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Versions: 00 01 02                                                      
Internet Engineering Task Force                            R. Kunze, Ed.
Internet-Draft                                       Deutsche Telekom AG
Intended status: Informational                              July 1, 2011
Expires: January 2, 2012


A framework for Management and Control of optical interfaces supporting
                                G.698.2
          draft-kunze-g-698-2-management-control-framework-00

Abstract

   This document provides a framework that describes a solution space
   for the control and management of optical interfaces according to the
   Black Link approach as specified by ITU-T [ITU.G698.2] and further
   revisions.  In particular, it examines topological elements and
   related network management measures.

   Optical Routing and Wavelength assignment based on WSON is out of
   scope.  This document concentrates on the management of optical
   interfaces.  The application of a dynamic control plane, e.g. for
   auto-discovery or for the distribtion of interface parameters, is
   complementary.  Anyway, this work is not in conflict with WSON but
   leverages and supports related work already done for management plane
   and control plane.

   The framework document will not address the client mapping into
   G.709.  This document only addresses the lower layers.  Furthermore,
   support for Fast Fault Detection, to e.g. trigger Protection
   Switching is provided by the WDM interface capability of the client
   interface (e.g.  ITU-T G.709) is out of scope for this work.
   Additionally the wavelength ordering process and the process how to
   determine the demand for a new wavelength from A to Z is out of
   scope.

Status of This Memo

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

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

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



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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on January 2, 2012.

Copyright Notice

   Copyright (c) 2011 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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

































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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
     1.1.  Requirements Language  . . . . . . . . . . . . . . . . . .  5
   2.  Terminology and Definitions  . . . . . . . . . . . . . . . . .  5
   3.  DWDM Black Link Management Solution Space  . . . . . . . . . .  6
     3.1.  Description of Client Network Layer - WDM connection . . .  7
       3.1.1.  Traditional WDM deployments  . . . . . . . . . . . . .  7
       3.1.2.  Black Link Deployments . . . . . . . . . . . . . . . .  8
   4.  Black Link Operation scenarios . . . . . . . . . . . . . . . . 10
     4.1.  Bringing into service  . . . . . . . . . . . . . . . . . . 10
     4.2.  Configuration Management . . . . . . . . . . . . . . . . . 10
     4.3.  In service (performance management)  . . . . . . . . . . . 10
     4.4.  Fault Clearance  . . . . . . . . . . . . . . . . . . . . . 10
   5.  Black Link Control and Management Solutions  . . . . . . . . . 10
     5.1.  BL Separate Operation and Management Approaches  . . . . . 11
       5.1.1.  Direct connection to the management system . . . . . . 12
       5.1.2.  Indirect connection to the WDM management system . . . 14
     5.2.  Control Plane Considerations . . . . . . . . . . . . . . . 15
       5.2.1.  Black Link deployment with common control plane  . . . 15
       5.2.2.  Black Link deployment with an separate control
               plane  . . . . . . . . . . . . . . . . . . . . . . . . 16
   6.  Requirements for BL and FW deployments . . . . . . . . . . . . 16
     6.1.  Interoperability Aspects . . . . . . . . . . . . . . . . . 16
   7.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 17
   8.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 18
   9.  Security Considerations  . . . . . . . . . . . . . . . . . . . 18
   10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 18
   11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 18
     11.1. Normative References . . . . . . . . . . . . . . . . . . . 18
     11.2. Informative References . . . . . . . . . . . . . . . . . . 19




















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1.  Introduction

   The usage of the Black Link approach in carrier long haul and
   aggregation networks adds a further option for operators to
   facilitate their networks.  The integration of optical coloured
   interfaces into routers and other types of clients could lead to a
   lot of benefits regarding an efficient and optimized data transport
   for higher layer services.

   Carriers deploy their networks today as a combination of transport
   and packet infrastructure.  This ensures high available and flexible
   data transport.  Both network technologies are managed usually by
   different operational units using different management concepts.
   This is the status quo in many carrier networks today.  In the case
   of a black link deployment, where the coloured interface moves into
   the client (e.g. router), it is necessary to establish a management
   connection between the client providing the coloured interface and
   the corresponding EMS (Element Management System) of the transport
   network to ensure that the coloured interface parameters can be
   managed in the same way as traditional deployments allow this.

   The objective of this document is to provide a framework that
   describes the solution space for the control and management of WDM
   Black Links as specified by ITU-T [ITU.G698.2] and further revisions.
   In particular, it examines topological elements and related network
   management measures.

