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Versions: (draft-ietf-ccamp-te-metric-recording) 00 01 02 03 04 05 06

     TEAS Working Group                                        Zafar Ali
     Internet Draft                                       George Swallow
     Intended status: Standard Track                   Clarence Filsfils
     Expires: May 12, 2018                            Matt Hartley
                                                           Cisco Systems
                                                            Kenji Kumaki
                                                        KDDI Corporation
                                                          Ruediger Kunze
                                                     Deutsche Telekom AG
                                                       November 13, 2017
     
     
          Resource ReserVation Protocol-Traffic Engineering (RSVP-TE)
           extension for recording TE Metric of a Label Switched Path
                     draft-ietf-teas-te-metric-recording-06
     
     Status of this Memo
     
     This Internet-Draft is submitted in full conformance with the
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     This Internet-Draft will expire on May 12, 2018.
     
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     This document may contain material from IETF Documents or IETF
     Contributions published or made publicly available before November
     10, 2008.  The person(s) controlling the copyright in some of this
     material may not have granted the IETF Trust the right to allow
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     Without obtaining an adequate license from the person(s)
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     Abstract
     
     There are many scenarios in which Traffic Engineering (TE) metrics
     such as cost, delay and delay variation associated with the TE link
     formed by Label Switched Path (LSP) are not available to the
     ingress and egress nodes. This draft provides extensions for the
     Resource ReserVation Protocol- Traffic Engineering (RSVP-TE) to
     support automatic collection of cost, delay and delay variation
     information for the TE link formed by a LSP.
     
     Conventions used in this document
     
     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 RFC 2119
     [RFC2119].
     
     Table of Contents
     
        1. Introduction ......................................... 3
        1.1. Use Cases  ......................................... 4
              1.1.1. GMPLS ...................................... 4
              1.1.2. Inter-area tunnels with loose-hops ......... 4
        2. RSVP-TE Requirement .................................. 4
        2.1. Cost, Delay and Delay Variation Collection
             Indication ......................................... 4
        2.2. Cost, Delay and Delay Variation Collection ......... 5
        2.3. Cost, Delay and Delay Variation Update ............. 5
        2.4. Cost Definition .................................... 5
        3. Encoding ............................................. 5
        3.1. Cost, Delay and Delay Variation Collection Flags ... 5
        3.2. RRO Cost Subobject ................................. 6
        3.3. RRO Delay Subobject ................................ 7
        3.4. RRO Delay Variation Subobject ...................... 7
        4. Signaling Procedures ................................. 8
        4.1. Cost, Delay and Delay Variation Collection ......... 9
        4.2. Metric Update ......................................12
        4.3. Domain Boundaries ..................................12
        4.4. Endpoint processing ................................12
        4.5. Compatibility ......................................13
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        5. Manageability Considerations .........................13
        5.1. Policy Configuration ...............................13
        6. Security Considerations ..............................14
        7. IANA Considerations ..................................14
        7.1. RSVP Attribute Bit Flags ...........................14
        7.2. ROUTE_RECORD subobject .............................15
        7.3. Policy Control Failure Error subcodes ..............15
        8. Acknowledgments ......................................15
        9. References ...........................................16
        9.1. Normative References ...............................16
        9.2. Informative References .............................16
     
     
     1. Introduction
     
        In certain networks, such as financial information networks,
        network performance information (e.g. delay, delay variation) is
        becoming as critical to data path selection as other metrics
        [RFC7471], [DRAFT-ISIS-TE-METRIC]. If cost, delay or delay
        variation associated with a Forwarding Adjacency (FA) or a
        Routing Adjacency (RA) LSP is not available to the ingress or
        egress node, it cannot be advertised as an attribute of the TE
        link (FA or RA). There are scenarios in packet and optical
        networks where the route information of an LSP may not be
        provided to the ingress node for confidentiality reasons and/or
        the ingress node may not run the same routing instance as the
        intermediate nodes traversed by the path. Similarly, there are
        scenarios in which measuring delay and/ or delay variation on a
        TE link formed by a LSP is not supported. In such scenarios, the
        ingress node cannot determine the cost, delay and delay
        variation properties of the LSP's route.
     
