendors are developing related YANG
models. The subsystems of a disaggregated WDM-TE-node are:
Single degree subsystemsAdd/drop subsystemsOptical transponder subsystems
These subsystems are separate network elements and each network
element provides a separate management and control interface. The
subsystems are typically interconnected using short fiber patch
cables and form together a disaggregated WDM-TE-node. This
disaggregated WDM-TE-node architecture is depicted in
below.
As this document defines TE topology YANG model augmentations
for the TE topology YANG
model provided at the north-bound interface of the optical domain
controller, it is a valid assumption that the optical domain
controller abstracts the subsystems of a disaggregated WDM-TE-node
and presents the disaggregated WDM-TE-node in the same way as an
integrated WDM-node hiding all the interconnects that are not
relevant from an external TE topology view.
[Editor's note: the following text still needs to be updated based
on the agreed terminology]
When an optical OTSi signal traverses a ROADM node, optical
impairments are imposed on the signal by various passive or active
optical components inside the ROADM node. Examples of optical
impairments are:
Chromatic dispersion (CD)Polarization mode dispersion (PMD)Polarization dependent loss (PDL)Optical amplifier noise due to amplified spontaneous emission
(ASE)In-band cross-talkFiltering effects (for further study)
A ROADM node contains a wavelength selective photonic switching
function (WSS)that is capable of switching media channels (MCs)
described in . These MCs can be
established between two line ports of the ROADM or between a line
port and an Add/Drop port of the ROADM. The Add/Drop ports of a
ROADM are those ports to which optical transponders are connected.
Typically, add/drop ports deal with a single channel signal (single
OTSi), but principally this could also be a group of OTSi signals
(OTSiG). The optical impairments associated with these MCs are
different and the paths of the MCs inside the ROADM node can be
categorized as follows:
Express path: MC path between two line ports of the ROADM
(unidirectional)Add Path: MC path from an Add port to a line port of the ROADMDrop path: MC path from a line port to a Drop port of the ROADM
Due to the symmetrical architecture of the ROADM node, the optical
impairments associated with the express path are typically the same
between any two line ports of the ROADM whereas the optical
impairments for the add and drop paths are different and therefore
have to be modeled separately.
The optical impairments associated with each of the three types of
ROADM-node-internal paths described above are modeled as optical
impairment parameter sets. These parameter sets are modeled as an
augmentation of the te-node-attributes defined in
.
The te-node-attributes are augmented with a list of
roadm-path-impairments for the three ROADM path types distinguished
by the impairment-type. Each roadm-path-impairments list entry
contains the set of optical impairment parameters for one of the
three path types indicated by the impairment-type. For the optical
feasibility calculation based on the optical impairments, it is
necessary to know whether the optical power of the OTSi stays within
a certain power window. This is reflected by some optical power
related parameters such as loss parameters or power parameters,
which are included in the optical impairment parameter sets (see
tree view in ).
defines a connectivity
matrix and a local link connectivity list for the TE node. The
connectivity matrix describes the connectivity for the express paths
between the different lines of the ROADM and the local link
connectivity list describes the connectivity for the Add and Drop
paths of the ROADM. These matrices are augmented with a new
roadm-path-impairment matrix element, an add-path-impairment, and
drop-path-impairment matrix element, respectively, which are defined
as a pointer to the corresponding entry in the
roadm-path-impairments list (leaf-ref).
The YANG model defined in this document supports the following
optical protection architectures:
Individual OTSi protection
OMS MCG protection = TE-link protection between adjacent
WDM-TE-nodes
Individual OTSi protection is a protection architecture where an
individual OTSi signal is protected as described in Appendix III of
ITU-T Recommendation G.873.1 .
This protection architecture requires dedicated photonic protection
functions in the optical domain that are typically provided by
dedicated protection hardware. These photonic protection functions
are a photonic splitter function splitting the OTSi signal in
transmit direction and a photonic selector function selecting the
OTSi signal in receive direction from one of the two protection
legs between the two protection functions terminating the individual
OTSi protection.
This individual OTSi protection scheme can be considered as a
photonic 1+1 protection scheme (1+1 sub-network connection
protection (SNCP) in ITU-T terminology).
In order to achieve short protection switching times, it is
necessary that the OTSi signals of the two legs are identical in
terms of wavelength, modulation format, FEC, etc., which means no
receiver configuration changes when a protection switch at the
selector occurs selecting the other leg. This is important when 3R
regenerators are needed between the two end-points terminating the
protected segment, which typically is end-to-end.
In case of individual OTSi protection without 3R regenerators,
two end-to-end MC paths are associated with the OTSi signal. In the
YANG model, this is modeled as leaf list of the otsi providing the
e2e-mc-path-id for the two end-to-end MC paths associated with the
individually 1+1 protected OTSi. This scenario is depicted in
(forward direction) and
(reverse direction)below.
|
+-----------+ +-----------+
| WDM Node1 | +-----+ +-----+ | WDM Node2 |
| +----| | WDM | | WDM | |----+ |
| | -o---------->o-----o----->o-----o---------->o- | |
| OT | / | |Node3| |Node4| | \ | OT |
| +--+ | / | +-----+ +-----+ | \ | +--+ |
-o-o o-o- | | -o-o o-o-
| +--+ | \ | +-----+ +------+ +-----+ | / | +--+ |
| | \ | | WDM | | WDM | | WDM | | / | |
| | -o---->o-----o---->o------o---->o-----o---->o- | |
| +----| |Node5| | Node6| |Node7| |----+ |
| Splitter| +-----+ +------+ +-----+ |Selector |
+-----------+ +-----------+
|------------------------------------------------------->|
end-to-end MC path2
]]>
For each OMS MCG (TE-link) along the two end-to-end MC paths in
forward direction (end-to-end MC path1 and end-to-end MC path2) as
well as the two end-to-end MC paths in reverse direction (end-to-end
MC path1' and end-to-end MC path2'), the e2e-mc-path-id is provided
for the individually protected OTSi signal. Based on this
information, it is possible to construct the end-to-end MC paths
between the optical transponders terminating the individually 1+1
protected OTSi.
In the scenario depicted in and
, the e2e-mc-path-id of
end-to-end MC path1 and end-to-end MC path1' is provided for the
TE-links between WDM Node1 and WDM Node3, WDM Node3 and WDM Node4 as
well as WDM Node4 and WDM Node2 while the e2e-mc-path-id of
end-to-end MC path2 and end-to-end MC path2' is provided for the
TE-links between WDM Node1 and WDM Node5, WDM Node5 and WDM Node6,
WDM Node6 and WDM Node7 as well as WDM Node7 and WDM Node2.
If a 3R regenerator is crossed on one of the two legs or even on
both legs, the end-to-end MCs are terminated on both sides of the
3R regenerator. The configured-termination-type attribute set to
"3r-regeneration" shall be used to indicate that the transceivers
are forming a 3R regenerator instead of terminating the layer 0
tunnel (layer 0 service).
At WDM-nodes containing a 3R regenerator, the end-2-end MCs are
stitched together forming the end-to-end path for the layer 0 tunnel
(layer 0 service). This is reflected in the leaf list of the OTSi,
which now lists all e2e-mc-path-ids of the end-to-end MC paths on
the two legs of the individually 1+1 protected OTSi signal.
In the scenario depicted in
and below where a 3R
regenerator is crossed in WDM Node6 on the lower leg, the
e2e-mc-path-id leaf list has 3 entries (assumption: the same
e2e-mc-path-id can be used for the path in forward and reverse
direction):
The e2e-mc-path-id identifying end-to-end MC path1 from WDM
Node1 via WDM Node3 and WDM Node4 to WDM Node2 as well as
end-to-end MC path1' in reverse direction (upper leg)
The e2e-mc-path-id identifying end-to-end MC path2 from WDM
Node1 via WDM Node5 to WDM Node6 containing the 3R regenerator
as well as end-to-end MC path2' in reverse direction (left
hand segment of the lower leg)
The e2e-mc-path-id identifying end-to-end MC path3 from WDM
Node6 containing the 3R regenerator via WDM Node7 to WDM
Node2 as well as end-to-end MC path3' in reverse direction
(right hand segment of the lower leg)
Based on this modeling approach it is possible to identify the
end-2-end MCs stitched together at 3R regenerators on each of the
two legs of the individually protected 1+1 OTSi signal. Like for
the case without 3R regenerators is also possible to associate
two end-to-end paths in forward and reverse direction for the two
legs between the optical transponders terminating the individually
1+1 protected OTSi in WDM Node1 and WDM Node2, respectively:
end-to-end MC path1 and end-to-end MC path1' (upper leg)
end-to-end MC path2 and end-to-end MC path2' stitched together
with end-to-end MC path3 and end-to-end MC path3' (lower leg)
OT and OTSi protection function are an integral part of the
WDM-TE-node
OT and OTSi protection/ROADM functions are in two adjacent
WDM-TE-node (remote OT)
OT and OTSi protection function are both in an adjacent
WDM-TE-node (protected remote OT)
The different use cases are described in following sub-sections and
examples are provided how these uses cases can be modeled properly
using the optical impairment aware TE-topology YANG data model.
OT and OTSi protection function are an integral part of the
WDM-TE-node
This use case is based on the architecture illustrated in
and the following entities are all
integral parts of the WDM-TE-node:
Local optical transponder
Splitter/selector protection function
ROADM function
illustrates such a WDM-TE-node
configuration in transmit/forward direction where the protection
function is an optical splitter and
illustrates the same WDM-TE-node configuration in receive/reverse
direction where the protection function is an optical selector
selecting one of the two incoming OTSi signals and switching to the
other incoming OTSi signal when the optical power of the selected
OTSi signal drops below a pre-defined threshold.
The TE-topology YANG model has been augmented to describe this
protection architecture. The already existing optional
protection-type leaf of the TTP associated with the optical
transceiver is used to indicate whether the TTP is protected, i.e.,
whether it is connected to a protection function or whether it is
unprotected, i.e., whether it is directly connected to an add-drop
port of the ROADM function in the WDM-TE-node.
