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Versions: (draft-kern-ccamp-rsvp-te-sdh-otn-oam-ext) 00 01 02 03 04 05 06

Network Working Group                                            A. Kern
Internet-Draft                                                 A. Takacs
Intended status: Standards Track                                Ericsson
Expires: September 3, 2012                                 March 2, 2012


    GMPLS RSVP-TE Extensions for SONET/SDH and OTN OAM Configuration
              draft-ietf-ccamp-rsvp-te-sdh-otn-oam-ext-04

Abstract

   GMPLS has been extended to support connection establishment in both
   SONET/SDH [RFC4606] and OTN [RFC4328] networks.  However support for
   the configuration of the supervision functions is not specified.
   Both SONET/SDH and OTN implement supervision functions to qualify the
   transported signals.  This document defines extensions to RSVP-TE for
   SONET/SDH and OTN OAM configuration based on the OAM Configuration
   Framework defined in [GMPLS-OAM-FWK].

































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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].

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

   This Internet-Draft will expire on September 3, 2012.

Copyright Notice

   Copyright (c) 2012 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
   2.  Overview of SONET/SDH and OTN OAM related functions  . . . . .  5
     2.1.  Continuity supervision . . . . . . . . . . . . . . . . . .  5
     2.2.  Connectivity supervision . . . . . . . . . . . . . . . . .  5
       2.2.1.  SONET/SDH  . . . . . . . . . . . . . . . . . . . . . .  5
       2.2.2.  OTN  . . . . . . . . . . . . . . . . . . . . . . . . .  5
     2.3.  Signal quality supervision . . . . . . . . . . . . . . . .  6
       2.3.1.  SONET/SDH  . . . . . . . . . . . . . . . . . . . . . .  6
       2.3.2.  OTN  . . . . . . . . . . . . . . . . . . . . . . . . .  6
     2.4.  Delay measurement  . . . . . . . . . . . . . . . . . . . .  6
   3.  RSVP-TE signaling extensions . . . . . . . . . . . . . . . . .  7
     3.1.  Operation overview . . . . . . . . . . . . . . . . . . . .  7
       3.1.1.  Continuity Check supervision . . . . . . . . . . . . .  7
       3.1.2.  Connectivity Monitoring supervision  . . . . . . . . .  8
         3.1.2.1.  SDH/SONET  . . . . . . . . . . . . . . . . . . . .  8
         3.1.2.2.  OTN  . . . . . . . . . . . . . . . . . . . . . . .  8
       3.1.3.  Signal quality supervision . . . . . . . . . . . . . .  9
     3.2.  Signaling support of Virtual Concatenation Groups (VCG)  .  9
     3.3.  OAM types and functions  . . . . . . . . . . . . . . . . . 10
     3.4.  SONET/SDH OAM Configuration sub-TLV  . . . . . . . . . . . 10
     3.5.  OTN OAM Configuration sub-TLV  . . . . . . . . . . . . . . 11
     3.6.  TTI Configuration Sub-TLV  . . . . . . . . . . . . . . . . 11
       3.6.1.  SDH TTI Configuration Sub-TLV  . . . . . . . . . . . . 11
       3.6.2.  OTN TTI Configuration Sub-TLV  . . . . . . . . . . . . 12
     3.7.  Degraded signal thresholds Sub-TLV . . . . . . . . . . . . 14
   4.  Error handling . . . . . . . . . . . . . . . . . . . . . . . . 16
   5.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 17
   6.  Security Considerations  . . . . . . . . . . . . . . . . . . . 18
   7.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 19
   8.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 20
     8.1.  Normative References . . . . . . . . . . . . . . . . . . . 20
     8.2.  Informative References . . . . . . . . . . . . . . . . . . 20
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 22
















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1.  Introduction

   Both SONET/SDH and OTN implement supervision functions to qualify the
   transported signals.  Supervision functions include continuity,
   connectivity, signal quality, alignment and payload supervision.  The
   ITU-T G.806 [G.806] recommendation defines the generic framework of
   the supervision functions, which are then further specified for
   SONET/SDH and OTN in technology specific documents.

   GMPLS has been extended to support connection establishment in SONET/
   SDH [RFC4606], OTN [RFC4328] and OTNv3 [OTNv3_SIG] networks.  These
   documents however do not support the configuration of the respective
   supervision functions.

