Network Working Group                                          A. Takacs
Internet-Draft                                                  Ericsson
Intended status: Standards Track                                D. Fedyk
Expires: August 1, 2010 April 28, 2011                                   Alcatel-Lucent
                                                                   J. He
                                                                  Huawei
                                                        January 28,
                                                        October 25, 2010

     OAM Configuration Framework and Requirements for

             GMPLS RSVP-TE
               draft-ietf-ccamp-oam-configuration-fwk-03 extensions for OAM Configuration
               draft-ietf-ccamp-oam-configuration-fwk-04

Abstract

   OAM is an integral part of transport connections, hence it is
   required that OAM functions are activated/deactivated in sync with
   connection commissioning/decommissioning; avoiding spurious alarms
   and ensuring consistent operation.  In certain technologies OAM
   entities are inherently established once the connection is set up,
   while other technologies require extra configuration to establish and
   configure OAM entities.  This document specifies extensions to
   RSVP-TE to support the establishment and configuration of OAM
   entities along with LSP signaling.

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

Status of this Memo

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

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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
   2.  Requirements . . . . . . . . . . . . . . . . . . . . . . . . .  6
   3.  GMPLS  RSVP-TE based OAM Configuration  . . . . . . . . . . . . . . . .  8
     3.1.  Establishment of OAM Entities and Functions  . . . . . . .  8
     3.2.  Adjustment of OAM Parameters . . . . . . . . . . . . . . . 10
     3.3.  Deleting OAM Entities  . . . . . . . . . . . . . . . . . . 10
   4.  RSVP-TE Extensions . . . . . . . . . . . . . . . . . . . . . . 12
     4.1.  LSP Attributes Flags . . . . . . . . . . . . . . . . . . . 12
     4.2.  OAM Configuration TLV  . . . . . . . . . . . . . . . . . . 12 13
       4.2.1.  OAM Function Flags Sub-TLV . . . . . . . . . . . . . . 14
       4.2.2.  Technology Specific sub-TLVs . . . . . . . . . . . . . 14
     4.3.  Administrative Status Information  . . . . . . . . . . . . 14 15
     4.4.  Handling OAM Configuration Errors  . . . . . . . . . . . . 15
     4.5.  Considerations on Point-to-Multipoint OAM Configuration  . 16
   5.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 16 18
   6.  Security Considerations  . . . . . . . . . . . . . . . . . . . 17 19
   7.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 18
   Appendix A.  Discussion on Alternatives 20
   8.  References . . . . . . . . . . . . . 19
   8. . . . . . . . . . . . . . 21
     8.1.  Normative References . . . . . . . . . . . . . . . . . . . 21
     8.2.  Informative References . . . . . . . . . . . . . . . . . . 21
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 22 23

1.  Introduction

   GMPLS is designed as an out-of-band control plane supporting dynamic
   connection provisioning for any suitable data plane technology;
   including spatial switching (e.g., incoming port or fiber to outgoing
   port or fiber), wavelength-division multiplexing (e.g., DWDM), time-
   division multiplexing (e.g., SONET/SDH, G.709), and lately Ethernet
   Provider Backbone Bridging -- Traffic Engineering (PBB-TE) and MPLS
   Transport Profile (MPLS-TP).  In most of these technologies there are
   Operations and Management (OAM) functions employed to monitor the
   health and performance of the connections and to trigger data plane
   (DP) recovery mechanisms.  Similarly to connections, OAM functions
   follow general principles but also have some technology specific
   characteristics.

   OAM is an integral part of transport connections, hence it is
   required that OAM functions are activated/deactivated in sync with
   connection commissioning/decommissioning; avoiding spurious alarms
   and ensuring consistent operation.  In certain technologies OAM
   entities are inherently established once the connection is set up,
   while other technologies require extra configuration to establish and
   configure OAM entities.  In some situations the use of OAM functions,
   like those of Fault- (FM) and Performance Management (PM), may be
   optional confirming to actual network management policies.  Hence the
   network operator must be able to choose which kind of OAM functions
   to apply to specific connections and with what parameters the
   selected OAM functions should be configured and operated.  To achieve
   this objective OAM entities and specific functions must be
   selectively configurable.

   In general, it is required that the management plane and control
   plane connection establishment mechanisms are synchronized with OAM
   establishment and activation.  In particular, if the GMPLS control
   plane is employed it is desirable to bind OAM setup and configuration
   to connection establishment signaling to avoid two separate
   management/configuration steps (connection setup followed by OAM
   configuration) which increases delay, processing and more importantly
   may be prune to misconfiguration errors.  Once OAM entities are setup
   and configured, pro-active as well as on-demand OAM functions can be
   activated via the management plane.  On the other hand, it should be
   possible to activate/deactivate pro-active OAM functions via the
   GMPLS control plane as well.

