[Docs] [txt|pdf] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits] [IPR]

Versions: (draft-takacs-ccamp-oam-configuration-fwk) 00 01 02 03 04 05 06 07 08 09 10 11 12 13 RFC 7260

Network Working Group                                          A. Takacs
Internet-Draft                                                  Ericsson
Intended status: Standards Track                                D. Fedyk
Expires: December 17, 2013                                Alcatel-Lucent
                                                                   J. He
                                                                  Huawei
                                                           June 15, 2013


             GMPLS RSVP-TE extensions for OAM Configuration
               draft-ietf-ccamp-oam-configuration-fwk-10

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 [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
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

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

   This Internet-Draft will expire on December 17, 2013.

Copyright Notice



Takacs, et al.          Expires December 17, 2013               [Page 1]

Internet-Draft       RSVP-TE based OAM Configuration           June 2013


   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
   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.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Requirements . . . . . . . . . . . . . . . . . . . . . . . . .  4
   3.  RSVP-TE based OAM Configuration  . . . . . . . . . . . . . . .  6
     3.1.  Establishment of OAM Entities and Functions  . . . . . . .  7
     3.2.  Adjustment of OAM Parameters . . . . . . . . . . . . . . .  8
     3.3.  Deleting OAM Entities  . . . . . . . . . . . . . . . . . .  9
   4.  RSVP-TE Extensions . . . . . . . . . . . . . . . . . . . . . . 10
     4.1.  LSP Attributes Flags . . . . . . . . . . . . . . . . . . . 10
     4.2.  OAM Configuration TLV  . . . . . . . . . . . . . . . . . . 11
       4.2.1.  OAM Function Flags Sub-TLV . . . . . . . . . . . . . . 12
       4.2.2.  Technology Specific Sub-TLVs . . . . . . . . . . . . . 13
     4.3.  Administrative Status Information  . . . . . . . . . . . . 13
     4.4.  Handling OAM Configuration Errors  . . . . . . . . . . . . 14
     4.5.  Considerations on Point-to-Multipoint OAM Configuration  . 14
   5.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 16
   6.  Security Considerations  . . . . . . . . . . . . . . . . . . . 17
   7.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 17
   8.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 17
     8.1.  Normative References . . . . . . . . . . . . . . . . . . . 17
     8.2.  Informative References . . . . . . . . . . . . . . . . . . 18
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19














Takacs, et al.          Expires December 17, 2013               [Page 2]

Internet-Draft       RSVP-TE based OAM Configuration           June 2013


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 Ethernet Provider
   Backbone Bridging - Traffic Engineering (PBB-TE) and MPLS.  In most
   of these technologies, there are Operations, Administration and
   Maintenance (OAM) functions employed to monitor the health and
   performance of the connections and to trigger data plane (DP)
   recovery mechanisms.  Similar to connection provisioning, OAM
   functions follow general principles, but also have some technology
   specific characteristics.

   OAM is an integral part of transport connections.  Therefore 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,
   such as Fault Management (FM) and Performance Management (PM), may be
   optional (based on network management policies).  Hence, the network
   operator must be able to choose which set of OAM functions to apply
   to specific connections and which parameters should be configured and
   activated.  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 prone 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.  In some
   situations it may be possible to use the GMPLS control plane to
   control on-demand OAM functions too.

   This document describes requirements for OAM configuration and
   control via RSVP-TE.  Extensions to the RSVP-TE protocol are
   specified providing a framework to configure and control OAM entities
   along with the capability to carry technology specific information.



Takacs, et al.          Expires December 17, 2013               [Page 3]

Internet-Draft       RSVP-TE based OAM Configuration           June 2013


   Extensions can be grouped into: generic elements that are applicable
   to any OAM solution; and technology specific elements that provide
   additional configuration parameters, which may only be needed for a
   specific OAM technology.  This document specifies the technology
   agnostic elements 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 used to set up the LSPs that
   are to be monitored using OAM.


2.  Requirements

   This section summarizes various technology-specific OAM requirements
   which can be used as a basis for an OAM configuration framework.

   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] 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 time frames.

