path: root/doc/rfc/rfc4783.txt

Network Working Group                                     L. Berger, Ed.
Request for Comments: 4783                                          LabN
Updates: 3473                                              December 2006
Category: Standards Track


               GMPLS - Communication of Alarm Information

Status of This Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The IETF Trust (2006).

Abstract

   This document describes an extension to Generalized MPLS (Multi-
   Protocol Label Switching) signaling to support communication of alarm
   information.  GMPLS signaling already supports the control of alarm
   reporting, but not the communication of alarm information.  This
   document presents both a functional description and GMPLS-RSVP
   specifics of such an extension.  This document also proposes
   modification of the RSVP ERROR_SPEC object.

   This document updates RFC 3473, "Generalized Multi-Protocol Label
   Switching (GMPLS) Signaling Resource ReserVation Protocol-Traffic
   Engineering (RSVP-TE) Extensions", through the addition of new,
   optional protocol elements.  It does not change, and is fully
   backward compatible with, the procedures specified in RFC 3473.
















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Table of Contents

   1. Introduction ....................................................3
      1.1. Background .................................................3
   2. Alarm Information Communication .................................4
   3. GMPLS-RSVP Details ..............................................5
      3.1. ALARM_SPEC Objects .........................................5
           3.1.1. IF_ID ALARM_SPEC (and ERROR_SPEC) TLVs ..............5
           3.1.2. Procedures ..........................................9
           3.1.3. Error Codes and Values .............................10
           3.1.4. Backwards Compatibility ............................11
      3.2. Controlling Alarm Communication ...........................11
           3.2.1. Updated Admin_Status Object ........................11
           3.2.2. Procedures .........................................11
      3.3. Message Formats ...........................................12
      3.4. Relationship to GMPLS UNI .................................13
      3.5. Relationship to GMPLS E-NNI ...............................14
   4. Security Considerations ........................................14
   5. IANA Considerations ............................................15
      5.1. New RSVP Object ...........................................15
      5.2. New Interface ID Types ....................................16
      5.3. New Registry for Admin-Status Object Bit Fields ...........16
      5.4. New RSVP Error Code .......................................16
   6. References .....................................................17
      6.1. Normative References ......................................17
      6.2. Informative References ....................................17
   7. Acknowledgments ................................................18
   8. Contributors ...................................................18























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1.  Introduction

   GMPLS signaling provides mechanisms that can be used to control the
   reporting of alarms associated with a label switched path (LSP).
   This support is provided via Administrative Status Information
   [RFC3471] and the Admin_Status object [RFC3473].  These mechanisms
   only control if alarm reporting is inhibited.  No provision is made
   for communication of alarm information within GMPLS.

   The extension described in this document defines how the alarm
   information associated with a GMPLS LSP may be communicated along the
   path of the LSP.  Communication both upstream and downstream is
   supported.  The value in communicating such alarm information is that
   this information is then available at every node along the LSP for
   display and diagnostic purposes.  Alarm information may also be
   useful in certain traffic protection scenarios, but such uses are out
   of the scope of this document.  Alarm communication is supported via
   a new object, new error/alarm information TLVs, and a new
   Administrative Status Information bit.

   The communication of alarms, as described in this document, is
   controllable on a per-LSP basis.  Such communication may be useful
   within network configurations where not all nodes support
   communication to a user for reporting of alarms and/or communication
   is needed to support specific applications.  The support of this
   functionality is optional.

   The communication of alarms within GMPLS does not imply any
   modification in behavior of processing of alarms, or for the
   communication of alarms outside of GMPLS.  Additionally, the
   extension described in this document is not intended to replace any
   (existing) data plane fault propagation techniques.

   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].

1.1.  Background

   Problems with data plane state can often be detected by associated
   data plane hardware components.  Such data plane problems are
   typically filtered based on elapsed time and local policy.  Problems
   that pass the filtering process are normally raised as alarms.  These
   alarms are available for display to operators.  They also may be
   collected centrally through means that are out of the scope of this
   document.





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   Not all data plane problems cause the LSP to be immediately torn
   down.  Further, there may be a desire, particularly in optical
   transport networks, to retain an LSP and communicate relevant alarm
   information even when the data plane state has failed completely.