For unprotected TTPs associated with an optical transceiver, the
local-link-connectivity list describes the potential connectivity
between the TTP and the LTPs of the WDM-TE-node that are the local
end-points of the TE-links (OMS MCGs) interconnecting the
WDM-TE-node with its neighbors, also often called degrees of the
WDM-TE-node as opposed to its add-drop ports.
For protected TTPs, the local-link-connectivity list has been
augmented such that is is capable of describing the potential
connectivity not only between the TTP and a single LTP a
(unprotected case) but is now capable to describe the potential
connectivity to additional LTPs including the related optical
impairments. If the optical impairments are the same for all
local-link-connectivity list entries for a particular TTP, which
is usually the case, the optical impairments shall be omitted for
the additional LTPs leading to a more compact topology description.
If the optical impairments are different, however, they can be
described for each additional LTP entry separately.
A local-link-connectivity list example for a protected TTP in JSON
format is provided in .
o------\ | LTP 1 |
| | +----| | / | | \------o-------o->
--o-->| | Tx o--->o---o | | | |
| | +----| | \ | | | |
<-o---| | Rx o | ---o-->o---\ | Line |
| | +----| +--------+ | \ | LTP 2 |
| | | | \ o-------o->
| +------------+ internal | \ | |
| AD ports o \ | |
| | \ | Line |
| | \ | LTP 3 |
| | \---o-------o->
| o | |
| | | |
| +--------------+ |
+---------------------------------------------------------+
]]> | | Tx o | ---o<--o------\ | LPT 1 |
| | +----| | / | | \------o-------o<-
<-o---| | Rx o<---o---o | | | |
| | +----| | \ | | | |
| | TTP| | ---o<--o---\ | Line |
| +------------+ +--------+ | \ | LTP 2 |
| | \ o-------o<-
| internal | \ | |
| AD ports o \ | |
| | \ | Line |
| | \ | LTP 3 |
| | \---o-------o<-
| o | |
| | | |
| +--------------+ |
+---------------------------------------------------------+
]]> OT and OTSi protection/ROADM functions are in two adjacent
WDM-TE-node (remote OT)
This use case is based on the architecture illustrated in
where the optical transponder is not part
of the WDM-TE-node containing the ROADM function (WDM-TE-Node-2) but
is part of a separate WDM-TE-node (WDM-TE-Node-1) containing one or
more optical transponders (remote OTs). WDM-TE-Node-2 contains:
Splitter/selector protection function
ROADM function
illustrates such a network configuration
in transmit/forward direction showing the two WDM-TE-nodes where the
protection function is the optical splitter in WDM-TE-Node-2 and
illustrates the same network
configuration in receive/reverse direction where the protection
function is the optical selector in WDM-TE-Node-2 selecting one of
the two incoming OTSi signals and switching to the other incoming
OTSi signal when the optical power of the selected OTSi signal drops
below a pre-defined threshold.
In the network configuration shown in and
, respectively, the two WDM-TE-nodes are
interconnected via a TE-link carrying a single OTSi signal.
This TE-link interconnects the remote OT with an add-drop port of
WDM-TE-Node-2 and in the following the qualifier "add-drop" is used
to refer to that LTP as opposed to the line LTPs representing
degrees of WDM-TE-Node-2.
Similar to the protected TTP in ,
the optional protection-type leaf is used to indicate whether the
add-drop LTP is connected to a protection function and then to two
line LTPs via the ROADM function inside WDM-TE-Node-2 or whether it
is connected to a single line LTP via the ROADM function inside
WDM-TE-Node-2 (unprotected add-drop LTP). While the protection-type
attribute was already defined for the TTP, the YANG model has been
augmented to also support this optional attribute for the LTP.
For protected LTPs, the connectivity-matrix has been augmented such
that it is capable of describing the potential connectivity not only
from an add-drop LTP to a single line LTP (unprotected case) but is
now capable to describe the potential connectivity to additional
line LTPs (protected case) including the related optical
impairments. If the optical impairments are the same from the
protected ad-drop LTP to all line LTPs, which is usually the case,
the optical impairments shall be omitted for the additional LTPs
leading to a more compact connectivity matrix description. If the
optical impairments are different, however, they can be described
for each additional LTP separately.
o------\ | LTP 1 |
| | +----| |LTP| / | | \------o-------o->
--o-->| | Tx o----->o-->o---o | | | |
| | +----| | | \ | | | |
<-o---| | Rx o | | ---o-->o---\ | Line |
| | +----| | +--------+ | \ | LTP 2 |
| | | | | \ o-------o->
| +------------+ |AD LTP | \ | |
| | o----------------o \ | |
| | | | \ | Line |
| | |unprot. AD LTPs | \ | LTP 3 |
| | | | \---o-------o->
| | o----------------o | |
| | |AD LTP | | |
| | | +--------------+ |
+----------------+ +---------------------------------------+
]]> | | Tx o | | ---o<--o------\ | LTP 1 |
| | +----| | | / | | \------o-------o<-
<-o---| | Rx o<-----o<--o---o | | | |
| | +----| |AD | \ | | | |
| | TTP| |LTP| ---o<--o---\ | Line |
| +------------+ | +--------+ | \ | LTP 2 |
| | | | \ o-------o<-
| | |AD LTP | \ | |
| | o----------------o \ | |
| | | | \ | Line |
| | |unprot. AD LTPs | \ | LTP 3 |
| | | | \---o-------o<-
| | o----------------o | |
| | |AD LTP | | |
| | | +--------------+ |
+----------------+ +---------------------------------------+
]]> OT and protection function are both in an adjacent
WDM-TE-node (protected remote OT)
The use case illustrated in is similar to
the use case in . The difference
compared to use case (i) is that WDM-TE-Node-1 does not contain the
ROADM function but contains:
Optical transponder function including the transceiver
Splitter/selector protection function
WDM-TE-Node-1 can be a data center device or a router router device
that supporting 1+1 OTSi protection for its OTs while WDM-TE-Node-2
is a WDM-TE-node providing add-drop ports for remote OTs as depicted
in . WDM-TE-Node-1 and WDM-TE-Node-2 are
interconnected via two separate TE-links, each carrying a single
OTSi signal. The protection configuration for the protected TTP in
WDM-TE-Node-1 can be described in the same way as for use case (i)
using the local-link-connectivity list.
o----o------\ | LTP 1 |
| | +----| | /LTP| |LTP | \------o-------o->
--o-->| | Tx o-->o---o | | | | |
| | +----| | \ | |AD | | |
<-o---| | Rx o | ---o----->o----o---\ | Line |
| | +----| | LTP| |LTP | \ | LTP 2 |
| | | +--------+ | | \ o-------o->
| +------------+ | | | \ | |
| | o----o \ | |
| | |AD | \ | Line |
| | |LTPs| \ | LTP 3 |
| | | | \---o-------o->
| | o----o | |
| | | | | |
| | | +--------------+ |
+-----------------------------+ +---------------------------+
]]>
OMS MCG protection is a 1+1 protection architecture where a TE-link
representing an OMS MCG between two adjacent WDM-TE-nodes is 1+1
protected. This media layer protection type is also described in
Appendix III of .
illustrates this 1+1 OMS MCG
protection type and shows a 1+1 protected TE-link together with an
unprotected TE-link between the same two adjacent WDM-TE-Nodes. The
protected TE-link in is composed of an
underlying primary and secondary TE-link. This modeling approach is
described below.
1+1 OMS MCG protection is a local protection scheme, which can be
modeled based on TE-link properties already defined in
. The 1+1 protected TE-link is associated
with the two underlying TE-links representing the physical links,
which are forming the 1+1 protection group together with the
splitter and selector functions in the adjacent WDM-TE-Nodes as
depicted in . This modeling approach
is described in more detail in
.
Alternatively, it is possible to model the 1+1 OMS MCG protection
as single protected TE-link abstracting the two underlying physical
links as well as the splitter and selector functions in the two
adjacent WDM-TE-Nodes. This modeling approach is described in more
detail in .
For both modeling approaches, the splitter and selector functions
are not represented as separate entities in the model. Their optical
impairments can be taken into account in the optical impairments of
the ROADM paths in the two adjacent WDM-TE-Nodes (connectivity
matrix and LLCL, respectively) or in the optical impairments of the
1+1 protected TE-link abstracting the two underlying physical OMS
links.
o-------->o--> | | | |
| | | | / | prim. | \ | | | |
| | o-->o--o | | o--o-->o | |
| | | | \ | second.| / | | | |
| | | | -->o-------->o--> | | | |
| | | +-------+ +-------+ | | |
| | | Selector| Line 1 |Splitter | | |
| | | +-------+ +-------+ | | |
| | | | <--o<--------o<-- | | | |
| | | | / | prim. | \ | | | |
| | o<--o--o | | o--o<--o | |
| | | | \ | second.| / | | | |
| | | | <--o<--------o<-- | | | |
| | | +-------+ TE-link +-------+ | | |
| | | | | | | |
| | | | unprot. | | | |
| | o---------->o-------->o---------->o | |
| | | | Line 2 | | | |
| | o<----------o<--------o<----------o | |
| | | | TE-link | | | |
| | | | | | | |
| +-------+ | | +-------+ |
| | | |
+-----------------------+ +-----------------------+
]]>
This modeling approach models the 1+1 protected TE-link as an
additional TE-link entity on top of the primary and secondary
TE-link between the two adjacent WDM-TE-Nodes terminating the
1+1 OMS MCG protection group formed by these two TE-links and the
splitter and selector functions in the two nodes. This 1+1 protected
TE-link is associated with underlying primary and secondary TE-links
forming the 1+1 protection group. The following "te-link-attributes"
already defined in and
can be used for
modeling the 1+1 protected TE-link ("te-link-attributes"
augmentation copied from :
These attributes are used as follows:
"underlay": the presence of this container is indicating that
an underlying protection scheme exists
"enabled": (boolean) is set to 'true'
"primary-path": is referencing the primary OMS MCG (TE-link)
"backup-path": is referencing the secondary OMS MCG (TE-link)
"protection-type" (identityref) set to
'link-protection-1-plus-1' as defined in
The optical impairments for the underlying primary and secondary
TE-link can be described as for unprotected TE-links. It may also be
possible to only describe the optical impairments for the 1+1
protected TE-link. In this case the optical impairments of the worse
of the two underlying TE-links shall be used. This should be
sufficient as input for path computation (worst case optical
feasibility consideration).
