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Versions: (draft-ginsberg-isis-te-app) 00 01

Networking Working Group                                     L. Ginsberg
Internet-Draft                                                 P. Psenak
Intended status: Standards Track                           Cisco Systems
Expires: April 15, 2018                                       S. Previdi
                                                              Individual
                                                           W. Henderickx
                                                                   Nokia
                                                                J. Drake
                                                        Juniper Networks
                                                        October 12, 2017


                  IS-IS TE Attributes per application
                     draft-ietf-isis-te-app-01.txt

Abstract

   Existing traffic engineering related link attribute advertisements
   have been defined and are used in RSVP-TE deployments.  In cases
   where multiple applications wish to make use of these link attributes
   the current advertisements do not support application specific values
   for a given attribute nor do they support indication of which
   applications are using the advertised value for a given link.

   This draft introduces new link attribute advertisements which address
   both of these shortcomings.  It also discusses backwards
   compatibility issues and how to minimize duplicate advertisements in
   the presence of routers which do not support the extensions defined
   in this document.

Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any



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   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on April 15, 2018.

Copyright Notice

   Copyright (c) 2017 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Requirements Discussion . . . . . . . . . . . . . . . . . . .   3
   3.  Legacy Advertisements . . . . . . . . . . . . . . . . . . . .   4
     3.1.  Legacy sub-TLVs . . . . . . . . . . . . . . . . . . . . .   4
     3.2.  Legacy SRLG Advertisements  . . . . . . . . . . . . . . .   5
   4.  Advertising Application Specific Link Attributes  . . . . . .   5
     4.1.  Application Identifier Bit Mask . . . . . . . . . . . . .   5
     4.2.  Application Specific Link Attributes sub-TLV  . . . . . .   7
     4.3.  Application Specific SRLG TLV . . . . . . . . . . . . . .   8
   5.  Deployment Considerations . . . . . . . . . . . . . . . . . .   9
   6.  Attribute Advertisements and Enablement . . . . . . . . . . .  10
   7.  Interoperability, Backwards Compatibility and Migration
       Concerns  . . . . . . . . . . . . . . . . . . . . . . . . . .  10
     7.1.  RSVP-TE only deployments  . . . . . . . . . . . . . . . .  11
     7.2.  Multiple Applications: Common Attributes with  RSVP-TE  .  11
     7.3.  Multiple Applications: All Attributes Not Shared w RSVP-
           TE  . . . . . . . . . . . . . . . . . . . . . . . . . . .  11
     7.4.  Deprecating legacy advertisements . . . . . . . . . . . .  11
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  12
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .  13
   10. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  13
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  13
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  13
     11.2.  Informative References . . . . . . . . . . . . . . . . .  14
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  14




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1.  Introduction

   Advertisement of link attributes by the Intermediate-System-to-
   Intermediate-System (IS-IS) protocol in support of traffic
   engineering (TE) was introduced by [RFC5305] and extended by
   [RFC5307], [RFC6119], and [RFC7810].  Use of these extensions has
   been associated with deployments supporting Traffic Engineering over
   Multiprotocol Label Switching (MPLS) in the presence of Resource
   Reservation Protocol (RSVP) - more succinctly referred to as RSVP-TE.

   In recent years new applications have been introduced which have use
   cases for many of the link attributes historically used by RSVP-TE.
   Such applications include Segment Routing Traffic Engineering (SRTE)
   and Loop Free Alternates (LFA).  This has introduced ambiguity in
   that if a deployment includes a mix of RSVP-TE support and SRTE
   support (for example) it is not possible to unambiguously indicate
   which advertisements are to be used by RSVP-TE and which
   advertisements are to be used by SRTE.  If the topologies are fully
   congruent this may not be an issue, but any incongruence leads to
   ambiguity.

   An additional issue arises in cases where both applications are
   supported on a link but the link attribute values associated with
   each application differ.  Current advertisements do not support
   advertising application specific values for the same attribute on a
   specific link.