        One possible way to address this issue is to configure cost,
        delay and delay variation values manually. However, in the event
        of an LSP being rerouted (e.g. due to re-optimization), such
        configuration information may become invalid. Consequently, in
        cases where that an LSP is advertised as a TE-Link, the ingress
        and/or egress nodes cannot provide the correct delay, delay
        variation and cost information associated with the TE-Link
        automatically.
     
        In summary, there is a requirement for the ingress and egress
        nodes to learn the cost, delay and delay variation information
        of the TE link formed by a LSP. This document provides a
        mechanism to collect the cost, delay and delay variation
        information of a LSP, which can then be advertised as properties
        of the TE-link formed by that LSP.  Note that specification of
        the use of the collected cost, delay and delay variation
        information is outside the scope of this document.
     
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     1.1. Use Cases
     
        This section describes some of the use cases for the TE metric
        recording.
     
     1.1.1. GMPLS
     
        In Generalized Multi-Protocol Label Switching (GMPLS) networks
        signaling bidirectional LSPs, the egress node cannot determine
        the cost, delay and delay variation properties of the LSP path.
        A multi-domain or multi-layer network is an example of such
        networks. A GMPLS User-Network Interface (UNI) [RFC4208] is also
        an example of such networks.
     
     1.1.2. Inter-area tunnels with loose-hops
     
        When a LSP is established over multiple IGP-areas using loose
        hops in the ERO, the ingress node may only has knowledge of the
        first IGP-area traversed by the LSP. In this case, it cannot
        determine the cost, delay and delay variation properties of the
        LSP path.
     
     2. RSVP-TE Requirement
     
        This section outlines RSVP-TE requirements for the support of
        the automatic collection of cost, delay and delay variation
        information of an LSP.
     
        As RSVP-TE requirements for cost, delay and delay variation
        collection are similar, many parts of this section are written
        such that they apply equally to cost, delay and delay variation
        collection. There is also very strong similarity of these RSVP-
        requirements with SRLG recording [DRAFT-SRLG-RECORDING].
     
     2.1. Cost, Delay and Delay Variation Collection Indication
     
        The ingress node of the LSP needs be capable of indicating
        whether the cost and/or delay and/ or delay variation
        information of the LSP is to be collected during the signaling
        procedure of setting up an LSP. A separate collection indication
        flag for each of these attributes is required. There is no need
        for cost and/or delay and/ or delay variation to be collected
        without an explicit request for it being made by the ingress
        node.
     
        It may be preferable for the cost and/ or delay and/ or delay
        variation collection request to be understood by all nodes along
        the LSP's path, or it may be more important for the LSP to be
        established successfully even if it traverses nodes that cannot
        supply the requested information or have not implemented the
        procedures specified in this document. It is desirable for the
     
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        ingress node to make the cost, delay and delay variation
        collection request in a manner that best suits its own policy.
     
     2.2. Cost, Delay and Delay Variation Collection
     
        If requested, the cost and/or delay and/ or delay variation
        information is collected during the setup of an LSP. Each of the
        cost, delay or delay variation can be collected independently.
        Cost and/ or delay and/ or delay variation information is for
        each hop is added to the Path RRO during Path message
        processing. The corresponding information is also added to the
        Resv RRO during Resv processing at each hop.  The endpoints of
        the LSP can use the collected information, for example, for
        routing, sharing and TE link configuration purposes.
     
     2.3. Cost, Delay and Delay Variation Update
     
        When the cost and/or delay and/ or delay variation information
        of an existing LSP for which corresponding information was
        collected during signaling changes, the relevant nodes of the
        LSP need to be capable of updating the associated information of
        the LSP.  This means that the signaling procedure needs to be
        capable of updating the new cost and/or delay and/ or delay
        variation information.
     