o---------->o--> | | | |
LTP1| | RP1| | / | prim. | \ | |RP2 | |LTP6
--->o-->o.......o-->o--o | | o--o-->o.......o-->o--->
| | | | \ | second. | / | | | |
| | | | -->o---------->o--> | | | |
| +-------+ +-------+LTP3 LTP5+-------+ +-------+ |
| | | |
+-----------------------+ +-----------------------+
--+ +--
ROADM port | | ROADM port
RP1 o---------------------------------->o RP2
| |
--+ +--
1+1 protected OMS MCG (TE-link)
between ROADM ports RP1 and RP2
underlying primary and secondary TE-links:
--+ +--
| prim. |
LTP2 o---------->o LTP4
LTP3 o---------->o LTP5
| second. |
--+ +--
connectivity matrix provides optical impairments in
forward direction between LTPs in the two WDM-TE-Nodes:
* LTP1 and LTP2, * LTP4 and LTP6,
* LTP1 and LTP3 * LTP5 and LTP6
]]> and
illustrate this modeling
approach including the LTPs in WDM-TE-Node-1 and WDM-TE-Node-2,
respectively.
In addition to the physical view, the following TE-links are
shown in the two directions:
The 1+1 protected TE-link
The underlying primary TE-link
The underlying secondary TE-link
The optical impairments of the splitter (outgoing direction) and
the selector (incoming direction) are included in the optical
impairments described by the connectivity matrix and the local link
connectivity list for the TE node.
For the example shown in
in forward direction, the connectivity matrix describes the optical
impairments between LPT1 and LTP2 as well as LTP1 and LTP3 for
WDM-TE-Node-1. Likewise, the connectivity matrix describes the
optical impairments between LPT4 and LTP6 as well as LTP5 and LTP6
in WDM-TE-Node-2. The same applies to the corresponding LTPs in
reverse direction.
This modeling approach abstracts the two physical OMS links carrying
the same OMS MCG together with the splitter and selector functions
in the two WDM-TE-Nodes forming the OMS protection group into a
single TE-link. When this modeling approach is used the
"te-link-attributes" already defined in and
are used as follows:
"underlay": this container must not be present
"protection-type" (identityref) set to
'link-protection-1-plus-1' as defined in
The optical impairments exposed for this 1+1 protected TE-link are
typically based on the optical impairments of the worse of the two
underlying physical OMS links including the optical impairments
imposed by the splitter (outgoing direction) and selector (incoming
direction).
and
illustrate this modeling
approach where the splitter/selector in the adjacent WDM-TE-Nodes,
WDM-TE-Node-1 and WDM-TE-Node-2, as well as the two physical OMS MCG
links are abstracted into a single 1+1 protected TE-link. This is
illustrated by the the dotted line surrounding these four physical
entities in and
, respectively. Based on
this modeling approach, the ROADM port connected to the
splitter/selector function is modeled as LTP for the 1+1 protected
TE-link (LTP2 in WDM-TE-Node-1 and LTP3 in WDM-TE-Node-2).
In this example, the connectivity matrix describes the optical
impairments between LPT1 and LTP2 in WDM-TE-Node-1. Likewise, the
connectivity matrix describes the optical impairments between LPT3
and LTP4 in WDM-TE-Node-2.
o---------->o--> . | | |
LTP1| | LTP2| . / | | \ . |LTP3 | |LTP4
--->o-->o.......o-->o--o | | o--o-->o.......o-->o--->
| | | . \ | | / . | | |
| | | . -->o---------->o--> . | | |
| +-------+ +...................+.......+ +-------+ |
| | | |
+-----------------------+ +-----------------------+
--+ +--
ROADM port | | ROADM port
LTP2 o---------------------------------->o LTP3
| |
--+ +---
Splitter/Selector abstracted into
1+1 protected OMS MCG (TE-link)
connectivity matrix provides optical impairments in
forward direction between LTPs in the two WDM-TE-Nodes:
* LTP1 and LTP2 * LTP3 and LTP4
]]>
Alternatively, the optical impairments imposed by the splitter and
selector in each of the two adjacent WDM-TE-Nodes can also be
included in the optical impairments described by the connectivity
matrix of the two nodes instead of taking them into account as
optical impairments of the 1+1 protected TE-link.
This is illustrated in in
forward direction and in
reverse direction below.
In this case, the two physical ports on both ends of the 1+1
protected TE-link are abstracted into a single LTP, LTP2 and LTP3,
in forward direction and LTP3' and LTP2' in reverse direction.
o---------->o--> | | | |
LTP1| | | | / |LTP2 LTP3| \ | | | |LTP4
--->o-->o.......o-->o--o | | o--o-->o.......o-->o--->
| | | | \ |LTP2 LTP3| / | | | |
| | | | -->o---------->o--> | | | |
| +-------+ +-------+...........+-------+ +-------+ |
| | | |
+-----------------------+ +-----------------------+
--+ +--
| |
LTP2 o---------->o LTP3
| |
--+ +--
1+1 protected
OMS MCG (TE-link)
connectivity matrix provides optical impairments in
forward direction between LTPs in the two WDM-TE-Nodes:
* LTP1 and LTP2 * LTP3 and LTP4
]]>
[Editor's note: tree view below always has to be updated before
submitting a new revision!]
../../../mode-id
| | +--ro supported-organizational-modes*
| | -> ../../../mode-id
| +--ro configured-mode? union
| +--ro line-coding-bitrate? identityref
| +--ro tx-channel-power?
| | power-in-dbm-or-null
| +--ro rx-channel-power?
| | power-in-dbm-or-null
| +--ro rx-total-power?
| | power-in-dbm-or-null
| +--ro outgoing-otsi
| | +--ro otsi-group-ref? leafref
| | +--ro otsi-ref? leafref
| +--ro incoming-otsi
| | +--ro otsi-group-ref? leafref
| | +--ro otsi-ref? leafref
| +--ro configured-termination-type? enumeration
+--rw regen-groups!
+--ro regen-group* [group-id]
+--ro group-id uint32
+--ro regen-metric? uint32
+--ro transponder-ref*
-> ../../../transponders/transponder/transponder-id
augment /nw:networks/nw:network/nt:link/tet:te
/tet:te-link-attributes:
+--ro OMS-attributes
+--ro generalized-snr? l0-types:snr
+--ro equalization-mode? identityref
+--ro (power-param)?
| +--:(channel-power)
| | +--ro nominal-carrier-power?
| | l0-types:power-in-dbm-or-null
| +--:(power-spectral-density)
| +--ro nominal-power-spectral-density?
| l0-types:decimal-16-digits-or-null
+--ro media-channel-groups!
| +--ro media-channel-group* []
| +--ro media-channels* []
| +--ro flexi-n? l0-types:flexi-n
| +--ro flexi-m? l0-types:flexi-m
| +--ro otsi-group-ref? leafref
| +--ro otsi-ref* []
| | +--ro otsi-carrier-ref? leafref
| | +--ro e2e-mc-path-ref* leafref
| +--ro delta-power? l0-types:power-in-dbm-or-null
+--ro OMS-elements!
+--ro OMS-element* [elt-index]
+--ro elt-index uint16
+--ro oms-element-uid? union
+--ro reverse-element-ref
| +--ro link-ref?
| | -> ../../../../../../../../nt:link/link-id
| +--ro oms-element-ref* leafref
+--ro (element)
+--:(amplifier)
| +--ro geolocation
| | +--ro altitude? int64
| | +--ro latitude? geographic-coordinate-degree
| | +--ro longitude? geographic-coordinate-degree
| +--ro amplifier
| +--ro type-variety string
| +--ro operational
| +--ro amplifier-element* []
| +--ro name?
| | string
| +--ro frequency-range
| | +--ro lower-frequency frequency-thz
| | +--ro upper-frequency frequency-thz
| +--ro actual-gain
| | l0-types:gain-in-db-or-null
| +--ro tilt-target
| | l0-types:decimal-2-digits-or-null
| +--ro out-voa
| | l0-types:loss-in-db-or-null
| +--ro in-voa
| | l0-types:loss-in-db-or-null
| +--ro total-output-power
| | l0-types:power-in-dbm-or-null
| +--ro (power-param)?
| | +--:(channel-power)
| | | +--ro nominal-carrier-power?
| | | l0-types:power-in-dbm-or-null
| | +--:(power-spectral-density)
| | +--ro nominal-power-spectral-density?
| | l0-types:decimal-16-digits-or-null
| +--ro raman-direction?
| | enumeration
| +--ro raman-pump* []
| +--ro frequency?
| | l0-types:frequency-thz
| +--ro power?
| l0-types:decimal-2-digits-or-null
+--:(fiber)
| +--ro fiber
| +--ro type-variety string
| +--ro length
| | l0-types:decimal-2-digits-or-null
| +--ro loss-coef
| | l0-types:decimal-2-digits-or-null
| +--ro total-loss
| | l0-types:loss-in-db-or-null
| +--ro pmd?
| | l0-types:decimal-2-digits-or-null
| +--ro conn-in?
| | l0-types:loss-in-db-or-null
| +--ro conn-out?
| l0-types:loss-in-db-or-null
+--:(concentratedloss)
+--ro concentratedloss
+--ro loss l0-types:loss-in-db-or-null
augment /nw:networks/nw:network/nw:node/tet:te
/tet:tunnel-termination-point:
+--ro ttp-transceiver* [transponder-ref transceiver-ref]
+--ro transponder-ref
| -> ../../../../transponders/transponder/transponder-id
+--ro transceiver-ref leafref
augment /nw:networks/nw:network/nw:node/tet:te
/tet:tunnel-termination-point:
+--ro sliceable-transponder-list* [carrier-id]
+--ro carrier-id uint32
augment /nw:networks/nw:network/nw:node/nt:termination-point:
+--rw protection-type? identityref
augment /nw:networks/nw:network/nw:node/tet:te
/tet:te-node-attributes:
+--ro roadm-path-impairments* [roadm-path-impairments-id]
+--ro roadm-path-impairments-id uint32
+--ro (impairment-type)?
