< draft-ietf-ccamp-dwdm-if-mng-ctrl-fwk-04.txt   draft-ietf-ccamp-dwdm-if-mng-ctrl-fwk-05.txt >
Internet Engineering Task Force R. Kunze, Ed. Internet Engineering Task Force R. Kunze, Ed.
Internet-Draft Deutsche Telekom Internet-Draft Deutsche Telekom
Intended status: Informational G. Grammel, Ed. Intended status: Informational G. Grammel, Ed.
Expires: September 14, 2017 Juniper Expires: December 18, 2017 Juniper
D. Beller D. Beller
Nokia Nokia
G. Galimberti, Ed. G. Galimberti, Ed.
Cisco Cisco
March 13, 2017 June 16, 2017
A framework for Management and Control of DWDM optical interface A framework for Management and Control of DWDM optical interface
parameters parameters
draft-ietf-ccamp-dwdm-if-mng-ctrl-fwk-04 draft-ietf-ccamp-dwdm-if-mng-ctrl-fwk-05
Abstract Abstract
To ensure an efficient data transport, meeting the requirements To ensure an efficient data transport, meeting the requirements
requested by today's IP-services the control and management of DWDM requested by today's IP-services the control and management of DWDM
interfaces is a precondition for enhanced multilayer networking and interfaces are a precondition for enhanced multilayer networking and
for an further automation of network provisioning and operation. for a further automation of network provisioning and operation. This
This document describes use cases and requirements for the control document describes use cases, requirements and solutions for the
and management of optical interfaces parameters according to control and management of optical interfaces parameters according to
different types of single channel DWDM interfaces. The focus is on different types of single channel DWDM interfaces. The focus is on
automating the network provisioning process irrespective on how it is automating the network provisioning process irrespective on how it is
triggered i.e. by EMS, NMS or GMPLS. This document covers management triggered i.e. by EMS, NMS or GMPLS. This document covers management
as well as control plane considerations in different management cases as well as control plane considerations in different management cases
of single channel DWDM interfaces. The purpose is to identify the of single channel DWDM interfaces. The purpose is to identify the
necessary information elements and processes to be used by control or necessary information elements and processes to be used by control or
management systems for further processing. management systems for further processing.
Status of This Memo Status of This Memo
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 14, 2017. This Internet-Draft will expire on December 18, 2017.
Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 4 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Terminology and Definitions . . . . . . . . . . . . . . . . . 4 2. Terminology and Definitions . . . . . . . . . . . . . . . . . 3
3. Solution Space . . . . . . . . . . . . . . . . . . . . . . . 5 3. Solution Space . . . . . . . . . . . . . . . . . . . . . . . 5
3.1. Comparison of approaches for transverse compatibility . . 6 3.1. Comparison of approaches for transverse compatibility . . 5
3.1.1. Multivendor DWDM line system with transponders . . . 6 3.1.1. Multivendor DWDM line system with transponders . . . 5
3.1.2. Integrated single channel DWDM deployments on the 3.1.2. Integrated single channel DWDM deployments on the
client site . . . . . . . . . . . . . . . . . . . . . 7 client site . . . . . . . . . . . . . . . . . . . . . 6
4. Solutions for managing and controlling single channel optical 4. Solutions for managing and controlling single channel optical
interface . . . . . . . . . . . . . . . . . . . . . . . . . . 9 interface . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.1. Separate Operation and Management Approaches . . . . . . 10 4.1. Separate Operation and Management Approaches . . . . . . 9
4.1.1. Direct connection to the management system . . . . . 10 4.1.1. Direct connection to the management system . . . . . 9
4.1.2. Direct connection to the DWDM management system . . . 11 4.1.2. Direct connection to the DWDM management system
4.2. Control Plane Considerations . . . . . . . . . . . . . . 13 (first optical node) . . . . . . . . . . . . . . . . 10
4.2.1. Considerations using GMPLS UNI . . . . . . . . . . . 14 4.2. Control Plane Considerations . . . . . . . . . . . . . . 12
5. Use cases . . . . . . . . . . . . . . . . . . . . . . . . . . 15 4.2.1. Considerations using GMPLS UNI . . . . . . . . . . . 13
5.1. Service Setup . . . . . . . . . . . . . . . . . . . . . . 15 5. Use cases . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.2. Link monitoring Use Cases . . . . . . . . . . . . . . . . 16 5.1. Service Setup . . . . . . . . . . . . . . . . . . . . . . 14
5.2.1. Pure Access Link (AL) Monitoring Use Case . . . . . . 18 5.2. Link monitoring Use Cases . . . . . . . . . . . . . . . . 15
5.2.2. Power Control Loop Use Case . . . . . . . . . . . . . 21 5.2.1. Pure Access Link (AL) Monitoring Use Case . . . . . . 17
6. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 23 5.2.2. Power Control Loop Use Case . . . . . . . . . . . . . 20
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 25 6. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 22
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 25 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 24
9. Security Considerations . . . . . . . . . . . . . . . . . . . 25 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24
10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 25 9. Security Considerations . . . . . . . . . . . . . . . . . . . 24
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 26 10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 24
11.1. Normative References . . . . . . . . . . . . . . . . . . 26 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 25
11.2. Informative References . . . . . . . . . . . . . . . . . 27 11.1. Normative References . . . . . . . . . . . . . . . . . . 25
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 28 11.2. Informative References . . . . . . . . . . . . . . . . . 26
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 27
1. Introduction 1. Introduction
The usage of the single channel DWDM interfaces (e.g. in routers) The usage of the single channel DWDM interfaces (e.g. in routers)
connected to a DWDM Network (which include ROADMs and optical connected to a DWDM Network (which include ROADMs and optical
amplifiers) adds a further networking option for operators allowing amplifiers) adds a further networking option for operators allowing
new scenarios and requiring more control/management plane new scenarios but require harmonised control and management plane
integration. interaction between different network domains.
Carriers deploy their networks today as a combination of transport Carriers deploy their networks today based on transport und packet
and packet infrastructures to ensure high availability and flexible network infrastructures as domains to ensure high availability and a
data transport. Both network technologies are usually managed by high level of redundancy. Both network domains were operated and
different operational units using different management concepts. managed separately. This is the status quo in many carrier networks
This is the status quo in many carrier networks today. In the case today. In the case of deployments, where the optical transport
of deployments, where the optical transport interface moves into the interface moves into the client device (e.g. router) an interaction
client device (e.g. , router), it is necessary to coordinate the between those domains becomes necessary.
management of the optical interface at the client domain with the
optical transport domain. There are different levels of
coordination, which are specified in this framework.
