Network Working Group                             Dimitri Papadimitriou
    Internet Draft                                         Martin Vigoureux
    Intended Status: Proposed Standard                       Alcatel-Lucent
    Expiration Date: January 10, 2010                        Kohei Shiomoto
    Creation Date: July 11, 2009                                        NTT
                                                           Deborah Brungard
                                                                        ATT
                                                         Jean-Louis Le Roux
                                                             France Telecom
    
    
           Generalized Multi-Protocol Label Switching (GMPLS) Protocol
         Extensions for Multi-Layer and Multi-Region Networks (MLN/MRN)
    
                  draft-ietf-ccamp-gmpls-mln-extensions-06.txt
    
    Status of this Memo
    
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    Abstract
    
       There are specific requirements for the support of networks
       comprising Label Switching Routers (LSR) participating in different
       data plane switching layers controlled by a single Generalized Multi
       Protocol Label Switching (GMPLS) control plane instance, referred to
       as GMPLS Multi-Layer Networks/Multi-Region Networks (MLN/MRN).
    
       This document defines extensions to GMPLS routing and signaling
       protocols so as to support the operation of GMPLS Multi-Layer/Multi-
       Region Networks. It covers the elements of a single GMPLS control
       plane instance controlling multiple LSP regions or layers within a
       single TE domain.
    
    
    
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    Table of Content
    
       1. Introduction................................................ 2
       2. Summary of the Requirements and Evaluation.................. 3
       3. Interface adjustment capability descriptor (IACD)........... 3
       4. Multi-Region Signaling...................................... 6
       5. Virtual TE link............................................. 8
       6. Backward Compatibility...................................... 13
       7. Security Considerations..................................... 13
       8. IANA Considerations Sections................................ 13
       9. References.................................................. 14
    
    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 [RFC2119].
    
       In addition the reader is assumed to be familiar with [RFC3945],
       [RFC3471], [RFC4201], [RFC4202], [RFC4203], [RFC4206], and [RFC5307].
    
    1. Introduction
    
       Generalized Multi-Protocol Label Switching (GMPLS) [RFC3945]
       extends MPLS to handle multiple switching technologies: packet
       switching (PSC), layer-two switching (L2SC), TDM switching (TDM),
       wavelength switching (LSC) and fiber switching (FSC). A GMPLS
       switching type (PSC, TDM, etc.) describes the ability of a node to
       forward data of a particular data plane technology, and uniquely
       identifies a control plane Label Switched Path (LSP) region. LSP
       Regions are defined in [RFC4206]. A network comprised of multiple
       switching types (e.g. PSC and TDM) controlled by a single GMPLS
       control plane instance is called a Multi-Region Network (MRN).
    
       A data plane layer is a collection of network resources capable of
       terminating and/or switching data traffic of a particular format.
       For example, LSC, TDM VC-11 and TDM VC-4-64c represent three
       different layers. A network comprising transport nodes participating
       in different data plane switching layers controlled by a single GMPLS
       control plane instance is called a Multi-Layer Network (MLN).
    
       The applicability of GMPLS to multiple switching technologies
       provides the unified control and operations for both LSP provisioning
       and recovery. This document covers the elements of a single GMPLS
       control plane instance controlling multiple layers within a given TE
    
    
    
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       domain. A TE domain is defined as group of Label Switching Routers
       (LSR) that enforces a common TE policy. A Control Plane (CP) instance
       can serve one, two or more layers. Other possible approaches such as
       having multiple CP instances serving disjoint sets of layers are
       outside the scope of this document.
    
       The next sections provide the procedural aspects in terms of routing
       and signaling for such environments as well as the extensions
       required to instrument GMPLS to provide the capabilities for MLM/MRN
       unified control. The rationales and requirements for Multi-Layer/
       Region networks are set forth in [MLN-REQ]. These requirements
       are evaluated against GMPLS protocols in [MLN-EVAL] and several
       areas where GMPLS protocol extensions are required are identified.
    
       This document defines GMPLS routing and signaling extensions so as
       to cover GMPLS MLN/MRN requirements.
    
    2. Summary of the Requirements and Evaluation
    
       As identified in [MLN-EVAL], most MLN/MRN requirements rely on
       mechanisms and procedures (such as local procedures and policies, or
       specific TE mechanisms and algorithms) that are outside the scope of
       the GMPLS protocols, and thus do not require any GMPLS protocol
       extensions.
    
       Four areas for extensions of GMPLS protocols and procedures have been
       identified in [MLN-EVAL]:
    
       o GMPLS routing extensions for the advertisement of the internal
         adjustment capability of hybrid nodes. See Section 3.2.2 of [MLN-
         EVAL].
    
       o GMPLS signaling extensions for constrained multi-region signaling
         (Switching Capability inclusion/exclusion). See Section 3.2.1 of
         [MLN-EVAL]. An additional eXclude Route object (XRO) Label
         subobject is also defined since absent from [RFC4874].
    
       o GMPLS signaling extensions for the setup/deletion of Virtual TE-
         links (as well as exact trigger for its actual provisioning). See
         Section 3.1.1.2 of [MLN-EVAL].
    
       o GMPLS routing and signaling extensions for graceful TE-link
         deletion. See Section 3.1.1.3 of [MLN-EVAL].
    