+--:(roadm-express-path)
| +--ro roadm-express-path* []
| +--ro frequency-range
| | +--ro lower-frequency frequency-thz
| | +--ro upper-frequency frequency-thz
| +--ro roadm-pmd? union
| +--ro roadm-cd?
| | l0-types:decimal-5-digits-or-null
| +--ro roadm-pdl?
| | l0-types:loss-in-db-or-null
| +--ro roadm-inband-crosstalk?
| | l0-types:decimal-2-digits-or-null
| +--ro roadm-maxloss?
| l0-types:loss-in-db-or-null
+--:(roadm-add-path)
| +--ro roadm-add-path* []
| +--ro frequency-range
| | +--ro lower-frequency frequency-thz
| | +--ro upper-frequency frequency-thz
| +--ro roadm-pmd? union
| +--ro roadm-cd?
| | l0-types:decimal-5-digits-or-null
| +--ro roadm-pdl?
| | l0-types:loss-in-db-or-null
| +--ro roadm-inband-crosstalk?
| | l0-types:decimal-2-digits-or-null
| +--ro roadm-maxloss?
| | l0-types:loss-in-db-or-null
| +--ro roadm-pmax?
| | l0-types:power-in-dbm-or-null
| +--ro roadm-osnr? l0-types:snr-or-null
| +--ro roadm-noise-figure?
| l0-types:decimal-5-digits-or-null
+--:(roadm-drop-path)
+--ro roadm-drop-path* []
+--ro frequency-range
| +--ro lower-frequency frequency-thz
| +--ro upper-frequency frequency-thz
+--ro roadm-pmd? union
+--ro roadm-cd?
| l0-types:decimal-5-digits-or-null
+--ro roadm-pdl?
| l0-types:loss-in-db-or-null
+--ro roadm-inband-crosstalk?
| l0-types:decimal-2-digits-or-null
+--ro roadm-maxloss?
| l0-types:loss-in-db-or-null
+--ro roadm-minloss?
| l0-types:loss-in-db-or-null
+--ro roadm-typloss?
| l0-types:loss-in-db-or-null
+--ro roadm-pmin?
| l0-types:power-in-dbm-or-null
+--ro roadm-pmax?
| l0-types:power-in-dbm-or-null
+--ro roadm-ptyp?
| l0-types:power-in-dbm-or-null
+--ro roadm-osnr? l0-types:snr-or-null
+--ro roadm-noise-figure?
l0-types:decimal-5-digits-or-null
augment /nw:networks/nw:network/nw:node/tet:te
/tet:information-source-entry/tet:connectivity-matrices:
+--ro roadm-path-impairments? leafref
augment /nw:networks/nw:network/nw:node/tet:te
/tet:information-source-entry/tet:connectivity-matrices
/tet:connectivity-matrix:
+--ro roadm-path-impairments? leafref
augment /nw:networks/nw:network/nw:node/tet:te
/tet:te-node-attributes/tet:connectivity-matrices:
+--ro roadm-path-impairments?
-> ../../roadm-path-impairments/roadm-path-impairments-id
augment /nw:networks/nw:network/nw:node/tet:te
/tet:te-node-attributes/tet:connectivity-matrices
/tet:connectivity-matrix:
+--ro roadm-path-impairments? leafref
augment /nw:networks/nw:network/nw:node/tet:te
/tet:te-node-attributes/tet:connectivity-matrices
/tet:connectivity-matrix/tet:from:
+--ro additional-ltp* [ltp-ref]
+--ro ltp-ref
| -> ../../../../../../../nt:termination-point/tp-id
+--ro roadm-path-impairments? leafref
augment /nw:networks/nw:network/nw:node/tet:te
/tet:te-node-attributes/tet:connectivity-matrices
/tet:connectivity-matrix/tet:to:
+--ro additional-ltp* [ltp-ref]
+--ro ltp-ref
| -> ../../../../../../../nt:termination-point/tp-id
+--ro roadm-path-impairments? leafref
augment /nw:networks/nw:network/nw:node/tet:te
/tet:tunnel-termination-point
/tet:local-link-connectivities:
+--ro add-path-impairments? leafref
+--ro drop-path-impairments? leafref
augment /nw:networks/nw:network/nw:node/tet:te
/tet:tunnel-termination-point
/tet:local-link-connectivities
/tet:local-link-connectivity:
+--ro add-path-impairments? leafref
+--ro drop-path-impairments? leafref
+--ro llc-transceiver* [ttp-transponder-ref ttp-transceiver-ref]
| +--ro ttp-transponder-ref
| | -> ../../../../ttp-transceiver/transponder-ref
| +--ro ttp-transceiver-ref
| | -> ../../../../ttp-transceiver/transceiver-ref
| +--ro is-allowed? boolean
| +--ro add-path-impairments? leafref
| +--ro drop-path-impairments? leafref
+--ro additional-ltp* [ltp-ref]
+--ro ltp-ref
| -> ../../../../../../nt:termination-point/tp-id
+--ro add-path-impairments? leafref
+--ro drop-path-impairments? leafref
]]>
[Editor's note: YANG code below always has to be updated before
submitting a new revision!]
WG List:
Editor: Young Lee
Editor: Haomian Zheng
Editor: Nicola Sambo
Editor: Victor Lopez
Editor: Gabriele Galimberti
Editor: Giovanni Martinelli
Editor: Jean-Luc Auge
Editor: Le Rouzic Esther
Editor: Julien Meuric
Editor: Italo Busi
Editor: Dieter Beller
Editor: Sergio Belotti
Editor: Griseri Enrico
Editor: Gert Grammel ";
description
"This module contains a collection of YANG definitions for
impairment-aware optical networks.
Copyright (c) 2023 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 Revised 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 XXXX; see
the RFC itself for full legal notices.";
// RFC Ed.: replace XXXX with actual RFC number and remove
// this note
// replace the revision date with the module publication date
// the format is (year-month-day)
revision 2023-07-07 {
description
"Initial Version";
reference
"RFC XXXX: A Yang Data Model for Impairment-aware
Optical Networks";
}
/*
* Identities
*/
identity otsi-protection {
base te-types:lsp-protection-type;
description
"Individual OTSi(G) protection LSP protection type.";
reference
"ITU-T G.873.1 v5.2 (02/2022): Optical transport network:
Linear protection";
}
// groupings
grouping sliceable-transponder-attributes {
description
"Configuration of a sliceable transponder.";
list sliceable-transponder-list {
key "carrier-id";
config false;
description "List of carriers";
leaf carrier-id {
type uint32;
description "Identifier of the carrier";
}
}
}
/*
* Groupings
*/
grouping amplifier-params {
description "describes parameters for an amplifier";
container amplifier {
description
"amplifier type, operatonal parameters are described.";
leaf type-variety {
type string;
mandatory true ;
description
"String identifier of amplifier type referencing
a specification in a separate equipment catalog";
}
container operational {
description "amplifier operational parameters";
list amplifier-element {
description
"The list of parallel amplifier elements within an
amplifier used to amplify different frequency ranges.";
leaf name {
type string;
description
"The name of the amplifier element as specified in
the vendor's specification associated with the
type-variety.";
}
container frequency-range {
description
"The frequency range amplified by the amplifier
element.";
uses l0-types:frequency-range;
}
leaf actual-gain {
type l0-types:gain-in-db-or-null;
mandatory true ;
description
"The value of the gain provided by the amplification
stage of the optical amplifier.";
}
leaf tilt-target {
type l0-types:decimal-2-digits-or-null;
units "dB";
mandatory true ;
description
"The tilt target defined between lower and upper
frequency of the amplifier frequency range.";
}
leaf out-voa {
type l0-types:loss-in-db-or-null;
mandatory true;
description
"Loss introduced by the Variable Optical Attenuator
(VOA) at the output of the amplification stage of
the amplifier, if present.";
}
leaf in-voa {
type l0-types:loss-in-db-or-null;
mandatory true;
description
"Loss introduced by the Variable Optical Attenuator
(VOA) at the input of the amplification stage of the
amplifier, if present";
}
leaf total-output-power {
type l0-types:power-in-dbm-or-null;
mandatory true;
description
"It represent total output power measured in the range
specified by the frequency-range.