   [GMPLS-OAM-FWK] defines a technology-agnostic framework for GMPLS to
   support the establishment and configuration of the pro-active OAM
   functions of signalled connections.  The properties of the OAM
   functions are exchanged during connection establishment and may be
   modified during the life of the connection.  The technology specific
   parameters to be exchanged are to be described in accompanying
   documents.  This document defines the extensions for SONET/SDH and
   OTN OAM configuration for end-to-end monitoring.





























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2.  Overview of SONET/SDH and OTN OAM related functions

   SONET/SDH [G.707] and OTN [G.709v3] provide a variety of supervision
   functions.  Among these functions we consider continuity,
   connectivity and signal quality supervision functions, as these are
   the candidates for GMPLS based configuration.  We also consider delay
   measurement management function of OTN.

2.1.  Continuity supervision

   Continuity supervision provides methods monitoring the health of a
   connection (trail).

2.2.  Connectivity supervision

   The connectivity supervision function provides a method to detect
   misconnections.  The detection procedure is based on emitting a Trace
   Trail Identifier (TTI) known by both endpoints.  The TTI is included
   by the source node as an overhead signal for each connection.  The
   receiver node then compares the received TTI with the expected value
   and decides if a miss-connection occurred.

2.2.1.  SONET/SDH

   In case of SONET/SDH, connectivity supervision is implemented in the
   Regeneration Section (RS) and in the lower and higher order path
   layers (LOVC and HOVC).  In all layers the TTI encodes only the
   Access Point Identifier (API) of the source node.  In the various
   layers the lengths of these TTIs are different.  In RS the TTI
   (encoded in J0 octet) is either 1 or 16 octets long.  In higher order
   paths the TTI (encoded in J1), is either 16 or 64 octet long.  In
   lower order paths the TTI is transmitted in the J2 byte and is 16
   octet long.

2.2.2.  OTN

   In case of OTN, connectivity supervision is supported by the OTUk and
   ODUk digital hierarchy layers.  In both layers, the length of the TTI
   is 64 octets, but only the first 32 octets are considered for
   connectivity supervision.  This first part is further divided into a
   Source Access Point Identifier (SAPI) and a Destination Access Point
   Identifier (DAPI).  Connectivity supervision may consider either the
   SAPI or DAPI only or both.  The structure of the SAPI and DAPI is
   specified in [G.709].







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2.3.  Signal quality supervision

   The quality of the transmitted signal is monitored as a ratio of bad
   frames.  If the number of such frames reaches a threshold a defect
   state is declared.  To detect the correctness of the frames an Error
   Detection Code (EDC), such as Bit Interleaved Parity (BIP), is used.
   The distribution of the errors is assumed to follow either Poisson or
   a bursty distribution.  For Poisson distribution an EDC violation
   ratio is defined as the threshold; while for the bursty model the
   threshold is defined as a number of consecutive 1-second time
   intervals in which the EDC violation exceeds a predefined ratio.  In
   case of Poisson error distribution two defect state levels are
   defined: the Excessive Error and Degraded Signal defect.  In the case
   of the bursty model, only the Degraded Signal defect level is
   considered.

2.3.1.  SONET/SDH

   SONET/SDH supports both Excessive Error and Degraded Signal defect
   levels and supports both Poisson and bursty error distribution
   models.  These signal quality parameters are configured for the
   Multiplexing Section (MS) and the LOVC and HOVC path layers.

2.3.2.  OTN

   For OTN, in the digital transport layers (OTUk and ODUk) only the
   bursty error distribution model errors with the Degraded Signal
   defect level is supported.  Two parameters are defined: Ratio of the
   bad frames in a one second interval (0% to 100% or 0 to number of
   frames per 1-second interval) and Number of consecutive intervals
   (between 2 and 10).  Signal quality supervision in the optical
   transport layers is not specified by [G.798], it is indicated to be
   for further study.

2.4.  Delay measurement

   [G.709v3] introduced a tool for measuring round-trip delay of a
   bidirectional ODU path or tandem connection.  For implementing delay
   measurement a one-bit delay measurement (DM) signal is defined in the
   ODUk header.  That signal is constant value (either 0 or 1).  One
   endpoint initiates a delay measurement by inverting the bit emitted
   in the DM signal.  The remote endpoint loops back the DM signal;
   therefore, the delay measurement initiating node will receive the
   inverted signal from the remote endpoint.  This way the initiating
   endpoint will determine the round trip delay.