   Optical Routing and Wavelength assignment based on WSON is out of
   scope.  This document concentrates on the management of optical
   interfaces.  The application of a dynamic control plane, e.g. for
   auto-discovery or distribute interface parameters, is complementary.
   Anyway, this work is not in conflict with WSON but leverages and
   supports related work already done for management plane and control
   plane.

   Furthermore, support for Fast Fault Detection, to e.g. trigger
   Protection Switching is provided by the WDM interface capability of
   the client interface (e.g.  ITU-T G.709) is out of scope for this
   work.  Additionally the wavelength ordering process and the process
   how to determine the demand for a new wavelength from A to Z is out
   of scope.

   Note that Control and Management Plane are two separate entities that
   are handling the same information in different ways.  This document
   covers management as well as control plane considerations in
   different management cases of colored interfaces.





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1.1.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

2.  Terminology and Definitions

   Black Link: The Black Link [ITU.G698.2] allows supporting an optical
   transmitter/receiver pair of one or different vendors to inject a
   DWDM channel and run it over an optical network composed of
   amplifiers, filters, add-drop multiplexers from a different vendor.
   Therefore the standard defines the ingress and egress parameters at
   the interface Ss and Rs.

   Coloured Interface: The term coloured interface defines the single
   channel optical interface that is used to bridge long distances and
   is directly connected with a DWDM system.  Coloured interfaces
   operate on a fix wavelength or within a wavelength band (tunability).
   Coloured interface is a more generic term and it is a superset of the
   Black Link.

   Friendly Wavelength: A friendly wavelength is a wavelength that is
   generated or originated by an optical interface that is not part of
   the WDM system but completely managed and known by the WDM system.

   Alien Wavelength: Alien Wavelength: An alien wavelength is a
   wavelength that is generated or originated by an optical interface
   that is not part of the WDM system and not managed and known by the
   WDM system.

   Forward error correction (FEC): FEC is an important way of improving
   the performance of high-capacity long haul optical transmission
   systems.  Employing FEC in optical transmission systems yields system
   designs that can accept relatively large BER (much more than 10-12)
   in the optical transmission line (before decoding).

   Intra-domain Interface (IaDI): The intra-domain interface (line site
   of the optical system) is a physical interface within an optical
   administrative or vendor domain and is implemented as:

   a.  standardized single channel interface specified according to
       G.698.2 (standardized optical interface AND OTUk according G.709)
       or

   b.  proprietary single channel interface proprietary optical
       interface OR functionally specified OTUkV according G.709, i.e.
       proprietary FEC.



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   Inter-Domain Interface(IrDI): The inter-domain interface is a
   physical interface that represents the boundary between two
   administrative domains as well as the boundary between client and
   optical domain.

   Management Plane: Management Plane: The management plane supports
   FCAPS (Fault, Configuration, Accounting, Performance and Security
   Management) capabilities for carrier networks.

   Control Plane: The control plane supports signalling, path
   computation, routing, path setup and restoration.

   Client Network Layer: The client network layer is the layer above (on
   top) the WDM layer, from the perspective of the WDM layer.

   Transponder: A Transponder is a network element that performs O/E/O
   (Optical /Electrical/Optical) conversion.  In this document it is
   referred only transponders with 3R (rather than 2R or 1R
   regeneration) as defined in [ITU.G.872]

3.  DWDM Black Link Management Solution Space

   Basically the management of optical interfaces using a Black Link
   deals with aspects needed for setup, tear down and maintenance of
   wavelengths and all related optical parameters, which are demanded by
   a client network layer (the layer above WDM).  The following types of
   WDM networks are considered for a management of optical interfaces
   using a black link:

   a.  Passive WDM

   b.  Legacy point to point WDM systems

   c.  Legacy WDM systems with OADMs

   d.  Transparent optical networks supporting specific IPoDWDM
       functions, interfaces or protocols

   Table 1 provides a list of tasks, which are related to BL management,
   It is indicated which domain (optical or client) is responsible for a
   task.  The relevance of a task for each type of WDM network is also
   indicated.