   Although error information can be reported using PathErr, ResvErr,
   and Notify messages, these messages typically indicate a problem in
   signaling state and can only report one problem at a time.  This
   makes it hard to correlate all of the problems that may be associated
   with a single LSP and to allow an operator examining the status of an
   LSP to view a full list of current problems.  This situation is
   exacerbated by the absence of any way to communicate that a problem
   has been resolved and a corresponding alarm cleared.

   The extensions defined in this document allow an operator or a
   software component to obtain a full list of current alarms associated
   with all of the resources used to support an LSP.  The extensions
   also ensure that this list is kept up-to-date and synchronized with
   the real alarm status in the network.  Finally, the extensions make
   the list available at every node traversed by an LSP.

2.  Alarm Information Communication

   A new object is introduced to carry alarm information details.  The
   details of alarm information are much like the error information
   carried in the existing ERROR_SPEC objects.  For this reason the
   communication of alarm information uses a format that is based on the
   communication of error information.

   The new object introduced to carry alarm information details is
   called an ALARM_SPEC object.  This object has the same format as the
   ERROR_SPEC object, but uses a new C-Num to avoid the semantics of
   error processing.  Also, additional TLVs are defined for the IF_ID
   ALARM_SPEC objects to support the communication of information
   related to a specific alarm.  These TLVs may also be useful when
   included in ERROR_SPEC objects, e.g., when the ERROR_SPEC object is
   carried within a Notify message.

   While the details of alarm information are like the details of
   existing error communication, the semantics of processing differ.
   Alarm information will typically relate to changes in data plane
   state, without changes in control state.  Alarm information will
   always be associated with in-place LSPs.  Such information will also
   typically be most useful to operators and applications other than
   control plane protocol processing.  Finally, while error information
   is communicated within PathErr, ResvErr, and Notify messages
   [RFC3473], alarm information will be carried within Path and Resv
   messages.



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   Path messages are used to carry alarm information to downstream
   nodes, and Resv messages are used to carry alarm information to
   upstream nodes.  The intent of sending alarm information both
   upstream and downstream is to provide the same visibility to alarm
   information at any point along an LSP.  The communication of multiple
   alarms associated with an LSP is supported.  In this case, multiple
   ALARM_SPEC objects will be carried in the Path or Resv messages.

   The addition of alarm information to Path and Resv messages is
   controlled via a new Administrative Status Information bit.
   Administrative Status Information is carried in the Admin_Status
   object.

3.  GMPLS-RSVP Details

   This section provides the GMPLS-RSVP [RFC3473] specification for
   communication of alarm information.  The communication of alarm
   information is OPTIONAL.  This section applies to nodes that support
   communication of alarm information.

3.1.  ALARM_SPEC Objects

   The ALARM_SPEC objects use the same format as the ERROR_SPEC object,
   but with class number of 198 (assigned by IANA in the form 11bbbbbb,
   per Section 3.1.4).

   o  Class = 198, C-Type = 1
      Reserved.  (C-Type value defined for ERROR_SPEC, but is not
      defined for use with ALARM_SPEC.)

   o  Class = 198, C-Type = 2
      Reserved.  (C-Type value defined for ERROR_SPEC, but is not
      defined for use with ALARM_SPEC.)

   o  IPv4 IF_ID ALARM_SPEC object: Class = 198, C-Type = 3
      Definition same as IPv4 IF_ID ERROR_SPEC [RFC3473].

   o  IPv6 IF_ID ALARM_SPEC object: Class = 198, C-Type = 4
      Definition same as IPv6 IF_ID ERROR_SPEC [RFC3473].

3.1.1.  IF_ID ALARM_SPEC (and ERROR_SPEC) TLVs

   The following new TLVs are defined for use with the IPv4 and IPv6
   IF_ID ALARM_SPEC objects.  They may also be used with the IPv4 and
   IPv6 IF_ID ERROR_SPEC objects.  See [RFC3471] Section 9.1.1 for the
   original definition of these values.  Note the length provided below
   is for the total TLV.  All TLVs defined in this section are OPTIONAL.




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   The defined TLVs MUST follow any interface identifying TLVs.  No
   rules apply to the relative ordering of the TLVs defined in this
   section.

