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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: September 10, 2009                                       Nortel
                                                                   J. He
                                                                  Huawei
                                                           March 9, 2009


     OAM Configuration Framework and Requirements for GMPLS RSVP-TE
               draft-ietf-ccamp-oam-configuration-fwk-01

Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with the
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   This Internet-Draft will expire on September 10, 2009.















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Copyright Notice

   Copyright (c) 2009 IETF Trust and the persons identified as the
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   This document is subject to BCP 78 and the IETF Trust's Legal
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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.








































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Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  5
   2.  Requirements . . . . . . . . . . . . . . . . . . . . . . . . .  7
   3.  GMPLS RSVP-TE Extensions . . . . . . . . . . . . . . . . . . . 10
     3.1.  Operation overview . . . . . . . . . . . . . . . . . . . . 10
     3.2.  LSP Attributes flags . . . . . . . . . . . . . . . . . . . 11
     3.3.  OAM Configuration TLV  . . . . . . . . . . . . . . . . . . 12
     3.4.  Monitoring Disabled - Admin_Status bit . . . . . . . . . . 13
     3.5.  OAM configuration errors . . . . . . . . . . . . . . . . . 13
   4.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 15
   5.  Security Considerations  . . . . . . . . . . . . . . . . . . . 16
   6.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 17
   Appendix A.  Discussion on alternatives  . . . . . . . . . . . . . 18
   7.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 20
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 21
   Intellectual Property and Copyright Statements . . . . . . . . . . 22



























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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 capability to carry technology specific information.  Extensions
   can be grouped into generic elements that are applicable to any OAM



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   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.

   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.





































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2.  Requirements

   MPLS OAM requirements are described in [RFC4377].  It provides
   requirements to create consistent OAM functionality for MPLS
   networks.  GMPLS OAM requirements are described in [GMPLS-OAM].  The
   GMPLS OAM requirements are based on the MPLS OAM requirements
   [RFC4377], in addition it also considers the existing OAM techniques
   in non-packet 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].  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].  MPLS-TP poses requirements on the control plane
   to configure and control OAM entities.

   o  The use of OAM functions SHOULD be optional for the operator.  A
      network operator SHOULD be able to choose which OAM functions to
      use and which Maintenance Entity to apply them to.

   o  The MPLS-TP control pane MUST support the configuration and
      modification of OAM maintenance points as well as the activation/
      deactivation of OAM when the transport path is established or
      modified.  OAM functions SHOULD be configurable as part of
      connectivity (LSP or PW) management.

   Ethernet Connectivity Fault Management (CFM) defines an adjunct
   connectivity monitoring OAM flow to check the liveliness of Ethernet
   networks [IEEE-CFM].  With PBB-TE [IEEE-PBBTE] Ethernet networks will



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   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) [GELS-Framework] 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
   solution.  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]
   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.



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      That is generic OAM parameters and data plane or OAM technology
      specific parameters must be separated.

















































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3.  GMPLS RSVP-TE Extensions

3.1.  Operation overview

   In general, two types of Maintenance Poits (MPs) can be
   distinguished: Maintenance End Points (MEPs) and Maintenance
   Intermediate Points (MIPs).  MEPs are located 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 of an ME with the same unique ME
   Assocication ID (MA ID).  Each MEP must have unique identification
   (MEP ID) within a Maintenance Entity.

   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 with an MA ID and MEP
   IDs.  The MA ID may be used to detect misconfiguration errors and
   leaking OAM traffic.  While the MEP ID can be used to demultiplex and
   identify the originating MEP of OAM messages.  Since MIPs do not
   originate OAM packets, on top of the configuration of Maintenance
   Entity associations, no specific configuration is required for them.

   In addition to the MA and MEP 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.


                                 MEP
                           +-------------+
                           |OAM Functions|
                           | FM   |   PM |
                           +------+------+
                           |    MEP ID   |
                           +-------------+
                           |    MA ID    |
                           +-------------+
                           +-------------+
                           | connection  |
                           +-------------+

   In some cases all the above parameters may be either derived form



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   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 a MA with MPs 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.