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3.  RSVP-TE signaling extensions

3.1.  Operation overview

   RFC 4606 and RFC 4328 define the RSVP-TE extensions necessary to
   manage SDH/SONET and OTN optical and digital hierarchy connections.
   Connections for recent version of OTN, the OTNv3 are configured
   according to [OTNv3_SIG].  The monitoring functions associated to
   these connections may be configured together with configuring the
   connection itself.

   The LSP Attribute Flag "OAM MEP entities desired" [GMPLS-OAM-FWK] is
   used to signal that the monitoring functions at the endpoints must be
   established.  The "OAM MIP entities desired" flag must be set to 0
   and must be ignored.

   To configure OAM parameters the OAM Configuration TLV can be included
   in the LSP_ATTRIBUTES object.  The TLV identifies which OAM
   technology ("OAM Type" field) to be used as well as which OAM
   functions are to be enabled (OAM Function Flags sub-TLV).  For SONET/
   SDH and OTN the "Continuity Check" and "Connectivity Verification"
   flags control the Continuity and Connectivity supervision functions,
   while the "Performance Monitoring/Loss" flag enables the Signal
   Quality supervision function.

   Recent release of OTN [G.709v3] introduced delay measurement for
   paths.  Such node enables delay measurement by setting "Performance
   Monitoring/Delay" flag.  By setting that flag the node also indicates
   that it will initiate the delay measurement proactively; therefore,
   the remote endpoint node should not initate delay measurement over
   the configured connection proactively.  Equipments designed according
   to earlier version of G709 must clear "Performance Monitoring/Loss"
   flag and upon receiving OAM configuration message with "Performance
   Monitoring/Delay" flag set must generate "OAM Problem/Unsupported OAM
   Function" error.  The "Performance Monitoring/Delay" flag must be
   cleared for SONET/SDH as it is not supported by SONET/SDH.

   For additional details the appropriate technology specific sub-TLV
   can be carried in the OAM Configuration TLV.

3.1.1.  Continuity Check supervision

   In case of both discussed technologies, setting up continuity
   supervision function for a connection does not need further
   configuration besides enabling it.  Therefore, by setting the
   "Connectivity Monitoring" Flag of OAM Function implicitly enables the
   continuity supervision function as well.




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3.1.2.  Connectivity Monitoring supervision

3.1.2.1.  SDH/SONET

   [G.707] defines three bytes (signals) for connectivity supervision
   purposes: the J0 byte in RS layer, the J1 and J2 bytes in HOVC and
   LOVC layers.  These bytes encode 1 octet, 16 octet or 64 octet long
   unstructured octet streams.  The source node emits this stream and
   the destination node matches it with an expected one.  When the
   destination detects mismatch, defect state will be declared.

   Since these streams encode an identifier defined for the source node,
   different stream will to be emitted in the upstream and downstream
   directions for bidirectional connections.  During the configuration
   the egress node has to be configured with the TTI value to be
   expected in the downstream direction and the TTI value to be emitted
   in the upstream direction.  Therefore the SONET/SDH OAM Configuration
   TLV carries two Connectivity Supervision TLVs.

3.1.2.2.  OTN

   [G.709] defines a 64 octet long TTI, where the first 32 octets have a
   generic structure: a zero octet, a 15 octet long SAPI, a second zero
   octet and finally the 15 octet long DAPI.

   For a unidirectional connection a single Connection Supervision TLV
   encodes elements of the TTI to be emitted.  This TLV also specifies
   which parts of the TTI are compared to the expected values (only
   SAPI, only DAPI, both SAPI and DAPI).

   In case of a bidirectional connection an endpoint can use a common
   API value for SAPI (for transmitted signal) and DAPI (for received
   signal).  (See Figure 1.)  The TTI values used in downstream and
   upstream directions are derived from the two API values: the
   downstream TTI will have the form of [0, API_a, 0, API_z] while the
   upstream TTI will use the form of [0, API_z, 0 API_a].