       The first three requirements are addressed in Sections 3, 4, and 5 of
       this document, respectively. The fourth requirement is addressed in
       [GMPLS-RR] with additional context provided by [GR-TELINK].
    
    
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       Companion documents address GMPLS OAM (see [GMPLS OAM]) aspects that
       have been identified in [MLN-EVAL].
    
    3. Interface adjustment capability descriptor (IACD)
    
       In the MRN context, nodes that have at least one interface that
       supports more than one switching capability are called Hybrid nodes
       [MLN-REQ]. The logical composition of a hybrid node contains at least
       two distinct switching elements that are interconnected by "internal
       links" to provide adjustment between the supported switching
       capabilities. These internal links have finite capacities that MUST
       be taken into account when computing the path of a multi-region
       TE-LSP.
    
       The advertisement of the internal adjustment capability is required
       as it provides critical information when performing multi-region path
       computation.
    
    3.1 Overview
    
       In an MRN environment, some LSRs could contain multiple switching
       capabilities such as PSC and TDM, or PSC and LSC, all under the
       control of a single GMPLS instance,
    
       These nodes, hosting multiple Interface Switching Capabilities (ISC)
       [RFC4202], are required to hold and advertise resource information on
       link states and topology, just like other nodes (hosting a single
       ISC). They may also have to consider some portions of internal node
       resources use to terminate hierarchical LSPs, since in circuit-
       switching technologies (such as TDM, LSC, and FSC) LSPs require the
       use of resources allocated in a discrete manner (as pre-determined by
       the switching type). For example, a node with PSC+LSC hierarchical
       switching capability can switch a lambda LSP, but cannot terminate
       the Lambda LSP if there is no available (i.e., not already in use)
       adjustment capability between the LSC and the PSC switching
       components. Another example occurs when L2SC (Ethernet) switching can
       be adapted in LAPS X.86 and GFP for instance before reaching the TDM
       switching matrix. Similar circumstances can occur, if a switching
       fabric that supports both PSC and L2SC functionalities is assembled
       with LSC interfaces enabling "lambda" encoding. In the switching
       fabric, some interfaces can terminate Lambda LSPs and perform frame
       (or cell) switching whilst other interfaces can terminate Lambda LSPs
       and perform packet switching.
    
       Therefore, within multi-region networks, the advertisement of the
       so-called adjustment capability to terminate LSPs (not the interface
    
    
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       capability since the latter can be inferred from the bandwidth
       available for each switching capability) provides the information to
       take into account when performing multi-region path computation. This
       concept enables a node to discriminate the remote nodes (and thus
       allows their selection during path computation) with respect to their
       adjustment capability e.g. to terminate LSPs at the PSC or LSC level.
    
       Hence, we introduce the capability of discriminating the (internal)
       adjustment capability from the (interface) switching capability by
       defining an Interface Adjustment Capability Descriptor (IACD).
    
       A more detailed problem statement can be found in [MLN-EVAL].
    
    3.2 Interface Adjustment Capability Descriptor (IACD)
    
       The interface adjustment capability descriptor (IACD) provides the
       information for the forwarding/switching) only capability.
    
       Note that the addition of the IACD as a TE link attribute does not
       modify the format of the Interface Switching Capability Descriptor
       (ISCD) defined in [RFC4202], and does not change how the ISCD sub-TLV
       is carried in the routing protocols or how it is processed when it is
       received [RFC4201], [RFC4203].
    
       The receiving LSR uses its Link State Database to determine the
       IACD(s) of the far-end of the link. Different Interface Adjustment
       Capabilities at two ends of a TE link are allowed.
    
    3.2.1 OSPF
    
       In OSPF, the IACD sub-TLV is defined as an optional sub-TLV of the TE
       Link TLV (Type 2, see [RFC3630]), with Type 24 (to be assigned by
       IANA) and variable length.
    
       The IACD sub-TLV format is defined as follows:
    
         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
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        | Lower SC      | Lower Encoding| Upper SC      |Upper Encoding |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |                  Max LSP Bandwidth at priority 0              |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |                  Max LSP Bandwidth at priority 1              |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |                  Max LSP Bandwidth at priority 2              |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    
    
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        |                  Max LSP Bandwidth at priority 3              |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |                  Max LSP Bandwidth at priority 4              |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |                  Max LSP Bandwidth at priority 5              |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |                  Max LSP Bandwidth at priority 6              |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |                  Max LSP Bandwidth at priority 7              |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |        Adjustment Capability-specific information             |
        |                  (variable)                                   |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    
          Lower Switching Capability (SC) field (byte 1) - 8 bits
    
             Indicates the Lower Switching Capability associated to the
             Lower Encoding field (byte 2). The value of the Lower Switching
             Capability field MUST be set to the value of Switching
             Capability of the ISCD sub-TLV advertized for this TE Link. If
             multiple ISCD sub-TLVs are advertized for that TE link, the
             Lower Switching Capability (SC) value MUST be set to the value
             of SC to which the adjustment capacity is associated.
    