The objective of this document is to provide a framework that This framework specifies different levels of control and management
describes the solution space for the control and management of single plane interaction to support the usage of single channel optical
channel interfaces and providing use cases on how to manage these interfaces in carrier networks in an efficient manner.
solutions. In particular, it examines topological elements and
related network management measures. From an architectural point of The objective of this document is to provide a framework for the
view, the network can be considered as a set of pre- configured/ control and management of transceiver interfaces based on the
qualified unidirectional, single-fiber, network connections between corresponding use cases and requirements to ensure an efficient and
reference points S and R shown in figure 2. The optical transport optimized data transport.
network is managed and controlled in order to provide optical
connections at the intended centre frequencies and the optical
interfaces are managed and controlled to generate signals of the
intended centre frequencies and further parameters as specified for
example in ITU-T Recommendations G.698.2 and G.798. The management
or control plane of the client and DWDM network is aware of the
parameters of the interfaces to properly set up the optical link.
This knowledge can be used furthermore, to support fast fault
detection.
Optical routing and wavelength assignment based on WSON is out of Optical routing and wavelength assignment based on WSON is out of
scope although can benefit of the way the optical parameters are scope although can benefit of the way the optical parameters are
exchanged between the Client and the DWDM Network. exchanged between the Client and the DWDM Network. Also, the
wavelength ordering process and the process how to determine the
Additionally, the wavelength ordering process and the process how to demand for a new wavelength path through the network is out of scope.
determine the demand for a new wavelength from A to Z is out of
scope.
Note that the Control and Management Planes are two separate entities Note that the Control and Management Planes are two separate entities
that are handling the same information in different ways. This that are handling the same information in different ways.
document covers management as well as control plane considerations in
different management cases of single channel DWDM interfaces.
1.1. Requirements Language 1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
2. Terminology and Definitions 2. Terminology and Definitions
The current generation of WDM netwoks are single vendor networks The current generation of WDM netwoks are single vendor networks
where the optical line system and the transponders are tightly where the optical line system and the transponders are tightly
integrated. The DWDM interfaces migration from the transponders to integrated. The DWDM interfaces migration from the transponders to
the colored interfaces changes this scenario, by introducing a the colored interfaces change this scenario, by introducing a
standardized interface at the level of OCh between the DWDM interface standardized interface at the level of OCh between the DWDM interface
and the DWDM network. and the DWDM network.
Black Link: The Black Link [ITU.G698.2] allows supporting an optical Black Link: The Black Link [ITU.G698.2] allows supporting an optical
transmitter/receiver pair of a single vendor or from different transmitter/receiver pair of a single vendor or from different
vendors to provide a single optical channel interface and transport vendors to provide a single optical channel interface and transport
it over an optical network composed of amplifiers, filters, add-drop it over an optical network composed of amplifiers, filters, add-drop
multiplexers which may be from a different vendor. Therefore the multiplexers which may be from a different vendor. Therefore the
standard defines the ingress and egress parameters for the optical standard defines the ingress and egress parameters for the optical
interfaces at the reference points Ss and Rs. interfaces at the reference points Ss and Rs.
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Intra-domain interface (IaDI) [G.872]: A physical interface within an Intra-domain interface (IaDI) [G.872]: A physical interface within an
administrative domain. administrative domain.
Inter-domain interface (IrDI) [G.872]: A physical interface that Inter-domain interface (IrDI) [G.872]: A physical interface that
represents the boundary between two administrative domains. represents the boundary between two administrative domains.
Management Plane [G.8081]: The management plane performs management Management Plane [G.8081]: The management plane performs management
functions for the transport plane, the control plane and the system functions for the transport plane, the control plane and the system
as a whole. It also provides coordination between all the planes. as a whole. It also provides coordination between all the planes.
The following management functional areas are performed in the The following management functional areas are performed in the
management plane: performance management; fault management; management plane: performance management, fault management,
configuration management; accounting management and security configuration management, accounting management and security
management. management.
Control Plane[G.8081]: The control plane performs neighbour Control Plane[G.8081]: The control plane performs neighbour
discovery, call control and connection control functions. Through discovery, call control and connection control functions. Through
signalling, the control plane sets up and releases connections, and signalling, the control plane sets up and releases connections, and
may restore a connection in case of a failure. The control plane may restore a connection in case of a failure. The control plane
also performs other functions in support of call and connection also performs other functions in support of call and connection
control, such as neighbour discovery and routing information control, such as neighbour discovery and routing information
dissemination. dissemination.
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referred only transponders with 3R (rather than 2R or 1R referred only transponders with 3R (rather than 2R or 1R
regeneration) as defined in [ITU.G.872]. regeneration) as defined in [ITU.G.872].
Client DWDM interface: A Transceiver element that performs E/O Client DWDM interface: A Transceiver element that performs E/O
(Electrical/Optical) conversion. In this document it is referred as (Electrical/Optical) conversion. In this document it is referred as
the DWDM side of a transponder as defined in [ITU.G.872]. the DWDM side of a transponder as defined in [ITU.G.872].
3. Solution Space 3. Solution Space
The solution space of this document is focusing on aspects related to The solution space of this document is focusing on aspects related to
the management of single-channel optical interface parameters of the management and control of single-channel optical interface
physical point-to-point and ring DWDM applications on single-mode parameters of physical point-to-point and ring DWDM applications on
optical fibres and allows the direct connection of a wide variety of single-mode optical fibres and allows the direct connection of a wide
equipment using a DWDM link, for example variety of equipment using a DWDM link, for example
1. A digital cross-connect with multiple optical interfaces, 1. A digital cross-connect with multiple optical interfaces,
supplied by a different vendor from the line system supplied by a different vendor from the line system
2. Devices as routing, switching or compute nodes, each from a 2. Devices as routing, switching or compute nodes, each from a
different vendor, supplying one channel each different vendor, providing optical line interfaces
3. A combination of the above 3. A combination of the above
3.1. Comparison of approaches for transverse compatibility 3.1. Comparison of approaches for transverse compatibility
This section describes two ways to achieve transverse compatibility. This section describes two ways to achieve transverse compatibility.