   MPLS-TP defines a profile of MPLS targeted at transport applications
   [RFC5921].  This profile specifies the specific MPLS characteristics



Takacs, et al.          Expires December 17, 2013               [Page 4]

Internet-Draft       RSVP-TE based OAM Configuration           June 2013


   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 [RFC5654] and [RFC5860].  MPLS-TP poses
   the following requirements on the control plane to configure and
   control OAM entities:

   o  From [RFC5860]: OAM functions MUST operate and be configurable
      even in the absence of a control plane.  Conversely, it SHOULD be
      possible to configure as well as enable/disable the capability to
      operate OAM functions as part of connectivity management, and it
      SHOULD also be possible to configure as well as enable/disable the
      capability to operate OAM functions after connectivity has been
      established.

   o  From [RFC5654]: 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 flow to check the liveliness of Ethernet
   networks [IEEE.802.1Q-2011].  With PBB-TE [IEEE.802.1Q-2011] Ethernet
   networks support explicitly-routed Ethernet connections.  CFM can be
   used to track the liveliness of PBB-TE connections and detect data
   plane failures.  In IETF, the GMPLS controlled Ethernet Label
   Switching (GELS) (see [RFC5828] and [RFC6060]) work extended the
   GMPLS control plane to support the establishment of 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, needs to provide a general
   framework to be applicable to a wide range of data plane technologies
   and OAM solutions.  There are three typical data plane technologies
   used for transport applications: wavelength based such as WSON, TDM
   based such as SDH/SONET, and packet based such as MPLS-TP [RFC5921]
   and Ethernet PBB-TE [IEEE.802.1Q-2011].  For 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



Takacs, et al.          Expires December 17, 2013               [Page 5]

Internet-Draft       RSVP-TE based OAM Configuration           June 2013


      operator is only concerned about critical alarms.  Therefore 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.  This allows 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 between fast failure detection
      and data 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 used to
      continuously collect information about specific characteristics of
      the connection.  For consistent measurement of Service Level
      Agreements (SLAs), it MUST be possible to set common configuration
      parameters for the LSP.

   o  The extensions MUST allow the operator to use only a minimal set
      of OAM configuration and control features if supported by the OAM
      solution or network management policy.  Generic OAM parameters and
      data plane or OAM technology specific parameters MUST be
      supported.


3.  RSVP-TE based OAM Configuration

   In general, two types of Maintenance 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, a 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
   unambiguously identify MPs and MEs.

   In addition to MP and ME identification parameters, pro-active OAM
   functions (e.g., Continuity Check (CC) and Performance Monitoring
   (PM)) may have additional parameters that require configuration as



Takacs, et al.          Expires December 17, 2013               [Page 6]

Internet-Draft       RSVP-TE based OAM Configuration           June 2013


   well.  In particular, the frequency of periodic CC packets and the
   measurement interval for loss and delay measurements may need to be
   configured.

   The above parameters may be either derived from LSP provisioning
   information, or alternatively, pre-configured default values can be
   used.  In the simplest case, the control plane MAY provide
   information on whether or not OAM entities need to be setup for the
   signaled LSP.  If OAM entities are created, control plane signaling
   MUST also provide a 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.
   Therefore, the OAM configuration framework allows selecting a
   specific OAM solution to be used for the signaled LSP and provides
   means to carry detailed OAM configuration information in technology
   specific TLVs.

3.1.  Establishment of OAM Entities and Functions

   In order to avoid spurious alarms, OAM functions should 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 with the first signaling of the LSP.  The below procedures
   apply to both cases.

   Before initiating a Path message with OAM Configuration information,
   an initiating node MUST establish and configure the corresponding OAM
   entities locally.  But until the LSP is established, OAM source
   functions MUST NOT start sending any OAM messages.  In the case of
   bidirectional connections, in addition to the OAM source function,
   the initiator node MUST set up the OAM sink function and prepare it
   to receive OAM messages.  During this time the OAM alarms MUST be
   suppressed (e.g., due to missing or unidentified OAM messages).  To
   achieve OAM alarm suppression, Path message MUST be sent with the
   "OAM Alarms Enabled" ADMIN_STATUS flag cleared.

   When the Path message arrives at the receiver, the remote end MUST
   establish and configure OAM entities according to the OAM information
   provided in the Path message.  If this is not possible, a PathErr



Takacs, et al.          Expires December 17, 2013               [Page 7]

Internet-Draft       RSVP-TE based OAM Configuration           June 2013


   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, in addition to
   the OAM sink function, an OAM source function MUST be set up and,
   according to the requested configuration, 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
   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 exchange, OAM entities are established and configured for
   the LSP and OAM messages are exchanged.  OAM alarms can now be
   enabled.  The initiator, during the period when OAM alarms are
   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,



Takacs, et al.          Expires December 17, 2013               [Page 8]

Internet-Draft       RSVP-TE based OAM Configuration           June 2013


   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 parameters 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 an 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 (e.g., lower frequency of monitoring packets) than what
   has been in operation 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 alarms, first the LSP MUST be re-signaled with
   "OAM Alarms Enabled" 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-signaled with the updated
   OAM Configuration TLV.  Changes between the contents of the
   previously signaled OAM Configuration TLV and the currently received
   TLV represent which functions MUST be removed/added.