   This document defines extensions which address these issues.  Also,
   as evolution of use cases for link attributes can be expected to
   continue in the years to come, this document defines a solution which
   is easily extensible to the introduction of new applications and new
   use cases.

2.  Requirements Discussion

   As stated previously, evolution of use cases for link attributes can
   be expected to continue - so any discussion of existing use cases is
   limited to requirements which are known at the time of this writing.
   However, in order to determine the functionality required beyond what
   already exists in IS-IS, it is only necessary to discuss use cases
   which justify the key points identified in the introduction - which
   are:

   1.  Support for indicating which applications are using the link
       attribute advertisements on a link

   2.  Support for advertising application specific values for the same
       attribute on a link



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   [RFC7855] discusses use cases/requirements for SR.  Included among
   these use cases is SRTE which is defined in [SR-POLICY].  If both
   RSVP-TE and SRTE are deployed in a network, link attribute
   advertisements can be used by one or both of these applications.  As
   there is no requirement for the link attributes advertised on a given
   link used by SRTE to be identical to the link attributes advertised
   on that same link used by RSVP-TE, there is a clear requirement to
   indicate independently which link attribute advertisements are to be
   used by each application.

   As the number of applications which may wish to utilize link
   attributes may grow in the future, an additional requirement is that
   the extensions defined allow the association of additional
   applications to link attributes without altering the format of the
   advertisements or introducing new backwards compatibility issues.

   Finally, there may still be many cases where a single attribute value
   can be shared among multiple applications, so the solution must
   minimize advertising duplicate link/attribute pairs whenever
   possible.

3.  Legacy Advertisements

   There are existing advertisements used in support of RSVP-TE.  These
   advertisements include sub-TLVs for TLVs 22, 23, 141, 222, and 223
   and TLVs for SRLG advertisement.

3.1.  Legacy sub-TLVs

   Sub-TLVs for TLVs 22, 23, 141, 222, and 223

   Code Point/Attribute Name
   --------------------------
    3 Administrative group (color)
    9 Maximum link bandwidth
   10 Maximum reservable link bandwidth
   11 Unreserved bandwidth
   14 Extended Administrative Group
   33 Unidirectional Link Delay
   34 Min/Max Unidirectional Link Delay
   35 Unidirectional Delay Variation
   36 Unidirectional Link Loss
   37 Unidirectional Residual Bandwidth
   38 Unidirectional Available Bandwidth
   39 Unidirectional Utilized Bandwidth






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3.2.  Legacy SRLG Advertisements

   TLV 138 GMPLS-SRLG
     Supports links identified by IPv4 addresses and
     unnumbered links

   TLV 139 IPv6 SRLG
     Supports links identified by IPv6 addresses


   Note that [RFC6119] prohibits the use of TLV 139 when it is possible
   to use TLV 138.

4.  Advertising Application Specific Link Attributes

   Two new code points are defined in support of Application Specific
   Link Attribute Advertisements:

   1) Application Specific Link Attributes sub-TLV for TLVs 22, 23, 141,
   222, and 223

   2)Application Specific Shared Risk Link Group (SRLG) TLV

   In support of these new advertisements, an application bit mask is
   defined which identifies the application(s) associated with a given
   advertisement.

   The following sections define the format of these new advertisements.

4.1.  Application Identifier Bit Mask

   Identification of the set of applications associated with link
   attribute advertisements utilizes two bit masks.  One bit mask is for
   standard applications where the definition of each bit is defined in
   a new IANA controlled registry.  A second bit mask is for non-
   standard User Defined Applications(UDAs).

   The encoding defined below is used by both the Application Specific
   Link Attributes sub-TLV and the Application Specific SRLG TLV.