   Ingress Node                                           Egress Node
    ( API_a )    TTI_upstream = [0, API_z, 0, API_a ]      ( API_z )
   | Rx port | -- < -- < -- < -- < -- < -- < -- < -- < -- | Tx Port |
   | Tx port | -- > -- > -- > -- > -- > -- > -- > -- > -- | Rx Port |
                 TTI_downstream = [0, API_a, 0, API_z ]

   Figure 1: TTI construction when a single API identifies the receiver
                        and transmitter interfaces

   Then, a single Connectivity Supervision TLV is defined.  The SAPI
   field carries the API of the ingress node (API_a) that initiates the



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   signaling, while the DAPI carries the API of the egress node (API_z).

   On the other hand, it is possible that the endpoints use different
   values as SAPI and DAPI to identify the transmitter and receiver
   ports of a bidirectional connection (See Figure 2).  In this case the
   TTIs to be used in the two directions are independent, thus, they
   must be explicitly configured.  Therefore, two Connectivity
   Supervision TLVs are added to the OTN OAM Configuration TLV.  Each
   TLV encodes whether it defines the downstream or the upstream TTI.

   Ingress Node                                           Egress Node
    ( API_a1 )    TTI_upstream = [0, API_z1, 0, API_a1 ]   ( API_z1 )
   | Rx port | -- < -- < -- < -- < -- < -- < -- < -- < -- | Tx Port |
   | Tx port | -- > -- > -- > -- > -- > -- > -- > -- > -- | Rx Port |
    ( API_a2 )    TTI_downstream = [0, API_a2, 0, API_z2 ] ( API_z2 )

   Figure 2: TTI construction when dedicated APIs identify the receiver
                        and transmitter interfaces

3.1.3.  Signal quality supervision

   Signal quality supervision function is implemented in MS, HOVC, LOVC
   layers of SDH/SONET.  All three layers support exceeded error level
   with Poisson error distribution model and degraded signal defect
   level with both, Poisson and bursty error distribution model.
   Dedicated Signal quality supervision TLVs encode each level,
   therefore when the "Performance Monitoring/Loss" flag is set; several
   such TLVs can be added to the SONET/SDH OAM Configuration TLV.  If a
   configuration TLV for a particular level is missing the default
   parameters for that level is to be applied.

   The OTN supports only Degraded Signal defect with bursty error model
   in OTUk and ODUk layers.  Thus, the only parameters to be encoded
   are: the threshold for bad frames in a 1-second interval and the
   number of consecutive 1-second intervals with excessive bad frames.
   Furthermore, as only one level is allowed a single Signal quality
   supervision TLV is added to the OTN OAM Configuration TLV.

3.2.  Signaling support of Virtual Concatenation Groups (VCG)

   A key capability of both, SONET/SDH and OTN is the support of virtual
   concatenation.  This inverse multiplexing method uses multiplicity of
   parallel basic signals.  The supervision function parameters of these
   basic signals can be different.

   [RFC6344] summarises GMPLS signaling capabilities to support virtual
   concatenation and proposes extensions to that.  A Virtual
   Concatenated Group (VCG) is constructed from several individual data



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   plane signals.  The co-routed signals of a VCG could be provisioned
   together using a single RSVP-TE session (co-signaled).  As different
   OAM configuration may be applied to each of these individual signals,
   the OAM configuration extension is applied as follows.

   We assume that the same OAM type and the same set of OAM functions
   apply to every individual signal of the VCG.  A single OAM
   Configuration TLV is carried in the LSP_ATTRIBUTES Object, while
   multiple instances of technology specific OAM configuration sub-TLVs
   are added: one instance per individual signal.  The order of these
   TLVs refers to the logical order of the basic signals (as they are
   listed in the Label Object).

   [RFC6344] allows extension/pruning of a VCG.  To achieve it the
   traffic descriptor, which encodes how the VCG is structured, in the
   RSVP-TE session is updated.  If the VCG is updated the contents of
   the OAM Configuration TLV needs to be updated accordingly.

3.3.  OAM types and functions

   This document defines two new code points for the "OAM Type" field of
   the OAM Configuration TLV, defined in [GMPLS-OAM-FWK]: SONET/SDH OAM
   and OTN Digital Hierarchy OAM.