Optical power is especially needed to re-compute/check
consistency of span (fiber+ concentrated loss) loss
value, with respect to loss/gain information on
elements.";
}
uses power-param;
leaf raman-direction {
type enumeration {
enum co-propagating {
description
"Co-propagating indicates that optical pump light
is injected in the same direction to the optical
signal that is amplified (forward pump).";
}
enum counter-propagating {
description
"Counter-propagating indicates that optical pump
light is injected in opposite direction to the
optical signal that is amplified (backward pump).";
}
}
description
"The direction of injection of the raman pump.";
}
list raman-pump {
description
"The list of pumps for the Raman amplifier.";
leaf frequency {
type l0-types:frequency-thz;
description
"The raman pump central frequency.";
}
leaf power {
type l0-types:decimal-2-digits-or-null;
units "Watts";
description
"The total pump power considering a depolarized pump
at the raman pump central frequency.";
}
}
} // list amplifier-element
} // container operational
} // container amplifier
} // grouping amplifier-params
grouping fiber-params {
description
"String identifier of fiber type referencing a
specification in a separate equipment catalog";
container fiber {
description "fiber characteristics";
leaf type-variety {
type string ;
mandatory true ;
description "fiber type";
}
leaf length {
type l0-types:decimal-2-digits-or-null;
units km;
mandatory true ;
description "length of fiber";
}
leaf loss-coef {
type l0-types:decimal-2-digits-or-null;
units dB/km;
mandatory true ;
description "loss coefficient of the fiber";
}
leaf total-loss {
type l0-types:loss-in-db-or-null;
mandatory true ;
description
"includes all losses: fiber loss and conn-in and
conn-out losses";
}
leaf pmd {
type l0-types:decimal-2-digits-or-null;
units "ps";
description "pmd of the fiber";
}
leaf conn-in{
type l0-types:loss-in-db-or-null;
description "connector-in";
}
leaf conn-out{
type l0-types:loss-in-db-or-null;
description "connector-out";
}
}
}
grouping roadm-common-path {
description
"The optical impairments of a ROADM which are common to all
its paths (express path, add path or drop path).";
leaf roadm-pmd {
type union {
type decimal64 {
fraction-digits 8;
range "0..max";
}
type empty;
}
units "ps";
description
"Polarization Mode Dispersion (PMD), when known, or an
empty value when unknown.";
}
leaf roadm-cd {
type l0-types:decimal-5-digits-or-null;
units "ps/nm";
description "Chromatic Dispersion (CD)";
}
leaf roadm-pdl {
type l0-types:loss-in-db-or-null;
description "Polarization Dependent Loss (PDL)";
}
leaf roadm-inband-crosstalk {
type l0-types:decimal-2-digits-or-null;
units "dB";
description
"In-band crosstalk, or coherent crosstalk, can occur in
components that can have multiple same wavelength inputs
with the inputs either routed to different output ports,
or all but one blocked";
}
leaf roadm-maxloss {
type l0-types:loss-in-db-or-null;
description
"This is the maximum expected path loss from the
ROADM ingress to the ROADM egress
assuming no additional path loss is added";
}
} // grouping roadm-common-path
grouping roadm-express-path {
description
"The optical impairments of a ROADM express path.";
uses roadm-common-path;
} // grouping roadm-express-path
grouping roadm-add-path {
description
"The optical impairments of a ROADM add path.";
uses roadm-common-path {
refine roadm-inband-crosstalk {
description
"In-band crosstalk, or coherent crosstalk,
can occur in components that can have multiple same
wavelength inputs,with the inputs either
routed to different output ports,
or all but one blocked.
In the case of add path it is the total
of the add block + egress WSS crosstalk contributions.";
}
refine roadm-maxloss {
description
"This is the maximum expected add path loss from
the add/drop port input to the ROADM egress,
assuming no additional add path loss is added.
This is used to establish the minimum required
transponder output power required
to hit the ROADM egress target power
levels and preventing
to hit the WSS attenuation limits.
If the add path contains an internal amplifier
this loss value should be based
on worst case expected amplifier gain due to
ripple or gain uncertainty";
}
}
leaf roadm-pmax {
type l0-types:power-in-dbm-or-null;
description
"This is the maximum (per carrier) power level
permitted at the add block input ports,
that can be handled by the ROADM node.
This may reflect either add amplifier power
contraints or WSS adjustment limits.
Higher power transponders would need to have
their launch power reduced
to this value or lower";
}
leaf roadm-osnr {
type l0-types:snr-or-null;
description
"Optical Signal-to-Noise Ratio (OSNR).
If the add path contains the ability to adjust the
carrier power levels into an add path amplifier
(if present) to a target value,
this reflects the OSNR contribution of the
add amplifier assuming this target value is obtained.
The worst case OSNR based on the input power and
NF calculation method, and this value, should be used
(if both are defined).";
}
leaf roadm-noise-figure {
type l0-types:decimal-5-digits-or-null;
units "dB";
description
"Noise Figure. If the add path contains an amplifier,
this is the noise figure of that amplifier inferred
to the add port.
This permits add path OSNR calculation based
on the input power levels to the add block
without knowing the ROADM path losses to
the add amplifier.";
}
} // grouping roadm-add-path
grouping roadm-drop-path {
description
"The optical impairments of a ROADM drop path";
uses roadm-common-path {
refine roadm-inband-crosstalk {
description
"In-band crosstalk, or coherent crosstalk, can occur in
components that can have multiple same wavelength
inputs,with the inputs either routed to different
output ports,or all but one blocked.
In the case of drop path it is the total
of the ingress
to drop e.g. WSS and drop block crosstalk
contributions.";
}
refine roadm-maxloss {
description
"The net loss from the ROADM input,to the output
of the drop block.
If ROADM ingress to drop path includes an amplifier,
the amplifier gain reduces the net loss.
This is before any additional drop path attenuation
that may be required
due to drop amplifier power contraints.
The max value correspond to worst case expected loss,
including amplifier gain ripple or uncertainty.
It is the maximum output power of the drop
amplifier.";
}
}
leaf roadm-minloss {
type l0-types:loss-in-db-or-null;
description
"The net loss from the ROADM input, to the
output of the drop block.
If this ROADM ingress to drop path includes
an amplifier,the amplifier gain reduces the net loss.
This is before any additional drop path attenuation
that may be required due to drop amplifier power
contraints.
The min value correspond to best case expected loss,
including amplifier gain ripple or uncertainty.";
}
leaf roadm-typloss {
type l0-types:loss-in-db-or-null;
description
"The net loss from the ROADM input,
to the output of the drop block.
If this ROADM ingress to drop path
includes an amplifier,
the amplifier gain reduces the net loss.
This is before any additional drop path
attenuation
that may be required due to drop amplifier
power contraints.
The typ value correspond to typical case
expected loss.";
}
leaf roadm-pmin {
type l0-types:power-in-dbm-or-null;
description
"If the drop path has additional loss
that is added, for example,
to hit target power levels into a
drop path amplifier, or simply, to reduce the
power of a strong carrier
(due to ripple,for example),
then the use of the ROADM input power levels and
the above drop losses is not appropriate.
This parameter corresponds to the min per
carrier power levels
expected at the output of the drop block.
A detail example of the comparison using
these parameters is
detailed in section xxx of the document yyy.";
}
leaf roadm-pmax {
type l0-types:power-in-dbm-or-null;
description
"If the drop path has additional loss that is added,
for example, to hit target power levels into a
drop path amplifier,or simply,to reduce the power
of a strong carrier(due to ripple,for example),
then the use of the ROADM input power levels and the
above drop losses is not appropriate.
This parameter corresponds to the best case per
carrier power levels expected at the output of the
drop block.
A detail example of the comparison using
these parameters
is detailed in section xxx of the document yyy";
}
leaf roadm-ptyp {
type l0-types:power-in-dbm-or-null;
description
"If the drop path has additional loss that is added,
for example, to hit target power levels into a
drop path amplifier,or simply,to reduce the
power of a strong carrier(due to ripple,for example),
then the use of the ROADM input power levels and
the above drop losses is not appropriate.
This parameter corresponds to the typical case
per carrier power levels expected
at the output of the drop block.";
}
leaf roadm-osnr {
type l0-types:snr-or-null;
description
"Optical Signal-to-Noise Ratio (OSNR).
Expected OSNR contribution of the drop path
amplifier(if present)
for the case of additional drop path loss
(before this amplifier)
in order to hit a target power level (per carrier).
If both, the OSNR based on the ROADM
input power level
(Pcarrier =
Pref+10Log(carrier-baudrate/ref-baud) + delta-power)
and the input inferred NF(NF.drop),
and this OSNR value, are defined,
the minimum value between these two should be used";
}
leaf roadm-noise-figure {
type l0-types:decimal-5-digits-or-null;
units "dB";
description
"Drop path Noise Figure.
If the drop path contains an amplifier,
this is the noise figure
of that amplifier, inferred to the
ROADM ingress port.
This permits to determine
amplifier OSNR contribution
without having to specify the
ROADM node's losses to that amplifier.
This applies for the case of no
additional drop path loss,
before the amplifier, in order to reduce the power
of the carriers to a target value";
}
} // grouping roadm-drop-path
grouping concentratedloss-params {
description "concentrated loss";
container concentratedloss{
description "concentrated loss";
leaf loss {
type l0-types:loss-in-db-or-null;
mandatory true;
description
"Loss introduced by the concentrated loss element.";
}
}
}
grouping power-param{
description
"optical power or PSD after the ROADM or after the out-voa";
choice power-param {
description
"select the mode: channel power or power spectral density";
case channel-power {
when "/nw:networks/nw:network/nt:link/tet:te
/tet:te-link-attributes/OMS-attributes
/equalization-mode='carrier-power'";
leaf nominal-carrier-power{
type l0-types:power-in-dbm-or-null;
description
" Reference channel power. Same grouping is used for the
OMS power after the ROADM (input of the OMS) or after the
out-voa of each amplifier. ";
}
}
case power-spectral-density{
when "/nw:networks/nw:network/nt:link/tet:te
/tet:te-link-attributes/OMS-attributes
/equalization-mode='power-spectral-density'";
leaf nominal-power-spectral-density{
type l0-types:decimal-16-digits-or-null;
units W/Hz ;
description
" Reference power spectral density after
the ROADM or after the out-voa.
Typical value : 3.9 E-14, resolution 0.1nW/MHz";
}
}
}
}
grouping oms-general-optical-params {
description "OMS link optical parameters";
leaf generalized-snr {
type l0-types:snr;
description "generalized snr";
}
leaf equalization-mode{
type identityref {
base l0-types:type-power-mode;
}
description
"The equalization mode.
When not present it indicates that the information about
the equalization mode is not reported.
Reporting this value is needed to support optical
impairments applications.";
}
uses power-param;
}
grouping otsi-group {
description "OTSiG definition , representing client
digital information stream supported by one or more OTSi";
list otsi {
key "otsi-carrier-id";
config false;
description
"list of OTSi contained in one OTSiG.
The list could also be of only one element";
leaf otsi-carrier-id {
type uint16;
description "OTSi carrier-id";
}
leaf otsi-carrier-frequency {
type union {
type l0-types:frequency-thz;
type empty;
}
description
"OTSi carrier frequency, equivalent to the
actual configured transmitter frequency, when known, or
an empty value when unknown.";
}
leaf-list e2e-mc-path-id {
type uint16;
description
"The list of the possible end-to-end Media Channel
(e2e-MC) paths associated with the OTSi which have
different optical impairments.