          Lower Encoding (byte 2) - 8 bits
    
           Contains one of the values specified in Section 3.1.1 of
             [GMPLS-SIG] and updates.
    
          Upper Switching Capability (SC) field (byte 3) - 8 bits
    
             Indicates the Upper Switching capability. The Upper Switching
             Capability field MUST be set to one of the values defined in
             [RFC4202]
    
          Upper Encoding (byte 4) - 8 bits
    
             Set to the encoding of the available adjustment capacity and to
             0xFF when the corresponding SC value has no access to the wire,
             i.e., there is no ISC sub-TLV for this upper switching
             capability. The adjustment capacity is the set of resources
             associated to the upper switching capability.
    
          The Adjustment Capability-specific information - variable
    
           This field is defined so as to leave the possibility for
             future addition of technology-specific information associated
    
    
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             to the adjustment capability.
    
          Other fields MUST be processed as specified in [RFC4202] and
          [RFC4203].
    
       The bandwidth values provide an indication of the resources still
       available to perform insertion/extraction for a given adjustment at a
       given priority (resource pool concept: set of shareable available
       resources that can be assigned dynamically).
    
       Multiple IACD sub-TLVs MAY be present within a given TE Link TLV.
    
       The presence of the IACD sub-TLV as part of the TE Link TLV does not
       modify the format/messaging and the processing associated to the ISCD
       sub-TLV defined in [RFC4203].
    
    3.2.2 IS-IS
    
       In IS-IS, the IACD sub-TLV is an optional sub-TLV of the Extended IS
       Reachability TLV (see [RFC5305]) with Type 24 (to be assigned by
       IANA).
    
       The IACD sub-TLV format is defined as follows:
    
         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
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        | Lower SC      | Lower Encoding| Upper SC      |Upper Encoding |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |                  Max LSP Bandwidth at priority 0              |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |                  Max LSP Bandwidth at priority 1              |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |                  Max LSP Bandwidth at priority 2              |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |                  Max LSP Bandwidth at priority 3              |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |                  Max LSP Bandwidth at priority 4              |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |                  Max LSP Bandwidth at priority 5              |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |                  Max LSP Bandwidth at priority 6              |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |                  Max LSP Bandwidth at priority 7              |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |        Adjustment Capability-specific information             |
        |                  (variable)                                   |
    
    
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        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    
       The fields of the IACD sub-TLV have the same processing and
       interpretation rules as defined in Section 3.2.1.
    
       Multiple IACD sub-TLVs MAY be present within a given extended IS
       reachability TLV.
    
       The presence of the IACD sub-TLV as part of the extended IS
       reachability TLV does not modify format/messaging and processing
       associated to the ISCD sub-TLV defined in [RFC5307].
    
    4. Multi-Region Signaling
    
       Section 6.2 of [RFC4206] specifies that when a region boundary node
       receives a Path message, the node determines whether or not it is at
       the edge of an LSP region with respect to the ERO carried in the
       message. If the node is at the edge of a region, it must then
       determine the other edge of the region with respect to the ERO,
       using the IGP database. The node then extracts from the ERO the
       sub-sequence of hops from itself to the other end of the region.
    
       The node then compares the sub-sequence of hops with all existing FA-
       LSPs originated by the node:
    
       o If a match is found, that FA-LSP has enough unreserved bandwidth
         for the LSP being signaled, and the G-PID of the FA-LSP is
         compatible with the G-PID of the LSP being signaled, the node uses
         that FA-LSP as follows. The Path message for the original LSP is
         sent to the egress of the FA-LSP. The PHOP in the message is the
         address of the node at the head-end of the FA-LSP. Before sending
         the Path message, the ERO in that message is adjusted by removing
         the subsequence of the ERO that lies in the FA-LSP, and replacing
         it with just the end point of the FA-LSP.
    
       o If no existing FA-LSP is found, the node sets up a new FA-LSP.
         That is, it initiates a new LSP setup just for the FA-LSP.
    
         Note: compatible G-PID implies that traffic can be processed by
         both ends of the FA-LSP without dropping traffic after its
         establishment.
    
       Applying the procedure of [RFC4206], in a MRN environment MAY lead to
       setup single-hop FA-LSPs between each pair of nodes. Therefore,
       considering that the path computation is able to take into account
       richness of information with regard to the SC available on given
       nodes belonging to the path, it is consistent to provide enough
    
    
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       signaling information to indicate the SC to be used and over which
       link. Particularly, in case a TE link has multiple SCs advertised as
       part of its ISCD sub-TLVs, an ERO does not provide a mechanism to
       select a particular SC.
    