   OAM source functions MUST be deleted first and only after the "OAM
   Alarms Disabled" can 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, MUST remove
   the OAM source, hence terminating the OAM message flow associated to



Takacs, et al.          Expires December 17, 2013               [Page 9]

Internet-Draft       RSVP-TE based OAM Configuration           June 2013


   the downstream direction.  In the case of a bidirectional connection,
   it MUST leave in place the OAM sink functions associated to the
   upstream direction.  The remote end, after receiving the Path
   message, MUST 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 (IANA to assign): "OAM MEP entities desired" is allocated in
   the LSP Attributes Flags TLV to be used in the LSP_ATTRIBUTES object.
   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 additional
   parameters need to be configured, an OAM Configuration TLV MAY be
   included in the LSP_ATTRIBUTES or LSP_REQUIRED_ATTRIBUTES object.

   One bit (IANA to assign): "OAM MIP entities desired" is allocated in
   the LSP Attributes Flags TLV to be used in the LSP_ATTRIBUTES or
   LSP_REQUIRED_ATTRIBUES objects.  This bit MUST only be set if the



Takacs, et al.          Expires December 17, 2013              [Page 10]

Internet-Draft       RSVP-TE based OAM Configuration           June 2013


   "OAM MEP entities desired" bit is set.  If the "OAM MIP entities
   desired" bit is set in the LSP_ATTRIBUTES Flags 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 signaled 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.  When carried in the LSP_REQUIRED_ATTRIBUTES object,
   it is indicating that intermediate nodes MUST recognize and react on
   the OAM configuration information.


    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              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    OAM Type   |                 Reserved                      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   ~                           sub-TLVs                            ~
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

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

   OAM Type: specifies the technology specific OAM method.  When carried
   in the LSP_REQUIRED_ATTRIBUTES Object, if the requested OAM method is
   not supported at any given node an error MUST be generated: "OAM
   Problem/Unsupported OAM Type".  When carried in the LSP_ATTRIBUTES
   Object, intermediate nodes not supporting the OAM Type pass the
   object forward unchanged as specified in [RFC5420], and only Label
   Edge Nodes MUST generate an error if the OAM Type is not supported at
   the LSP end-point.


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




Takacs, et al.          Expires December 17, 2013              [Page 11]

Internet-Draft       RSVP-TE based OAM Configuration           June 2013


   This document defines no types.  IANA is 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 in the OAM Configuration TLV.  If the included technology
   specific OAM configuration sub-TLV is different from what is
   specified in the OAM Type an error MUST be generated: "OAM Problem/
   OAM Type Mismatch".  IANA is requested to maintain the sub-TLV space
   in the new "RSVP-TE OAM Configuration Registry".


     Sub-TLV Type                  Description
     ------------      ------------------------------------
         0                          Reserved
         1                  OAM Function Flags Sub-TLV
        2-31               Reserved for generic Sub-TLVs
        32-          Reserved for technology specific Sub-TLVs

   Note that there is a hierarchical dependency between the OAM
   configuration elements.  First, the "OAM MEP entities desired" flag
   needs to be set.  Only when that flag is set MAY an "OAM
   Configuration TLV" be included in the LSP_ATTRIBUTES or
   LSP_REQUIRED_ATTRIBUTES Object.  When this TLV is present, based on
   the "OAM Type" field, it 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 be generated: "OAM Problem/Configuration
   Error".

4.2.1.  OAM Function Flags Sub-TLV

   As the first sub-TLV the "OAM Function Flags Sub-TLV" MUST always be
   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 be generated: "OAM
   Problem/Unsupported OAM Function".












Takacs, et al.          Expires December 17, 2013              [Page 12]

Internet-Draft       RSVP-TE based OAM Configuration           June 2013


    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
   Length field of the TLV.  Bits are numbered from left to right.  IANA
   is requested to maintain the OAM Function Flags in the new "RSVP-TE
   OAM Configuration Registry".  This document defines the following
   flags.


    OAM Function Flag bit#      Description
    ---------------------  ---------------------------
     0                     Continuity Check (CC)
     1                     Connectivity Verification (CV)
     2                     Fault Management Signal (FMS)
     3                     Performance Monitoring/Loss (PM/Loss)
     4                     Performance Monitoring/Delay (PM/Delay)
     5                     Performance Monitoring/Throughput Measurement
                           (PM/Throughput)

4.2.2.  Technology Specific Sub-TLVs

   One technology specific sub-TLV MAY 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, when
   used, MUST be carried within the OAM Configuration TLV.  IANA is
   requested to maintain the OAM technology specific sub-TLV space in
   the new "RSVP-TE OAM Configuration Registry".