   This document describes requirements on OAM configuration and control
   via RSVP-TE, and specifies extensions to the RSVP-TE protocol
   providing a framework to configure and control OAM entities along
   with the capability to carry technology specific information.
   Extensions can be grouped into generic elements that are applicable
   to any OAM solution and technology specific elements that provide
   additional configuration parameters, only needed for a specific OAM
   technology.  This document specifies the technology agnostic
   elements, which alone can be used to establish and control OAM
   entities in the case no technology specific information is needed,
   and specifies the way additional technology specific OAM parameters
   are provided.

   This document addresses end-to-end OAM configuration, that is, the
   setup of OAM entities bound to an end-to-end LSP, and configuration
   and control of OAM functions running end-to-end in the LSP.
   Configuration of OAM entities for LSP segments and tandem connections
   are out of the scope of this document.

   The mechanisms described in this document provide an additional
   option for bootstrapping OAM that is not intended to replace or
   deprecate the use of other technology specific OAM bootstrapping
   techniques; e.g., LSP Ping [RFC4379] for MPLS networks.  The
   procedures specified in this document are intended only for use in
   environments where RSVP-TE signaling is already in use to set up the
   LSPs that are to be monitored using OAM.

2.  Requirements

   MPLS OAM requirements are described in [RFC4377], which provides
   requirements to create consistent OAM functionality for MPLS
   networks.

   The following list is an excerpt of MPLS OAM requirements documented
   in [RFC4377].  Only a few requirements are discussed that bear a
   direct relevance to the discussion set forth in this document.

   o  It is desired to support the automation of LSP defect detection.
      It is especially important in cases where large numbers of LSPs
      might be tested.

   o  In particular some LSPs may require automated ingress-LSR to
      egress-LSR testing functionality, while others may not.

   o  Mechanisms are required to coordinate network responses to
      defects.  Such mechanisms may include alarm suppression,
      translating defect signals at technology boundaries, and
      synchronizing defect detection times by setting appropriately
      bounded detection timeframes.

   MPLS-TP defines a profile of MPLS targeted at transport applications
   [MPLS-TP-FWK].
   [RFC5921].  This profile specifies the specific MPLS characteristics
   and extensions required to meet transport requirements, including
   providing additional OAM, survivability and other maintenance
   functions not currently supported by MPLS.  Specific OAM requirements
   for MPLS-TP are specified in
   [MPLS-TP-OAM-REQ]. [RFC5654] [RFC5860].  MPLS-TP poses
   requirements on the control plane to configure and control OAM
   entities:

   o  The use of  OAM functions SHOULD MUST operate and be optional for configurable even in the operator.  A
      network operator absence
      of a control plane.  Conversely, it SHOULD be able possible to choose which
      configure as well as enable/disable the capability to operate OAM
      functions to
      use as part of connectivity management, and which Maintenance Entity it SHOULD also
      be possible to apply them to. configure as well as enable/disable the capability
      to operate OAM functions after connectivity has been established.

   o  The MPLS-TP control plane MUST support the configuration and
      modification of OAM maintenance points as well as the activation/
      deactivation of OAM when the transport path or transport service
      is established or modified.

   Ethernet Connectivity Fault Management (CFM) defines an adjunct
   connectivity monitoring OAM functions SHOULD flow to check the liveliness of Ethernet
   networks [IEEE-CFM].  With PBB-TE [IEEE-PBBTE] Ethernet networks will
   support explicitly-routed Ethernet connections.  CFM can be configurable as part used to
   track the liveliness of
      connectivity (LSP or PW) management. PBB-TE connections and detect data plane
   failures.  In IETF the GMPLS controlled Ethernet Label Switching
   (GELS) (see [RFC5828] and [GMPLS-PBBTE]) work is extending the GMPLS
   control plane to support the establishment of point-to-point PBB-TE
   data plane connections.  Without control plane support separate
   management commands would be needed to configure and start CFM.

   GMPLS based OAM configuration and control should be general to be
   applicable to a wide range of data plane technologies and OAM
   solutions.  There are three typical data plane technologies used for
   transport application, which are wavelength based such as WSON, TDM
   based such as SDH/SONET, packet based such as MPLS-TP [MPLS-TP-FWK] [RFC5921] and
   Ethernet PBB-TE [IEEE-PBBTE].  In all these data planes, the operator
   MUST be able to configure and control the following OAM functions.

   o  It MUST be possible to explicitly request the setup of OAM
      entities for the signaled LSP and provide specific information for
      the setup if this is required by the technology.

   o  Control of alarms is important to avoid false alarm indications
      and reporting to the management system.  It MUST be possible to
      enable/disable alarms generated by OAM functions.  In some cases
      selective alarm control may be desirable when, for instance, the
      operator is only concerned about critical alarms thus the non-
      service affecting alarms should be inhibited.

   o  When periodic messages are used for liveliness check (continuity
      check) of LSPs it MUST be possible to set the frequency of
      messages allowing proper configuration for fulfilling the
      requirements of the service and/or meeting the detection time
      boundaries posed by possible congruent connectivity check
      operations of higher layer applications.  For a network operator
      to be able to balance the trade-off in fast failure detection and
      overhead it is beneficial to configure the frequency of continuity
      check messages on a per LSP basis.

   o  Pro-active Performance Monitoring (PM) functions are continuously
      collecting information about specific characteristics of the
      connection.  For consistent measurement of Service Level
      Agreements (SLAs) it may be required that measurement points agree
      on a common probing rate to avoid measurement problems.

   o  The extensions MUST allow the operator to use only a minimal set
      of OAM configuration and control features if the data plane
      technology, the OAM solution or network management policy allows.
      The extensions must be reusable as much as reasonably possible.
      That is generic OAM parameters and data plane or OAM technology
      specific parameters must be separated.