   MA and MEP IDs as well as 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.

3.2.  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.  [RFC4420]
   defines a new object for RSVP-TE messages to allow the signaling of
   arbitrary attribute parameters making RSVP-TE easily extensible to
   support new applications.  Furthermore, [RFC4420] 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 object and the
   LSP_REQUIRED_ATTRIBUTES objects are defined in [RFC4420] 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 [RFC4420]: 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 additional
   parameters are needed to configure the OAM entities an OAM
   Configuration TLV may be included in the LSP_ATTRIBUTES object.

   One bit (11 IANA to assign): "OAM MIP entities desired" is allocated



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   in the LSP Attributes Flags TLV.  If the "OAM MIP entities desired"
   bit is set it is indicating that the establishment of OAM MIP
   entities are required at the transit nodes of the signaled LSP.  This
   bit can only be set if the "OAM MEP entities desired" bit is set.  If
   the establishment of MIPs is not supported an error must be
   generated: "OAM Problem/MIP establishment not supported".

   One bit (12 IANA to assign): "Alarm indication desired" is allocated
   in the LSP Attributes Flags TLV.  If the "Alarm indication desired"
   bit is set it is indicating that the OAM entities of the signaled LSP
   should be notified of lower layer failures.  In the case of
   hierarchical LSPs this will create an association between the
   underlying (server) LSP's OAM entities and the currently signaled
   (client) LSP's OAM entities.

3.3.  OAM Configuration TLV

   This TLV specifies which OAM technology/method should be used for the
   LSP.  The OAM Configuration TLV is carried in the LSP_ATTRIBUTES
   object in Path 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) (IANA)     |           Length              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    OAM Type   |   Reserved    |         OAM Function          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   ~                           sub-TLVs                            ~
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

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

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

   This document defines no types.  The receiving node based on the OAM
   Type will check if a corresponding technology specific OAM
   configuration sub-TLV is included.  If different technology specific
   OAM configuration sub-TLV is included than what was specified in the
   OAM Type an error must be generated: "OAM Problem/OAM Type Mismatch".





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

   There is a hierarchy in between the OAM configuration elements.
   First, the "OAM MEP (and MIP) entities desired" flag needs to be set,
   if it is set an "OAM Configuration TLV" may be included in the
   LSP_ATTRIBUTES object, if this TLV is present based on the OAM Type a
   technology specific OAM configuration sub-TLV may be present.  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".

   OAM Function Flags: specifies pro-active OAM functions (e.g.,
   connectivity monitoring, loss and delay measurement) that should be
   established and configured.  If the selected OAM Function(s) is(are)
   not supported an error must be generated: "OAM Problem/Unsupported
   OAM Function".

   This document defines the following flags.


       OAM Function Flag                Description
     ---------------------      ---------------------------
             0                   Connectivity Monitoring
             1                   Performance Monitoring/Loss
             2                   Performance Monitoring/Delay

3.4.  Monitoring Disabled - Admin_Status bit

   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].

   One bit is 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 bit (IANA to assign) this draft
   introduces the Monitoring Disabled (M) bit.  When this bit is set the
   monitoring and OAM triggered alarms of the LSP are disabled (e.g., no
   continuity check messages are sent, no AIS is generated).

3.5.  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.



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   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 an the error value: "OAM Problem/
   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 (IANA to assign): "Unsupported OAM Function" in the
   PathErr message.































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4.  IANA Considerations

   One bit (Monitoring Disabled (M)) needs to be allocated in the
   ADMIN_STATUS Object.

   One bit ("OAM entities desired") needs to be allocated in the LSP
   Attributes Flag Registry.

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

   One new Error Code: "OAM Problem" and three new values: "MEP
   establishment not supported", "MIP establishment not supported",
   "Unsupported OAM Type" and "Unsupported OAM Function" needs to be
   assigned.



