      Type    Length     Description
      ----------------------------------
      512       8        REFERENCE_COUNT
      513       8        SEVERITY
      514       8        GLOBAL_TIMESTAMP
      515       8        LOCAL_TIMESTAMP
      516    variable    ERROR_STRING

   The Reference Count TLV has the following format:

       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             |             Length            |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                        Reference Count                        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      Reference Count: 32 bits

         The number of times this alarm has been repeated as determined
         by the reporting node.  This field MUST NOT be set to zero, and
         TLVs received with this field set to zero MUST be ignored.

      Only one Reference Count TLV may be included in an object.

   The Severity TLV has the following format:

       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             |             Length            |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |            Reserved                   |Impact |   Severity    |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      Reserved: 20 bits

         This field is reserved.  It MUST be set to zero on generation,
         MUST be ignored on receipt, and MUST be forwarded unchanged and
         unexamined by transit nodes.






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      Impact: 4 bits

         Indicates the impact of the alarm indicated in the TLV.  See
         [M.20] for a general discussion on classification of failures.
         The following values are defined in this document.  The details
         of the semantics may be found in [M.20].

          Value     Definition
          -----     ---------------------
            0       Unspecified impact
            1       Non-Service Affecting (Data traffic not interrupted)
            2       Service Affecting (Data traffic is interrupted)

      Severity: 8 bits

         Indicates the impact of the alarm indicated in the TLV.  See
         [RFC3877] and [M.3100] for more information on severity.  The
         following values are defined in this document.  The details of
         the semantics may be found in [RFC3877] and [M.3100]:

          Value     Definition
          -----     ----------
            0       Cleared
            1       Indeterminate
            2       Critical
            3       Major
            4       Minor
            5       Warning

      Only one Severity TLV may be included in an object.

   The Global Timestamp TLV has the following format:

       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             |             Length            |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                        Global Timestamp                       |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+











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      Global Timestamp: 32 bits

         An unsigned fixed-point integer that indicates the number of
         seconds since 00:00:00 UT on 1 January 1970 according to the
         clock on the node that originates this TLV.  This time MAY
         include leap seconds if they are used by the local clock and
         SHOULD contain the same time value as used by the node when the
         alarm is reported through other systems (such as within the
         Management Plane) if global time is used in those reports.

      Only one Global Timestamp TLV may be included in an object.

   The Local Timestamp TLV has the following format:

       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             |             Length            |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                        Local Timestamp                        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      Local Timestamp: 32 bits

         Number of seconds reported by the local system clock at the
         time the associated alarm was detected on the node that
         originates this TLV.  This number is expected to be meaningful
         in the context of the originating node.  For example, it may
         indicate the number of seconds since the node rebooted or may
         be a local representation of an unsynchronized real-time clock.

      Only one Local Timestamp TLV may be included in an object.

   The Error String TLV has the following format:

       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             |             Length            |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                                                               |
      //          Error String      (NULL padded display string)      //
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+







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      Error String: 32 bits minimum (variable)

         A string of characters in US-ASCII, representing the type of
         error/alarm.  This string is padded to the next largest 4-byte
         boundary using null characters.  Null padding is not required
         when the string is 32-bit aligned.  The contents of error
         string are implementation dependent.  See the condition types
         listed in Appendices of [GR833] for a list of example strings.
         Note length includes padding.

      Multiple Error String TLVs may be included in an object.

3.1.2.  Procedures

   This section applies to nodes that support the communication of alarm
   information.  ALARM_SPEC objects are carried in Path and Resv
   messages.  Multiple ALARM_SPEC objects MAY be present.

   Nodes that support the extensions defined in this document SHOULD
   store any alarm information from received ALARM_SPEC objects for
   future use.  All ALARM_SPEC objects received in Path messages SHOULD
   be passed unmodified downstream in the corresponding Path messages.
   All ALARM_SPEC objects received in Resv messages SHOULD be passed
   unmodified upstream in the corresponding Resv messages.  ALARM_SPEC
   objects are merged in transmitted Resv messages by including a copy
   of all ALARM_SPEC objects received in corresponding Resv Messages.

   To advertise local alarm information, a node generates an ALARM_SPEC
   object for each alarm and adds it to both the Path and Resv messages
   for the impacted LSP.

