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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.

Berger Standards Track [Page 1] RFC 4783 GMPLS - Communication of Alarm Information December 2006

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

Berger Standards Track [Page 2] RFC 4783 GMPLS - Communication of Alarm Information December 2006

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.

Berger Standards Track [Page 3] RFC 4783 GMPLS - Communication of Alarm Information December 2006

 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.

Berger Standards Track [Page 4] RFC 4783 GMPLS - Communication of Alarm Information December 2006

 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.

Berger Standards Track [Page 5] RFC 4783 GMPLS - Communication of Alarm Information December 2006

 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.

Berger Standards Track [Page 6] RFC 4783 GMPLS - Communication of Alarm Information December 2006

    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                       |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Berger Standards Track [Page 7] RFC 4783 GMPLS - Communication of Alarm Information December 2006

    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)      //
    |                                                               |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Berger Standards Track [Page 8] RFC 4783 GMPLS - Communication of Alarm Information December 2006

    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

Berger Standards Track [Page 9] RFC 4783 GMPLS - Communication of Alarm Information December 2006

 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.

Berger Standards Track [Page 10] RFC 4783 GMPLS - Communication of Alarm Information December 2006

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

Berger Standards Track [Page 11] RFC 4783 GMPLS - Communication of Alarm Information December 2006

 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.

Berger Standards Track [Page 12] RFC 4783 GMPLS - Communication of Alarm Information December 2006

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.

Berger Standards Track [Page 13] RFC 4783 GMPLS - Communication of Alarm Information December 2006

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

Berger Standards Track [Page 14] RFC 4783 GMPLS - Communication of Alarm Information December 2006

 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.

Berger Standards Track [Page 15] RFC 4783 GMPLS - Communication of Alarm Information December 2006

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.

Berger Standards Track [Page 16] RFC 4783 GMPLS - Communication of Alarm Information December 2006

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.

Berger Standards Track [Page 17] RFC 4783 GMPLS - Communication of Alarm Information December 2006

 [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

Berger Standards Track [Page 18] RFC 4783 GMPLS - Communication of Alarm Information December 2006

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Berger Standards Track [Page 19]

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