             OAM Type           Description
           ------------      ------------------
               3                SONET/SDH OAM
               4                OTN Digital Hierarchy OAM

   The "OAM Function Flags sub-TLV", defined in [GMPLS-OAM-FWK].  SONET/
   SDH and OTN supervision functions are defined in this document for
   the following flags: "Continuity Check", "Connectivity Verification",
   "Performance Monitoring/Loss" and "Performance Monitoring/Delay".

3.4.  SONET/SDH OAM Configuration sub-TLV

   SONET/SDH OAM Configuration sub-TLV is defined to encode the
   parameters of continuity, connectivity and signal quality supervision
   functions for SONET/SDH networks.

      0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |           Type (4) (IANA)     |           Length              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                                                               |
      ~                           sub TLVs                            ~
      |                                                               |



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      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   Type: indicates a new type: the SONET/SDH OAM Configuration TLV (IANA
   to define).

   Length: indicates the total length including sub-TLVs

3.5.  OTN OAM Configuration sub-TLV

   OTN OAM Configuration TLV is defined to encode the parameters of
   continuity, connectivity and signal quality supervision functions for
   OTN.

      0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |           Type (5) (IANA)     |           Length              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                                                               |
      ~                           sub TLVs                            ~
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   Type: indicates a new type: the OTN OAM Configuration TLV (IANA to
   define).

   Length: indicates the total length including sub-TLVs

3.6.  TTI Configuration Sub-TLV

3.6.1.  SDH TTI Configuration Sub-TLV

   This sub-TLV is carried in the SONET/SDH OAM Configuration sub-TLV,
   if the Connectivity Verification OAM Function Flag is set.  In every
   supporting layers the TTI identifies the source interface (SAPI);
   however, the length of this identifier varies layer-by-layer (See
   Section 2.2.1).  Therefore, a generic TLV is defined supporting
   various TTI lengths.











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      0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |         Type (1) (IANA)       |         Length                |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |A|U|            Reserved       |              TTI              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                                                               |
      ~                            TTI cont                          ~
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Flag "A", when set enables the AIS insertion on detecting TTI
   mismatch.

   Flat "U" encodes if the TTI refers to the downstream TTI (U=0) or the
   upstream one (U=1).

   The TTI field carries the TTI to be transmitted by the source node
   and to be expected by the sink.  The TLV is padded to 4-octets.

   If the specified length and format of the TTI carried in this TLV is
   not supported by the referred SONET/SDH layer, error must be
   generated: "OAM Problem/TTI Length Mismatch".

3.6.2.  OTN TTI Configuration Sub-TLV

   This sub-TLV is carried in the OTN OAM Configuration sub-TLV, if the
   Connectivity Verification OAM Function Flag is set.






















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      0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |         Type (1) (IANA)       |         Length = 32           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |A|S|D|APP|      Reserved       |              SAPI             |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                            SAPI cont                          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                            SAPI cont                          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                            SAPI cont                          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |     SAPI      |                      DAPI                     |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                            DAPI cont                          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                            DAPI cont                          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                            DAPI cont                          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Three control flags are defined.  Flag "A" indicates that AIS
   insertion on detecting TTI mismatch (failing the connectivity
   verification) is required (A=1) or not (A=0).  The next two flags
   define which parts of the received TTI are compared to the expected
   one.  If flag "S" is set the TTI octets 1 to 15 are matched to the
   expected SAPI value.  If the flag "D" is set the TTI octets 17 to 31
   are matched to the expected DAPI value.  If both "S" and "D" are set
   both parts of TTI are compared to SAPI and DAPI values.  Setting both
   "S" and "D" bits to 0 is invalid, and if encountered error must be
   generated: "OAM Problem/Invalid CC/CV configuration".

   The next two bits "APP" encode the applicability of the TTI
   configuration and the following code points are defined:

      0 - Single TTI configuration: the TTI configuration is done
      according only to this TLV and no further TTI configuration TLVs
      are expected.  This code point is used for unidirectional
      connections and for bidirectional connections with common APIs
      (See Figure 1)

      1 - Downstream TTI for double TTI configuration: the current TLV
      instruct the configuration of the TTI to be used in downstream
      direction (See Figure 2).

      2 - Upstream TTI for double TTI configuration: the current TLV
      instruct the configuration of the TTI to be used in upstream



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      direction (See Figure 2).

