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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: May 14, 2014                                  November 10, 2013


    GMPLS RSVP-TE Extensions for SONET/SDH and OTN OAM Configuration
              draft-ietf-ccamp-rsvp-te-sdh-otn-oam-ext-06

Abstract

   GMPLS has been extended to support connection establishment in both
   SONET/SDH and OTN networks.  However support for the configuration of
   the OAM functions is not specified.  Both SONET/SDH and OTN implement
   OAM functions to monitor 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 a separate
   document.  This document supports, but does not modify, ITU-T OAM
   mechanisms.

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

   This Internet-Draft will expire on May 14, 2014.









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Copyright Notice

   Copyright (c) 2013 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
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   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Overview of SONET/SDH and OTN OAM related functions . . . . .   3
     2.1.  Continuity supervision  . . . . . . . . . . . . . . . . .   3
     2.2.  Connectivity supervision  . . . . . . . . . . . . . . . .   3
       2.2.1.  SONET/SDH . . . . . . . . . . . . . . . . . . . . . .   4
       2.2.2.  OTN . . . . . . . . . . . . . . . . . . . . . . . . .   4
     2.3.  Signal quality supervision  . . . . . . . . . . . . . . .   4
       2.3.1.  SONET/SDH . . . . . . . . . . . . . . . . . . . . . .   4
       2.3.2.  OTN . . . . . . . . . . . . . . . . . . . . . . . . .   4
     2.4.  Delay measurement . . . . . . . . . . . . . . . . . . . .   5
   3.  RSVP-TE signaling extensions  . . . . . . . . . . . . . . . .   5
     3.1.  Operation overview  . . . . . . . . . . . . . . . . . . .   5
       3.1.1.  Continuity Check supervision  . . . . . . . . . . . .   6
       3.1.2.  Connectivity Monitoring supervision . . . . . . . . .   6
         3.1.2.1.  SDH/SONET . . . . . . . . . . . . . . . . . . . .   6
         3.1.2.2.  OTN . . . . . . . . . . . . . . . . . . . . . . .   6
       3.1.3.  Signal quality supervision  . . . . . . . . . . . . .   7
     3.2.  Signaling support of Virtual Concatenation Groups (VCG) .   8
     3.3.  OAM types and functions . . . . . . . . . . . . . . . . .   8
     3.4.  SONET/SDH OAM Configuration Sub-TLV . . . . . . . . . . .   9
     3.5.  OTN OAM Configuration Sub-TLV . . . . . . . . . . . . . .   9
     3.6.  SDH TTI Configuration Sub-TLV . . . . . . . . . . . . . .   9
     3.7.  OTN TTI Configuration Sub-TLV . . . . . . . . . . . . . .  10
     3.8.  Degraded Signal Thresholds Sub-TLV  . . . . . . . . . . .  12
   4.  Error handling  . . . . . . . . . . . . . . . . . . . . . . .  13
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  13
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  14
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  14
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  15
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  15
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  15



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   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  16

1.  Introduction

   Both SONET/SDH and OTN implement OAM functions to monitor 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], and in OTN [RFC4328] [RFC6344] networks.  These
   documents however do not support the configuration of the respective
   OAM supervision functions.

   [I-D.ietf-ccamp-oam-configuration-fwk] defines a technology-agnostic
   framework for GMPLS to support the establishment and configuration of
   the pro-active OAM functions of signaled 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.

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

   SONET/SDH [G.707] and OTN [G.709] 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 functionality for OTN.  The reader should refer to the
   ITU-T documents for additional information.  Familiarity with GMPLS,
   SONET/SDH and OTN terminology is assumed.

2.1.  Continuity supervision

   Continuity supervision provides methods for 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 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
   determines if a mis-connection occurred.



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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 byte) is either 1 or 16 bytes long.  In higher order
   paths the TTI (encoded in J1), is either 16 or 64 bytes long.  In
   lower order paths, the TTI is transmitted in the J2 byte and is 16
   bytes 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 bytes, but only the first 32 bytes 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].