   0 1 2 3 4 5 6 7
   +-+-+-+-+-+-+-+-+
   |   SABML+F     |  1 octet
   +-+-+-+-+-+-+-+-+
   |   UDABML+F    |  1 octet
   +-+-+-+-+-+-+-+-+
   |   SABM         ...  0 - 127 octets
   +-+-+-+-+-+-+-+-+



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   |   UDABM        ...  0 - 127 octets
   +-+-+-+-+-+-+-+-+

   SABML+F (1 octet)
       Standard Application Bit Mask Length/Flags

             0 1 2 3 4 5 6 7
            +-+-+-+-+-+-+-+-+
            |L|  SA-Length  |
            +-+-+-+-+-+-+-+-+

      L-flag: Applications listed (both Standard and
       User Defined) MUST use the legacy advertisements
       for the corresponding link found in TLVs 22, 23,
       141, 222, and 223 or TLV 138 or TLV 139 as appropriate.

      SA-Length: Indicates the length in octets (0-127) of the Bit Mask
       for Standard Applications.

   UDABML+F (1 octet)
       User Defined Application Bit Mask Length/Flags

             0 1 2 3 4 5 6 7
            +-+-+-+-+-+-+-+-+
            |R| UDA-Length  |
            +-+-+-+-+-+-+-+-+

      R: Reserved. Transmitted as 0 and ignored on receipt

      UDA-Length: Indicates the length in octets (0-127) of the Bit Mask
       for User Defined Applications.


   SABM  (variable length)
      Standard Application Bit Mask

      (SA-Length * 8) bits

      This is omitted if SA-Length is 0.


             0 1 2 3 4 5 6 7 ...
            +-+-+-+-+-+-+-+-+...
            |R|S|F|          ...
            +-+-+-+-+-+-+-+-+...


         R-bit: RSVP-TE



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         S-bit: Segment Routing Traffic Engineering

         F-bit: Loop Free Alternate

   UDABM  (variable length)
      User Defined Application Bit Mask

      (UDA Length * 8) bits

             0 1 2 3 4 5 6 7 ...
            +-+-+-+-+-+-+-+-+...
            |                ...
            +-+-+-+-+-+-+-+-+...

      This is omitted if UDA-Length is 0.

   NOTE: If both SA-length and UDA-Length are zero, then the
   attributes associated with this attribute identifier bit mask
   MAY be used by any Standard Application and any User Defined
   Application.


   Standard Application Bits are defined/sent starting with Bit 0.
   Additional bit definitions that may be defined in the future SHOULD
   be assigned in ascending bit order so as to minimize the number of
   octets that will need to be transmitted.  Undefined bits MUST be
   transmitted as 0 and MUST be ignored on receipt.  Bits that are NOT
   transmitted MUST be treated as if they are set to 0 on receipt.

   User Defined Application bits have no relationship to Standard
   Application bits and are NOT managed by IANA or any other standards
   body.  It is recommended that bits are used starting with Bit 0 so as
   to minimize the number of octets required to advertise all UDAs.

4.2.  Application Specific Link Attributes sub-TLV

   A new sub-TLV for TLVs 22, 23, 141, 222, and 223 is defined which
   supports specification of the applications and application specific
   attribute values.

      Type: 15 (suggested value - to be assigned by IANA)
      Length: Variable (1 octet)
      Value:

        Application Bit Mask (as defined in Section 3.1)

        Link Attribute sub-sub-TLVs - format matches the
        existing formats defined in [RFC5305] and [RFC7810]



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   When the L-flag is set in the Application Identifiers, all of the
   applications specified in the bit mask MUST use the link attribute
   sub-TLV advertisements listed in Section 3.1 for the corresponding
   link.  Application specific link attribute sub-sub-TLVs for the
   corresponding link attributes MUST NOT be advertised for the set of
   applications specified in the Standard/User Application Bit Masks and
   all such advertisements MUST be ignored on receipt.

   Multiple sub-TLVs for the same link MAY be advertised.  When multiple
   sub-TLVs for the same link are advertised, they SHOULD advertise non-
   conflicting application/attribute pairs.  A conflict exists when the
   same application is associated with two different values of the same
   link attribute for a given link.  In cases where conflicting values
   for the same application/attribute/link are advertised all the
   conflicting values MUST be ignored.