     2.4. Cost Definition
     
        Although the terms delay and delay variation are well
        understood, "cost" may be ambiguous; in particular, in the
        context of a LSP that traverses nodes and links operated by
        different entities, there may be no common definition of cost.
        However, there are situations in which the entire LSP may be
        within a single AS (e.g. inter-area LSPs) in which cost
        discovery is useful.
     
        The precise meaning and interpretation of numerical costs is a
        matter for the network operator. For the purposes of this
        document, two constraints are assumed:
     
          . A higher cost represents an inferior path.
     
          . Simple addition of costs for different sections of a path
             must make sense.
     
     3. Encoding
     
     3.1. Cost, Delay and Delay Variation Collection Flags
     
        In order to indicate nodes that cost and/or Delay and/ or Delay
        variation collection is desired, this document defines the
        following new flags in the Attribute Flags TLV (see RFC 5420
     
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        [RFC5420]), which MAY be carried in an LSP_REQUIRED_ATTRIBUTES
        or LSP_ATTRIBUTES Object:
     
        - Cost Collection flag (Bit number to be assigned by IANA)
     
        - Delay Collection flag (Bit number to be assigned by IANA)
     
        - Delay Variation Collection flag (Bit number to be assigned by
        IANA)
     
        The Cost, Delay and Delay Variation Collection flags are
        meaningful on a Path message.  If the Cost Collection flag is
        set to 1, it means that the cost information SHOULD be reported
        to the ingress and egress node along the setup of the LSP.
        Similarly, if the Delay Collection flag is set to 1, it means
        that the Delay information SHOULD be reported to the ingress and
        egress node along the setup of the LSP. Likewise, if the Delay
        Variation Collection flag is set to 1, it means that the Delay
        Variation information SHOULD be reported to the ingress and
        egress node along the setup of the LSP.
     
        The rules of the processing of the Attribute Flags TLV are not
        changed.
     
     3.2. RRO Cost Subobject
     
        This document defines a new RRO sub-object (ROUTE_RECORD sub-
        object) to record the cost information of the LSP.  Its format
        is modeled on the RRO sub-objects defined in RFC 3209 [RFC3209].
     
     
        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     |D|  Reserved (must be zero)    |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                              Cost                             |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     
     
           Type: The type of the sub-object (value to be assigned by
           IANA).
     
           Length: The Length field contains the total length of the
           sub-object in bytes, including the Type and Length fields.
           The Length value is set to 8.
     
           Direction bit (D-bit)
     
           If not set, the cost contained in this sub-object applies to
           the downstream direction. If set, it applies to the upstream
           direction.
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           Reserved: This field is reserved for future use. It MUST be
           set to 0 on transmission and MUST be ignored when received.
     
           Cost: Cost of the local TE link along the route of the LSP.
     
     3.3. RRO Delay Subobject
     
        This document defines a new RRO sub-object (ROUTE_RECORD sub-
        object) to record the delay information of the LSP.  Its format
        is modeled on the RRO sub-objects defined in RFC 3209 [RFC3209].
     
        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      |D|  Reserved (must be zero)    |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |A|  Reserved   |                      Delay                    |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     
     
           Type: The type of the sub-object (value to be assigned by
           IANA).
     
           Length: The Length field contains the total length of the
           sub-object in bytes, including the Type and Length fields.
           The Length value is set to 8.
     
           Direction bit (D-bit)
     
           If not set, the Delay contained in this sub-object applies to
           the downstream direction. If set, it applies to the upstream
           direction.
     
           A-bit: These fields represent the Anomalous (A) bit
           associated with the Downstream and Upstream Delay
           respectively, as defined in RFC 7471 [RFC7471].
     
           Reserved: These fields are reserved for future use. They MUST
           be set to 0 when sent and MUST be ignored when received.
     
           Delay: Delay of the local TE link along the route of the LSP,
           encoded as 24-bit integer, as defined in RFC 7471 [RFC7471].
           When set to the maximum value 16,777,215 (16.777215 sec), the
           delay is at least that value and may be larger.
     