   In all cases, appropriate Error Node Address, Error Code, and Error
   Values MUST be set (see below for a discussion on Error Code and
   Error Values).  As the InPlace and NotGuilty flags only have meaning
   in ERROR_SPEC objects, they SHOULD NOT be set.  TLVs SHOULD be
   included in the ALARM_SPEC object to identify the interface, if any,
   associated with the alarm.  The TLVs defined in [RFC3471] for
   identifying interfaces in the IF_ID ERROR_SPEC object [RFC3473]
   SHOULD be used for this purpose, but note that TLVs type 4 and 5
   (component interfaces) are deprecated by [RFC4201] and SHOULD NOT be
   used.  TLVs SHOULD also be included to indicate the severity
   (Severity TLV), the time (Global Timestamp and/or Local Timestamp
   TLVs), and a (brief) string (Error String TLV) associated with the
   alarm.  The reference count TLV MAY also be included to indicate the
   number of times an alarm has been repeated at the reporting node.
   ALARM_SPEC objects received from other nodes are not impacted by the
   addition of local ALARM_SPEC objects, i.e., they continue to be
   processed as described above.  The choice of which alarm or alarms to



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   advertise and which to omit is a local policy matter, and may be
   configurable by the user.

   There are two ways to indicate time.  A global timestamp TLV is used
   to provide an absolute time reference for the occurrence of an alarm.
   The local timestamp TLV is used to provide time reference for the
   occurrence of an alarm that is relative to other information
   advertised by the node.  The global timestamp SHOULD be used on nodes
   that maintain an absolute time reference.  Both timestamp TLVs MAY be
   used simultaneously.

   Note, ALARM_SPEC objects SHOULD NOT be added to the Path and Resv
   states of LSPs that are in "alarm communication inhibited" state.
   ALARM_SPEC objects MAY be added to the state of LSPs that are in an
   "administratively down" state.  These states are indicated by the I
   and A bits of the Admin_Status object; see Section 3.2.

   To remove local alarm information, a node simply removes the matching
   locally generated ALARM_SPEC objects from the outgoing Path and Resv
   messages.  A node MAY modify a locally generated ALARM_SPEC object.

   Normal refresh and trigger message processing applies to Path or Resv
   messages that contain ALARM_SPEC objects.  Note that changes in
   ALARM_SPEC objects from one message to the next may include a
   modification in the contents of a specific ALARM_SPEC object, or a
   change in the number of ALARM_SPEC objects present.  All changes in
   ALARM_SPEC objects SHOULD be processed as trigger messages.

   Failure to follow the above directives, in particular the ones
   labeled "SHOULD" and "SHOULD NOT", may result in the alarm
   information not being properly or fully communicated.

3.1.3.  Error Codes and Values

   The Error Codes and Values used in ALARM_SPEC objects are the same as
   those used in ERROR_SPEC objects.  New Error Code values for use with
   both ERROR_SPEC and ALARM_SPEC objects may be assigned to support
   alarm types defined by other standards.

   In this document we define one new Error Code.  The Error Code uses
   the value 31 and is referred to as "Alarms".  The values used in the
   Error Values field when the Error Code is "Alarms" are the same as
   the values defined in the IANAItuProbableCause Textual Convention of
   IANA-ITU-ALARM-TC-MIB in the Alarm MIB [RFC3877].  Note that these
   values are managed by IANA; see http://www.iana.org.






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3.1.4.  Backwards Compatibility

   The support of ALARM_SPEC objects is OPTIONAL.  Non-supporting nodes
   will (according to the rules defined in [RFC2205]) pass the objects
   through the node unmodified, because the ALARM_SPEC object has a
   C-Num of the form 11bbbbbb.

   This allows alarm information to be collected and examined in a
   network built from a collection of nodes some of which support the
   communication of alarm information, and some of which do not.

3.2.  Controlling Alarm Communication

   Alarm information communication is controlled via Administrative
   Status Information as carried in the Admin_Status object.  A new bit
   is defined, called the I bit, that indicates when alarm communication
   is to be inhibited.  The definition of this bit does not modify the
   procedures defined in Section 7 of [RFC3473].

3.2.1.  Updated Admin_Status Object

   The format of the Admin_Status object is updated to include the I
   bit:

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |            Length             | Class-Num(196)|   C-Type (1)  |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |R|                        Reserved                   |I| |T|A|D|
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Inhibit Alarm Communication (I): 1 bit
         When set, indicates that alarm communication is disabled for
         the LSP and that nodes SHOULD NOT add local alarm information.