   For a given application, the setting of the L-flag MUST be the same
   in all sub-TLVs for a given link.  In cases where this constraint is
   violated, the L-flag MUST be considered set for this application.

   A new registry of sub-sub-TLVs is to be created by IANA which defines
   the link attribute sub-sub-TLV code points.  A sub-sub-TLV is defined
   for each of the existing sub-TLVs listed in Section 3.1.  Format of
   the sub-sub-TLVs matches the format of the corresponding legacy sub-
   TLV and IANA is requested to assign the legacy sub-TLV identifer to
   the corresponding sub-sub-TLV.

4.3.  Application Specific SRLG TLV

   A new TLV is defined to advertise application specific SRLGs for a
   given link.  Although similar in functionality to TLV 138 (defined by
   [RFC5307]) and TLV 139 (defined by [RFC6119], a single TLV provides
   support for IPv4, IPv6, and unnumbered identifiers for a link.
   Unlike TLVs 138/139, it utilizes sub-TLVs to encode the link
   identifiers in order to provide the flexible formatting required to
   support multiple link identifier types.















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       Type: 238 (Suggested value - to be assigned by IANA)
       Length: Number of octets in the value field (1 octet)
       Value:
         Neighbor System-ID + pseudo-node ID (7 octets)
         Application Bit Mask (as defined in Section 3.1)
         Length of sub-TLVs (1 octet)
         Link Identifier sub-TLVs (variable)
         0 or more SRLG Values (Each value is 4 octets)

       The following Link Identifier sub-TLVs are defined. The type
       values are suggested and will be assigned by IANA - but as
       the formats are identical to existing sub-TLVs defined for
       TLVs 22, 23, 141, 222, and 223 the use of the suggested sub-TLV
       types is strongly encouraged.

       Type    Description
        4      Link Local/Remote Identifiers (see [RFC5307])
        6      IPv4 interface address (see [RFC5305])
        8      IPv4 neighbor address (see [RFC5305])
       12      IPv6 Interface Address (see [RFC6119])
       13      IPv6 Neighbor Address (see [RFC6119])

   At least one set of link identifiers (IPv4, IPv6, or unnumbered) MUST
   be present.  TLVs which do not meet this requirement MUST be ignored.

   Multiple TLVs for the same link MAY be advertised.

   When the L-flag is set in the Application Identifiers, SRLG values
   MUST NOT be included in the TLV.  Any SRLG values which are
   advertised MUST be ignored.  Based on the link identifiers advertised
   the corresponding legacy TLV (see Section 3.2) can be identified and
   the SRLG values advertised in the legacy TLV MUST be used by the set
   of applications specified in the Application Bit Mask.

   For a given application, the setting of the L-flag MUST be the same
   in all TLVs for a given link.  In cases where this constraint is
   violated, the L-flag MUST be considered set for this application.

5.  Deployment Considerations

   If link attributes are advertised associated with zero length
   application bit masks for both standard applications and user defined
   applications, then that set of link attributes MAY be used by any
   application.  If support for a new application is introduced on any
   node in a network in the presence of such advertisements, these
   advertisements MAY be used by the new application.  If this is not
   what is intended, then existing advertisements MUST be readvertised




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   with an explicit set of applications specified before a new
   application is introduced.

6.  Attribute Advertisements and Enablement

   This document defines extensions to support the advertisement of
   application specific link attributes.

   Whether the presence of link attribute advertisements for a given
   application indicates that the application is enabled on that link
   depends upon the application.  Similarly, whether the absence of link
   attribute advertisements indicates that the application is not
   enabled depends upon the application.

   The advertisement of link attributes to be used by RSVP-TE implies
   that RSVP is enabled on that link.