     3.4. RRO Delay Variation Subobject
     
        This document defines a new RRO sub-object (ROUTE_RECORD sub-
        object) to record the delay variation information of the LSP.
     
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        Its format is modeled on the RRO sub-objects defined in RFC 3209
        [RFC3209].
     
        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      |D|  Reserved (must be zero)    |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |A|  Reserved   |                 Delay Variation               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     
     
           Type: The type of the sub-object (value to be assigned by
           IANA).
     
           Length: The Length field contains the total length of the
           sub-object in bytes, including the Type and Length fields.
           The Length value is set to 8.
     
           Direction bit (D-bit)
     
           If not set, the Delay Variation contained in this sub-object
           applies to the downstream direction. If set, it applies to
           the upstream direction.
     
           A-bit: These fields represent the Anomalous (A) bit
           associated with the Downstream and Upstream Delay Variation
           respectively, as defined in RFC 7471 [RFC7471].
     
           Reserved: These fields are reserved for future use. It SHOULD
           be set to 0 when sent and MUST be ignored when received.
     
           Delay Variation: Delay Variation of the local TE link along
           the route of the LSP, encoded as 24-bit integer, as defined
           in RFC 7471 [RFC7471]. When set to the maximum value
           16,777,215 (16.777215 sec), the delay variation is at least
           that value and may be larger.
     
     4. Signaling Procedures
     
        As signaling procedure for cost, delay and delay variation
        collection is similar, many parts of this section are written
        such that they apply equally to cost, delay and delay variation
        collection. There is also very strong similarity of these
        procedures with SRLG recording [DRAFT-SRLG-RECORDING].
     
        The ingress node of the LSP MUST be capable of indicating
        whether the Cost and/ or Delay and/ or Delay Variation
        information of the LSP is to be collected during the signaling
        procedure of setting up an LSP.
     
     
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        A node MUST NOT push Cost and/ or Delay and/ or Delay Variation
        sub-object(s) in the RECORD_ROUTE without also pushing either an
        IPv4 sub-object, an IPv6 sub-object, an Unnumbered Interface ID
        sub-object or a Path Key sub-object or an SRLG sub-object.
     
        As described in RFC 3209 [RFC3209], the RECORD_ROUTE object is
        managed as a stack.  The Cost and/ or Delay and/ or Delay
        Variation sub-object(s) SHOULD be pushed by the node before the
        node IP address or link identifier. These sub-object(s) SHOULD
        be pushed after the Attribute sub-object, if present, and after
        the LABEL sub-object, if requested, and after the SRLG sub-
        object, if requested. These sub-object(s) MUST be pushed within
        the hop to which it applies.
     
        RFC 5553 [RFC5553] describes mechanisms to carry a PKS (Path Key
        Sub-object) in the RRO so as to facilitate confidentiality in
        the signaling of inter-domain TE LSPs, and allows the path
        segment that needs to be hidden (that is, a Confidential Path
        Segment (CPS)) to be replaced in the RRO with a PKS. If the CPS
        contains Cost and/ or Delay and/ or Delay Variation Sub-objects,
        these MAY be retained in the RRO by adding them again after the
        PKS Sub-object in the RRO.  The CPS is defined in RFC 5520
        [RFC5520].
     
        The rules of the processing of the LSP_REQUIRED_ATTRIBUTES,
        LSP_ATTRIBUTE and ROUTE_RECORD Objects are not changed.
     
     4.1. Cost, Delay and Delay Variation Collection
     
        Per RFC 3209 [RFC3209], an ingress node initiates the recording
        of the route information of an LSP by adding a RRO to a Path
        message. If an ingress node also desires Cost and/or Delay
        and/or Delay Variation recording, it MUST set the appropriate
        flag(s) in the Attribute Flags TLV which MAY be carried either
        in an LSP_REQUIRED_ATTRIBUTES Object when the collection is
        mandatory, or in an LSP_ATTRIBUTES Object when the collection is
        desired, but not mandatory.
     