3.  GMPLS  RSVP-TE based OAM Configuration

   In general, two types of Maintenance Poits Points (MPs) can be
   distinguished: Maintenance End Points (MEPs) and Maintenance
   Intermediate Points (MIPs).  MEPs reside at the ends of an LSP and
   are capable of initiating and terminating OAM messages for Fault
   Management (FM) and Performance Monitoring (PM).  MIPs on the other
   hand are located at transit nodes of an LSP and are capable of
   reacting to some OAM messages but otherwise do not initiate messages.
   Maintenance Entity (ME) refers to an association of MEPs and MIPs
   that are provisioned to monitor an LSP.  The ME association is
   achieved by configuring MPs to belong to the same ME.

   When an LSP is signaled, forwarding association is established
   between endpoints and transit nodes via label bindings.  This
   association creates a context for the OAM entities monitoring the
   LSP.  On top of this association OAM entities may be configured to
   unambigously identify MPs and MEs.

   In addition to MP and ME identification parameters pro-active OAM
   functions (e.g., Continuity Check (CC), Performance Monitoring) may
   have specific parameters requiring configuration as well.  In
   particular, the frequency of periodic CC packets and the measurement
   interval for loss and delay measurements may need to be configured.

   In some cases all the above parameters may be either derived form
   some exiting information or pre-configured default values can be
   used.  In the simplest case the control plane needs to provide
   information whether or not OAM entities need to be setup for the
   signaled LSP.  If OAM entities are created signaling must provide
   means to activate/deactivate OAM message flows and associated alarms.

   OAM identifiers as well as the configuration of OAM functions are
   technology specific, i.e., vary depending on the data plane
   technology and the chosen OAM solution.  In addition, for any given
   data plane technology a set of OAM solutions may be applicable.  The
   OAM configuration framework allows selecting a specific OAM solution
   to be used for the signaled LSP and provides technology specific TLVs
   to carry further detailed configuration information.

3.1.  Establishment of OAM Entities and Functions

   In order to avoid spurious alarms OAM functions must be setup and
   enabled in the appropriate order.  When using the GMPLS control
   plane, establishment and enabling of OAM functions must be bound to
   RSVP-TE message exchanges.

   An LSP may be signaled and established without OAM configuration
   first, and OAM entities may be added later with a subsequent re-
   signaling of the LSP.  Alternatively, the LSP may be setup with OAM
   entities right with the first signaling of the LSP.  The below
   procedures apply to both cases.

   Before the initiator first sends a Path messages with OAM
   Configuration information, it MUST establish and configure the
   corresponding OAM entities locally, however OAM source functions MUST
   NOT start sending any OAM messages.  In the case of bidirectional
   connections, the initiator node MUST setup the OAM sink function to
   be prepared to receive OAM messages but MUST suppress any OAM alarms
   (e.g., due to missing or unidentified OAM messages).  The Path
   message MUST be sent with the "OAM Alarms Enabled" ADMIN_STATUS flag
   cleared, i.e, data plane OAM alarms are suppressed.

   When the Path message arrives at the receiver, the remote end MUST
   establish and configure OAM entities according to the OAM information
   provided in Path message.  If this is not possible a PathErr SHOULD
   be sent and neither the OAM entities nor the LSP SHOULD be
   established.  If OAM entities are established successfully, the OAM
   sink function MUST be prepared to receive OAM messages but MUST not
   generate any OAM alarms (e.g., due to missing or unidentified OAM
   messages).  In the case of bidirectional connections, an OAM source
   function MUST be setup and, according to the requested configuration,
   it
   the OAM source function MUST start sending OAM messages.  Then a Resv
   message is sent back, including the OAM Configuration TLV that
   corresponds to the actually established and configured OAM entities
   and functions.  Depending on the OAM technology, some elements of the
   OAM Configuration TLV MAY be updated/changed; i.e., if the remote end
   is not supporting a certain OAM configuration it may suggest an
   alternative setting, which may or may not be accepted by the
   initiator of the Path message.  If it is accepted, the initiator will
   reconfigure its OAM functions according to the information received
   in the Resv message.  If the alternate setting is not acceptable a
   ResvErr may be sent tearing down the LSP.  Details of this operation
   are technology specific and should be described in accompanying
   technology specific documents.

   When the initiating side receives the Resv message it completes any
   pending OAM configuration and enables the OAM source function to send
   OAM messages.