      See Section 7.1 of [RFC3473] for the definition of the remaining
      bits.

3.2.2.  Procedures

   The I bit may be set and cleared using the procedures defined in
   Sections 7.2 and 7.3 of [RFC3473].  A node that receives (or
   generates) an Admin_Status object with the A or I bits set (1),
   SHOULD remove all locally generated alarm information from the
   matching LSP's outgoing Path and Resv messages.  When a node receives
   (or generates) an Admin_Status object with the A and I bits clear (0)
   and there is local alarm information present, it SHOULD add the local



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   alarm information to the matching LSP's outgoing Path and Resv
   messages.

   The processing of non-locally generated ALARM_SPEC objects MUST NOT
   be impacted by the contents of the Admin_Status object; that is,
   received ALARM_SPEC objects MUST be forwarded unchanged regardless of
   the received or transmitted settings of the I and A bits.  Note that,
   per [RFC3473], the absence of the Admin_Status object is equivalent
   to receiving an object containing values all set to zero (0).

   I bit related processing behavior MAY be overridden locally based on
   configuration.

   When generating Notify messages for LSPs with the I bit set, the TLVs
   described in this document MAY be added to the ERROR_SPEC object sent
   in the Notify message.

3.3.  Message Formats

   This section presents the RSVP message-related formats as modified by
   this document.  The formats specified in [RFC3473] served as the
   basis of these formats.  The objects are listed in suggested
   ordering.

   The format of a Path message is as follows:

 <Path Message> ::=       <Common Header> [ <INTEGRITY> ]
                          [ [<MESSAGE_ID_ACK> | <MESSAGE_ID_NACK>] ... ]
                          [ <MESSAGE_ID> ]
                          <SESSION> <RSVP_HOP>
                          <TIME_VALUES>
                          [ <EXPLICIT_ROUTE> ]
                          <LABEL_REQUEST>
                          [ <PROTECTION> ]
                          [ <LABEL_SET> ... ]
                          [ <SESSION_ATTRIBUTE> ]
                          [ <NOTIFY_REQUEST> ]
                          [ <ADMIN_STATUS> ]
                          [ <POLICY_DATA> ... ]
                          [ <ALARM_SPEC> ... ]
                          <sender descriptor>

 <sender descriptor> is not modified by this document.








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 The format of a Resv message is as follows:

 <Resv Message> ::=       <Common Header> [ <INTEGRITY> ]
                          [ [<MESSAGE_ID_ACK> | <MESSAGE_ID_NACK>] ... ]
                          [ <MESSAGE_ID> ]
                          <SESSION> <RSVP_HOP>
                          <TIME_VALUES>
                          [ <RESV_CONFIRM> ]  [ <SCOPE> ]
                          [ <NOTIFY_REQUEST> ]
                          [ <ADMIN_STATUS> ]
                          [ <POLICY_DATA> ... ]
                          [ <ALARM_SPEC> ... ]
                          <STYLE> <flow descriptor list>

 <flow descriptor list> is not modified by this document.

3.4.  Relationship to GMPLS UNI

   [RFC4208] defines how GMPLS may be used in an overlay model to
   provide a user-to-network interface (UNI).  In this model,
   restrictions may be applied to the information that is signaled
   between an edge-node and a core-node.  This restriction allows the
   core network to limit the information that is visible outside of the
   core.  This restriction may be made for confidentiality, privacy, or
   security reasons.  It may also be made for operational reasons, for
   example, if the information is only applicable within the core
   network.

   The extensions described in this document are candidates for
   filtering as described in [RFC4208].  In particular, the following
   observations apply.

   o  An ingress or egress core-node MAY filter alarms from the GMPLS
      core to a client-node UNI LSP.  This may be to protect information
      about the core network, or to indicate that the core network is
      performing or has completed recovery actions for the GMPLS LSP.

   o  An ingress or egress core-node MAY modify alarms from the GMPLS
      core when sending to a client-node UNI LSP.  This may facilitate
      the UNI client's ability to understand the failure and its effect
      on the data plane, and enable the UNI client to take corrective
      actions in a more appropriate manner.

   o  Similarly, an egress core-node MAY choose not to request alarm
      reporting on Path messages that it sends downstream to the overlay
      network.