Section 3.1.1 describes the classic model based on well defined Section 3.1.1 describes the classic model based on well defined
inter-domain interfaces. Section 3.1.2 defines a model ensuring inter-domain interfaces. Section 3.1.2 defines a model ensuring
interoperability on the line side of the optical network. interoperability on the line side of the optical network.
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administrative domain towards the client node. ITU-T G.698.2 for administrative domain towards the client node. ITU-T G.698.2 for
example specifies the parameter set for a certain set of example specifies the parameter set for a certain set of
applications. applications.
This document elaborates only the IaDI Interface as shown in Figure 1 This document elaborates only the IaDI Interface as shown in Figure 1
as transversely compatible and multi-vendor interface within one as transversely compatible and multi-vendor interface within one
administrative domain controlled by the network operator. administrative domain controlled by the network operator.
3.1.2. Integrated single channel DWDM deployments on the client site 3.1.2. Integrated single channel DWDM deployments on the client site
In case of a deployment as shown in Figure 2, through the use of In case of a deployment as shown in Figure 2, through the use of DWDM
single channel DWDM interfaces, multi-vendor interconnection can also interfaces, multi-vendor interconnection can also be achieved while
be achieved while removing the need for one short reach transmitter removing the need for one short reach transmitter and receiver pair
and receiver pair per channel (eliminating the transponders). per channel (eliminating the transponders).
Figure 2 shows a set of reference points, for single-channel Figure 2 shows a set of reference points, for single-channel
connection (Ss and Rs) between transmitters (Tx) and receivers (Rx). connection (Ss and Rs) between transmitters (Tx) and receivers (Rx).
Here the DWDM network elements include an optical multiplexer (OM) Here the DWDM network elements include an optical multiplexer (OM)
and an optical demultiplexer (OD) (which are used as a pair with the and an optical demultiplexer (OD) (which are used as a pair with the
peer element), one or more optical amplifiers and may also include peer element), one or more optical amplifiers and may also include
one or more OADMs. one or more OADMs.
|==================== Black Link =======================| |==================== Black Link =======================|
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Rs = Reference point at the DWDM network element tributary input Rs = Reference point at the DWDM network element tributary input
Lx = Lambda x Lx = Lambda x
OM = Optical Mux OM = Optical Mux
OD = Optical Demux OD = Optical Demux
OADM = Optical Add Drop Mux OADM = Optical Add Drop Mux
Linear DWDM network as per ITU-T G.698.2 Linear DWDM network as per ITU-T G.698.2
Figure 2: Linear Black Link Figure 2: Linear Black Link
As shown in Figure 2, the administrative domain may consists of The single administrative domain may consist of several vendor
several vendor domains. Even a in that case a common north bound domains. Even in that case a common network management and control
management interface is required to ensure a consistent management of is required to ensure a consistent operation and provisioning of the
the entire connection. entire connection.
The following documents[DWDM-interface-MIB], [YANG], [LMP] define The following documents[DWDM-interface-MIB], [YANG], [LMP] define
such a protocol- FIX-THE-REFERENCE specific information using SNMP/ such a protocol- FIX-THE-REFERENCE specific information using SNMP/
SMI, Yang models and LMP TLV to support the direct exchange of SMI, Yang models and LMP TLV to support the direct exchange of
information between the client and the network control plane. information between the client and the network management and control
plane.
4. Solutions for managing and controlling single channel optical 4. Solutions for managing and controlling single channel optical
interface interface
Operation and management of WDM systems is traditionally seen as a Operation and management of WDM systems is traditionally seen as a
homogenous group of tasks that could be carried out best when a homogenous group of tasks that could be carried out best when a
single management system or an umbrella management system is used. single management system or an umbrella management system is used.
Currently each WDM vendor provides an Element Management System (EMS) Currently each WDM vendor provides an Element Management System (EMS)
that also administers the wavelengths. that also provisions the wavelengths. In a multi-vendor line system,
such single-vendor EMS requirement is no more effective. New methods
of managing and controlling line systems need to be looked at.
Therefore from the operational point of view the following approaches Therefore from the operational point of view the following approaches
will be considered to manage and operate optical interfaces. will be considered to manage and operate optical interfaces.
1. Separate operation and management of client device and the 1. Separate operation and management of client device and the
transport network whereas the single channel interface of the transport network whereas the interface of the client belongs to
client belongs to the administrative domain of the transport the administrative domain of the transport network and will be
network and will be managed by the transport group. This results managed by the transport group. This results in two different
in two different approaches to send information to the management approaches to send information to the management system
system
a.Direct connection from the client to the management a. Direct connection from the client to the management system,
system,ensuring a management of the single channel of the optical ensuring a management of the DWDM interface of the optical
network (e.g. EMS, NMS) network (e.g. EMS, NMS)
b.Indirect connection to the management system of the optical b. Indirect connection to the management system of the optical
network using a protocol (LMP) between the client device and the network using a protocol (LMP) between the client device and the
directly connected WDM system node to exchange management directly connected WDM system node to exchange management
information with the optical domain information with the optical domain
2. Common operation and management of client device including the 2. Common operation and management of client device including the
single channel DWDM part and the Transport network single channel DWDM part and the Transport network
The first option keeps the status quo in large carrier networks as The first option keeps the status quo in large carrier networks as
mentioned above. In that case it must be ensured that the full FCAPS mentioned above. In that case it must be ensured that the full FCAPS
Management (Fault, Configuration, Accounting, Performance and Management (Fault, Configuration, Accounting, Performance and
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Figure 3: Connecting Single Channel optical interfaces to the Figure 3: Connecting Single Channel optical interfaces to the
Transport Management system Transport Management system
The exchange of management information between client device and the The exchange of management information between client device and the
management system assumes that some form of a direct management management system assumes that some form of a direct management
communication link exists between the client device and the DWDM communication link exists between the client device and the DWDM
management system (e.g. EMS). This may be an Ethernet Link or a DCN management system (e.g. EMS). This may be an Ethernet Link or a DCN
connection (management communication channel MCC). connection (management communication channel MCC).
It must be ensured that the optical network interface can be managed It must be ensured that the optical network interface can be managed
in a standardised way to enable interoperable solutions between in a standardized way to enable interoperable solutions between
different optical interface vendors and vendors of the optical different optical interface vendors and vendors of the optical
network management application. RFC 3591 [RFC3591] defines managed network management application. RFC 3591 [RFC3591] defines managed
objects for the optical interface type but needs further extension to objects for the optical interface type but needs further extension to
cover the optical parameters required by this framework document. cover the optical parameters required by this framework document.