       In order to limit the modifications to existing RSVP-TE procedures
       ([RFC3473] and referenced), this document defines a new sub-object of
       the eXclude Route Object (XRO), see [RFC4874], called the Switching
       Capability sub-object. This sub-object enables (when desired) the
       explicit identification of at least one switching capability to be
       excluded from the resource selection process described above.
    
       Including this sub-object as part of the XRO that explicitly
       indicates which SCs have to be excluded (before initiating the
       procedure described here above) over a specified TE link, solves the
       ambiguous choice among SCs that are potentially used along a given
       path and give the possibility to optimize resource usage on a multi-
       region basis. Note that implicit SC inclusion is easily supported by
       explicitly excluding other SCs (e.g. to include LSC, it is required
       to exclude PSC, L2SC, TDM and FSC).
    
       The approach followed here is to concentrate exclusions in XRO and
       inclusions in ERO. Indeed, the ERO specifies the topological
       characteristics of the path to be signaled. Usage of EXRS subobjects
       would also lead in the exclusion over certain portions of the LSP
       during the FA-LSP setup. Thus, it is more suited to extend generality
       of the elements to the excluded in the XRO but also prevent complex
       consistency checks but also transpositions between EXRS and XRO at
       FA-LSP head-ends.
    
    4.1 XRO Subobject Encoding
    
       The contents of an EXCLUDE_ROUTE object defined in [RFC4874] are a
       series of variable-length data items called subobjects.
    
       This document defines the Switching Capability (SC) subobject of the
       XRO (Type 35), its encoding and processing. It also complements the
       subobjects defined in [RFC4874] with a Label subobject (Type 3).
    
    4.1.1 SC Subobject Encoding
    
       XRO Subobject Type 35: Switching Capability
    
          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
         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
         |L|    Type     |     Length    |   Attribute   | Switching Cap |
    
    
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         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    
          L
             0 indicates that the attribute specified MUST be excluded
             1 indicates that the attribute specified SHOULD be avoided
    
          Attribute
    
             0 reserved value
    
             1 indicates that the specified SC SHOULD be excluded or
               avoided with respect to the preceding numbered (Type 1 or
               Type 2) or unnumbered interface (Type) subobject.
    
          Switching Cap (8-bits)
    
             Switching Capability value to be excluded.
    
       The Switching Capability subobject MUST follow the set of one or more
       numbered or unnumbered interface sub-objects to which this sub-object
       refers.
    
       In case, of loose hop ERO subobject, the XRO sub-object MUST precede
       the loose-hop sub-object identifying the tail-end node/interface of
       the traversed region(s).
    
    4.1.2 Label Subobject Encoding
    
       XRO Subobject Type 3: Switching Capability
    
    
          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
         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
         |L|    Type     |    Length     |    Reserved   |    C-Type     |
         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
         |                             Label                             |
         |                              ...                              |
         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    
          L
             0 indicates that the attribute specified MUST be excluded.
             1 indicates that the attribute specified SHOULD be avoided.
    
    
          Type
    
    
    
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             3  Label
    
          Length
    
             The Length contains the total length of the subobject in bytes,
             including the Type and Length fields. The Length is always
             divisible by 4.
    
          C-Type
    
             The C-Type of the Label to be excluded.
    
          Label
    
             The value of the label to excluded is defined per [RFC3471].
    
          Reserved
    
             This field is reserved. It SHOULD be set to zero on
             transmission and MUST be ignored on receipt.
    
       Label subobjects MUST follow the numbered or unnumbered interface
       sub-objects to which they refer and MAY follow the Switching
       Capability sub-object.
    
       When XRO label sub-objects are following the Switching Capability
       sub-object, the corresponding label values MUST be compatible with
       the SC capability to be explicitly excluded.
    
    5. Virtual TE link
    
       A virtual TE link is defined as a TE link between two upper layer
       nodes that is not associated with a fully provisioned FA-LSP in a
       lower layer [MLN-REQ]. A virtual TE link is advertised as any TE
       link, following the rules in [RFC4206] defined for fully provisioned
       TE links. A virtual TE link represents thus the potentiality to setup
       an FA-LSP in the lower layer to support the TE link that has been
       advertised. In particular, the flooding scope of a virtual TE link is
       within an IGP area, as is the case for any TE link.
    
       Two techniques can be used for the setup, operation, and maintenance
       of virtual TE links. The corresponding GMPLS protocols extensions are
       described in this section. The procedures described in this section
       complement those defined in [RFC4206] and [HIER-BIS].
    
    5.1 Edge-to-edge Association
    
    
    
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       This approach, that does not require state maintenance on transit
       LSRs, relies on extensions to the GMPLS RSVP-TE Call procedure (see
       [RFC4974]).
    
       This technique consists of exchanging identification and TE
       attributes information directly between TE link end points through
       the establishment of a call between terminating LSRs. These TE link
       end-points correspond to the LSP head-end and tail-end points of the
       LSPs that will be established. The end-points MUST belong to the same
       (LSP) region.
    