This list is meaningful in case the OTSi can be associated
with multiple end-to-end Media Channel (e2e-MC) paths
(e.g., when OPS protection is configured).
The list can be empty when the OTSi has only one
e2e-MC path.";
}
} // OTSi list
} // OTSiG grouping
grouping media-channel-groups {
description "media channel groups";
container media-channel-groups {
presence
"When present, it indicates that the list media channel
groups is reported.";
description
"The top level container for the list of media channel
groups.";
list media-channel-group {
description
"The list of media channel groups";
list media-channels {
// key "flexi-n";
description
"list of media channels represented as (n,m)";
// this grouping add both n.m values
uses l0-types:flexi-grid-frequency-slot;
leaf otsi-group-ref {
type leafref {
path "/nw:networks/nw:network/otsis/" +
"otsi-group/otsi-group-id";
}
description
"Reference to the OTSiG to which the OTSis carried by
this media channel belong to.";
}
list otsi-ref {
description
"The list of references to the OTSis and their
end-to-end Media Channel (e2e-MC) paths within the
OTSiG carried by this media channel.";
leaf otsi-carrier-ref {
type leafref {
path "/nw:networks/nw:network/otsis/" +
"otsi-group[otsi-group-id=current()" +
"/../../otsi-group-ref]/" +
"otsi/otsi-carrier-id" ;
}
description
"Reference to the OTSi within the OTSiG carried
by this media channel.";
}
leaf-list e2e-mc-path-ref {
type leafref {
path "/nw:networks/nw:network/otsis/" +
"otsi-group[otsi-group-id=current()" +
"/../../otsi-group-ref]/" +
"otsi[otsi-carrier-id=current()" +
"/../otsi-carrier-ref]/e2e-mc-path-id";
}
description
"References to the end-to-end Media Channel (e2e-MC)
paths of this OTSi which are routed through this
media channel.";
}
}
leaf delta-power {
type l0-types:power-in-dbm-or-null;
description
" Deviation from the reference carrier power defined
for the OMS.";
}
} // media channels list
} // media-channel-groups list
}
} // media media-channel-groups grouping
grouping oms-element {
description "OMS description";
container OMS-elements {
presence
"When present, it indicates that the list of OMS elements
is reported.";
description
"The top level container for the list of OMS elements.";
list OMS-element {
key "elt-index";
description
"defines the spans and the amplifier blocks of
the amplified lines";
leaf elt-index {
type uint16;
description
"ordered list of Index of OMS element
(whether it's a Fiber, an EDFA or a
Concentratedloss)";
}
leaf oms-element-uid {
type union {
type string;
type empty;
}
description
"Unique id of the element, if it exists and it is known.
When unknown, an empty value is reported.
When it does not exist, the attribute is not present.";
}
container reverse-element-ref {
description
"It contains references to the elements which are
associated with this element in the reverse
direction.";
leaf link-ref {
type leafref {
path "../../../../../../../../nt:link/nt:link-id";
}
description
"The reference to the OMS link which the OMS elements
belongs to.";
}
leaf-list oms-element-ref {
type leafref {
path "../../../../../../../../nt:link[nt:link-id="
+ "current()/../link-ref]/tet:te/"
+ "tet:te-link-attributes/OMS-attributes/"
+ "OMS-elements/OMS-element/elt-index";
}
description
"The references to the OMS elements.";
}
}
choice element {
mandatory true;
description "OMS element type";
case amplifier {
uses tet:geolocation-container;
uses amplifier-params;
}
case fiber {
uses fiber-params;
}
case concentratedloss {
uses concentratedloss-params ;
}
}
}
}
}
grouping otsi-ref {
description
"References to an OTSi.
This grouping is intended to be reused within the
transceiver's list only.";
leaf otsi-group-ref {
type leafref {
path "../../../../../../otsis/otsi-group/" +
"otsi-group-id";
}
description
"The OTSi generated by the transceiver's transmitter.";
}
leaf otsi-ref {
type leafref {
path "../../../../../../otsis/otsi-group" +
"[otsi-group-id=current()/../otsi-group-ref]/otsi/" +
"otsi-carrier-id";
}
description
"The OTSi generated by the transceiver's transmitter.";
}
}
/*
* Data nodes
*/
augment "/nw:networks/nw:network/nw:network-types"
+ "/tet:te-topology" {
description "optical-impairment topology augmented";
container optical-impairment-topology {
presence
"Indicates an impairment-aware topology of optical networks";
description
"Container to identify impairment-aware topology type";
reference
"RFC8345: A YANG Data Model for Network Topologies.";
}
}
augment "/nw:networks/nw:network" {
when "nw:network-types/tet:te-topology" +
"/optical-imp-topo:optical-impairment-topology" {
description
"This augment is only valid for Optical Impairment
topology.";
}
description
"Network augmentation for optical impairments data.";
container otsis {
presence
"When present, it indicates that OTSi information is
reported.";
description
"The information about the OTSis configured on the WDM-TE
link.";
list otsi-group {
key "otsi-group-id";
config false;
description
"the list of possible OTSiG representing client digital
stream";
leaf otsi-group-id {
type string;
description
"A network-wide unique identifier of otsi-group element.
It could be structured e.g., as an URI or as an UUID.";
}
uses otsi-group;
} // list of OTSiG
}
}
augment "/nw:networks/nw:network/nw:node" {
when "../nw:network-types/tet:te-topology" +
"/optical-imp-topo:optical-impairment-topology" {
description
"This augment is only valid for Optical Impairment.";
}
description
"Node augmentation for optical impairments data.";
container transponders {
presence
"If present, it indicates that the list of transponders is
reported.";
description
"The top level container for the list of transponders.";
list transponder {
key "transponder-id";
config false;
description "The list of transponders.";
leaf transponder-id {
type uint32;
description "transponder identifier";
}
leaf termination-type-capabilities {
type enumeration {
enum tunnel-only {
description
"The transponder can only be used in an Optical
Tunnel termination configuration.";
}
enum 3r-only {
description
"The transponder can only be used in a 3R
configuration.";
}
enum 3r-or-tunnel {
description
"The transponder can be configure to be used either
in an Optical Tunnel termination configuration or in
a 3R configuration.";
}
}
description
"Describes whether the transponder can be used in an
Optical Tunnel termination configuration or in a 3R
configuration (or both).";
}
leaf supported-3r-mode {
when '(../termination-type-capabilities = "3r-only") or
(../termination-type-capabilities = "3r-or-tunnel")'
{
description
"Applies only when the transponder supports 3R
configuration.";
}
type enumeration {
enum unidir {
description
"Unidirectional 3R configuration.";
}
enum bidir {
description
"Bidirectional 3R configuration.";
}
}
description
"Describes the supported 3R configuration type.";
}
list transceiver {
key "transceiver-id";
config false;
min-elements 1;
description "list of transceiver related to a transponder";
leaf transceiver-id {
type uint32;
description "transceiver identifier";
}
uses l0-types:transceiver-capabilities;
leaf configured-mode {
type union {
type empty;
type leafref {
path "../supported-modes/supported-mode/mode-id";
}
}
description
"Reference to the configured mode for transceiver
compatibility approach.
The empty value is used to report that no mode has
been configured and there is no default mode.
When not present, the configured-mode is not reported
by the server.";
}
uses l0-types:common-transceiver-configured-param;
container outgoing-otsi {
when "../../../../../otsis" {
description
"It applies only when the OTSi information is
reported.";
}
description
"The OTSi generated by the transceiver's transmitter.";
uses otsi-ref;
}
container incoming-otsi {
when "../../../../../otsis" {
description
"It applies only when the OTSi information is
reported.";
}
description
"The OTSi received by the transceiver's received.";
uses otsi-ref;
}
leaf configured-termination-type {
type enumeration {
enum unused-transceiver {
description
"The transcevier is not used.";
}
enum tunnel-termination {
description
"The transceiver is currently used in an Optical
Tunnel termination configuration.";
}
enum 3r-regeneration {
description
"The transceiver is currently used in a 3R
configuration.";
}
}
description
"Describes whether the current configuration of the
transceiver is used in an Optical Tunnel termination
configuration or in a 3R configuration.
If empty, it means that the information about the
configured-termination-type is not reported.";
}
} // end of list of transceiver
} // end list of transponder
}
container regen-groups {
presence
"When present, it indicates that the list of 3R groups
is reported.";
description
"The top level container for the list of 3R groups.";
list regen-group {
key "group-id";
config false;
description
"The list of 3R groups.