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   +---------------------------------------+---------+----+----+---+---+
   |                  Task                 |  Domain |  a |  b | c | d |
   +---------------------------------------+---------+----+----+---+---+
   |   determination of centre frequency   |  client |  R |  R | R | R |
   |  configuration of centre frequency at | optical | NR | NR | R | R |
   |               colored IF              |         |    |    |   |   |
   |     path computation of wavelength    | optical | NR | NR | R | R |
   |         routing of wavelength         | optical | NR | NR | R | R |
   |    wavelength setup across optical    |  client |  ? |  ? | R | R |
   |                network                |         |    |    |   |   |
   |     detection of wavelength fault     | optical |  R |  R | R | R |
   |   fault isolation, identification of  | optical | NR |  R | R | R |
   |              root failure             |         |    |    |   |   |
   | repair actions within optical network | optical |  R |  R | R | R |
   |   protection switching of wavelength  | optical | NR | NR | R | R |
   |       restoration of wavelength       | optical | NR | NR | R | R |
   +---------------------------------------+---------+----+----+---+---+

              Table 1: List of tasks related to BL management

   Furthermore the following deployment cases will be considered:

   a.  Exclusive Black Link deployment

   b.  Black Link deplyoment in combination with grey client network
       interfaces

   Case b) is motivated by the usage of legacy equipment using the
   traditional connection as described in Figure 1 combined with the BL
   approach.

3.1.  Description of Client Network Layer - WDM connection

3.1.1.  Traditional WDM deployments

   The ordinary connection of a client layer network towards a WDM
   system is based today on client interfaces (grey) bridging short or
   intermediate distances between client and WDM system.  The Optical
   Signal incoming into the WDM system must be converted (OEO
   conversion) to corresponding WDM wavelength grid and the power level
   that is applicable for the WDM transmission path.  This conversion is
   done by a component termed as transponder (see Figure 1).

   After that OEO conversion the signal complies with the parameters
   that are specified for a certain WDM link.






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   Figure 1 shows the traditional Client - WDM interconnection using
   transponders for wavelength conversion.  IrDI and IaDI as defined in
   Section 2 specifying the different demarcation areas related to
   external and internal connections


               IrDI                            IaDI
                |                                |
                .                                .
                |   +----------------------------|---+
                .   |     +    WDM Domain     +  .   |
                |   |     |\                 /|  |   |
   +------+     .   |     | \     |\        / |  .   |          +------+
   |  CL  |-->--+---+--T/-|OM|----|/-------|OD|--+-\T+------->--| CL   |
   |      |--<--+---+--T/-|  |----- /|-----|  |--.-\T+-------<--|      |
   +------+     |   |     | /       \|      \ |  |   |          +------+
                .   |     |/                 \|  .   |
                |   |     +                   +  |   |
                .   +----------------------------.---+
                |                                |

           CL = Client
           T/ = Transponder
           OM = Optical Mux
           OD = Optical Demux


         Figure 1: Inter and Intra-Domain Interface Identification

   The management and control of WDM and client layer is done by
   different control and management solutions.  Different operational
   units are responsible for client and WDM layer.

3.1.2.  Black Link Deployments

   In case of a black link deployment Figure 2 the DWDM transceiver is
   located directly at the client and the grey interfaces will be saved.
   In that case a solution must be found to manage that coloured
   interface in the same way as in the traditional case.  This
   requirement must be fulfilled especially in the cases where legacy
   equipment and Black Link Wavelength interfaces will be used in
   parallel or together and the operational situation is unchanged.









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   Figure 2 shows a set of reference points, for the linear "black-link"
   approach, for single-channel connection (Ss and Rs) between
   transmitters (Tx) and receivers (Rx).  Here the WDM network elements
   include an OM and an OD (which are used as a pair with the opposing
   element), one or more optical amplifiers and may also include one or
   more OADMs.


           +-------------------------------------------------+
       Ss  |              DWDM Network Elements              | Rs
  +---+ |  |  | \                                       / |  |  | +---+
  Tx L1----|->|   \    +------+            +------+   /   |--|--->Rx L1
  +---+    |  |    |   |      |  +------+  |      |  |    |  |    +---+
  +---+    |  |    |   |      |  |      |  |      |  |    |  |    +---+
  Tx L2----|->| OM |-|>|------|->| OADM |--|------|->| OD |--|--->Rx L2
  +---+    |  |    |   |      |  |      |  |      |  |    |  |    +---+
  +---+    |  |    |   |      |  +------+  |      |  |    |  |    +---+
  Tx L3----|->|   /    | DWDM |    |  ^    | DWDM |   \   |--|--->Rx L3
  +---+    |  | /      | Link +----|--|----+ Link |     \ |  |    +---+
           +-----------+           |  |           +----------+
                                +--+  +--+
                                |        |
                                v        |
                              +---+    +---+
                              RxLx     TxLx
                              +---+    +---+
       Ss = reference point at the DWDM network element tributary output
       Rs = reference point at the DWDM network element tributary input
       Lx = Lambda x
       OM = Optical Mux
       OD = Optical Demux
       OADM = Optical Add Drop Mux


   from Fig. 5.1/G.698.2

                        Figure 2: Linear Black Link

   Independent from the WDM networks that are considered the usage of
   colored interfaces must perform as well in mixed setups with both
   legacy and colored interface equipment using the BL.