       Once the call is established the resulting association populates the
       local Traffic Engineering DataBase (TEDB) and the resulting virtual
       TE link is advertised as any other TE link. The latter can then be
       used to attract traffic. When an upper layer/region LSP tries to make
       use of this virtual TE link, one or more FA LSPs MUST be established
       using the procedures defined in [RFC4206] to make the virtual TE link
       "real" and allow it to carry traffic by nesting the upper
       layer/region LSP.
    
       In order to distinguish usage of such call from the call and
       associated procedures defined in [RFC4974], a CALL ATTRIBUTES object
       is introduced.
    
    5.1.1 CALL_ATTRIBUTES Object
    
       The CALL_ATTRIBUTES object is used to signal attributes required in
       support of a call, or to indicate the nature or use of a call. It is
       modeled on the LSP-ATTRIBUTES object defined in [RFC5420]. The
       CALL_ATTRIBUTES object MAY also be used to report call operational
       state on a Notify message.
    
       The CALL_ATTRIBUTES object class is 201 (TBD by IANA) of the form
       11bbbbbb. This C-Num value (see [RFC2205], Section 3.10) ensures that
       LSRs that do not recognize the object pass it on transparently.
    
       One C-Type is defined, C-Type = 1 for CALL Attributes. This object is
       OPTIONAL and MAY be placed on Notify messages to convey additional
       information about the desired attributes of the call.
    
       CALL_ATTRIBUTES class = 201, C-Type = 1
    
          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
         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
         |                                                               |
         //                       Attributes TLVs                       //
    
    
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         |                                                               |
         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    
       The Attributes TLVs are encoded as described in Section 5.1.3.
    
    5.1.2 Processing
    
       If an egress (or intermediate) LSR does not support the object, it
       forwards it unexamined and unchanged. This facilitates the exchange
       of attributes across legacy networks that do not support this new
       object.
    
    5.1.3 Attributes TLVs
    
       Attributes carried by the CALL_ATTRIBUTES object are encoded within
       TLVs. One or more TLVs MAY be present in each object.
    
       There are no ordering rules for TLVs, and no interpretation SHOULD be
       placed on the order in which TLVs are received.
    
       Each TLV is encoded as follows.
    
         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              |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |                                                               |
        //                            Value                            //
        |                                                               |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    
          Type
    
             The identifier of the TLV.
    
          Length
    
             Indicates the total length of the TLV in octets.  That is, the
             combined length of the Type, Length, and Value fields, i.e.,
             four plus the length of the Value field in octets.
    
             The entire TLV MUST be padded with between zero and three
             trailing zeros to make it four-octet aligned.  The Length field
             does not count any padding.
    
          Value
    
    
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             The data field for the TLV padded as described above.
    
    5.1.4 Attributes Flags TLV
    
       The TLV Type 1 indicates the Attributes Flags TLV. Other TLV types
       MAY be defined in the future with type values assigned by IANA (see
       Section 8). The Attributes Flags TLV MAY be present in a
       CALL_ATTRIBUTES object.
    
       The Attribute Flags TLV value field is an array of units of 32 flags
       numbered from the most significant bit as bit zero. The Length field
       for this TLV is therefore always a multiple of 4 bytes, regardless of
       the number of bits carried and no padding is required.
    
       Unassigned bits are considered as reserved and MUST be set to zero on
       transmission by the originator of the object. Bits not contained in
       the TLV MUST be assumed to be set to zero. If the TLV is absent
       either because it is not contained in the CALL_ATTRIBUTES object or
       because this object is itself absent, all processing MUST be
       performed as though the bits were present and set to zero. That is to
       say, assigned bits that are not present either because the TLV is
       deliberately foreshortened or because the TLV is not included MUST be
       treated as though they are present and are set to zero.
    
    5.1.5 Call Inheritance Flag
    
       This document introduces a specific flag (most significant bit (msb)
       position bit 0) of the Attributes Flags TLV, to indicate that the
       association initiated between the end-points belonging to a call
       results into a (virtual) TE link advertisement.
    
       The Call Inheritance Flag MUST be set to 1 in order to indicate that
       the established association is to be translated into a TE link
       advertisement. The value of this flag SHALL by default be set to 1.
       Setting this flag to 0 results in a hidden TE link or in deleting the
       corresponding TE link advertisement (by setting the corresponding
       Opaque LSA Age to MaxAge) if the association had been established
       with this flag set to 1. In the latter case, the corresponding FA-LSP
       SHOULD also be torn down to prevent unused resources.
    
       The Notify message used for establishing the association is defined
       as per [RFC4974]. Additionally, the Notify message MUST carry an
       LSP_TUNNEL_INTERFACE_ID Object, that allows identifying unnumbered
       FA-LSPs ([RFC3477], [RFC4206], [HIER-BIS]) and numbered FA-LSPs
       ([RFC4206], [HIER-BIS]).
    
    
    
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    5.2. Soft Forwarding Adjacency (Soft FA)
    
       The Soft Forwarding Adjacency (Soft FA) approach consists of setting
       up the FA LSP at the control plane level without actually committing
       resources in the data plane. This means that the corresponding LSP
       exists only in the control plane domain. Once such FA is established
       the corresponding TE link can be advertised following the procedures
       described in [RFC4206].
    