Any 3R group represent a group of transponder in which an
a an electrical connectivity is either in place or could
be dynamically provided, to associated transponders used
for 3R regeneration.";
leaf group-id {
type uint32;
description
"Group identifier used an index to access elements in the
list of 3R groups.";
}
leaf regen-metric {
type uint32;
description
"The cost permits choice among different group of
transponders during path computation";
}
leaf-list transponder-ref {
type leafref {
path "../../../transponders/transponder/transponder-id";
}
description
"The list of transponder belonging to this 3R group.";
}
} // end 3R-group
}
}
augment "/nw:networks/nw:network/nt:link/tet:te"
+ "/tet:te-link-attributes" {
when "../../../nw:network-types/tet:te-topology/"
+ "optical-imp-topo:optical-impairment-topology" {
description
"This augment is only valid for Optical Impairment
topology.";
}
description "Optical Link augmentation for impairment data.";
container OMS-attributes {
config false;
description "OMS attributes";
uses oms-general-optical-params;
uses media-channel-groups;
uses oms-element;
}
}
augment "/nw:networks/nw:network/nw:node/tet:te"
+ "/tet:tunnel-termination-point" {
when "../../../nw:network-types/tet:te-topology/"
+ "optical-imp-topo:optical-impairment-topology" {
description
"This augment is only valid for Impairment with
non-sliceable transponder model";
}
description
"Tunnel termination point augmentation for non-sliceable
transponder model.";
list ttp-transceiver {
when "../../../transponders" {
description
"It applies only when the list of transponders is
reported.";
}
key "transponder-ref transceiver-ref";
config false;
min-elements 1;
description
"The list of the transceivers used by the TTP.";
leaf transponder-ref {
type leafref {
path "../../../../transponders/transponder/transponder-id";
}
description
"The reference to the transponder hosting the transceiver
of the TTP.";
}
leaf transceiver-ref {
type leafref {
path "../../../../transponders/transponder" +
"[transponder-id=current()/../transponder-ref]/" +
"transceiver/transceiver-id";
}
description
"The reference to the transceiver of the TTP.";
}
} // list of transceivers
} // end of augment
augment "/nw:networks/nw:network/nw:node/tet:te"
+ "/tet:tunnel-termination-point" {
when "../../../nw:network-types/tet:te-topology/"
+ "optical-imp-topo:optical-impairment-topology" {
description
"This augment is only valid for optical impairment
with sliceable transponder model";
}
description
"Tunnel termination point augmentation for sliceable
transponder model.";
uses sliceable-transponder-attributes;
}
// Should this leaf be moved to te-topology?
augment "/nw:networks/nw:network/nw:node/nt:termination-point" {
when "../../nw:network-types/tet:te-topology/"
+ "optical-imp-topo:optical-impairment-topology" {
description
"This augment is only valid for Optical Impairment
topology";
}
description
"Augment LTP";
leaf protection-type {
type identityref {
base te-types:lsp-protection-type;
}
description
"The protection type that this LTP is capable of.
When not present it indicates that the information about
the protection type is not reported.";
}
}
augment "/nw:networks/nw:network/nw:node/tet:te"
+ "/tet:te-node-attributes" {
when "../../../nw:network-types/tet:te-topology"
+ "/optical-imp-topo:optical-impairment-topology" {
description
"This augment is only valid for Optical Impairment
topology";
}
description
"node attributes augmentantion for optical-impairment ROADM
node";
list roadm-path-impairments {
key "roadm-path-impairments-id";
config false;
description
"The set of optical impairments related to a ROADM path.";
leaf roadm-path-impairments-id {
type uint32;
description "index of the ROADM path-impairment list";
}
choice impairment-type {
description "type path impairment";
case roadm-express-path {
list roadm-express-path {
description
"The list of optical impairments on a ROADM express
path for different frequency ranges.
Two elements in the list must not have the same range
or overlapping ranges.";
container frequency-range {
description
"The frequency range for which these optical
impairments apply.";
uses l0-types:frequency-range;
}
uses roadm-express-path;
}
}
case roadm-add-path {
list roadm-add-path {
description
"The list of optical impairments on a ROADM add
path for different frequency ranges.
Two elements in the list must not have the same range
or overlapping ranges.";
container frequency-range {
description
"The frequency range for which these optical
impairments apply.";
uses l0-types:frequency-range;
}
uses roadm-add-path;
}
}
case roadm-drop-path {
list roadm-drop-path {
description
"The list of optical impairments on a ROADM add
path for different frequency ranges.
Two elements in the list must not have the same range
or overlapping ranges.";
container frequency-range {
description
"The frequency range for which these optical
impairments apply.";
uses l0-types:frequency-range;
}
uses roadm-drop-path;
}
}
}
} // list path impairments
} // augmentation for optical-impairment ROADM
augment "/nw:networks/nw:network/nw:node/tet:te/"
+ "tet:information-source-entry/tet:connectivity-matrices"{
when "../../../../nw:network-types/tet:te-topology/"
+ "optical-imp-topo:optical-impairment-topology" {
description
"This augment is only valid for Optical Impairment
topology ";
}
description
"Augment default TE node connectivity matrix information
source.";
leaf roadm-path-impairments {
type leafref {
path "../../../tet:te-node-attributes/"
+ "roadm-path-impairments/roadm-path-impairments-id";
}
config false;
description
"Pointer to the list set of ROADM optical impairments";
}
} // augmentation connectivity-matrices information-source
augment "/nw:networks/nw:network/nw:node/tet:te/"
+ "tet:information-source-entry/tet:connectivity-matrices/"
+ "tet:connectivity-matrix" {
when "../../../../../nw:network-types/tet:te-topology/"
+ "optical-imp-topo:optical-impairment-topology" {
description
"This augment is only valid for Optical Impairment
topology ";
}
description
"Augment TE node connectivity matrix entry information
source.";
leaf roadm-path-impairments {
type leafref {
path "../../../../tet:te-node-attributes/"
+ "roadm-path-impairments/roadm-path-impairments-id";
}
config false;
description
"Pointer to the list set of ROADM optical impairments";
}
} // augmentation connectivity-matrix information-source
augment "/nw:networks/nw:network/nw:node/tet:te/"
+ "tet:te-node-attributes/tet:connectivity-matrices" {
when "../../../../nw:network-types/tet:te-topology/"
+ "optical-imp-topo:optical-impairment-topology" {
description
"This augment is only valid for Optical Impairment
topology ";
}
description
"Augment default TE node connectivity matrix.";
leaf roadm-path-impairments {
type leafref {
path "../../roadm-path-impairments/"
+ "roadm-path-impairments-id";
}
config false; /*the identifier in the list */
/*"roadm-path-impairments" of ROADM optical impairment*/
/*is read-only as the rest of attributes*/
description "pointer to the list set of ROADM optical
impairments";
}
} // augmentation connectivity-matrices
augment "/nw:networks/nw:network/nw:node/tet:te/"
+ "tet:te-node-attributes/"
+ "tet:connectivity-matrices/tet:connectivity-matrix" {
when "../../../../../nw:network-types/tet:te-topology/"
+ "optical-imp-topo:optical-impairment-topology" {
description
"This augment is only valid for
Optical Impairment topology ";
}
description
"Augment TE node connectivity matrix entry.";
leaf roadm-path-impairments {
type leafref {
path "../../../roadm-path-impairments/"
+ "roadm-path-impairments-id";
}
config false;
description "pointer to the list set of ROADM optical
impairments";
}
} // augmentation connectivity-matrix
augment "/nw:networks/nw:network/nw:node/tet:te/"
+ "tet:te-node-attributes/tet:connectivity-matrices/"
+ "tet:connectivity-matrix/tet:from" {
when "../../../../../../nw:network-types/tet:te-topology/"
+ "optical-imp-topo:optical-impairment-topology" {
description
"This augment is only valid for
Optical Impairment topology ";
}
description
"Augment the attributes for the 'from' LTP for the TE node
connectivity matrix entry.";
list additional-ltp {
when "derived-from-or-self(../../../../../../"
+ "nt:termination-point"
+ "[nt:tp-id=current()/../../tet:to/tet:tp-ref]/"
+ "optical-imp-topo:protection-type,"
+ "'optical-imp-topo:otsi-protection')" {
description
"This list applies only when the 'to' LTP for this
connectivity matrix entry supports individual OTSi(G)
protection.";
}
key "ltp-ref";
config false;
description
"The restricted list of the potential secondary LTPs that
can be selected when the 'from' LTP of this connectivity
matrix entry is selected as a working LTP.
If this list is empty, all the other LTPs that can reach
the 'to' LTP of this connectivity matrix entry can be
selected as secondary LTPs.";
leaf ltp-ref {
type leafref {
path "../../../../../../../nt:termination-point/nt:tp-id";
}
description
"The reference to the potential secondary LTP that can be
selected when the 'from' LTP of this connectivity matrix
entry is selected as a working LTP";
}
leaf roadm-path-impairments {
type leafref {
path "../../../../../../../tet:te/tet:te-node-attributes/"
+ "roadm-path-impairments/roadm-path-impairments-id";
}
description
"Pointer to ROADM optical impairments of the ROADM path
between this secondary 'from' LTP and the 'to' LTP of
this connectivity matrix entry.";
}
}
} // augmentation connectivity-matrix from
augment "/nw:networks/nw:network/nw:node/tet:te/"
+ "tet:te-node-attributes/tet:connectivity-matrices/"
+ "tet:connectivity-matrix/tet:to" {
when "../../../../../../nw:network-types/tet:te-topology/"
+ "optical-imp-topo:optical-impairment-topology" {
description
"This augment is only valid for
Optical Impairment topology ";
}
description
"Augment the attributes for the 'to' LTP for the TE node
connectivity matrix entry.";
list additional-ltp {
when "derived-from-or-self(../../../../../../"
+ "nt:termination-point"
+ "[nt:tp-id=current()/../../tet:from/tet:tp-ref]/"
+ "optical-imp-topo:protection-type,"
+ "'optical-imp-topo:otsi-protection')" {
description
"This list applies only when the 'from' LTP for this
connectivity matrix entry supports individual OTSi(G)
protection.";
}
key "ltp-ref";
config false;
description
"The restricted list of the potential secondary LTPs that
can be selected when the 'to' LTP of this connectivity
matrix entry is selected as a working LTP.