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




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   For OTN, in the digital transport layers (OTUk and ODUk), only the
   bursty error distribution model 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.709] 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 bit is a 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.

3.  RSVP-TE signaling extensions

3.1.  Operation overview

   RFC 4328, RFC 4606 and RFC6344 defined the GMPLS RSVP-TE extensions
   necessary to manage SONET/SDH and OTN optical and digital hierarchy
   connections.  The monitoring functions associated to these
   connections MAY be configured when configuring the connections.

   The LSP Attribute Flag "OAM MEP entities desired"
   [I-D.ietf-ccamp-oam-configuration-fwk] MUST be 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 MAY 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.

   The recent revision of OTN [G.709] introduced delay measurement
   capability for paths.  A node MAY enable delay measurement by setting
   the "Performance Monitoring/Delay" flag.  By setting that flag, the
   node also indicates that it will initiate the delay measurement;
   therefore, the remote endpoint node SHOULD NOT initiate delay



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   measurement over the configured connection.  Equipment designed to
   earlier versions of G709 MUST clear the "Performance Monitoring/Loss"
   flag and upon receiving an 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
   MAY be carried in the OAM Configuration TLV.

3.1.1.  Continuity Check supervision

   In case of both SONET/SDN and OTN technologies, setting up the
   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.

3.1.2.  Connectivity Monitoring supervision

3.1.2.1.  SDH/SONET

   [G.707] defines three TTI overhead bytes (signals) for connectivity
   supervision: the J0 byte in RS layer, the J1 byte in the HOVC layer
   and the J2 byte in the LOVC layer.  The source node transmits the TTI
   and the destination node matches it with the expected one.  When the
   destination detects mismatch, a defect state will be declared.

   Since these bytes encode a TTI identifier defined for the source
   node, different stream will be emitted in the upstream and downstream
   directions for bidirectional connections.  During the configuration
   the downstream (destination) 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 byte long TTI format, where the first 32 bytes
   have a generic structure: a zero byte, a 15 bytes long SAPI, a second
   zero byte and finally the 15 bytes long DAPI format.

   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).




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   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
   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 the MS, HOVC,
   LOVC layers of SONET/SDH.  All three layers support exceeded error
   level with Poisson error distribution model and degraded signal
   defect level with both of the Poisson and bursty error distribution
   models.  Dedicated Signal quality supervision TLVs encode each level,
   therefore when the "Performance Monitoring/Loss" flag is set; several
   such TLVs MAY 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 SHOULD be applied.



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   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 MAY be added to the OTN OAM Configuration TLV.

3.2.  Signaling support of Virtual Concatenation Groups (VCG)

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

   [RFC6344] describes GMPLS signaling capabilities to support virtual
   concatenation.  A Virtual Concatenated Group (VCG) is constructed
   from several individual data plane signals.  The co-routed signals of
   a VCG may 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 each individual signal of the VCG.  A single OAM
   Configuration TLV MUST be carried in the LSP_ATTRIBUTES Object, while
   multiple instances of technology specific OAM configuration sub-TLVs
   MAY be added: one instance per individual signal.  The order of these
   TLVs references the logical order of the individual 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 MUST 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
   [I-D.ietf-ccamp-oam-configuration-fwk]: SONET/SDH OAM and OTN Digital
   Hierarchy OAM.

   The "OAM Function Flags Sub-TLV" is defined in
   [I-D.ietf-ccamp-oam-configuration-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".




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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 (34) (IANA)    |           Length              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                                                               |
      ~                           sub TLVs                            ~
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



   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 (35) (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.  SDH TTI Configuration Sub-TLV




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   This sub-TLV is carried in the SONET/SDH OAM Configuration Sub-TLV,
   if the Connectivity Verification OAM Function Flag is set.  In each
   supporting layer, 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.