       There are two techniques to setup Soft FAs:
    
       o The first one consists in setting up the FA LSP by precluding
         resource commitment during its establishment. These are known as
         pre-planned LSPs.
    
       o The second technique consists in making use of path provisioned
         LSPs only. In this case, there is no associated resource demand
         during the LSP establishment. This can be considered as the RSVP-TE
         equivalent of the Null service type specified in [RFC2997].
    
    5.2.1 Pre-Planned LSP Flag
    
       The LSP ATTRIBUTES object and Attributes Flags TLV are defined in
       [RFC5420]. The present document defines a new flag, the Pre-Planned
       LSP flag, in the existing Attributes Flags TLV (numbered as Type 1).
    
       The position of this flag is TBD in accordance with IANA assignment.
       This flag, part of the Attributes Flags TLV, follows general
       processing of [RFC5420] for LSP_REQUIRED_ATTRIBUTE object. That is,
       LSRs that do not recognize the object reject the LSP setup
       effectively saying that they do not support the attributes requested.
       Indeed, the newly defined attribute requires examination at all
       transit LSRs along the LSP being established.
    
       The Pre-Planned LSP flag can take one of the following values:
    
       o When set to 0 this means that the LSP MUST be fully provisioned.
         Absence of this flag (hence corresponding TLV) is therefore
         compliant with the signaling message processing per [RFC3473])
    
       o When set to 1 this means that the LSP MUST be provisioned in the
         control plane only.
    
       If an LSP is established with the Pre-Planned flag set to 1, no
       resources are committed at the data plane level.
    
    
    
    
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       The operation of committing data plane resources occurs by re-
       signaling the same LSP with the Pre-Planned flag set to 0. It is
       RECOMMENDED that no other modifications are made to other RSVP
       objects during this operation. That is each intermediate node,
       processing a flag transiting from 1 to 0 shall only be concerned with
       the commitment of data plane resources and no other modification of
       the LSP properties and/or attributes.
    
       If an LSP is established with the Pre-Planned flag set to 0, it MAY
       be re-signaled by setting the flag to 1.
    
    5.2.2 Path Provisioned LSPs
    
       There is a difference in between an LSP that is established with 0
       bandwidth (path provisioning) and an LSP that is established with a
       certain bandwidth value not committed at the data plane level (i.e.
       pre-planned LSP).
    
       Mechanisms for provisioning (pre-planned or not) LSP with 0 bandwidth
       is straightforward for PSC the SENDER_TSPEC/FLOWSPEC, the Peak Data
       Rate field of Int-Serv objects, see [RFC2210], is set to 0. For L2SC
       LSP, the CIR, EIR, CBS, and EBS MUST be set of 0 in the Type 2 sub-
       TLV of the Ethernet Bandwidth Profile TLV. In these cases, upon LSP
       resource commitment, actual traffic parameter values are used to
       perform corresponding resource reservation.
    
       However, mechanisms for provisioning (pre-planned or not) TDM or LSC
       LSP with 0 bandwidth is currently not possible because the exchanged
       label value is tightly coupled with resource allocation during LSP
       signaling (see e.g. [RFC4606] for SDH/SONET LSP). For TDM and LSC
       LSP, a NULL Label value is used to prevent resource allocation at the
       data plane level. In these cases, upon LSP resource commitment,
       actual label value exchange is performed to commit allocation of
       timeslots/wavelengths.
    
    6. Backward Compatibility
    
       New objects and procedures defined in this document are running
       within a given TE domain, defined as group of LSRs that enforces a
       common TE policy. Thus, the extensions defined in this document are
       expected to run in the context of a consistent TE policy.
       Specification of a consistent TE policy is outside the scope of this
       document.
    
       In such TE domains, we distinguish between edge LSRs and intermediate
       LSRs. Edge LSRs MUST be able to process Call Attribute as defined in
       Section 5.1 if this is the method selected for creating edge-to-edge
    
    
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       associations. In that domain, intermediate LSRs are by definition
       transparent to the Call processing.
    
       In case the Soft FA method is used for the creation of virtual TE
       links, edge and intermediate LSRs MUST support processing of the LSP
       ATTRIBUTE object per Section 5.2.
    
    7. Security Considerations
    
       This document does not introduce any new security consideration from
       the ones already detailed in [MPLS-SEC] that describes the MPLS and
       GMPLS security threats, the related defensive techniques, and the
       mechanisms for detection and reporting. Indeed, the applicability of
       the proposed GMPLS extensions is limited to single TE domain. Such a
       domain is under the authority of a single administrative entity. In
       this context, multiple switching layers comprised within such TE
       domain are under the control of a single GMPLS control plane
       instance.
    