        When a node receives a Path message which carries an
        LSP_REQUIRED_ATTRIBUTES Object with the Cost Collection Flag
        set, if local policy determines that the Cost information is not
        to be provided to the endpoints, it MUST return a PathErr
        message with:
     
           o  Error Code 2 (policy) and
     
           o  Error subcode "Cost Recording Rejected" (value to be
        assigned by IANA)
     
        to reject the Path message. Similarly, when a node receives a
        Path message which carries an LSP_REQUIRED_ATTRIBUTES Object
        with the Delay Collection Flag set, if local policy determines
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        that the Delay information is not to be provided to the
        endpoints, it MUST return a PathErr message with:
     
           o  Error Code 2 (policy) and
     
           o  Error subcode "Delay Recording Rejected" (value to be
        assigned by IANA)
     
        to reject the Path message. Likewise, when a node receives a
        Path message which carries an LSP_REQUIRED_ATTRIBUTES Object
        with the Delay Variation Collection Flag set, if local policy
        determines that the Delay Variation information is not to be
        provided to the endpoints, it MUST return a PathErr message
        with:
     
           o  Error Code 2 (policy) and
     
           o  Error subcode "Delay Variation Recording Rejected" (value
        to be assigned by IANA)
     
        to reject the Path message.
     
        When a node receives a Path message which carries an
        LSP_ATTRIBUTES Object and the Cost and/or Delay and/or Delay
        Variation Collection Flag set, if local policy determines that
        the corresponding information is not to be provided to the
        endpoints, or the information is not known, the Path message
        SHOULD NOT be rejected due to the recording restriction and the
        Path message SHOULD be forwarded without any Cost and/or Delay
        and/or Delay Variation sub-object(s) in the RRO of the
        corresponding outgoing Path message.
     
        If local policy permits the recording of the Cost and/or Delay
        and/or Delay Variation information, the processing node SHOULD
        add corresponding information for the local TE link, as defined
        below, to the RRO of the corresponding outgoing Path message.
        The A-bit for the Delay MUST be set as described in RFC 7471
        [RFC7471]. Similarly, the A-bit for the Delay Variation MUST be
        set as described in RFC 7471 [RFC7471]. It then forwards the
        Path message to the next node in the downstream direction. The
        processing node MUST retain a record of the Cost and/ or Delay
        and/ or Delay Variation Collection request for reference during
        Resv processing described below.
     
        If the addition of Cost and/or Delay and/or Delay Variation
        information to the RRO would result in the RRO exceeding its
        maximum possible size or becoming too large for the Path message
        to contain it, the requested information MUST NOT be added. If
        the Cost and/or Delay and/or Delay Variation collection request
        was contained in an LSP_REQUIRED_ATTRIBUTES Object, the
        processing node MUST behave as specified by RFC 3209 [RFC3209]
        and drop the RRO from the Path message entirely.  If the Cost
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        and/or Delay and/or Delay Variation collection request was
        contained in an LSP_ATTRIBUTES Object, the processing node MAY
        omit some or all of the corresponding information from the RRO;
        otherwise it MUST behave as specified by RFC 3209 [RFC3209] and
        drop the RRO from the Path message entirely.
     
        Following the steps described above, the intermediate nodes of
        the LSP can collect the Cost and/or Delay and/or Delay Variation
        information in the RRO during the processing of the Path message
        hop by hop.  When the Path message arrives at the egress node,
        the egress node receives the corresponding information in the
        RRO.
     
        Per RFC 3209 [RFC3209], when issuing a Resv message for a Path
        message, which contains an RRO, an egress node initiates the RRO
        process by adding an RRO to the outgoing Resv message.  The
        processing for RROs contained in Resv messages then mirrors that
        of the Path messages.
     