   After this round, OAM entities are established and configured for the
   LSP and OAM messages MAY are already be exchanged.  OAM alarms can now be
   enabled.  The initiator, while still keeping OAM alarms disabled
   sends a Path message with "OAM Alarms Enabled" ADMIN_STATUS flag set.
   The receiving node enables the OAM alarms after processing the Path
   message.  The initiator enables OAM alarms after it receives the Resv
   message.  Data plane OAM is now fully functional.

3.2.  Adjustment of OAM Parameters

   There may be a need to change the parameters of an already
   established and configured OAM function during the lifetime of the
   LSP.  To do so the LSP needs to be re-signaled with the updated
   parameters.  OAM parameters influence the content and timing of OAM
   messages and identify the way OAM defects and alarms are derived and
   generated.  Hence, to avoid spurious alarms, it is important that
   both sides, OAM sink and source, are updated in a synchronized way.
   First, the alarms of the OAM sink function should be suppressed and
   only then should expected OAM parameters be adjusted.  Subsequently,
   the parameters of the OAM source function can be updated.  Finally,
   the alarms of the OAM sink side can be enabled again.

   In accordance with the above operation, the LSP MUST first be re-
   signaled with "OAM Alarms Enabled" ADMIN_STATUS flag cleared and
   including the updated OAM Configuration TLV corresponding to the new
   parameter settings.  The initiator MUST keep its OAM sink and source
   functions running unmodified, but it MUST suppress OAM alarms after
   the updated Path message is sent.  The receiver MUST first disable
   all OAM alarms, then update the OAM paramaters according to the
   information in the Path message and reply with a Resv message
   acknowledging the changes by including the OAM Configuration TLV.
   Note that the receiving side has the possibility to adjust the
   requested OAM configuration parameters and reply with and updated OAM
   Configuration TLV in the Resv message, reflecting the actually
   configured values.  However, in order to avoid an extensive
   negotiation phase, in the case of adjusting already configured OAM
   functions, the receiving side SHOULD NOT update the parameters
   requested in the Path message to an extent that would provide lower
   performance than what has been configured previously.

   The initiator MUST only update its OAM sink and source functions
   after it received the Resv message.  After this Path/Resv message
   exchange (in both unidirectional and bidirectional LSP cases) the OAM
   parameters are updated and OAM is running according the new parameter
   settings.  However OAM alarms are still disabled.  A subsequent Path/
   Resv message exchange with "OAM Alarms Enabled" ADMIN_STATUS flag set
   is needed to enable OAM alarms again.

3.3.  Deleting OAM Entities

   In some cases it may be useful to remove some or all OAM entities and
   functions from an LSP without actually tearing down the connection.

   To avoid any spurious alarm, first the LSP SHOULD be re-signaled with
   "OAM Alarms" ADMIN_STATUS flag cleared but unchanged OAM
   configuration.  Subsequently, the LSP is re-signaled with "OAM MEP
   Entities desired" and "OAM MIP Entities desired" LSP ATTRIBUTES flags
   cleared, and without the OAM Configuration TLV, this MUST result in
   the deletion of all OAM entities associated with the LSP.  All
   control and data plane resources in use by the OAM entities and
   functions SHOULD be freed up.  Alternatively, if only some OAM
   functions need to be removed, the LSP is re-signalled with the
   updated OAM Configuration TLV.  Changes between the contents of the
   previously signalled OAM Configuration TLV and the currently received
   TLV represent which functions SHOULD be removed/added.

   First, OAM source functions SHOULD be deleted and only after that
   SHOULD the associated OAM sink functions be removed, this will ensure
   that OAM messages do not leak outside the LSP.  To this end the
   initiator, before sending the Path message, SHOULD remove the OAM
   source, hence terminating the OAM message flow associated to the
   downstream direction.  In the case of a bidirectional connection, it
   SHOULD leave in place the OAM sink functions associated to the
   upstream direction.  The remote end, after receiving the Path
   message, SHOULD remove all associated OAM entities and functions and
   reply with a Resv message without an OAM Configuration TLV.  The
   initiator completely removes OAM entities and functions after the
   Resv message arrived.

4.  RSVP-TE Extensions

4.1.  LSP Attributes Flags

   In RSVP-TE the Flags field of the SESSION_ATTRIBUTE object is used to
   indicate options and attributes of the LSP.  The Flags field has 8
   bits and hence is limited to differentiate only 8 options.  [RFC5420]
   defines new objects for RSVP-TE messages to allow the signaling of
   arbitrary attribute parameters making RSVP-TE easily extensible to
   support new applications.  Furthermore, [RFC5420] allows options and
   attributes that do not need to be acted on by all Label Switched
   Routers (LSRs) along the path of the LSP.  In particular, these
   options and attributes may apply only to key LSRs on the path such as
   the ingress LSR and egress LSR.  Options and attributes can be
   signaled transparently, and only examined at those points that need
   to act on them.  The LSP_ATTRIBUTES and the LSP_REQUIRED_ATTRIBUTES
   objects are defined in [RFC5420] to provide means to signal LSP
   attributes and options in the form of TLVs.  Options and attributes
   signaled in the LSP_ATTRIBUTES object can be passed transparently
   through LSRs not supporting a particular option or attribute, while
   the contents of the LSP_REQUIRED_ATTRIBUTES object must be examined
   and processed by each LSR.  One TLV is defined in [RFC5420]: the
   Attributes Flags TLV.