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4.  Black Link Operation scenarios

   A Comparison of the black link with the traditional operation
   scenarios provides an insight of similarities and distinctions in
   operation and management.  The following four use cases provide an
   overview about operation and maintenance processes.

4.1.  Bringing into service

   tbd.

4.2.  Configuration Management

   tbd.

4.3.  In service (performance management)

   tbd.

4.4.  Fault Clearance

   tbd.

5.  Black Link Control and Management Solutions

   Operation and management of WDM systems is traditionally seen as a
   homogenous group of tasks that could be carried out best when a
   single management system or an umbrella management system is used.
   Each WDM vendor provides a management system that also administrates
   the wavelengths.

   This old operational approach was predicted on a high amount/rate of
   connection oriented traffic in carrier networks.  This behaviour has
   been changed completely.  Today IP is the dominating traffic in the
   network and from the operating perspective it is more beneficial to
   use a common management and operation approach.  Due to a long
   history of operational separation it must be possible to manage and
   operate Black Link deployments with the traditional approach too.

   Therefore from the operational point of view in a pure Black Link or
   in a mixed setup with legacy equipment (transponders) there are two
   approaches to manage and operate the network.

   1.  Separate operation and management of client and Transport network

       a.  Direct link to the management system (e.g.  EMS, OSS)

       b.  Indirect link to the management system; using a protocol



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       between the peer node and the directly connected WDM system node
       to exchange management information

   2.  Common operation and management of IP and Transport network

   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
   Management (Fault, Configuration, Accounting, Performance and
   Security) capabilities are supported.  This means from the management
   staff point of view nothing changes.  The transceiver/receiver
   optical interface will be part of the optical management domain and
   will be managed from the transport management staff.

   The second option should be favoured if the underlying WDM transport
   network is mainly used to interconnect IP nodes and the service
   creation and restoration will be done on higher layers (e.g.  IP/
   MPLS).  Then it is more beneficial have a higher level of integration
   and a common management will be more efficient.

5.1.  BL Separate Operation and Management Approaches































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5.1.1.  Direct connection to the management system

   As depicted in Figure 3 one possibility to manage the optical
   interface within the client is a direct connection to the management
   system of the optical domain.  This ensures manageability as usual.



                        +-----+
                        | OSS |
                        |_____|
                        /_____/
                           |
                           |
                           |
                       +---+---+
                +----->+  EMS  |
               /       |       |
              /        +-------+
             /             | MI
       SNMP /              |                DCN Network
       --------------------+-------------------------------
          /         +------+-----------------------+
         /          |     +|     WDM Domain   +    |
        /           |     |\                 /|    |
   +---+--+         |     | \     |\        / |    |          +------+
   |  CL  |-/C------+--- -|OM|----|/-------|OD|--- +-------/C-|  CL  |
   |      |-/C------+--- -|  |----- /|-----|  |----+-------/C-|      |
   +------+         |     | /       \|      \ |    |          +------+
                    |     |/                 \|    |
                    |     +                   +    |
                    +------------------------------+

           CL = Client
           /C = Coloured Interface
           OM = Optical Mux
           OD = Optical Demux
           EMS = Element Management System
           MI= Management Interface



              Figure 3: Connecting BL on Transport Management

   The exchange of management information between client and management
   system assumes that some form of a direct link exists between the
   client node and the WDM management system (e.g.  EMS).  This may be
   an Ethernet Link or a DCN connection.



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   It must be ensured that the optical interface can be managed in a
   standardized way to enable interoperable solutions between different
   optical interface vendors and vendors of the optical network
   management software.  RFC 3591 [RFC3591] defines manage objects for
   the optical interface type but does not cover the scenarios described
   by this framework document.  Therefore an extension to this MIB for
   the optical interface has been drafted in [Black-Link-MIB].  In that
   case SNMP is used to exchange data between client and management
   system of the WDM domain.

   Note that a software update of the interface components of the client
   does not lead obligatory to an update of the software of the EMS and
   vice versa.






