Therefore an extension to this MIB for the optical interface has been Therefore an extension to this MIB for the optical interface has been
drafted in [DWDM-interface-MIB]. SNMP is used to read parameters and drafted in [DWDM-interface-MIB]. SNMP is used to read parameters and
get notifications and alarms, netconf and Yang models are needed to get notifications and alarms, netconf and yang models are needed to
easily provision the interface with the right parameter set as easily provision the interface with the right parameter set as
described in [YANG] described in [YANG]
Note that a software update of the optical interface components of Note that a software update of the optical interface components of
the client nodes must not lead obligatory to an update of the the client nodes must not lead obligatory to an update of the
software of the EMS and vice versa. software of the EMS and vice versa.
4.1.2. Direct connection to the DWDM management system 4.1.2. Direct connection to the DWDM management system (first optical
node)
An alternative as shown in Figure 4 can be used in cases where a more An alternative as shown in Figure 4 can be used in cases where a more
integrated relationship between transport node (e.g. OM or OD) and integrated relationship between transport node (e.g. OM or OD) and
client device is aspired. In that case a combination of control client device is aspired. In that case a combination of control
plane features and manual management will be used. plane features and manual management will be used.
+-----+ +-----+
| NMS | | NMS |
|_____| |_____|
/_____/ /_____/
| |
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connected node of the optical transport network LMP as specified in connected node of the optical transport network LMP as specified in
RFC 4209 [RFC4209] should be used. This extension of LMP may be used RFC 4209 [RFC4209] should be used. This extension of LMP may be used
between a peer node and an adjacent optical network node as depicted between a peer node and an adjacent optical network node as depicted
in Figure 4. in Figure 4.
The LMP based on RFC 4209 does not yet support the transmission of The LMP based on RFC 4209 does not yet support the transmission of
configuration data (information). This functionality must be added configuration data (information). This functionality must be added
to the existing extensions of the protocol. The use of LMP-WDM to the existing extensions of the protocol. The use of LMP-WDM
assumes that some form of a control channel exists between the client assumes that some form of a control channel exists between the client
node and the WDM equipment. This may be a dedicated lambda, an node and the WDM equipment. This may be a dedicated lambda, an
Ethernet Link, or other signalling communication channel (SCC or Ethernet Link.
IPCC).
4.2. Control Plane Considerations 4.2. Control Plane Considerations
The concept of integrated single channel DWDM interfaces equally The concept of integrated single channel DWDM interfaces equally
applies to management and control plane mechanisms. The general applies to management and control plane mechanisms. GMPLS control
GMPLS control plane for wavelength switched optical networks is work plane protocols have been extended for WSON, e.g. [RFC7689] for
under definition in the scope of WSON. One important aspect of the fixed grid signal and for flexi-grid [RFC7792]. One important aspect
BL is the fact that it includes the wavelength that is supported by of the [G.698.2] is the fact that it includes the wavelength that is
the given link. Thus a BL can logically be considered as a fiber supported by the given link. Therefore, the link can logically be
that is transparent only for a single wavelength. In other words, considered as a fiber that is transparent only for a single
the wavelength becomes a characteristic of the link itself. wavelength. In other words, the wavelength becomes a characteristic
of the link itself.
Nevertheless the procedure to light up the fiber may vary depending Nevertheless the procedure to light up the fiber may vary depending
on the implementation. Since the implementation is unknown a priori, on the implementation. Since the implementation is unknown a priori,
different sequences to light up a wavelength need to be considered: different sequences to light up a wavelength need to be considered:
1. Interface first, interface tuning: The transmitter is switched on 1. Interface first, interface tuning: The transmitter is switched on
and the link is immediately transparent to its wavelength. This and the link is immediately transparent to its wavelength. This
requires the transmitter to carefully tune power and frequency requires the transmitter to carefully tune power and frequency
not overload the line system or to create transients. not overload the line system or to create transients.
2. Interface first, OLS tuning: The transmitter is switched on first 2. Interface first, OLS tuning: The transmitter is switched on first
and can immediately go to the max power allowed since the OLS and can immediately go to the max power allowed since the OLS
performs the power tuning. This leads to an intermediate state performs the power tuning. This leads to an intermediate state
where the receiver does not receive a valid signal while the where the receiver does not receive a valid signal while the
transmitter is sending out one. Alarm suppression mechanisms transmitter is sending out one. Alarm suppression mechanisms
shall be employed to overcome that condition. shall be employed to overcome that condition.
3. OLS first, interface tuning: At first the OLS is tuned to be 3. OLS first, interface tuning: At first the OLS is tuned to be
transparent for a given wavelength, then transponders need to be transparent for a given wavelength, then transponders need to be
tuned up. Since the OLS in general requires the presence of a tuned up. Since the OLS in general requires the presence of a
wavelength to fine-tune it is internal facilities there may be a wavelength to fine-tune its internal facilities there may be a
period of time where a valid signal is transmitted but the period where a valid signal is transmitted but the receiver is
receiver is unable to detect it. This equally need to be covered unable to detect it. This equally need to be covered by alarm
by alarm suppression mechanisms. suppression mechanisms.
4. OLS first, OLS tuning: The OLS is programmed to be transparent 4. OLS first, OLS tuning: The OLS is programmed to be transparent
for a given wavelength, then the interfaces need to be switched for a given wavelength, then the interfaces need to be switched
on and further power tuning takes place. The sequencing of on and further power tuning takes place. The sequencing of
enabling the link needs to be covered as well. enabling the link needs to be covered as well.
The preferred way to address these in a Control Plane enabled network The preferred way to address these in a Control Plane enabled network
is neighbour discovery including exchange of link characteristics and is neighbour discovery including exchange of link characteristics and
link property correlation. The general mechanisms are covered in link property correlation. The general mechanisms are covered in
RFC4209 [LMP-WDM] and RFC 4204[LMP] which provides the necessary RFC4209 [LMP-WDM] and RFC 4204[LMP] which provides the necessary
skipping to change at page 14, line 15 skipping to change at page 13, line 16
signaling information but covers: signaling information but covers:
1. Control channel management 1. Control channel management
2. Link property correlation 2. Link property correlation
3. Link verification 3. Link verification
4. Fault management 4. Fault management
Extensions to LMP/LMP-WDM covering the code points of the BL Extensions to LMP/LMP-WDM covering the parameter sets (application
definition are needed. Additionally when client and server side are codes) are needed. Additionally, when client and server side are
managed by different operational entities, link state exchange is managed by different operational entities, link state exchange is
required to align the management systems. required to align the management systems.