   One bit (10 IANA to assign): "OAM MEP entities desired" is allocated
   in the LSP Attributes Flags TLV.  If the "OAM MEP entities desired"
   bit is set it is indicating that the establishment of OAM MEP
   entities are required at the endpoints of the signaled LSP.  If the
   establishment of MEPs is not supported an error must be generated:
   "OAM Problem/MEP establishment not supported".

   If the "OAM MEP entities desired" bit is set and but additional
   parameters are needed need also to be configured the OAM entities configured, an OAM Configuration TLV may MAY
   be included in the LSP_ATTRIBUTES object. Object.

   One bit (11 IANA to assign): "OAM MIP entities desired" is allocated
   in the LSP Attributes Flags TLV.  This bit can only be set if the
   "OAM MEP entities desired" bit is set.  If the "OAM MIP entities
   desired" bit is set in the LSP_ATTRIBUTES Flags TLV, it TLV in the
   LSP_REQUIRED_ATTRIBUTES Object, it is indicating that the
   establishment of OAM MIP entities is required at every transit node
   of the signalled LSP.  If the establishment of a MIP is not supported
   an error must be generated: "OAM Problem/MIP establishment not
   supported".

4.2.  OAM Configuration TLV

   This TLV provides information about which OAM technology/method
   should be used and carries sub-TLVs for any additional OAM
   configuration information.  The OAM Configuration TLV may be carried
   in the LSP_ATTRIBUTES or LSP_REQUIRED_ATTRIBUTES object in Path and
   Resv messages.

    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) (3) (IANA)     |           Length              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    OAM Type   |                 Reserved                      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   ~                           sub-TLVs                            ~
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type: indicates a new type: the OAM Configuration TLV (2) (3) (IANA to
   assign).

   OAM Type: specifies the technology specific OAM method.  If the
   requested OAM method is not supported an error must be generated:
   "OAM Problem/Unsupported OAM Type".

       OAM Type             Description
     ------------      --------------------
        0-255                Reserved

   This document defines no types.  IANA is requests requested to maintain the
   values in a new "RSVP-TE OAM Configuration Registry".

   The receiving node based on the OAM Type will check if a
   corresponding technology specific OAM configuration sub-TLV is
   included.  If the included technology specific OAM configuration sub-
   TLV is different than what is specified in the OAM Type an error must
   be generated: "OAM Problem/OAM Type Mismatch".

   Note that there is a hierarchical dependency in between the OAM
   configuration elements.  First, the "OAM MEP (and MIP) entities
   desired" flag needs to be set.  When it  Only when that is set MAY an "OAM
   Configuration TLV" may be included in the LSP_ATTRIBUTES or
   LSP_REQUIRED_ATTRIBUTES Object.  When this TLV is present, based on
   the "OAM Type" field, it
   may MAY carry a technology specific OAM
   configuration sub-TLV.  If this hierarchy is broken (e.g., "OAM MEP
   entities desired" flag is not set but an OAM Configuration TLV is
   present) an error must MUST be generated: "OAM Problem/Configuration
   Error".

4.2.1.  OAM Function Flags Sub-TLV

   As the first sub-TLV one "OAM Function Flags sub-TLV" MUST be always
   included in the "OAM Configuration TLV".  "OAM Function Flags"
   specifies which pro-active OAM functions (e.g., connectivity
   monitoring, loss and delay measurement) and which fault management
   signals MUST be established and configured.  If the selected OAM
   Function(s) is(are) not supported, an error must MUST be generated: "OAM
   Problem/Unsupported OAM Function".

    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              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   ~                      OAM Function Flags                       ~
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   OAM Function Flags is bitmap with extensible length based on the
   Lenght field of the TLV.  Bits are numbered from left to right as
   shown in the figure.  This document defines the following flags.

     OAM Function Flag bit#                Description
     ---------------------      ---------------------------
             0                   Continuity Check (CC)
             1                   Connectivity Verification (CV)
             2                   Performance Monitoring/Loss (PM/Loss)
             3                   Performance Monitoring/Delay (PM/Delay)

4.2.2.  Technology Specific sub-TLVs

   One technology specific sub-TLV SHOULD be defined for each "OAM
   Type".  This sub-TLV MUST contain any further OAM configuration
   information for that specific "OAM Type".  The technology specific
   sub-TLV may
   sub-TLV, when used, MUST be carried within the OAM Configuration TLV.

4.3.  Administrative Status Information

   Administrative Status Information is carried in the ADMIN_STATUS
   Object.  The Administrative Status Information is described in
   [RFC3471], the ADMIN_STATUS Object is specified for RSVP-TE in
   [RFC3473].