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5.1.2.  Indirect connection to the WDM management system

   The alternative as shown in Figure 4 can be used in cases where a
   more automated relationship between transport node and router is
   aspired.  In that case a combination of rudimentary control plane
   features and manual management will be used.  It is a first step into
   a more control plane oriented operation model.


                        +-----+
                        | OSS |
                        |_____|
                        /_____/
                           |
                           |
                           |
                       +---+---+
                       | EMS   |
                       |       |
                       +-------+
                           | MI
                           |
                           |
           LMP(XML) +------+-----------------------+
       +------------+---+ +|                  +    |
       |            |   | |\                 /|    |
   +---+--+         |   +-+ \     |\        / |    |          +------+
   |  CL  |-/C------+--- -|OM|----|/-------|OD|--- +-------/C-|  CL  |
   |      |-/C------+--- -|  |----- /|-----|  |----+-------/C-|      |
   +------+         |     | /       \|      \ |    |          +------+
                    |     |/                 \|    |
                    |     +                   +    |
                    +------------------------------+


           CL = Client
           /C = Coloured Interface
           OM = Optical Mux
           OD = Optical Demux
                   EMS= Element Management System
           MI= Management Interface


      Figure 4: Direct connection between peer node and first optical
                               network node

   For information exchange between client and the direct connected node
   of the optical transport network LMP as specified in RFC 4209



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   [RFC4209] can (should) be used.  This extension of LMP may be used
   between a peer node and an adjacent optical network node as depicted
   in Figure 4.

   Recently LMP based on RFC 4209 does not support the transmission of
   configuration data (information).  This functionality has to be added
   to the existing extensions of the protocol.  The use LMP-WDM assumes
   that some form of a control channel exists between the client node
   and the WDM equipment.  This may be a dedicated lambda, an Ethernet
   Link, or a DCN.  It is proposed to use an out of band signalling over
   a separate link or DCN to ensure a high availability.

5.2.  Control Plane Considerations

   Basically it is not mandatory necessary to run a control plane in
   Black Link scenarios at least not in simple black link case where
   clients will be connected point to point using a simple WDM
   infrastructure (multiplexer and amplifier).  As a first step it is
   possible to configure the entire link using the standard management
   system and a direct connection of the router or client to the EMS of
   the transport network.  Configuration information will be exchanged
   using SNMP (see sections Section 5.1.1).

   Looking at the control plane the following two scenarios may be
   considered:

   a.  A common control plane for transport and client network; this
       implies a single operation unit responsible for both client and
       transport network management.

   b.  A separate control plane for client and optical network without
       any interaction

   As mentioned in chapter Section 5.1.2 some control plane features
   like LMP in an enhanced version could be used.

   In such simple scenario it is imaginable to use only LMP to exchange
   information between the nodes of the optical domain.  LMP must be run
   between the both end-points of the link and between the edge node and
   the first optical network node.

5.2.1.  Black Link deployment with common control plane

   tbd.







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5.2.2.  Black Link deployment with an separate control plane

   tbd.

6.  Requirements for BL and FW deployments

   This section raises requirements from the carrier perspective and
   will be removed in a separate requirements draft if necessary.

6.1.  Interoperability Aspects

   For carrier network deployments, interoperability is a key
   requirement.  Today it is state-of-the-art to interconnect e.g.
   clients from different vendors and a WDM transport system using
   short-reach, grey interfaces.  Applying the Black Link (BL) concept,
   clients (e.g. routers) now become directly connected via transport
   interfaces which must be interoperable to each other.

   A progessive approach addressing interoperability is shown in
   Figure 5.According to the concept of ITU-T G.698.2 the black link,
   the single channel (coloured) Tx and the Rx can be provided by three
   different vendors, namely vendor A (black link designer), and vendors
   X and Y for the Tx/Rx.  The single-channel reference points Ss and Rs
   indicate the demarcation between the Tx/Rx and the black link, and
   the set of optical parameters refers to these reference points
   according to G.698.2.  However, G.698.2 does not give any insight
   into the client equipment (CL), e.g. routers or switches, containing
   the optical transmitters and receivers.  The electrical interfaces of
   the Tx/Rx are indicated by E1/E2.  The client equipment CL #1
   containing the Tx is provided by a vendor B1 who is not necessarily
   the same vendor as the vendor X of the Tx.  Multi-source agreements
   (MSA) for pluggable modules (e.g. for SFPs, XFPs, etc.) specify form
   factors and electrical interfaces thus enabling in principle to use a
   pluggable transmitter from any vendor who complies with the MSA.
   Similarly, the client equipment at the receiver side can be provided
   by a vendor B2 different from the vendor Y of the pluggable receiver.
   This modularity feature, i.e. the capability to use in principle
   different vendors for the client equipment, modular (pluggable)
   transmitters/receivers, and the black link is a key requirement
   addressing interoperability issues of the black link approach