   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 (IANA)           |         Length                |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |A|U|            Reserved       |              TTI              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   ~                            TTI cont                          ~
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


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

   Flag "U" encodes if the TTI refers to the downstream node's source
   TTI (U=0) or the upstream node's TTI (U=1) (expected TTI).

   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 bytes.

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

3.7.  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.

   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 (IANA)           |         Length = 32           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |A|S|D|APP|      Reserved       |              SAPI             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                            SAPI cont                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                            SAPI cont                          |



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   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                            SAPI cont                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     SAPI      |                      DAPI                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                            DAPI cont                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                            DAPI cont                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                            DAPI cont                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   Three control flags are defined.  Flag "A" indicates that AIS
   insertion when detecting a 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 bytes 1 to 15 are matched to the
   expected SAPI value.  If the flag "D" is set, the TTI bytes 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, an 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
      instructs the configuration of the TTI to be used in downstream
      direction (See Figure 2).

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




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   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".

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

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





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

4.  Error handling

   In addition to error values specified in
   [I-D.ietf-ccamp-oam-configuration-fwk] this document defines the
   following values for the "OAM Problem" Error Code.

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

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

   If in the OTN TTI Configuration Sub-TLV the "APP" field 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 in the OTN TTI Configuration Sub-TLV the "APP" field 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 in the OTN TTI Configuration Sub-TLV the "APP" field is set to
   either 1 or 2 and an unidirectional LSP is signaled (no
   UPSTREAM_LABEL) or the "APP" field is set to 3, an error must be
   generated "OAM Problem/Invalid OTN TTI Configuration - Invalid
   Applicability Code".

   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, an error must be generated
   "OAM Problem/Invalid Performance Monitoring/Loss Configuration".

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 defines two new
   values of the "OAM Type" field of the OAM Configuration TLV.  IANA is
   requested to make the following assignments in the RSVP-TE OAM
   Configuration Registry.



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    RSVP-TE OAM Configuration Registry

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

          Sub-TLV Type                           Description
       -------------------           -----------------------------------
              34                     SONET/SDH OAM Configuration Sub-TLV
              35                        OTN OAM Configuration Sub-TLV




   IANA is requested to maintain the SONET/SDH and OTN TLV Type space in
   the "RSVP-TE OAM Configuration Registry" for the sub-TLV types
   carried in the SONET/SDH and OTN OAM Configuration Sub-TLVs.  This
   document defines the following types.


      SONET/SDH and OTN TLV Type             Description
      --------------------------    --------------------------------
                0                             Reserved
                1                  SONET/SDH TTI Configuration Sub-TLV
                2                     OTN TTI Configuration Sub-TLV
                3                   Degraded Signal Thresholds Sub-TLV



   IANA is requested to assigne the following error values under the
   "OAM Problem" error code: "TTI Length Mismatch", "Invalid CC/CV
   Configuration", "Invalid OTN TTI Configuration - Missing Upstream TTI
   Configuration", "Invalid OTN TTI Configuration - Missing Downstream
   TTI Configuration", "Invalid OTN TTI Configuration - Invalid
   Applicability Code", "Invalid Performance Monitoring/Loss
   Configuration".

6.  Security Considerations

   Security aspects are addressed in the OAM configuration framework
   document [I-D.ietf-ccamp-oam-configuration-fwk].  This document does
   not introduce any additional security issues to those discussed in
   [I-D.ietf-ccamp-oam-configuration-fwk] and the SONET/SDH and OTN
   technology-specific RFCs.

7.  Acknowledgements




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

8.  References

8.1.  Normative References

   [I-D.ietf-ccamp-oam-configuration-fwk]
              Takacs, A., Fedyk, D., and H. Jia, "GMPLS RSVP-TE
              extensions for OAM Configuration", draft-ietf-ccamp-oam-
              configuration-fwk-10 (work in progress), June 2013.

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

8.2.  Informative References

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

   [G.709]    International Telecommunications Union, "Interfaces for
              the Optical Transport Network (OTN)", ITU-T Recommendation
              G.709, 2012.

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

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

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

   [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. van
              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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