        When a node receives a Resv message for an LSP for which Cost
        and/or Delay and/or Delay Variation Collection was specified,
        then when local policy allows recording of the requested
        information, the node SHOULD add corresponding information, to
        the RRO of the outgoing Resv message, as specified below.  The
        A-bit for the Delay MUST be set as described in RFC 7471
        [RFC7471]. Similarly, the A-bit for the Delay Variation MUST be
        set as described in RFC 7471 [RFC7471]. When the Resv message
        arrives at the ingress node, the ingress node can extract the
        requested information from the RRO in the same way as the egress
        node.
     
        Note that a link's Cost and/ or Delay and/ or Delay Variation
        information for the upstream direction cannot be assumed to be
        the same as that in the downstream.
     
          o For Path and Resv messages for a unidirectional LSP, a node
             SHOULD include Cost and/ or Delay and/ or Delay Variation
             sub-objects in the RRO for the downstream data link only.
     
          o For Path and Resv messages for a bidirectional LSP, a node
             SHOULD include Cost and/ or Delay and/ or Delay Variation
             sub-objects in the RRO for both the upstream data link and
             the downstream data link from the local node.  In this
             case, the node MUST include the metric information in the
             same order for both Path messages and Resv messages.  That
             is, the Cost and/ or Delay and/ or Delay Variation sub-
             object(s) for the upstream link is added to the RRO before
             the corresponding sub-object for the downstream link.
     
             If Cost and/ or Delay and/ or Delay Variation data is added
             for both the upstream and downstream links, the two sets of
             the data MUST be added in separate corresponding sub-
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             object(s). A single Cost or Delay or Delay Variation sub-
             object MUST NOT contain a mixture of the applicable data
             for upstream and downstream directions. When adding a Cost
             or Delay or Delay Variation sub-object to an RRO, the D-bit
             MUST be set appropriately to indicate the direction of the
             TE Link. If the same value applies in both directions, it
             SHOULD be added to both the corresponding upstream and
             downstream sub-objects.
     
        Based on the local policy, a transit node may edit a Path or
        Resv RRO to remove route information (e.g. node or interface
        identifier information) before forwarding it. A node that does
        this SHOULD summarize the cost, Delay and Delay Variation data.
        How a node that performs the RRO edit operation calculates the
        Cost and/ or Delay and/or Delay variation metric is beyond the
        scope of this document.
     
        A node SHOULD NOT add Cost or Delay or Delay Variation
        information without an explicit request for the corresponding
        information being made by the ingress node in the Path message.
     
     4.2. Metric Update
     
        When the Cost and/or Delay and/or Delay Variation information of
        a link is changed, the endpoints of LSPs using that link need to
        be aware of the changes.  When a change to Cost or Delay or
        Delay Variation information associated with a link occurs, the
        procedures defined in Section 4.4.3 of RFC 3209 [RFC3209] MUST
        be used to refresh the corresponding metric information if the
        change is to be communicated to other nodes according to the
        local node's policy.  If local policy is that the Cost and/or
        Delay and/or Delay Variation change SHOULD be suppressed or
        would result in no change to the previously signaled
        information, the node SHOULD NOT send an update.
     
     4.3. Domain Boundaries
     
        If mandated by local policy, a node MAY remove Cost and/or Delay
        and/or Delay Variation information from any RRO in a Path or
        Resv message being processed. A node that does this SHOULD
        summarize the Cost, Delay and Delay Variation data. How a node
        that performs the RRO edit operation calculates the Cost, Delay
        and/or Delay variation metric is beyond the scope of this
        document.
     
     4.4. Endpoint processing
     
        Based on the procedures described above, the endpoints can get
        the Cost and/or Delay and/or Delay Variation information
        automatically.  Then the endpoints can for instance advertise it
        as a TE link to the routing instance based on the procedure
        described in [RFC6107] and configure the corresponding TE metric
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        information of the Forwarding Adjacency (FA) or Routing
        Adjacency (RA) automatically. How the end point uses the
        collected information is outside the scope of this document.
     
        The ingress and egress nodes of a LSP may calculate the end-to-
        end Cost, Delay and/or Delay variation properties of the LSP
        from the supplied values in the Resv or Path RRO, respectively.
     