4.2.1. Considerations using GMPLS UNI 4.2.1. Considerations using GMPLS UNI
The deployment of single channel optical interfaces is leading to The deployment of single channel optical interfaces is leading to
some functional changes related to the control plane models and has some functional changes related to the control plane models and has
therefore some impact on the existing interfaces especially in the therefore some impact on the existing interfaces especially in the
case of an overlay model where the edge node requests resources from case of an overlay model where the edge node requests resources from
the core node and the edges node do not participate in the routing the core node and the edges node do not participate in the routing
protocol instance that runs among the core nodes. RFC 4208 [RFC4208] protocol instance that runs among the core nodes. RFC 4208 [RFC4208]
defines the GMPLS UNI that will be used between edge and core node. defines the GMPLS UNI that can be used between edge and core node.
In case of integrated interfaces deployment additional In case of integrated interfaces deployment additional
functionalities are needed to setup a connection. functionalities are needed to setup a connection.
It is necessary to differentiate between topology/signalling It is necessary to differentiate between topology/signalling
information and configuration parameters that are needed to setup a information and configuration parameters that are needed to setup a
wavelength path. RSVP-TE could be used for the signalling and the wavelength path. RSVP-TE could be used for the signalling and the
reservation of the wavelength path. But there are additional reservation of the wavelength path. But there are additional
information needed before RSVP-TE can start the signalling process. information needed before RSVP-TE can start the signalling process.
There are three possibilities to proceed: There are three possibilities to proceed:
skipping to change at page 15, line 6 skipping to change at page 14, line 6
b. RSVP-TE will be used to transport additional information b. RSVP-TE will be used to transport additional information
c. Leaking IGP information instead of exchanging this information c. Leaking IGP information instead of exchanging this information
needed from the optical network to the edge node (overlay will be needed from the optical network to the edge node (overlay will be
transformed to a border-peer model) transformed to a border-peer model)
Furthermore following issues should be addressed: Furthermore following issues should be addressed:
a) The Communication between peering edge nodes using an out of band a) The Communication between peering edge nodes using an out of band
control channel. The two nodes have to exchange their optical control channel. The two nodes sould exchange their optical
capabilities. An extended version of LMP is needed to exchange FEC capabilities. An extended version of LMP is needed to exchange FEC
Modulation scheme, etc. that must be the same. It would be helpful Modulation scheme, etc. that must be the same. It would be helpful
to define some common profiles that will be supported. Only if the to define some common profiles that will be supported. Only if the
profiles match with both interface capabilities it is possible start profiles match with both interface capabilities it is possible start
signalling. signaling.
b) Due to the bidirectional wavelength path that must be setup it is b) Due to the bidirectional wavelength path that must be setup it is
obligatory that the upstream edge node inserts a wavelength value obligatory that the upstream edge node inserts a wavelength value
into the path message for the wavelength path towards the upstream into the path message for the wavelength path towards the upstream
node itself. But in the case of an overlay model the client device node itself. But in the case of an overlay model the client device
may not have full information which wavelength must/should be may not have full information which wavelength must/should be
selectedand this information must be exchanged between the edge and selectedand this information must be exchanged between the edge and
the core node. the core node.
5. Use cases 5. Use cases
A Comparison with the traditional operation scenarios provides an A Comparison with the traditional operation scenarios provides an
insight of similarities and distinctions in operation and management insight of similarities and distinctions in operation and management
of single channel optical interfaces. The following use cases of DWDM interfaces. The following use cases provide an overview
provide an overview about operation and maintenance processes. about operation and maintenance processes.
5.1. Service Setup 5.1. Service Setup
It is necessary to differentiate between two operational issues for It is necessary to differentiate between different operational issues
setting up a light path (a DWDM connection is specific in having for setting up a light path (a DWDM connection is specific in having
defined maximum impairments) within an operational network. The defined maximum impairments) within an operational network.
first step is the preparation of the connection if no optical signal
is applied. Therefore it is necessary to define the path of the
connection.
The second step is to setup the connection between the client DWDM The first step is to determine if transceivers located at different
interface and the ROADM port. This is done using the NMS of the end-points are interoperable, i.e. support a common set of
optical transport network. From the operation point of view the task operational parameters. In this step it is required to determine
is similar in a Black Link scenario and in a traditional WDM transceiver capabilities in a way to be able to correlate them for
environment. The Black Link connection is measured by using BER interoperability purposes. Such parameters include modulation
tester which use optical interfaces according to G.698.2. These scheme, modulation parameters, FEC to name a few. If both
measurements are carried out in accordance with [ITU-TG.692]. When transceivers are controlled by the same NMS or CP, such data is
needed further connections for resilience are brought into service in readily available. However in cases like Fig.4 a protocol need to be
the same way. used to inform the controlling instance (NMS or CP) about transceiver
parameters. It is suggested to extend LMP for that purpose.
In addition some other parameters like the transmit optical power, The second step is to determine the feasibility of a lightpath
the received optical power, the frequency, etc. must be considered. between two transceivers without applying an optical signal.
Understanding the limitations of the transceiver pair, a route
through tho optical network has to be found, whereby each route has
an individual set of impairments deteriorating a wavelength traveling
along that route. Since a single transceiver can support multiple
parameter sets, the selection of a route may limit the permissible
parameter sets determined in step1.
If the optical interface moves into a client device some of changes The third step is then to setup the connection itself and to
from the operational point of view have to be considered. The centre determine the Wavelength. This is done using the NMS of the optical
frequency of the Optical Channel was determined by the setup process. transport network or by means of a control plane interaction such as
signaling and includes the route information as well as the parameter
set information necessary to enable communication.
The optical interfaces at both terminals are set to the centre In a fourth step, Optical monitoring is activated in the WDM network
frequency before interconnected with the dedicated ports of the WDM in order to monitor the status of the connection. The monitor
network. Optical monitoring is activated in the WDM network after functions of the optical interfaces at the terminals are also
the terminals are interconnected with the dedicated ports in order to activated in order to monitor the end to end connection.
monitor the status of the connection. The monitor functions of the
optical interfaces at the terminals are also activated in order to
monitor the end to end connection.