   Two bits are allocated for the administrative control of OAM
   monitoring.  In addition to the Reflect (R) bit, 7 bits are currently
   occupied (assigned by IANA or temporarily blocked by work in progress
   Internet drafts).  As the 24th and 25th bits (IANA to assign) this
   draft introduces the "OAM Flows Enabled" (M) and "OAM Alarms Enabled"
   (O) bits.  When the "OAM Flows Enabled" bit is set, OAM packets are
   sent if it is cleared no OAM packets are emitted.  When the "OAM
   Alarms Enabled" bit is set OAM triggered alarms are enabled and
   associated consequent actions are executed including the notification
   of the management system.  When this bit is cleared, alarms are
   suppressed and no action is executed and the management system is not
   notified.

4.4.  Handling OAM Configuration Errors

   To handle OAM configuration errors a new Error Code (IANA to assign)
   "OAM Problem" is introduced.  To refer to specific problems a set of
   Error Values is defined.

   If a node does not support the establishment of OAM MEP or MIP
   entities it must use the error value (IANA to assign): "MEP
   establishment not supported" or "MIP establishment not supported"
   respectively in the PathErr message.

   If a node does not support a specific OAM technology/solution it must
   use the error value (IANA to assign): "Unsupported OAM Type" in the
   PathErr message.

   If a different technology specific OAM configuration TLV is included
   than what was specified in the OAM Type an error must be generated
   with error value: "OAM Type Mismatch" in the PathErr message.

   There is a hierarchy in between the OAM configuration elements.  If
   this hierarchy is broken the error value: "Configuration Error" must
   be used in the PathErr message.

   If a node does not support a specific OAM Function it must use the
   error value: "Unsupported OAM Function" in the PathErr message.

5.  IANA

4.5.  Considerations

   Two bits ("OAM Alarms Enabled" (O) and "OAM Flows Enabled" (M)) needs
   to be allocated in on Point-to-Multipoint OAM Configuration

   RSVP-TE extensions for the ADMIN_STATUS Object.

   Two bits ("OAM MEP entities desired" and "OAM MIP entities desired")
   needs to be allocated establishment of point-to-multipoint
   (P2MP) LSPs are specified in the [RFC4875].  A P2MP LSP Attributes Flags Registry.

   This document specifies one new TLV to be carried in is comprised of
   multiple source-to-leaf (S2L) sub-LSPs.  These S2L sub-LSPs are set
   up between the
   LSP_ATTRIBUTES ingress and LSP_REQUIRED_ATTRIBUTES objects in Path egress LSRs and Resv
   messages: OAM Configuration TLV. are appropriately combined
   by the branch LSRs using RSVP semantics to result in a P2MP TE LSP.
   One new Error Code: "OAM Problem" and Path message may signal one or multiple S2L sub-LSPs for a set of new values: "MEP
   establishment not supported", "MIP establishment not supported",
   "Unsupported OAM Type", "Configuration Error" and "Unsupported OAM
   Function" needs to be assigned.

   The IANA is requested single
   P2MP LSP.  Hence the S2L sub-LSPs belonging to open a new registry: "RSVP-TE P2MP LSP can be
   signaled using one Path message or split across multiple Path
   messages.

   P2MP OAM
   Configuration Registry" that maintains mechanisms are very specific to the "OAM Type" code points and data plane technology,
   hence in this document we only highlight basic operations for P2MP
   OAM configuration.  We consider only the allocations configuration of "OAM Function Flags" within the root to
   leaves OAM Configuration
   TLV.

6.  Security Considerations

   The signaling flows of OAM related parameters P2MP LSPs and as such aspects of any return path
   are outside the automatic
   establishment scope of OAM entities introduces additional security
   considerations our discussions.  We also limit our
   consideration to those discussed cases where all leaves must successfully establish
   OAM entities in [RFC3473].  In particular, order a
   network element could be overloaded, if an attacker would request
   liveliness monitoring, with frequent periodic messages, P2MP OAM is successfully established.  In any
   case, the discussion set forth below provides only guidelines for a high
   number of LSPs, targeting a single network element.

   Security aspects will
   P2MP OAM configuration, details SHOULD be covered in more detailed specified in subsequent
   versions of this document.

7.  Acknowledgements technology
   specific documents.

   The authors would like root node may select if it uses a single Path message or multiple
   Path messages to thank Francesco Fondelli, Adrian Farrel,
   Loa Andersson, Eric Gray and Dimitri Papadimitriou for their useful
   comments.

Appendix A.  Discussion on Alternatives

   This appendix summarizes setup the discussions after IETF-71 about whole P2MP tree.  In the case when
   multiple Path messages are used the root node is responsible also to
   keep the way OAM configuration Configuration information should consistent in each of the sent
   Path messages, i.e., the same information MUST be carried included in RSVP-TE.