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5.  Security Considerations

   The signaling of OAM related parameters and the automatic
   establishment of OAM entities introduces additional security
   considerations to those discussed in [RFC3473].  In particular, a
   network element could be overloaded, if an attacker would request
   liveliness monitoring, with frequent periodic messages, for a high
   number of LSPs, targeting a single network element.

   Security aspects will be covered in more detailed in subsequent
   versions of this document.








































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6.  Acknowledgements

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














































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Appendix A.  Discussion on alternatives

   This appendix summarizes the discussions after IETF-71 about the way
   OAM configuration information should be carried in RSVP-TE.

   The first question is how the requirement for OAM establishment is
   signaled and how the operation of OAM is controlled.  There is a
   straightforward way to achieve these using existing objects and
   fields:

   o  Use one or more OAM flags in the LSP Attributes Flag TLV within
      the LSP_ATTRIBUTES/LSP_REQUIRED_ATTRIBUTES object to signal that
      OAM entities for the LSP need to be established.  If for any
      reason this cannot be done a notification is sent or an error is
      raised.

   o  Once the LSP with the desired OAM entities is established OAM
      operation may be controlled using one or more flags in the
      ADMIN_STATUS object.  For instance, the generation of connectivity
      monitoring messages can be disabled/enabled by setting/clearing a
      flag in the ADMIN_STATUS object.

   However, there are two alternatives when it comes to signaling the
   actual configuration parameters of OAM entities.

   o  Extension of the LSP_ATTRIBUTES object with new TLVs.

   o  Definition of a new RSVP-TE object to carry OAM information.

   In the first case, a new OAM configuration TLV is defined in the
   LSP_ATTRIBUTES object.  This TLV would provide the detailed
   information needed for LSPs with a set OAM flag in the LSP Attributes
   Flag TLV.  The rationale for this approach is that 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 to be
   beneficial not to allocate new RSVP-TE objects for the purpose of
   providing detailed information for new LSP Attribute Flags.
   Currently there is only one TLV, the Attributes Flag TLV, defined in
   the LSP_ATTRIBUTES object.  Defining a new TLV associated with one of
   the flags would make a precedence and possibly be a guideline for
   similar future extensions.

   The other alternative would be to allocate a dedicated object for OAM
   configuration information.  The rationale for this is that the
   complex information that may be required for OAM configuration would
   unnecessarily add complexity to LSP_ATTRIBUTES/
   LSP_REQUIRED_ATTRIBUTES objects and their processing mechanisms.



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   Furthermore, traditionally RSVP uses dedicated objects (*_SPECs) to
   carry configuration information of data plane entities, thus a new
   object like an "OAM_SPEC" may be a better fit to existing protocol
   elements.

   The authors of this document favor the first alternative (adding new
   TLVs to LSP_ATTRIBTES/LSP_REQUIRED_ATTRIBUTES.  However, which
   alternative to select for standardization is up for the working group
   to decide.  In any case, the information to be carried would be the
   same or very similar for both alternatives.









































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7.  References

   [GELS-Framework]
              "GMPLS Ethernet Label Switching Architecture and
              Framework", Internet Draft, work in progress.

   [GMPLS-OAM]
              "OAM Requirements for Generalized Multi-Protocol Label
              Switching (GMPLS) Networks", 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.

   [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.

   [RFC4420]  "Encoding of Attributes for Multiprotocol Label Switching
              (MPLS) Label Switched Path (LSP) Establishment Using
              Resource ReserVation Protocol-Traffic Engineering
              (RSVP-TE)", RFC 4420, February 2006.






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Authors' Addresses

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

   Email: attila.takacs@ericsson.com


   Don Fedyk
   Nortel
   600 Technology Park Drive
   Billerica, MA  01821
   USA

   Email: dwfedyk@nortel.com


   Jia He
   Huawei


   Email: hejia@huawei.com


























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