Furthermore it should be possible to automate this last step. After Furthermore it should be possible to automate this step. After
connecting the client device towards the first control plane managed connecting the client device towards the first control plane managed
transport node a control connection may e.g. be automatically transport node a control connection may e.g. be automatically
established using LMP to exchange configuration information. established using LMP.
If tunable interfaces are used in the scenario it would be possible
to define a series of backup wavelength routes for restoration that
could be tested and stored in backup profile. In fault cases this
wavelength routes can be used to recover the service.
5.2. Link monitoring Use Cases 5.2. Link monitoring Use Cases
The use cases described below are assuming that power monitoring The use cases described below are assuming that power monitoring
functions are available in the ingress and egress network element of functions are available in the ingress and egress network element of
the DWDM network, respectively. By performing link property the DWDM network, respectively. By performing link property
correlation it would be beneficial to include the current transmit correlation it would be beneficial to include the current transmit
power value at reference point Ss and the current received power power value at reference point Ss and the current received power
value at reference point Rs. For example if the Client transmitter value at reference point Rs. For example if the Client transmitter
power (OXC1) has a value of 0dBm and the ROADM interface measured power has a value of 0dBm and the ROADM interface measured power is
power (at OLS1) is -6dBm the fiber patch cord connecting the two -6dBm the fiber patch cord connecting the two nodes may be pinched or
nodes may be pinched or the connectors are dirty. More, the the connectors are dirty. As discussed before, the actual route or
interface characteristics can be used by the OLS network Control selection of a specific wavelength within the allowed set is outside
Plane in order to check the Optical Channels feasibility. Finally the scope of LMP. In GMPLS, the parameter selection (e.g. central
the OXC1 transceivers parameters (Application Code) can be shared frequency) is performed by RSVP-TE, routing is performed by IGP. ????
with OXC2 using the LMP protocol to verify the transceivers
compatibility. The actual route selection of a specific wavelength
within the allowed set is outside the scope of LMP. In GMPLS, the
parameter selection (e.g. central frequency) is performed by RSVP-TE.
G.698.2 defines a single channel optical interface for DWDM systems G.698.2 defines a single channel optical interface for DWDM systems
that allows interconnecting network-external optical transponders that allows interconnecting network-external optical transponders
across a DWDM network. The optical transponders are considered to be across a DWDM network. The optical transponders are external to the
external to the DWDM network. This so-called 'black link' approach DWDM network. This so-called 'black link' approach illustrated in
illustrated in Figure 5-1 of G.698.2 and a copy of this figure is Figure 5-1 of G.698.2 and a copy of this figure is provided below.
provided below. The single channel fiber link between the Ss/Rs The single channel fiber link between the Ss/Rs reference points and
reference points and the ingress/egress port of the network element the ingress/egress port of the network element on the domain boundary
on the domain boundary of the DWDM network (DWDM border NE) is called of the DWDM network (DWDM border NE) is called access link in this
access link in this contribution. Based on the definition in G.698.2 contribution. Based on the definition in G.698.2 it is part of the
it is considered to be part of the DWDM network. The access link DWDM network. The access link is typically realized as a passive
typically is realized as a passive fiber link that has a specific fiber link that has a specific optical attenuation (insertion loss).
optical attenuation (insertion loss). As the access link is an As the access link is an integral part of the DWDM network, it is
integral part of the DWDM network, it is desirable to monitor its desirable to monitor its attenuation. Therefore, it is useful to
attenuation. Therefore, it is useful to detect an increase of the detect an increase of the access link attenuation, for example, when
access link attenuation, for example, when the access link fiber has the access link fiber has been disconnected and reconnected
been disconnected and reconnected (maintenance) and a bad patch panel (maintenance) and a bad patch panel connection (connector) resulted
connection (connector) resulted in a significantly higher access link in a significantly higher access link attenuation (loss of signal in
attenuation (loss of signal in the extreme case of an open connector the extreme case of an open connector or a fiber cut). In the
or a fiber cut). In the following section, two use cases are following section, two use cases are presented and discussed:
presented and discussed:
1) pure access link monitoring 1) pure access link monitoring
2) access link monitoring with a power control loop 2) access link monitoring with a power control loop
These use cases require a power monitor as described in G.697 (see These use cases require a power monitor as described in G.697 (see
section 6.1.2), that is capable to measure the optical power of the section 6.1.2), that is capable to measure the optical power of the
incoming or outgoing single channel signal. The use case where a incoming or outgoing single channel signal. The use case where a
power control loop is in place could even be used to compensate an power control loop is in place could even be used to compensate an
increased attenuation as long as the optical transmitter can still be increased attenuation if the optical transmitter can still be
operated within its output power range defined by its application operated within its output power range defined by its application
code. code.
Figure 5 Access Link Power Monitoring Figure 5 Access Link Power Monitoring
+--------------------------+ +--------------------------+
| P(in) = P(Tx) - a(Tx) | | P(in) = P(Tx) - a(Tx) |
| ___ | | ___ |
+----------+ | \ / Power Monitor | +----------+ | \ / Power Monitor |
| | P(Tx) | V P(in) | | | P(Tx) | V P(in) |
skipping to change at page 19, line 23 skipping to change at page 18, line 23
- t: user defined threshold (tolerance) - t: user defined threshold (tolerance)
- P(out): measured current optical output power at the output port - P(out): measured current optical output power at the output port
of border DWDM NE of border DWDM NE
- a(Rx): access link attenuation in Rx direction (external - a(Rx): access link attenuation in Rx direction (external
transponder point of view) transponder point of view)
- P(Rx): current optical input power of receiver Rx - P(Rx): current optical input power of receiver Rx
Description: Description:
- The access link attenuation in both directions (a(Tx), a(Rx)) - The access link attenuation in both directions (a(Tx), a(Rx))
is known or can be determined as part of the commissioning is known or can be determined as part of the commissioning
process. Typically, both values are the same. process. Typically, both values are very similar.
- A threshold value t has been configured by the operator. This - A threshold value t has been configured by the operator. This
should also be done during commissioning. should also be done during commissioning.
- A control plane protocol (e.g. this draft) is in place that allows - A control plane protocol is in place that allows
to periodically send the optical power values P(Tx) and P(Rx) to periodically send the optical power values P(Tx) and P(Rx)
to the control plane protocol instance on the DWDM border NE. to the control plane protocol instance on the DWDM border NE.