   The first question is how all
   Path messages used to construct the requirement for OAM establishment is
   signaled and how multicast tree.  Each branching
   node will propagate the operation Path message downstream on each of OAM is controlled.  There is the
   branches, when constructing a
   straightforward way to achieve these using existing objects and
   fields:

   o  Use one or more Path message the OAM flags in Configuration
   information MUST be copied unchanged from the received Path message,
   including the related ADMIN_STATUS bits, LSP Attributes Flag TLV within Attribute Flags and the LSP_ATTRIBUTES/LSP_REQUIRED_ATTRIBUTES object to signal that
   OAM entities for Configuration TLV.  The latter two also imply that the LSP need to
   LSP_ATTRIBUTES and LSP_REQUIRED_ATTRIBUTES Object MUST be established.  If copied for any
      reason this cannot be done a notification is sent or an error is
      raised.

   o  Once
   the LSP with upstream Path message to the desired OAM entities is established subsequent downstream Path messages.

   Leaves MUST create and configure OAM
      operation may be controlled using one or more flags sink functions according to the
   parameters received in the
      ADMIN_STATUS object.  For instance, Path message, for P2MP OAM configuration
   there is no possibility for parameter negotiation on a per leaf
   basis.  This is due to the generation fact that the only OAM source function,
   residing in the root of connectivity
      monitoring messages the tree, can only operate with a single
   configuration which must be disabled/enabled obeyed by setting/clearing all leaves.  If a
      flag in leaf cannot
   accept the ADMIN_STATUS object.

   However, there are two alternatives when OAM parameters it comes MUST use the RRO Attributes sub-object
   [RFC5420] to signaling notify the
   actual configuration parameters of OAM entities.

   o  Extension root of the LSP_ATTRIBUTES object with new TLVs.

   o  Definition of a new RSVP-TE object to carry OAM information. problem.  In particular, if the first case, a new
   OAM configuration TLV is defined in was successful the
   LSP_ATTRIBUTES object.  This TLV leaf would provide the detailed
   information needed for LSPs with a set OAM the "OAM MEP
   entities desired" flag in the LSP RRO Attributes
   Flag TLV.  The rationale for this approach is that sub-object in addition to
   setting flags the LSP_ATTRIBUTES object may carry complementary
   information for all or some of the flags set.  Furthermore, as top
   level RSVP-TE objects may become scarce resources, it seems Resv
   message, while, if due to be
   beneficial any reason, OAM entities could not to allocate new RSVP-TE objects for be
   established the purpose of
   providing detailed information for new LSP Attribute Flags.
   Currently there is only one TLV, Resv message should be sent with the "OAM MEP
   entities desired" bit cleared in the RRO Attributes Flag TLV, defined sub-object.
   Branching nodes should collect and merge the received RROs according
   to the procedures described in [RFC4875].  This way, the LSP_ATTRIBUTES object.  Defining root when
   receiving the Resv message (or messages if multiple Path messages
   were used to setup the tree) will have a new TLV associated with one clear information on which
   of the flags would make a precedence and possibly be a guideline for
   similar future extensions.

   The leaves could the OAM sink functions be established.  If all
   leaves established OAM entities successfully, the root can enable the
   OAM message flow.  On the other alternative would hand, if at some leaves the
   establishment was unsuccessful additional actions will be needed
   before the OAM message flow can be enabled.  Such action could be to allocate a dedicated object for
   setup two independent P2MP LSPs.  One with OAM
   configuration information.  The rationale for this is that the
   complex Configuration
   information that may towards leaves which successfully setup OAM.  This can be required
   done by prunning the leaves which failed to setup OAM of the
   previously signalled P2MP LSP.  The other P2MP LSP could be
   constructed for leaves without OAM configuration would
   unnecessarily add complexity entities.  What exact procedures
   are needed are technology specific and should be described in
   technology specific documents.

5.  IANA Considerations

   Two bits ("OAM Alarms Enabled" (O) and "OAM Flows Enabled" (M)) needs
   to be allocated in the ADMIN_STATUS Object.

   Two bits ("OAM MEP entities desired" and "OAM MIP entities desired")
   needs to be allocated in the LSP Attributes Flags Registry.

   This document specifies one new TLV to LSP_ATTRIBUTES/ be carried in the
   LSP_ATTRIBUTES and LSP_REQUIRED_ATTRIBUTES objects in Path and Resv
   messages: OAM Configuration TLV.

   One new Error Code: "OAM Problem" and their processing mechanisms.

   Furthermore, traditionally RSVP uses dedicated objects (*_SPECs) to
   carry configuration information of data plane entities, thus a set of new
   object like an "OAM_SPEC" may values: "MEP
   establishment not supported", "MIP establishment not supported",
   "Unsupported OAM Type", "Configuration Error" and "Unsupported OAM
   Function" needs to be a better fit assigned.

   IANA is requested to existing protocol
   elements. open a new registry: "RSVP-TE OAM Configuration
   Registry" that maintains the "OAM Type" code points, an associated
   sub-TLV space, and the allocations of "OAM Function Flags" within the
   OAM Configuration TLV.