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.  Two bits (IANA to assign) are allocated by this draft:
   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"



Takacs, et al.          Expires December 17, 2013              [Page 13]

Internet-Draft       RSVP-TE based OAM Configuration           June 2013


   bit is set OAM triggered alarms are enabled and associated consequent
   actions are executed including the notification to 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 are defined under the "OAM Problem" error code.

   If a node does not support the establishment of OAM MEP or MIP
   entities it MUST use the error value: "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: "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 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.

4.5.  Considerations on Point-to-Multipoint OAM Configuration

   RSVP-TE extensions for the establishment of point-to-multipoint
   (P2MP) LSPs are specified in [RFC4875].  A P2MP LSP is comprised of
   multiple source-to-leaf (S2L) sub-LSPs.  These S2L sub-LSPs are set
   up between the ingress and egress LSRs, and are appropriately
   combined by the branch LSRs using RSVP semantics to result in a P2MP
   TE LSP.  One Path message may signal one or multiple S2L sub-LSPs for
   a single P2MP LSP.  Hence, the S2L sub-LSPs belonging to a P2MP LSP
   can be signaled using one Path message or split across multiple Path
   messages.

   P2MP OAM mechanisms are very specific to the data plane technology,
   therefore in this document, we only highlight the basic principles of
   P2MP OAM configuration.  We consider only the root to leaf OAM flows,
   and as such, aspects of the configuration of return paths are outside
   the scope of our discussions.  We also limit our consideration to the
   case where all leaves must successfully establish OAM entities with



Takacs, et al.          Expires December 17, 2013              [Page 14]

Internet-Draft       RSVP-TE based OAM Configuration           June 2013


   identical configuration in order the P2MP OAM is successfully
   established.  In any case, the discussion set forth below provides
   only guidelines for P2MP OAM configuration, details will be specified
   in technology specific documents.

   The root node may use a single Path message or multiple Path messages
   to setup the whole P2MP tree.  In the case when multiple Path
   messages are used, the root node is responsible to keep the OAM
   Configuration information consistent in each of the sent Path
   messages, i.e., the same information MUST be included in all Path
   messages used to construct the multicast tree.  Each branching node
   will propagate the Path message downstream on each of the branches,
   when constructing a Path message the OAM Configuration information
   MUST be copied unchanged from the received Path message, including
   the related ADMIN_STATUS bits, LSP Attribute Flags and the OAM
   Configuration TLV.  The latter two also imply that the LSP_ATTRIBUTES
   and LSP_REQUIRED_ATTRIBUTES Object MUST be copied for the upstream
   Path message to the subsequent downstream Path messages.

   Leaves MUST create and configure OAM sink functions according to the
   parameters received in the Path message, for P2MP OAM configuration
   there is no possibility for parameter negotiation on a per leaf
   basis.  This is due to the fact that the OAM source function,
   residing in the root of the tree, will operate with a single
   configuration, which then must be obeyed by all leaves.  If a leaf
   cannot accept the OAM parameters it MUST use the RRO Attributes sub-
   object [RFC5420] to notify the root about the problem.  In
   particular, if the OAM configuration was successful, the leaf would
   set the "OAM MEP entities desired" flag in the RRO Attributes sub-
   object in the Resv message.  On the other hand, if OAM entities could
   not be established the Resv message should be sent with the "OAM MEP
   entities desired" bit cleared in the RRO Attributes sub-object.
   Branching nodes should collect and merge the received RROs according
   to the procedures described in [RFC4875].  This way, the root when
   receiving the Resv message (or messages if multiple Path messages
   were used to set up the tree) will have a clear information about
   which of the leaves could establish the OAM functions.  If all leaves
   established OAM entities successfully, the root can enable the OAM
   message flow.  On the other 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 setup two
   independent P2MP LSPs.  One LSP with OAM Configuration information
   towards leaves which could successfully setup the OAM function.  This
   can be done by pruning the leaves which failed to setup OAM of the
   previously signaled P2MP LSP.  The other P2MP LSP could be
   constructed for leaves without OAM entities.  The exact procedures
   will be described in technology specific documents.




Takacs, et al.          Expires December 17, 2013              [Page 15]

Internet-Draft       RSVP-TE based OAM Configuration           June 2013


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 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 a set of new values: "MEP
   establishment not supported", "MIP establishment not supported",
   "Unsupported OAM Type", "Configuration Error", "OAM Type Mismatch"
   and "Unsupported OAM Function" needs to be assigned.

   IANA is requested to 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.