If this list is empty, all the other LTPs that can be
reached from the 'from' LTP of this connectivity matrix
entry can be selected as secondary LTPs.";
leaf ltp-ref {
type leafref {
path "../../../../../../../nt:termination-point/nt:tp-id";
}
description
"The reference to the potential secondary LTP that can be
selected when the 'to' LTP of this connectivity matrix
entry is selected as a working LTP";
}
leaf roadm-path-impairments {
type leafref {
path "../../../../../../../tet:te/tet:te-node-attributes/"
+ "roadm-path-impairments/roadm-path-impairments-id";
}
description
"Pointer to ROADM optical impairments of the ROADM path
between the 'from' LTP of this connectivity matrix entry
and this secondary LTP.";
}
}
} // augmentation connectivity-matrix to
augment "/nw:networks/nw:network/nw:node/tet:te/"
+ "tet:tunnel-termination-point/"
+ "tet:local-link-connectivities" {
when "../../../../nw:network-types/tet:te-topology/"
+ "optical-imp-topo:optical-impairment-topology" {
description
"This augment is only valid for Optical Impairment topology ";
}
description
"Augment default TTP LLC.";
leaf add-path-impairments {
type leafref {
path "../../../tet:te-node-attributes/"
+ "roadm-path-impairments/roadm-path-impairments-id" ;
}
config false;
description "pointer to the list set of ROADM optical
impairments";
}
leaf drop-path-impairments {
type leafref {
path "../../../tet:te-node-attributes/"
+ "roadm-path-impairments/roadm-path-impairments-id" ;
}
config false;
description "pointer to the list set of ROADM
optical impairments";
}
} // augmentation local-link-connectivities
augment "/nw:networks/nw:network/nw:node/tet:te/"
+ "tet:tunnel-termination-point/"
+ "tet:local-link-connectivities/"
+ "tet:local-link-connectivity" {
when "../../../../../nw:network-types/tet:te-topology/"
+ "optical-imp-topo:optical-impairment-topology" {
description
"This augment is only valid for
Optical Impairment topology ";
}
description
"Augment TTP LLC entry.";
leaf add-path-impairments {
type leafref {
path "../../../../tet:te-node-attributes/"
+ "roadm-path-impairments/roadm-path-impairments-id" ;
}
config false;
description "pointer to the list set of ROADM optical
impairments";
}
leaf drop-path-impairments {
type leafref {
path "../../../../tet:te-node-attributes/"
+ "roadm-path-impairments/roadm-path-impairments-id" ;
}
config false;
description "pointer to the list set of ROADM optical
impairments";
}
list llc-transceiver {
key "ttp-transponder-ref ttp-transceiver-ref";
config false;
description
"The list of transceivers having a LLC different from the
default LLC.";
leaf ttp-transponder-ref {
type leafref {
path "../../../../ttp-transceiver/transponder-ref";
}
description
"The reference to the transponder hosting the transceiver
of this LLCL entry.";
}
leaf ttp-transceiver-ref {
type leafref {
path "../../../../ttp-transceiver/transceiver-ref";
}
description
"The reference to the the transceiver of this LLCL entry.";
}
leaf is-allowed {
type boolean;
description
"'true' - connectivity from this transceiver is allowed;
'false' - connectivity from this transceiver is
disallowed.";
}
leaf add-path-impairments {
type leafref {
path "../../../../../tet:te-node-attributes/"
+ "roadm-path-impairments/roadm-path-impairments-id" ;
}
description "pointer to the list set of ROADM optical
impairments";
}
leaf drop-path-impairments {
type leafref {
path "../../../../../tet:te-node-attributes/"
+ "roadm-path-impairments/roadm-path-impairments-id" ;
}
description "pointer to the list set of ROADM
optical impairments";
}
}
list additional-ltp {
when "derived-from-or-self(../../../tet:protection-type,"
+ "'optical-imp-topo:otsi-protection')" {
description
"This list applies only to TTPs that support individual
OTSi(G) protection.";
}
key "ltp-ref";
config false;
description
"The restricted list of the potential secondary LTPs that
can be selected when the LTP associated with this LLCP
entry is selected as a working LTP.
If this list is empty, all the other LTPs that can be
reached by this TTP can be selected as secondary LTPs.";
leaf ltp-ref {
type leafref {
path "../../../../../../nt:termination-point/nt:tp-id";
}
description
"The reference to potential secondary LTP that can be
selected when the LTP associated with this LLCP entry is
selected as a working LTP";
}
leaf add-path-impairments {
type leafref {
path "../../../../../tet:te-node-attributes/"
+ "roadm-path-impairments/roadm-path-impairments-id" ;
}
description "pointer to the list set of ROADM optical
impairments";
}
leaf drop-path-impairments {
type leafref {
path "../../../../../tet:te-node-attributes/"
+ "roadm-path-impairments/roadm-path-impairments-id" ;
}
description "pointer to the list set of ROADM
optical impairments";
}
}
} // augmentation local-link-connectivity
}
]]>
The configuration, state, and action data defined in this document
are designed to be accessed via a management protocol with a secure
transport layer, such as NETCONF . The
NETCONF access control model provides the
means to restrict access for particular NETCONF users to a
preconfigured subset of all available NETCONF protocol operations
and content.
A number of configuration data nodes defined in this document are
read-only; however, these data nodes may be considered sensitive or
vulnerable in some network environments (TBD).
This document registers the following namespace URIs in the IETF XML
registry [RFC3688]:
This document registers the following YANG modules in the YANG
Module Names registry :
We thank Daniele Ceccarelli and Oscar G. De Dios for useful
discussions and motivation for this work.
Characteristics of multi-degree reconfigurable optical
add/drop multiplexersGeneric functional architecture of the optical media network
Generic functional architecture of the optical media network
Amendment 1Optical transport network: Linear protection Amendment 1
Interfaces for the Optical Transport Network (OTN)Spectral grids for WDM applications: DWDM frequency grid
Optical transport network physical layer interfacesArchitecture of optical transport networksAmplified multichannel dense wavelength division multiplexing
applications with single channel optical interfaces
Types and characteristics of optical transport network
equipmentOptical transport network: Linear protectionJSON Code Examples for Optical Protection Uses Cases
[Editor's note: JSON examples for optical protection use cases TBA!
JSON example for use case in
:
[Editor's note: The JSON example below needs to be updated and
aligned with and
.]
JSON example for use case in
with connectivity constraints:
[Editor's note: UC (ii) JSON example below needs to be updated and
aligned with and
.]
JSON example for use case in
[Editor's note: UC (iii) JSON example TBA!]
Optical Transponders in a Remote Shelf (Remote OTs) illustrates a configuration where
the optical transponders and the ROADM are located in a different
WDM-TE-nodes.
| | Tx o---------->o---->o | LTP 1 |
| | OT 1 +----| | | o-------o<--->
<-o---| | Rx o<----------o<----o | |
| | +----| | AD | | |
| | | | LTP | | |
| +------------+ | | | |
| | | | | Line |
| +------------+ | | | LTP 2 |
| | | | AD | o-------o<--->
| | +----| | LTPs| | |
--o-->| | Tx o---------->o---->o | |
| | +----| | | | |
<-o---| | Rx o<----------o<----o | |
| | OT 2 +----| | | | Line |
--o-->| | Tx o---------->o---->o | LTP 3 |
| | +----| | | o-------o<--->
<-o---| | Rx o<----------o<----o | |
| | +----| | | | |
| | | | | | |
| +------------+ | +------------+ |
| | | |
+----------------+ +--------------------------+
]]>
As described in , the external shelf can
be modeled as WDM-TE-Node with termination capability only (not
switching) and the add/drop link between a remote optical
transceiver and a ROADM add/drop port can be modeled as a WDM
TE-link with the same optical impairments as those defined for a
WDM TE-link between WDM-TE-nodes (OMS MCG).
If the two WDM-TE-Nodes are reported in different network topology
instances, the plug-id attribute, defined in
, can be used to discover the adjacency for
add/drop TE-links.
It is worth noting that there are no standard protocols for
automatic discovery of the adjacency between an external transceiver
and a ROADM add/drop port and therefore the information reported in
the plug-id can be either statically configured or provided through
vendor-specific discovery mechanisms.
Each add/drop TE-link carries a single OTSi between the transceiver
and ROADM add/drop port and one or more OTSis in the reverse
direction (between the ROADM add/drop and the transceiver).
Depending on control architecture (e.g., when the two WDM-TE-Nodes
are reported in different network topology instances by different
controllers), the controller reporting the WDM-TE-Node, abstracting
the external OT shelf, may be not able to provide the information
about the end-to-end MC configuration (i.e.,flexi-n and flexi-m)
nor of all the received OTSis, within the end-to-end MC, besides the
configured incoming OTSi, since the end-to-end MC configuration
depends on how the ROADM network is configured and the remote OT
shelf is not aware of that.
In this case only the incoming-otsi and outgoing-otsi can be
reported within anend-to-end MC with an unspecified frequency-slot
(i.e., without reporting flexi-n and flexi-m configuration of the
end-to-end MC).
When an OTSiG has more than one OTSi, its OTSis are carried by
different parallel add/drop TE-links. In order to represent the fact
that these OTSis are co-routed, the add/drop TE-links are bundled
together in a bundled add/drop TE-link. The finest granularity for
the bundled add/drop TE-link is the set of all the add/drop TE-links
terminating on the same OT.
For example, in , it is possible
to define two bundled add/drop TE-links, one for OT1 and one for OT2
or just one add/drop TE-link both OTs.
The model for a bundled add/drop TE-link and the relationship with
its component TE-links is already defined in the bundled-links
container of .
In the general case, the optical impairments and connectivity
constraints are reported for each add/drop TE-link and therefore no
optical impairments are reported in the bundled add/drop TE-link
that is used just to model the co-routing aspects of the OTSis
belonging to the same OTSiG.
The per-transceiver Local Link Connectivity (LLC) is used in the
WDM-TE-Node which abstracts the remote OT shelf (e.g., WDM-TE-Node-1
in ), to represent the association
between each transceiver and each LTP terminating the add/drop
TE-link which models the transceiver port.
The connectivity matrix in the WDM-TE-Node which abstract the edge
ROADM (e.g., WDM-TE-Node-2 in )
references the LTPs terminating the add/drop TE-links which models
the ROADM add/drop ports.
JSON Examples for Optical Transponders in a Remote Shelf
(Remote OTs)
[Editor's note: Introductory text TBA here.]
The JSON example below describes ... (TBA)
Line-folding as defined in has been used
for the JSON code example below.
ContributorsThanks to all of the contributors.Huawei Technologiesaguo@futurewei.comSmartopticsjonas.martensson@smartoptics.comAdditional AuthorsSamsung Electronicsyounglee.tx@gmail.comHuawei Technologieszhenghaomian@huawei.comScuola Superiore Sant'Annanicosambo@gmail.comCiscogiomarti@cisco.comOrangejeanluc.auge@orange.comOrangejulien.meuric@orange.comNokiaVictor.Lopez@nokia.comNokiaEnrico.Griseri@nokia.comJuniperggrammel@juniper.net