This is illustrated in Figure 3. This is illustrated in Figure 3.
- The DWDM border NE is capable to periodically measure the optical - The DWDM border NE is capable to periodically measure the optical
power Pin and Pout as defined in G.697 by power monitoring points power Pin and Pout as defined in G.697 by power monitoring points
depicted as yellow triangles in the figures below. depicted as yellow triangles in the figures below.
Access Link monitoring process: Access Link monitoring process:
- Tx direction: the measured optical input power Pin is compared - Tx direction: the measured optical input power Pin is compared
with the expected optical input power P(Tx) - a(Tx). If the with the expected optical input power P(Tx) - a(Tx). If the
skipping to change at page 23, line 19 skipping to change at page 22, line 19
degree of automation or should be fully automated. Simplifying and degree of automation or should be fully automated. Simplifying and
automating the entire management and provisioning process of the automating the entire management and provisioning process of the
network in combination with a higher link utilization and faster network in combination with a higher link utilization and faster
restoration times will be the major requirements that has been restoration times will be the major requirements that has been
addressed in this section. addressed in this section.
Data Plane interoperability as defined for example in [ITU.G698.2] is Data Plane interoperability as defined for example in [ITU.G698.2] is
a precondition to ensure plain solutions and allow the usage of a precondition to ensure plain solutions and allow the usage of
standardized interfaces between network and control/management plane. standardized interfaces between network and control/management plane.
The following requirements are focusing on the usage of integrated The following requirements are focusing on the usage of DWDM
single channel interfaces. interfaces.
1 To ensure a lean management and provisioning process of single 1 To ensure a lean management and provisioning process of single
channel interfaces management and control plane of the client channel interfaces management and control plane of the client
and DWDM network must be aware of the parameters of the and DWDM network must be aware of the parameters of the
interfaces and the optical network to properly setup the optical interfaces and the optical network to properly setup the optical
connection. connection.
2 A standard-based northbound API (to network management system) 2 A standard-based northbound API (to network management system)
based on Netconf should be supported, alternatively SNMP should based on Netconf should be supported, alternatively SNMP could
be supported too. be supported too.
3 A standard-based data model for single channel interfaces must be 3 A standard-based data model for single channel interfaces must be
supported to exchange optical parameters with control/management supported to exchange optical parameters with control/management
plane. plane.
4 Netconf should be used also for configuration of the single 4 Netconf should be used also for configuration of the single
channel interfaces including the power setting channel interfaces including the power setting
5 LMP should be extended and used in cases where optical 5 LMP should be extended and used in cases where optical
parameters need to be exchanged between peer nodes to correlate parameters need to be exchanged between peer nodes to correlate
link characteristics and adopt the working mode of the single link characteristics and adopt the working mode of the single
channel interface. channel interface.
6 LMP may be used to adjust the output power of the single 6 LMP may be used to adjust the output power of the single
channel DWDM interface to ensure that the interface works in channel DWDM interface to ensure that the interface works in
the right range. the right range.
7 Parameters e.g. PRE-FEC BER should be used to trigger a FRR 7 RSVP-TE may be used to exchange some relevant parameters between
mechanism on the IP control plane to reroute traffic before the client and the optical node (e.g. the label value), without
the link breaks. preventing the network to remain in charge of the optical path
computation
8 Power monitoring functions at both ends of the DWDM connection 8 Power monitoring functions at both ends of the DWDM connection
should be implemented to further automate the setup and should be used to further automate the setup and shoutdown
shoutdown process of the optical interfaces. process of the optical interfaces.
9 A standardized procedure to setup an optical connection should 9 A standardized procedure to setup an optical connection should
be defined and implemented in DWDM and client devices be defined and implemented in DWDM and client devices
(containing the single channel optical interface).LMP should be (containing the single channel optical interface).
used to ensure that the process follows the right order.
10 Pre-tested and configured backup paths should be stored in so 10 Pre-tested and configured backup paths should be stored in so
called backup profiles. In fault cases this wavelength routes called backup profiles. In fault cases this wavelength routes
should be used to recover the service. should be used to recover the service.
11 LMP may be used to monitor and observe the access link. 11 LMP may be used to monitor and observe the access link.
7. Acknowledgements 7. Acknowledgements
The authors would like to thank all who supported the work with The authors would like to thank all who supported the work with
skipping to change at page 26, line 32 skipping to change at page 25, line 32
Frank Luennemann Frank Luennemann
Deutsche Telekom Deutsche Telekom
Muenster Muenster
Germany Germany
email Frank.Luennemann@telekom.de email Frank.Luennemann@telekom.de
11. References 11. References
11.1. Normative References 11.1. Normative References
[RFC2863] McCloghrie, K. and F. Kastenholz, "The Interfaces Group [ITU.G.872]
MIB", RFC 2863, DOI 10.17487/RFC2863, June 2000, International Telecommunications Union, "Architecture of
<http://www.rfc-editor.org/info/rfc2863>. optical transport networks", ITU-T Recommendation G.872,
November 2001.
[ITU.G698.2]
International Telecommunications Union, "Amplified
multichannel dense wavelength division multiplexing
applications with single channel optical interfaces",
ITU-T Recommendation G.698.2, November 2009.
[ITU.G709]
International Telecommunications Union, "Interface for the
Optical Transport Network (OTN)", ITU-T Recommendation
G.709, March 2003.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>. <http://www.rfc-editor.org/info/rfc2119>.
[RFC2578] McCloghrie, K., Ed., Perkins, D., Ed., and J. [RFC2578] McCloghrie, K., Ed., Perkins, D., Ed., and J.
Schoenwaelder, Ed., "Structure of Management Information Schoenwaelder, Ed., "Structure of Management Information
Version 2 (SMIv2)", STD 58, RFC 2578, Version 2 (SMIv2)", STD 58, RFC 2578,
DOI 10.17487/RFC2578, April 1999, DOI 10.17487/RFC2578, April 1999,
skipping to change at page 27, line 10 skipping to change at page 26, line 26
[RFC2579] McCloghrie, K., Ed., Perkins, D., Ed., and J. [RFC2579] McCloghrie, K., Ed., Perkins, D., Ed., and J.
Schoenwaelder, Ed., "Textual Conventions for SMIv2", Schoenwaelder, Ed., "Textual Conventions for SMIv2",
STD 58, RFC 2579, DOI 10.17487/RFC2579, April 1999, STD 58, RFC 2579, DOI 10.17487/RFC2579, April 1999,
<http://www.rfc-editor.org/info/rfc2579>. <http://www.rfc-editor.org/info/rfc2579>.