      3 - Invalid.

   If the APP is set to 1 and the next or the previous sub-TLV is not an
   OTN TTI Configuration TLV with APP code point 2, then an error must
   be generated "OAM Problem/Invalid OTN TTI Configuration/Missing
   Upstream TTI configuration".

   If the APP is set to 2 and the next or the previous sub-TLV is not an
   OTN TTI Configuration TLV with APP code point 1, then an error must
   be generated "OAM Problem/Invalid OTN TTI Configuration/Missing
   Downstream TTI configuration".

   If the APP is set to either 1 or 2 and the unidirectional LSP is
   signaled (no UPSTREAM_LABEL is added to the message) or the APP is
   set to 3, an error must be generated "OAM Problem/Invalid OTN TTI
   Configuration/Invalid applicability code"

3.7.  Degraded signal thresholds Sub-TLV

   The Degraded signal thresholds Sub-TLV instructs the configuration of
   the signal quality supervision function.  This sub-TLV is applicable
   in both SONET/SDH and OTN cases.  This sub-TLV can be carried in both
   the SONET/SDH OAM Configuration sub-TLV or OTN OAM Configuration sub-
   TLV, if the PerformanceMonitoring/Loss OAM Function Flag is set.

      0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |         Type (2) (IANA)       |        Length = 4             |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |B|L|         Reserved          |    DEG_THR    |    DEG_M      |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Two flags are defined to encode the signal quality measurement.  The
   bit "B" encodes if distribution of errors is either Poisson (B=0) or
   Bursty (B=1).  In case of Poisson distribution of errors two levels
   of defects are defined and encoded with bit "L": excessive error
   (L=0) and degraded signal (L=1).  Since in case of Bursty
   distribution of errors only degraded signal defect is to be detected,
   therefore, in this latter case (B=1) the "L" bit must be set.
   Otherwise error must be generated: "OAM Problem/Invalid Performance
   Monitoring/Loss configuration".

   The field "DEG_THR" defines the threshold for the bad frames (BIP-8
   violations) in both, Poisson and bursty distributions of errors.  In
   the first case (B=0) this field encodes the quotient of the threshold



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   10e-X.  The possible values for excessive error are 3,4 and 5, while
   for degraded signal defect are 6,7,8 and 9.

   In the second case (B=1) it encodes ratio of the bad frames in a
   1-second period and can be set between 0 and 100, interpreted as
   ratios in percentage.

   The field "DEG_M" defines monitoring time-frame in 1 second periods
   assuming bursty distribution of errors.  The valid values are 2 to 10
   periods.









































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4.  Error handling

   In addition to error values specified in [GMPLS-OAM-FWK] this
   document defines the following values for the "OAM Problem" Error
   Code.

   o  In case of SONET/SDH if Performance Measurement/Delay flag is set
      in the OAM Functions Flag sub-TLV, an error must be generated "OAM
      Problem/Unsupported OAM Function".

   o  In case of OTN if the equipment does not support delay measurement
      and the Performance Measurement/Delay flag is set in the received
      OAM Functions Flag sub-TLV, an error must be generated "OAM
      Problem/Unsupported OAM Function".

   o  In case of SONET/SDH OAM when the length or format of the TTI to
      be configured is not supported by the referred SONET/SDH layer, an
      error must be generated: "OAM Problem/TTI Length Mismatch".

   o  If both "S" and "D" bits in OTN TTI Configuration TLV are set to
      0, error must be generated: "OAM Problem/Invalid CC/CV
      configuration"

   o  If the APP is set to 1 and the next or the previous sub-TLV is not
      an OTN TTI Configuration TLV with APP code point 2, then an error
      must be generated "OAM Problem/Invalid OTN TTI Configuration/
      Missing Upstream TTI configuration".

   o  If the APP is set to 2 and the next or the previous sub-TLV is not
      an OTN TTI Configuration TLV with APP code point 1, then an error
      must be generated "OAM Problem/Invalid OTN TTI Configuration/
      Missing Downstream TTI configuration".

   o  If the APP is set to either 1 or 2 and the unidirectional LSP is
      signaled (no UPSTREAM_LABEL is added to the message) or the APP is
      set to 3, an error must be generated "OAM Problem/Invalid OTN TTI
      Configuration/Invalid applicability code"

   o  If flag "B" in Degraded signal thresholds Sub-TLV is set to 1 and
      flag "L" in the same sub-TLV is set to 0 error must be generated
      "OAM Problem/Invalid Performance Monitoring/Loss configuration".