       Nevertheless, Call initiation, as depicted in section 5.1, MUST
       strictly remain under control of the TE domain administrator. To
       prevent any abuse of Call setup, edge nodes MUST ensure isolation of
       their call controller (i.e. the latter is not reachable via external
       TE domains). To further prevent man-in-the-middle attack, security
       associations MUST be established between edge nodes initiating and
       terminating calls. For this purpose, IKE [RFC4306] MUST be used for
       performing mutual authentication and establishing and maintaining
       these security associations.
    
    8. IANA Considerations
    
    8.1 RSVP
    
       IANA has 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.
    
       This document introduces a new class named CALL_ATTRIBUTES has been
       created in the 11bbbbbb range (201) with the following definition:
    
       Class Number  Class Name                            Reference
       ------------  -----------------------               ---------
       201           CALL ATTRIBUTES                [This I-D]
    
                     Class Type (C-Type):
    
                     1   Call Attributes                [This.I-D]
    
    
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       This document introduces two new subobjects for the EXCLUDE_ROUTE
       object [RFC4874], C-Type 1.
    
       Subobject Type   Subobject Description
       --------------   ---------------------
       3               Label
       35               Switching Capability (SC)
    
    
    8.2 OSPF
    
       IANA maintains Open Shortest Path First (OSPF) Traffic Engineering
       TLVs Registries included below for Top level Types in TE LSAs and
       Types for sub-TLVs of TE Link TLV (Value 2).
    
       This document defines the following sub-TLV of TE Link TLV (Value 2)
    
       Value  Sub-TLV
       -----  -------------------------------------------------
       24     Interface Adjustment Capability Descriptor (IACD)
    
    8.3 IS-IS
    
       This document defines the following new sub-TLV type of top-level TLV
       22 that need to be reflected in the ISIS sub-TLV registry for TLV 22:
    
       Type   Description                                        Length
       ----   -------------------------------------------------  ------
       24     Interface Adjustment Capability Descriptor (IACD)  Variable
    
    9. References
    
    9.1 Normative References
    
       [GMPLS-RR] Berger, L., Papadimitriou, D., and JP. Vasseur,
                  "PathErr Message Triggered MPLS and GMPLS LSP Reroute",
                  draft-ietf-mpls-gmpls-lsp-reroute, Work in progress.
    
       [HIER-BIS] Shiomoto, K., and Farrel, A., "Procedures for Dynamically
                  Signaled Hierarchical Label Switched Paths", draft-ietf
                  ccamp-lsp-hierarchy-bis, Work in progress.
    
       [RFC2205]  Braden, R., et al., "Resource ReSerVation Protocol
                  (RSVP) -- Version 1 Functional Specification",
                  RFC2205, September 1997.
    
    
    
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       [RFC2210]  Wroclawski, J., "The Use of RSVP with IETF
                  Integrated Services", RFC2210, September 1997.
    
       [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
                  Requirement Levels", BCP 14, RFC 2119, March 1997.
    
       [RFC2997]  Bernet, Y., Smith, A., and B. Davie, "Specification of the
                  Null Service Type", RFC2997, November 2000.
    
       [RFC3471]  Berger, L., et al., "Generalized Multi-Protocol Label
                  Switching (GMPLS) - Signaling Functional Description",
                  RFC3471, January 2003.
    
       [RFC3473]  Berger, L., "Generalized Multi-Protocol Label
                  Switching (GMPLS) Signaling Resource ReserVation
                  Protocol-Traffic Engineering (RSVP-TE) Extensions",
                  RFC3473, January 2003.
    
       [RFC3477]  Kompella, K., and Y. Rekhter, "Signalling Unnumbered Links
                  in Resource ReSerVation Protocol - Traffic Engineering
                  (RSVP-TE)", RFC3477, January 2003.
    
       [RFC3630]  Katz, D., et al., "Traffic Engineering (TE) Extensions to
                  OSPF Version 2," RFC3630, September 2003.
    
       [RFC3945]  Mannie, E. and al., "Generalized Multi-Protocol Label
                  Switching (GMPLS) Architecture", RFC3945, October 2004.
    
       [RFC4201]  Kompella, K., et al., "Link Bundling in MPLS Traffic
                  Engineering", RFC4201, October 2005.
    
       [RFC4202]  Kompella, K., Ed., and Rekhter, Y. Ed., "Routing
                  Extensions in Support of Generalized MPLS", RFC4202,
                  October 2005.
    
       [RFC4203]  Kompella, K., Ed., and Y. Rekhter, Ed., "OSPF Extensions
                  in Support of Generalized Multi-Protocol Label Switching
                  (GMPLS)", RFC4203, October 2005.
    
       [RFC4206]  Kompella, K., and Rekhter, Y., "LSP Hierarchy with
                  Generalized MPLS TE", RFC4206, October 2005.
    
       [RFC4306]  Kaufman, C., Ed., "Internet Key Exchange (IKEv2)
                  Protocol", RFC4306, December 2005.
    
       [RFC4606]  Mannie, E., and D. Papadimitriou, D., "Generalized Multi-
                  Protocol Label Switching (GMPLS) Extensions for
    
    
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                  Synchronous Optical Network (SONET) and Synchronous
                  Digital Hierarchy (SDH) Control. RFC4606, August 2006.
    