   RSVP-TE OAM Configuration Registry

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


   Sub-TLV Type                  Description
   ------------      ------------------------------------
       0                          Reserved
       1                  OAM Function Flags Sub-TLV
      2-31               Reserved for generic Sub-TLVs
      32-          Reserved for technology specific Sub-TLVs


   OAM Function Flag bit#      Description
   ----------------------  -------------------------------
     0                     Continuity Check (CC)
     1                     Connectivity Verification (CV)
     2                     Fault Management Signal (FMS)
     3                     Performance Monitoring/Loss (PM/Loss)
     4                     Performance Monitoring/Delay (PM/Delay)
     5                     Performance Monitoring/Throughput Measurement
                           (PM/Throughput)
     6-                    Reserved



Takacs, et al.          Expires December 17, 2013              [Page 16]

Internet-Draft       RSVP-TE based OAM Configuration           June 2013


6.  Security Considerations

   The signaling of OAM related parameters and the automatic
   establishment of OAM entities based on RSVP-TE messages adds a new
   aspect to 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 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 OAM configuration extensions rely on the 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 used to protect against many attacks described in
   [RFC5920].


7.  Acknowledgements

   The authors would like to thank Francesco Fondelli, Adrian Farrel,
   Loa Andersson, Eric Gray and Dimitri Papadimitriou for their useful
   comments.


8.  References

8.1.  Normative References

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

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

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

   [RFC5420]  Farrel, A., Papadimitriou, D., Vasseur, JP., and A.
              Ayyangarps, "Encoding of Attributes for MPLS LSP
              Establishment Using Resource Reservation Protocol Traffic
              Engineering (RSVP-TE)", RFC 5420, February 2009.





Takacs, et al.          Expires December 17, 2013              [Page 17]

Internet-Draft       RSVP-TE based OAM Configuration           June 2013


8.2.  Informative References

   [IEEE.802.1Q-2011]
              IEEE, "IEEE Standard for Local and metropolitan area
              networks -- Media Access Control (MAC) Bridges and Virtual
              Bridged Local Area Networks", IEEE Std 802.1Q, 2011.

   [RFC2747]  Baker, F., Lindell, B., and M. Talwar, "RSVP Cryptographic
              Authentication", RFC 2747, January 2000.

   [RFC4377]  Nadeau, T., Morrow, M., Swallow, G., Allan, D., and S.
              Matsushima, "Operations and Management (OAM) Requirements
              for Multi-Protocol Label Switched (MPLS) Networks",
              RFC 4377, February 2006.

   [RFC4379]  Kompella, K. and G. Swallow, "Detecting Multi-Protocol
              Label Switched (MPLS) Data Plane Failures", RFC 4379,
              February 2006.

   [RFC4875]  Aggarwal, R., Papadimitriou, D., and S. Yasukawa,
              "Extensions to Resource Reservation Protocol - Traffic
              Engineering (RSVP-TE) for Point-to-Multipoint TE Label
              Switched Paths (LSPs)", RFC 4875, May 2007.

   [RFC5654]  Niven-Jenkins, B., Brungard, D., Betts, M., Sprecher, N.,
              and S. Ueno, "Requirements of an MPLS Transport Profile",
              RFC 5654, September 2009.

   [RFC5828]  Fedyk, D., Berger, L., and L. Andersson, "Generalized
              Multiprotocol Label Switching (GMPLS) Ethernet Label
              Switching Architecture and Framework", RFC 5828,
              March 2010.

   [RFC5860]  Vigoureux, M., Ward, D., and M. Betts, "Requirements for
              Operations, Administration, and Maintenance (OAM) in MPLS
              Transport Networks", RFC 5860, May 2010.

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

   [RFC5921]  Bocci, M., Bryant, S., Frost, D., Levrau, L., and L.
              Berger, "A Framework for MPLS in Transport Networks",
              RFC 5921, July 2010.

   [RFC6060]  Fedyk, D., Shah, H., Bitar, N., and A. Takacs,
              "Generalized Multiprotocol Label Switching (GMPLS) Control
              of Ethernet Provider Backbone Traffic Engineering
              (PBB-TE)", RFC 6060, March 2011.



Takacs, et al.          Expires December 17, 2013              [Page 18]

Internet-Draft       RSVP-TE based OAM Configuration           June 2013


Authors' Addresses

   Attila Takacs
   Ericsson
   Konyves Kalman krt. 11.
   Budapest,   1097
   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



























Takacs, et al.          Expires December 17, 2013              [Page 19]


Html markup produced by rfcmarkup 1.107, available from http://tools.ietf.org/tools/rfcmarkup/