[RFC2580] McCloghrie, K., Ed., Perkins, D., Ed., and J. [RFC2580] McCloghrie, K., Ed., Perkins, D., Ed., and J.
Schoenwaelder, Ed., "Conformance Statements for SMIv2", Schoenwaelder, Ed., "Conformance Statements for SMIv2",
STD 58, RFC 2580, DOI 10.17487/RFC2580, April 1999, STD 58, RFC 2580, DOI 10.17487/RFC2580, April 1999,
<http://www.rfc-editor.org/info/rfc2580>. <http://www.rfc-editor.org/info/rfc2580>.
[RFC2863] McCloghrie, K. and F. Kastenholz, "The Interfaces Group
MIB", RFC 2863, DOI 10.17487/RFC2863, June 2000,
<http://www.rfc-editor.org/info/rfc2863>.
[RFC3591] Lam, H-K., Stewart, M., and A. Huynh, "Definitions of [RFC3591] Lam, H-K., Stewart, M., and A. Huynh, "Definitions of
Managed Objects for the Optical Interface Type", RFC 3591, Managed Objects for the Optical Interface Type", RFC 3591,
DOI 10.17487/RFC3591, September 2003, DOI 10.17487/RFC3591, September 2003,
<http://www.rfc-editor.org/info/rfc3591>. <http://www.rfc-editor.org/info/rfc3591>.
[RFC6205] Otani, T., Ed. and D. Li, Ed., "Generalized Labels for
Lambda-Switch-Capable (LSC) Label Switching Routers",
RFC 6205, DOI 10.17487/RFC6205, March 2011,
<http://www.rfc-editor.org/info/rfc6205>.
[RFC4209] Fredette, A., Ed. and J. Lang, Ed., "Link Management [RFC4209] Fredette, A., Ed. and J. Lang, Ed., "Link Management
Protocol (LMP) for Dense Wavelength Division Multiplexing Protocol (LMP) for Dense Wavelength Division Multiplexing
(DWDM) Optical Line Systems", RFC 4209, (DWDM) Optical Line Systems", RFC 4209,
DOI 10.17487/RFC4209, October 2005, DOI 10.17487/RFC4209, October 2005,
<http://www.rfc-editor.org/info/rfc4209>. <http://www.rfc-editor.org/info/rfc4209>.
[ITU.G698.2] [RFC6205] Otani, T., Ed. and D. Li, Ed., "Generalized Labels for
International Telecommunications Union, "Amplified Lambda-Switch-Capable (LSC) Label Switching Routers",
multichannel dense wavelength division multiplexing RFC 6205, DOI 10.17487/RFC6205, March 2011,
applications with single channel optical interfaces", <http://www.rfc-editor.org/info/rfc6205>.
ITU-T Recommendation G.698.2, November 2009.
[ITU.G709]
International Telecommunications Union, "Interface for the
Optical Transport Network (OTN)", ITU-T Recommendation
G.709, March 2003.
[ITU.G.872]
International Telecommunications Union, "Architecture of
optical transport networks", ITU-T Recommendation G.872,
November 2001.
11.2. Informative References 11.2. Informative References
[DWDM-interface-MIB] [DWDM-interface-MIB]
Internet Engineering Task Force, "A SNMP MIB to manage the Internet Engineering Task Force, "A SNMP MIB to manage the
DWDM optical interface parameters of DWDM applications", DWDM optical interface parameters of DWDM applications",
draft-galimkunze-ccamp-dwdm-if-snmp-mib draft-galimkunze- draft-galimkunze-ccamp-dwdm-if-snmp-mib draft-galimkunze-
ccamp-dwdm-if-snmp-mib, July 2011. ccamp-dwdm-if-snmp-mib, July 2011.
[ITU-TG.691] [ITU-TG.691]
ITU-T, "Optical interfaces for single channel STM-64 and ITU-T, "Optical interfaces for single channel STM-64 and
other SDH systems with optical amplifiers", other SDH systems with optical amplifiers",
ITU-T Recommendation ITU-T G.691, 2008. ITU-T Recommendation ITU-T G.691, 2008.
[ITU-TG.692]
ITU-T, "Transmission media characteristics -
Characteristics of optical components and sub-systems",
ITU-T Recommendation ITU-T G.692, 1998.
[ITU-TG.693] [ITU-TG.693]
ITU-T, "Optical interfaces for intra-office systems", ITU-T, "Optical interfaces for intra-office systems",
ITU-T Recommendation ITU-T G.693, 2009. ITU-T Recommendation ITU-T G.693, 2009.
[ITU-TG.8081]
ITU-T, "Terms and definitions for Automatically Switched
Optical Networks (ASON)", ITU-T Recommendation G.8081",
ITU-T Recommendation ITU-T G.8081, September 2010.
[ITU-TG.957] [ITU-TG.957]
ITU-T, "Optical interfaces for equipments and systems ITU-T, "Optical interfaces for equipments and systems
relating to the synchronous digital hierarchy", relating to the synchronous digital hierarchy",
ITU-T Recommendation ITU-T G.957, 2006. ITU-T Recommendation ITU-T G.957, 2006.
[ITU-TG.692]
ITU-T, "Transmission media characteristics -
Characteristics of optical components and sub-systems",
ITU-T Recommendation ITU-T G.692, 1998.
[ITU-TG.959.1] [ITU-TG.959.1]
ITU-T, "Optical transport network physical layer ITU-T, "Optical transport network physical layer
interfaces", ITU-T Recommendation ITU-T G.959.1, 2009. interfaces", ITU-T Recommendation ITU-T G.959.1, 2009.
[ITU-TG.8081]
ITU-T, "Terms and definitions for Automatically Switched
Optical Networks (ASON)", ITU-T Recommendation G.8081",
ITU-T Recommendation ITU-T G.8081, September 2010.
Authors' Addresses Authors' Addresses
Ruediger Kunze (editor) Ruediger Kunze (editor)
Deutsche Telekom Deutsche Telekom
Winterfeldtstr. 21-27 Winterfeldtstr. 21-27
10781 Berlin 10781 Berlin
Germany Germany
Phone: +491702275321 Phone: +491702275321
Email: RKunze@telekom.de Email: RKunze@telekom.de
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