        Typically, Cost and Delay are additive metrics, but Delay
        variation is not an additive metric. The means by which the
        ingress and egress nodes compute the end-to-end Cost, Delay and
        Delay variation metric from information recorded in the RRO is a
        local decision and is beyond the scope of this document.
     
        Based on the local policy, the ingress and egress nodes can
        advertise the calculated end-to-end Cost, Delay and/or Delay
        variation properties of the FA or RA LSP in TE link
        advertisement to the routing instance based on the procedure
        described in RFC 7471 [RFC7471], [DRAFT-ISIS-TE-METRIC].
     
     4.5. Compatibility
     
        A node that does not recognize the Cost and/or Delay and/or
        Delay Variation Collection Flag in the Attribute Flags TLV is
        expected to proceed as specified in RFC 5420 [RFC5420].
        Specifically, the node is expected to pass the TLV on unaltered
        if it appears in a LSP_ATTRIBUTES object. On the other hand, if
        the TLV appears in a LSP_REQUIRED_ATTRIBUTES object, the node is
        expected to reject the Path message with the Error Code and
        Value defined in RFC 5420 [RFC5420].
     
        A node that does not recognize the Cost and/or Delay and/or
        Delay Variation RRO sub-object is expected to behave as
        specified in RFC 3209 [RFC3209]: unrecognized sub-objects are to
        be ignored and passed on unchanged.
     
     5. Manageability Considerations
     
     5.1. Policy Configuration
     
        In a border node of inter-domain or inter-layer network, the
        following Cost and/or Delay and/or Delay Variation processing
        policy SHOULD be capable of being configured:
     
          o Whether the node is allowed to participate in Cost or Delay
             or Delay Variation collection.
     
          o Whether the node should notify changes to collected Cost
             and/ or Delay and/ or Delay Variation information to
             endpoint nodes as described in section 4.2.
     
     
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          o Whether the Cost and/or Delay and/or Delay Variation of the
             domain or specific layer network can be exposed to the
             nodes outside the domain or layer network, or whether they
             SHOULD be summarized, mapped to values that are
             comprehensible to nodes outside the domain or layer
             network, or removed entirely.
     
        A node using RFC 5553 [RFC5553] and PKS MAY apply the same
        policy.
     
     6. Security Considerations
     
        This document builds on the mechanisms defined in [RFC3473],
        which also discusses related security measures.  In addition,
        [RFC5920] provides an overview of security vulnerabilities and
        protection mechanisms for the GMPLS control plane.  The
        procedures defined in this document permit the transfer of Cost
        and/or Delay and/or Delay Variation data between layers or
        domains during the signaling of LSPs, subject to policy at the
        layer or domain boundary. It is recommended that domain/layer
        boundary policies take the implications of releasing Cost and/or
        Delay and/or Delay Variation information into consideration and
        behave accordingly during LSP signaling.
     
     7. IANA Considerations
     
     7.1. RSVP Attribute Bit Flags
     
        IANA has created a registry and manages the space of the
        Attribute bit flags of the Attribute Flags TLV, as described in
        section 11.3 of RFC 5420 [RFC5420], in the "Attribute Flags"
        section of the "Resource Reservation Protocol-Traffic
        Engineering (RSVP-TE) Parameters" registry located in
        http://www.iana.org/assignments/rsvp-te- parameters".
     
        This document introduces the following three new Attribute Bit
        Flags:
     
        Bit No      Name       Attribute    Attribute   RRO  Reference
     
                               Flags Path   Flags Resv
     
        ----------- ----------  ----------  ----------- ---  -------
     
        TBA by      Cost        Yes         No         Yes  This I-D
        IANA        Collection
                    Flag
     
     
        TBA by      Delay       Yes         No         Yes  This I-D
        IANA        Collection
                    Flag
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        TBA by      Delay       Yes         No         Yes  This I-D
        IANA        Variation
                    Collection
                    Flag
     