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3.5.  Relationship to GMPLS E-NNI

   GMPLS may be used at the external network-to-network interface
   (E-NNI); see [ASON-APPL].  At this interface, restrictions may be
   applied to the information that is signaled between an egress and an
   ingress core-node.

   This restriction allows the ingress core network to limit the
   information that is visible outside of its core network.  This
   restriction may be made for confidentiality, privacy, or security
   reasons.  It may also be made for operational reasons, for example,
   if the information is only applicable within the core network.

   The extensions described in this document are candidates for
   filtering as described in [ASON-APPL].  In particular, the following
   observations apply.

   o  An ingress or egress core-node MAY filter internal core network
      alarms.  This may be to protect information about the internal
      network or to indicate that the core network is performing or has
      completed recovery actions for this LSP.

   o  An ingress or egress core-node MAY modify internal core network
      alarms.  This may facilitate the peering E-NNI (i.e., the egress
      core-node) to understand the failure and its effect on the data
      plane, and take corrective actions in a more appropriate manner or
      prolong the generated alarms upstream/downstream as appropriated.

   o  Similarly, an egress/ingress core-node MAY choose not to request
      alarm reporting on Path messages that it sends downstream.

4.  Security Considerations

   Some operators may consider alarm information as sensitive.  To
   support environments where this is the case, implementations SHOULD
   allow the user to disable the generation of ALARM_SPEC objects, or to
   filter or correlate them at domain boundaries.

   This document introduces no additional security considerations.  See
   [RFC3473] for relevant security considerations.

   It may be noted that if the security considerations of [RFC3473] are
   breached, alarm information may be spoofed.  Such spoofing would be
   at most annoying and cause slight degradation of control plane
   performance since the details are provided for information only and
   do not result in protocol actions beyond the exchange of messages to
   convey the information.  If the protocol security is able to be
   breached sufficiently to allow spoofing of alarm information then



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   considerably more interesting and exciting damage can be caused by
   spoofing other elements of the protocol messages.

5.  IANA Considerations

   IANA administered assignment of new values for namespaces defined in
   this document and reviewed in this section.

5.1.  New RSVP Object

   IANA made the following assignments in the "Class Names, Class
   Numbers, and Class Types" section of the "RSVP PARAMETERS" registry
   located at http://www.iana.org/assignments/rsvp-parameters.

   A new class named ALARM_SPEC (198) was created in the 11bbbbbb range
   with following values

   o  Class = 198, C-Type = 1
      RFC 4783
      Reserved. (C-Type value defined for ERROR_SPEC, but is not
      defined for use with ALARM_SPEC.)

   o  Class = 198, C-Type = 2
      RFC 4783
      Reserved. (C-Type value defined for ERROR_SPEC, but is not
      defined for use with ALARM_SPEC.)

   o  IPv4 IF_ID ALARM_SPEC object: Class = 198, C-Type = 3
      RFC 4783
      Definition same as IPv4 IF_ID ERROR_SPEC [RFC3473].

   o  IPv6 IF_ID ALARM_SPEC object: Class = 198, C-Type = 4
      RFC 4783
      Definition same as IPv6 IF_ID ERROR_SPEC [RFC3473].

   The ALARM_SPEC object uses the Error Code and Error Values from the
   ERROR_SPEC object.














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5.2.  New Interface ID Types

   IANA made the following assignments in the "Interface_ID Types"
   section of the "GMPLS Signaling Parameters" registry located at
   http://www.iana.org/assignments/gmpls-sig-parameters.