6.  Security Considerations

   The authors signaling of this document favor OAM related parameters and the first alternative (adding automatic
   establishment of OAM entities based on RSVP-TE messages adds a new
   TLVs to LSP_ATTRIBTES/LSP_REQUIRED_ATTRIBUTES.  However, which
   alternative
   aspect to select the security considerations discussed in [RFC3473].  In
   particular, a network element could be overloaded, if a remote
   attacker could request liveliness monitoring, with frequent periodic
   messages, for standardization is up a high number of LSPs, targeting a single network
   element.  Such an attack can efficiently be prevented when mechanisms
   for message integrity and node authentication are deployed.  Since
   the working group
   to decide.  In any case, OAM configuratiuon extensions rely on the information hop-by-hop exchange of
   exiting RSVP-TE messages, procedures specified for RSVP message
   security in [RFC2747] can be used to mitigate possible attacks.

   For a more comprehensive discussion on GMPLS security please see the
   Security Framework for MPLS and GMPLS Networks [RFC5920].
   Cryptography can be carried used to protect against many attacks described in
   [RFC5920].

7.  Acknowledgements

   The authors would be the
   same or very similar like to thank Francesco Fondelli, Adrian Farrel,
   Loa Andersson, Eric Gray and Dimitri Papadimitriou for both alternatives. their useful
   comments.

8.  References

   [GELS-Framework]
              "GMPLS Ethernet

8.1.  Normative References

   [RFC3471]  "Generalized Multi-Protocol Label Switching Architecture and
              Framework", Internet Draft, work in progress.

   [GMPLS-OAM]
              "OAM Requirements for Generalized (GMPLS)
              Signaling Functional Description", RFC 3471, January 2003.

   [RFC3473]  "Generalized Multi-Protocol Label Switching (GMPLS) Networks",
              Signaling Resource ReserVation Protocol-Traffic
              Engineering (RSVP-TE) Extensions", RFC 3473, January 2003.

   [RFC5420]  "Encoding of Attributes for Multiprotocol Label Switching
              (MPLS) Label Switched Path (LSP) Establishment Using
              Resource ReserVation Protocol-Traffic Engineering
              (RSVP-TE)", RFC 5420, February 2009.

8.2.  Informative References

   [GMPLS-PBBTE]
              "Generalized Multiprotocol Label Switching (GMPLS) control
              of Ethernet Provider Backbone Traffic Engineering
              (PBB-TE)", Internet Draft, work in progress.

   [IEEE-CFM]
              "IEEE 802.1ag, Draft Standard for Connectivity Fault
              Management",  work in progress.

   [IEEE-PBBTE]
              "IEEE 802.1Qay Draft Standard for Provider Backbone
              Bridging Traffic Engineering",  work in progress.

   [MPLS-TP-FWK]
              "A Framework for MPLS in Transport Networks", Internet
              Draft, work in progress.

   [MPLS-TP-OAM-REQ]
              "Requirements for OAM in MPLS Transport Networks",
              Internet Draft, work in progress.

   [RFC2747]  "RSVP Cryptographic Authentication", RFC 2747,
              January 2000.

   [RFC3469]  "Framework for Multi-Protocol Label Switching (MPLS)-based
              Recovery", RFC 3469, February 2003.

   [RFC3471]  "Generalized Multi-Protocol Label Switching (GMPLS)
              Signaling Functional Description", RFC 3471, January 2003.

   [RFC3473]  "Generalized Multi-Protocol Label Switching (GMPLS)
              Signaling Resource ReserVation Protocol-Traffic
              Engineering (RSVP-TE) Extensions", RFC 3473, January 2003.

   [RFC4377]  "Operations and Management (OAM) Requirements for Multi-
              Protocol Label Switched (MPLS) Networks", RFC 4377,
              February 2006.

   [RFC5420]  "Encoding of Attributes for Multiprotocol Label Switching
              (MPLS)

   [RFC4379]  "Detecting Multi-Protocol Label Switched Path (LSP) Establishment Using (MPLS) Data Plane
              Failures", RFC 4379, February 2006.

   [RFC4875]  "Extensions to Resource ReserVation Protocol-Traffic Reservation Protocol - Traffic
              Engineering
              (RSVP-TE)", (RSVP-TE) for Point-to-Multipoint TE Label
              Switched Paths (LSPs)", RFC 5420, February 4875, May 2007.

   [RFC5654]  "Requirements of an MPLS Transport Profile", RFC 5654,
              September 2009.

   [RFC5828]  "GMPLS Ethernet Label Switching Architecture and
              Framework", RFC 5828, March 2010.

   [RFC5860]  "Requirements for OAM in MPLS Transport Networks",
              RFC 5860, May 2010.

   [RFC5920]  "Security Framework for MPLS and GMPLS Networks",
              RFC 5920, July 2010.

   [RFC5921]  "A Framework for MPLS in Transport Networks", RFC 5921,
              July 2010.

Authors' Addresses

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

   Email: attila.takacs@ericsson.com

   Don Fedyk
   Alcatel-Lucent
   Groton, MA  01450
   USA

   Email: donald.fedyk@alcatel-lucent.com

   Jia He
   Huawei

   Email: hejia@huawei.com