     
     7.2. ROUTE_RECORD sub-object
     
        IANA manages the "RSVP PARAMETERS" registry located at
        http://www.iana.org/assignments/rsvp-parameters. This document
        introduces the following three new RRO sub-object:
     
             Type         Name                        Reference
     
             ---------    ----------------------      ---------
     
             TBA by IANA  Cost sub-object             This I-D
     
             TBA by IANA  Delay sub-object            This I-D
     
             TBA by IANA  Delay Variation sub-object  This I-D
     
     7.3. Policy Control Failure Error subcodes
     
        IANA manages the assignments in the "Error Codes and Globally-
        Defined Error Value Sub-Codes" section of the "RSVP PARAMETERS"
        registry located at http://www.iana.org/assignments/rsvp-
        parameters. This document introduces the following three new
        Policy Control Failure Error sub-code:
     
        Value           Description                          Reference
        -----           -----------                          ---------
     
        TBA by IANA     Cost Recoding Rejected               This I-D
     
        TBA by IANA     Delay Recoding Rejected              This I-D
     
        TBA by IANA     Delay Variation Recoding Rejected    This I-D
     
     
     8. Acknowledgments
     
        Authors would like to thank Ori Gerstel, Gabriele Maria
        Galimberti, Luyuan Fang and Walid Wakim for their review
        comments.
     
     
     
     
     
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     9. References
     
     9.1. Normative References
     
        [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
                  Requirement Levels", BCP 14, RFC 2119, March 1997.
     
        [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan,
                  V., and G. Swallow, "RSVP-TE: Extensions to RSVP for
                  LSP Tunnels", RFC 3209, December 2001.
     
        [RFC3473]  Berger, L., "Generalized Multi-Protocol Lab Switching
                  (GMPLS) Signaling Resource ReserVation Protocol-
                  Traffic Engineering (RSVP-TE) Extensions", RFC 3473,
                  January 2003.
     
        [RFC5420] Farrel, A., Ed., Papadimitriou, D., Vasseur, JP., and
                  A. Ayyangarps, "Encoding of Attributes for MPLS LSP
                  Establishment Using Resource Reservation Protocol
                  Traffic Engineering (RSVP-TE)", RFC 5420, February
                  2009.
     
        [RFC7471] S. Giacalone, D. Ward, J. Drake, A. Atlas, S.
                  Previdi., "OSPF Traffic Engineering (TE) Metric
                  Extensions", RFC 7471, March 2015.
     
        [DRAFT-ISIS-TE-METRIC] S. Previdi, S. Giacalone, D. Ward, J.
                  Drake, A. Atlas, C. Filsfils, "IS-IS Traffic
                  Engineering (TE) Metric Extensions", draft-ietf-isis-
                  te-metric-extensions, work in progress.
     
     9.2. Informative References
     
        [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.
     
        [RFC2209] Braden, R. and L. Zhang, "Resource ReSerVation
                  Protocol (RSVP) -- Version 1 Message Processing
                  Rules", RFC 2209, September 1997.
     
        [RFC5920] Fang, L., Ed., "Security Framework for MPLS and GMPLS
                  Networks", RFC 5920, July 2010.
     
        [DRAFT-SRLG-RECORDING] F. Zhang, O. Gonzalez de Dios, M.
                  Hartley, Z. Ali, C. Margaria,, "RSVP-TE Extensions for
                  Collecting SRLG Information", draft-ietf-teas-rsvp-te-
                  srlg-collect.txt, work in progress.
     
     Authors' Addresses
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        Zafar Ali
        Cisco Systems, Inc.
        Email: zali@cisco.com
     
        George Swallow
        Cisco Systems, Inc.
        swallow@cisco.com
     
        Clarence Filsfils
        Cisco Systems, Inc.
        cfilsfil@cisco.com
     
        Matt Hartley
        Cisco Systems
        Email: mhartley@cisco.com
     
        Kenji Kumaki
        KDDI Corporation
        Email: ke-kumaki@kddi.com
     
        Rudiger Kunze
        Deutsche Telekom AG
        Ruediger.Kunze@telekom.de
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
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