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5.  IANA Considerations

   This document specifies two new sub-TLVs to be carried in the OAM
   Configuration TLV in the LSP_ATTRIBUTES or LSP_REQUIRED_ATTRIBUTES
   Objects in Path and Resv messages.  The document assigns values 3 and
   4 from the "OAM Type" field of the OAM Configuration TLV.

   The following error values need to be assigned under "OAM Problem"
   error code: "OAM Problem/Unsupported OAM Function", "OAM Problem/TTI
   Length Mismatch", "OAM Problem/Invalid CC/CV configuration", "OAM
   Problem/Invalid OTN TTI Configuration/Missing Upstream TTI
   configuration", "OAM Problem/Invalid OTN TTI Configuration/Missing
   Downstream TTI configuration", "OAM Problem/Invalid OTN TTI
   Configuration/Invalid applicability code", "OAM Problem/Invalid
   Performance Monitoring/Loss configuration".




































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6.  Security Considerations

   Security aspects are addressed in the OAM configuration framework
   document [GMPLS-OAM-FWK]















































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7.  Acknowledgements

   The authors would like to thank Francesco Fondelli for his useful
   comments.















































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8.  References

8.1.  Normative References

   [GMPLS-OAM-FWK]
              Takacs, A., Fedyk, D., and H. Jia, "OAM Configuration
              Framework and Requirements for GMPLS RSVP-TE",
              draft-ietf-ccamp-oam-configuration-fwk-01 (work in
              progress), March 2009.

8.2.  Informative References

   [G.707]    International Telecommunications Union, "Network node
              interface for the synchronous digital hierarchy (SDH)",
              ITU-T Recommendation G.707, January 2007.

   [G.709]    International Telecommunications Union, "Interfaces for
              the Optical Transport Network (OTN)", ITU-T
              Recommendation G.709, March 2003.

   [G.709v3]  International Telecommunications Union, "Interfaces for
              the Optical Transport Network (OTN)", ITU-T
              Recommendation G.709, December 2009.

   [G.798]    International Telecommunications Union, "Characteristics
              of optical transport network hierarchy equipment
              functional blocks", ITU-T Recommendation G.798,
              December 2006.

   [G.806]    International Telecommunications Union, "Characteristics
              of transport equipment - Description methodology and
              generic functionality", ITU-T Recommendation G.806,
              January 2009.

   [OTNv3_SIG]
              Zhang, F., Zhang, G., Belotti, S., Ceccarelli, D., and K.
              Pithewan, "Operating Virtual Concatenation (VCAT) and the
              Link Capacity Adjustment Scheme (LCAS) with Generalized
              Multi-Protocol Label Switching (GMPLS)",
              draft-ietf-ccamp-gmpls-signaling-g709v3-01 (work in
              progress), October 2011.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC4328]  Papadimitriou, D., "Generalized Multi-Protocol Label
              Switching (GMPLS) Signaling Extensions for G.709 Optical
              Transport Networks Control", RFC 4328, January 2006.



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   [RFC4606]  Mannie, E. and D. Papadimitriou, "Generalized Multi-
              Protocol Label Switching (GMPLS) Extensions for
              Synchronous Optical Network (SONET) and Synchronous
              Digital Hierarchy (SDH) Control", RFC 4606, August 2006.

   [RFC6344]  Bernstein, G., Caviglia, D., Rabbat, R., and H. Helvoort,
              "Operating Virtual Concatenation (VCAT) and the Link
              Capacity Adjustment Scheme (LCAS) with Generalized Multi-
              Protocol Label Switching (GMPLS)", RFC 6344, August 2011.










































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Authors' Addresses

   Andras Kern
   Ericsson
   Laborc u. 1.
   Budapest,   1037
   Hungary

   Email: andras.kern@ericsson.com


   Attila Takacs
   Ericsson
   Laborc u. 1.
   Budapest,   1037
   Hungary

   Email: attila.takacs@ericsson.com

































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