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                      +---------------------------+
                      |   Black Link (vendor A)   |
   +-----------+      |   +                   +   |      +-----------+
   |CL #1      |     -+---|\                 /|---+-     | CL #2     |
   |    +------+-+    |   | \   +-------+   / |   |    +-+------+    |
   | -+-|  Tx    |    |   |  |  |       |  |  |   |    |   Rx   |-+- |
   | -+-|(vendor +--+-+---|OM|--OADM    |--|OD|---+-+--+(vendor |-+- |
   | -+-|   X)   | Ss |   |  |  |       |  |  |   | RS |   Y)   |-+- |
   | E1 +------+-+    |   | /   +-------+   \ |   |    +-+------+ E2 |
   |           |     -+---|/                 \|---+-     |           |
   |(vendor B1)|      |   +                   +   |      |(vendor B2)|
   +-----------+      |                           |      +-----------+
                      +---------------------------+


           CL = Client
           /C = Coloured Interface
           OM = Optical Mux
           OD = Optical Demux
                   EMS= Element Management System
           MI= Management Interface


                    Figure 5: Interoperability aspects

   In practice, a network operator may not use five different vendors
   when implementing black link systems.  A simplified use case could be
   to choose the same vendor B for the client equipment on both sides
   (i.e. vendor B1 = vendor B2 = vendor B) and to choose the same vendor
   X for the Tx and Rx (i.e. vendor X = vendor Y) thus enabling to use
   universal pluggable modules for the optical transmitters and
   receivers.

   An even more simplified use case could be to choose the same vendor B
   for all client equipment and Tx/Rx (i.e.  B = B1 = X = B2 = Y) thus
   having only two vendors for the whole set-up, namely vendor A and
   vendor B, but to give up the possibility to use universal pluggable
   modules.

   Other vendor combinations could also be realized (e.g. vendor X =
   vendor Y = vendor A).

7.  Acknowledgements

   The author would like to thank Ulrich Drafz for the very good
   teamwork during the last years and the initial thoughts related to
   the packet optical integration.  Furthermore the author would like to
   thank all people involved within Deutsche Telekom for the support and



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   fruitful discussions.

8.  IANA Considerations

   This memo includes no request to IANA.

9.  Security Considerations

   This document has no requirement for a change to the security models
   within GMPLS, associated protocols and management interfaces.  As
   well as the LMP security models could be operated unchanged.

10.  Contributors

               Arnold Mattheus
                 Deutsche Telekom
                 Darmstadt
                 Germany
                 email arnold.Mattheus@telekom.de

               Manuel Paul
                 Deutsche Telekom
                 Berlin
                 Germany
                 email Manuel.Paul@telekom.de

               Josef Roese
                 Deutsche Telekom
                 Darmstadt
                 Germany
                 email j.roese@telekom.de

                             Frank Luennemann
                 Deutsche Telekom
                 Muenster
                             Germany
                 email Frank.Luennemann@telekom.de


11.  References

11.1.  Normative References

   [ITU.G.872]       International Telecommunications Union,
                     "Architecture of optical transport networks", ITU-
                     T Recommendation G.872, November 2001.

   [ITU.G698.2]      International Telecommunications Union, "Amplified



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                     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
                     Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC3591]         Lam, H-K., Stewart, M., and A. Huynh, "Definitions
                     of Managed Objects for the Optical Interface Type",
                     RFC 3591, September 2003.

   [RFC4209]         Fredette, A. and J. Lang, "Link Management Protocol
                     (LMP) for Dense Wavelength Division Multiplexing
                     (DWDM) Optical Line Systems", RFC 4209,
                     October 2005.

11.2.  Informative References

   [Black-Link-MIB]  Internet Engineering Task Force, "A SNMP MIB to
                     manage the optical parameters caracteristic of a
                     DWDM Black-Link", draft-galimbe-kunze-black-link-
                     mib-00 draft-galimbe-kunze-black-link-mib-00,
                     July 2011.

Author's Address

   Ruediger Kunze (editor)
   Deutsche Telekom AG
   Berlin,   10589
   DE

   Phone: +49 30 3497 3152
   EMail: ruediger.kunze@telekom.de













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