      512 8 REFERENCE_COUNT     RFC 4783
      513 8 SEVERITY            RFC 4783
      514 8 GLOBAL_TIMESTAMP    RFC 4783
      515 8 LOCAL_TIMESTAMP     RFC 4783
      516 variable ERROR_STRING RFC 4783

5.3.  New Registry for Admin-Status Object Bit Fields

   IANA created a new section titled "Administrative Status Information
   Flags" in the "GMPLS Signaling Parameters" registry located at
   http://www.iana.org/assignments/gmpls-sig-parameters and made the
   following assignments:

   Value       Name                              Reference
   ----------- -------------------------------- -----------------
   0x80000000  Reflect (R)                      [RFC3473/RFC3471]
   0x00000010  Inhibit Alarm Communication (I)  RFC 4783
   0x00000004  Testing (T)                      [RFC3473/RFC3471]
   0x00000002  Administratively down (A)        [RFC3473/RFC3471]
   0x00000001  Deletion in progress (D)         [RFC3473/RFC3471]

5.4.  New RSVP Error Code

   IANA made the following assignments in the "Error Codes and Values"
   section of the "RSVP PARAMETERS" registry located at
   http://www.iana.org/assignments/rsvp-parameters.

   31  Alarms                               RFC 4783

       The Error Value sub-codes for this Error Code have values and
       meanings identical to the values and meanings defined in the
       IANAItuProbableCause Textual Convention of IANA-ITU-ALARM-TC-MIB
       in the Alarm MIB [RFC3877].  Note that these values are already
       managed the IANA.











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6.  References

6.1.  Normative References

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

   [RFC2205]   Braden, R., Ed., Zhang, L., Berson, S., Herzog, S., and
               S. Jamin, "Resource ReSerVation Protocol (RSVP) --
               Version 1 Functional Specification", RFC 2205, September
               1997.

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

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

   [RFC3877]   Chisholm, S. and D. Romascanu, "Alarm Management
               Information Base (MIB)", RFC 3877, September 2004.

   [M.3100]    ITU Recommendation M.3100, "Generic Network Information
               Model", 1995.

6.2.  Informative References

   [RFC4201]   Kompella, K., Rekhter, Y., and L. Berger, "Link Bundling
               in MPLS Traffic Engineering (TE)", RFC 4201, October
               2005.

   [M.20]      ITU-T, "MAINTENANCE  PHILOSOPHY  FOR TELECOMMUNICATION
               NETWORKS", Recommendation M.20, October 1992.

   [GR833]     Bellcore, "Network Maintenance: Network Element and
               Transport Surveillance Messages" (GR-833-CORE), Issue 3,
               February 1999.

   [RFC4208]   Swallow, G., Drake, J., Ishimatsu, H., and Y. Rekhter,
               "Generalized Multiprotocol Label Switching (GMPLS) User-
               Network Interface (UNI): Resource ReserVation Protocol-
               Traffic Engineering (RSVP-TE) Support for the Overlay
               Model", RFC 4208, October 2005.






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   [ASON-APPL] Papadimitriou, D., et al., "Generalized MPLS (GMPLS)
               RSVP-TE signaling usage in support of Automatically
               Switched Optical Network (ASON)", Work in Progress, July
               2005.

7.  Acknowledgments

   Valuable comments and input were received from a number of people,
   including Wes Doonan, Bert Wijnen for the DISMAN reference, and Tom
   Petch for getting the DISMAN WG interactions started.  We also thank
   David Black, Lars Eggert, Russ Housley, Dan Romascanu, and Magnus
   Westerlund for their valuable comments.

8.  Contributors

   Contributors are listed in alphabetical order:

   Deborah Brungard
   AT&T Labs, Room MT D1-3C22
   200 Laurel Avenue
   Middletown, NJ 07748, USA
   Phone:  (732) 420-1573
   EMail:  dbrungard@att.com


   Igor Bryskin                               Adrian Farrel
   Movaz Networks, Inc.                       Old Dog Consulting
   7926 Jones Branch Drive
   Suite 615
   McLean VA, 22102, USA                      Phone: +44 (0) 1978 860944
   EMail:  ibryskin@movaz.com                 EMail: adrian@olddog.co.uk


   Dimitri Papadimitriou (Alcatel)            Arun Satyanarayana
   Francis Wellesplein 1                      Cisco Systems, Inc
   B-2018 Antwerpen, Belgium                  170 West Tasman Dr.
                                              San Jose, CA  95134 USA
   Phone:  +32 3 240-8491                     Phone: +1 408 853-3206
   EMail:  dimitri.papadimitriou@alcatel.be   EMail: asatyana@cisco.com

Editor's Address

   Lou Berger
   LabN Consulting, L.L.C.

   Phone:  +1 301-468-9228
   EMail:  lberger@labn.net




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Full Copyright Statement

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   Internet Society.






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