       [RFC5305]  Smit, H. and T. Li, "Intermediate System to
                  Intermediate System (IS-IS) Extensions for Traffic
                  Engineering (TE)", RFC5305, October 2008.
    
       [RFC5307]  Kompella, K., Ed., and Y. Rekhter, Ed., "Intermediate
                  System to Intermediate System (IS-IS) Extensions in
                  Support of Generalized Multi-Protocol Label Switching
                  (GMPLS)", RFC5307, October 2005.
    
       [RFC5420]  Farrel, A., et al., "Encoding of Attributes for
                  Multiprotocol Label Switching (MPLS) Label Switched Path
                  (LSP) Establishment Using Resource ReserVation Protocol-
                  Traffic Engineering (RSVP-TE)", RFC 5420, February 2009.
    
       [RFC4874]  Lee, C.Y., et al. "Exclude Routes - Extension to RSVP-TE,"
                  RFC4874, April 2007.
    
       [RFC4974]  Papadimitriou, D., and Farrel, A., "Generalized MPLS
                  (GMPLS) RSVP-TE Signaling Extensions in support of Calls,"
                  RFC4974, August 2007.
    
    9.2 Informative References
    
       [GMPLS-OAM] Nadeau, T., Otani, T. Brungard, D., and A. Farrel, "OAM
                   Requirements for Generalized Multi-Protocol Label
                   Switching (GMPLS) Networks", Work in Progress, October
                   2007.
    
       [GR-TELINK] Ali, Z., et al., "Graceful Shutdown in MPLS and
                   Generalized MPLS Traffic Engineering Networks", draft-
                   ietf-ccamp-mpls-graceful-shutdown, Work in progress.
    
       [MLN-EVAL]  Leroux, J.-L., et al., "Evaluation of existing GMPLS
                   Protocols against Multi Region and Multi Layer Networks
                   (MRN/MLN)", RFC 5339, September 2008.
    
       [MLN-REQ]   Shiomoto, K., et al., "Requirements for GMPLS-based
                   multi-region and multi-layer networks (MRN/MLN)",
                   RFC5212, July 2008.
    
       [MPLS-SEC]  Fang, L. Ed., "Security Framework for MPLS and GMPLS
                   Networks", draft-ietf-mpls-mpls-and-gmpls-security-
                   framework-03.txt, Work in progress.
    
    
    
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       [MLRT]      Imajuku, W., et al., "Multilayer routing using multilayer
                   switch capable LSRs", draft-imajuku-ml-routing-02.txt,
                   Work in Progress.
    
    Acknowledgments
    
       The authors would like to thank Mr. Wataru Imajuku for the
       discussions on adjustment between regions [MLRT].
    
    Author's Addresses
    
       Dimitri Papadimitriou
       Alcatel-Lucent Bell
       Copernicuslaan 50
       B-2018 Antwerpen, Belgium
       Phone: +32 3 2408491
       E-mail: dimitri.papadimitriou@alcatel-lucent.be
    
       Martin Vigoureux
       Alcatel-Lucent
       Route de Villejust
       91620 Nozay, France
       Tel : +33 1 30 77 26 69
       Email: martin.vigoureux@alcatel-lucent.fr
    
       Kohei Shiomoto
       NTT
       3-9-11 Midori-cho
       Musashino-shi, Tokyo 180-8585, Japan
       Phone: +81 422 59 4402
       Email: shiomoto.kohei@lab.ntt.co.jp
    
       Deborah Brungard
       ATT
       Rm. D1-3C22 - 200 S. Laurel Ave.
       Middletown, NJ 07748, USA
       Phone: +1 732 420 1573
       Email: dbrungard@att.com
    
       Jean-Louis Le Roux
       France Telecom
       Avenue Pierre Marzin
       22300 Lannion, France
       Phone: +33 (0)2 96 05 30 20
       Email: jean-louis.leroux@rd.francetelecom.com
    
    Contributors
    
    
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       Eiji Oki
       NTT Network Service Systems Laboratories
       3-9-11 Midori-cho
       Musashino-shi, Tokyo 180-8585, Japan
       Phone : +81 422 59 3441
       Email: oki.eiji@lab.ntt.co.jp
    
       Ichiro Inoue
       NTT Network Service Systems Laboratories
       3-9-11 Midori-cho
       Musashino-shi, Tokyo 180-8585, Japan
       Phone : +81 422 59 6076
       Email: ichiro.inoue@lab.ntt.co.jp
    
       Emmanuel Dotaro
       Alcatel-Lucent France
       Route de Villejust
       91620 Nozay, France
       Phone : +33 1 6963 4723
       Email: emmanuel.dotaro@alcatel-lucent.fr
    
       Gert Grammel
       Alcatel-Lucent SEL
       Lorenzstrasse, 10
       70435 Stuttgart, Germany
       Email: gert.grammel@alcatel-lucent.de
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
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