   In the case of SRTE, advertisement of application specific link
   attributes does NOT indicate enablement of SRTE.  The advertisements
   are only used to support constraints which may be applied when
   specifying an explicit path.  SRTE is implicitly enabled on all links
   which are part of the Segment Routing enabled topology independent of
   the existence of link attribute advertisements

   In the case of LFA, advertisement of link attributes does NOT
   indicate enablement of that application on that link.  Enablement is
   controlled by local configuration and/or the use of administrative
   tags.

   If, in the future, additional standard applications are defined to
   use this mechanism, the specification defining this use MUST define
   the relationship between application specific link attribute
   advertisements and enablement for that application.

7.  Interoperability, Backwards Compatibility and Migration Concerns

   Existing deployments of RSVP-TE utilize the legacy advertisements
   listed in Section 3.  Routers which do not support the extensions
   defined in this document will only process legacy advertisements and
   are likely to infer that RSVP-TE is enabled on the links for which
   legacy advertisements exist.  It is expected that deployments using
   the legacy advertisements will persist for a significant period of
   time - therefore deployments using the extensions defined in this
   document must be able to co-exist with use of the legacy
   advertisements by routers which do not support the extensions defined
   in this document.  The following sub-sections discuss
   interoperability and backwards compatibility concerns for a number of
   deployment scenarios.



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   Note that in all cases the defined strategy can be employed on a per
   link basis.

7.1.  RSVP-TE only deployments

   In deployments where RSVP-TE is the only application utilizing link
   attribute advertisements, use of the the legacy advertisements can
   continue without change.

7.2.  Multiple Applications: Common Attributes with RSVP-TE

   In cases where multiple applications are utilizing a given link, one
   of the applications is RSVP-TE, and all link attributes for a given
   link are common to the set of applications utilizing that link,
   interoperability is achieved by using legacy advertisements and
   sending application specific advertisements with L-bit set and no
   link attribute values.  This avoids duplication of link attribute
   advertisements.

7.3.  Multiple Applications: All Attributes Not Shared w RSVP-TE

   In cases where one or more applications other than RSVP-TE are
   utilizing a given link and one or more link attribute values are NOT
   shared with RSVP-TE, it is necessary to use application specific
   advertisements as defined in this document.  Attributes for
   applications other than RSVP-TE MUST be advertised using application
   specific advertisements which have the L-bit clear.  In cases where
   some link attributes are shared with RSVP-TE, this requires duplicate
   advertisements for those attributes.

   The discussion in this section applies to cases where RSVP-TE is NOT
   using any advertised attributes on a link and to cases where RSVP-TE
   is using some link attribute advertisements on the link but some link
   attributes cannot be shared with RSVP-TE.

7.4.  Deprecating legacy advertisements

   The extensions defined in this document support RSVP-TE as one of the
   supported applications - so a long term goal for deployments would be
   to deprecate use of the legacy advertisements in support of RSVP-TE.
   This can be done in the following step-wise manner:

   1)Upgrade all routers to support extensions in this document

   2)Readvertise all legacy link attributes using application specific
   advertisements with L-bit clear and R-bit set.

   3)Remove legacy advertisements



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8.  IANA Considerations

   This document defines a new sub-TLV for TLVs 22, 23, 141, 222, and
   223.

    Type  Description             22  23 141 222 223
    ----  ---------------------  --- --- --- --- ---
     15   Application Specific    y   y   y   y   y
           Link Attributes

   This document defines one new TLV:

    Type  Description            IIH SNP LSP Purge
    ----  ---------------------  --- --- --- -----
     238  Application Specific    n   n   y    n
           SRLG

   This document requests a new IANA registry be created to control the
   assignment of sub-sub-TLV codepoints for the Application Specific
   Link Attributes sub-TLV.  The suggested name of the new registry is
   "sub-sub-TLV code points for application link attributes".  The
   registration procedure is "Expert Review" as defined in [RFC8126].
   The following assignments are made by this document:

    Type   Description
   ---------------------------------------------------------
    3 Administrative group (color)
    9 Maximum link bandwidth
   10 Maximum reservable link bandwidth
   11 Unreserved bandwidth
   14 Extended Administrative Group
   33 Unidirectional Link Delay
   34 Min/Max Unidirectional Link Delay
   35 Unidirectional Delay Variation
   36 Unidirectional Link Loss
   37 Unidirectional Residual Bandwidth
   38 Unidirectional Available Bandwidth
   39 Unidirectional Utilized Bandwidth

   This document requests a new IANA registry be created to control the
   assignment of application bit identifiers.  The suggested name of the
   new registry is "Link Attribute Applications".  The registration
   procedure is "Expert Review" as defined in [RFC8126].  The following
   assignments are made by this document:







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    Bit #   Name
   ---------------------------------------------------------
     0      RSVP-TE (R-bit)
     1      Segment Routing Traffic Engineering (S-bit)
     2      Loop Free Alternate (F-bit)

   This document requests a new IANA registry be created to control the
   assignment of sub-TLV types for the application specific SRLG TLV.
   The suggested name of the new registry is "Sub-TLVs for TLV 238".
   The registration procedure is "Expert Review" as defined in
   [RFC8126].  The following assignments are made by this document:

    Value    Description
    ---------------------------------------------------------
      4      Link Local/Remote Identifiers (see [RFC5307])
      6      IPv4 interface address (see [RFC5305])
      8      IPv4 neighbor address (see [RFC5305])
     12      IPv6 Interface Address (see [RFC6119])
     13      IPv6 Neighbor Address (see [RFC6119])

9.  Security Considerations

   Security concerns for IS-IS are addressed in [ISO10589, [RFC5304],
   and [RFC5310].

10.  Acknowledgements

   The authors would like to thank Eric Rosen and Acee Lindem for their
   careful review and content suggestions.

11.  References

11.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC5304]  Li, T. and R. Atkinson, "IS-IS Cryptographic
              Authentication", RFC 5304, DOI 10.17487/RFC5304, October
              2008, <https://www.rfc-editor.org/info/rfc5304>.

   [RFC5305]  Li, T. and H. Smit, "IS-IS Extensions for Traffic
              Engineering", RFC 5305, DOI 10.17487/RFC5305, October
              2008, <https://www.rfc-editor.org/info/rfc5305>.





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   [RFC5307]  Kompella, K., Ed. and Y. Rekhter, Ed., "IS-IS Extensions
              in Support of Generalized Multi-Protocol Label Switching
              (GMPLS)", RFC 5307, DOI 10.17487/RFC5307, October 2008,
              <https://www.rfc-editor.org/info/rfc5307>.

   [RFC5310]  Bhatia, M., Manral, V., Li, T., Atkinson, R., White, R.,
              and M. Fanto, "IS-IS Generic Cryptographic
              Authentication", RFC 5310, DOI 10.17487/RFC5310, February
              2009, <https://www.rfc-editor.org/info/rfc5310>.

   [RFC6119]  Harrison, J., Berger, J., and M. Bartlett, "IPv6 Traffic
              Engineering in IS-IS", RFC 6119, DOI 10.17487/RFC6119,
              February 2011, <https://www.rfc-editor.org/info/rfc6119>.

   [RFC7810]  Previdi, S., Ed., Giacalone, S., Ward, D., Drake, J., and
              Q. Wu, "IS-IS Traffic Engineering (TE) Metric Extensions",
              RFC 7810, DOI 10.17487/RFC7810, May 2016,
              <https://www.rfc-editor.org/info/rfc7810>.

   [RFC8126]  Cotton, M., Leiba, B., and T. Narten, "Guidelines for
              Writing an IANA Considerations Section in RFCs", BCP 26,
              RFC 8126, DOI 10.17487/RFC8126, June 2017,
              <https://www.rfc-editor.org/info/rfc8126>.

11.2.  Informative References

   [RFC7855]  Previdi, S., Ed., Filsfils, C., Ed., Decraene, B.,
              Litkowski, S., Horneffer, M., and R. Shakir, "Source
              Packet Routing in Networking (SPRING) Problem Statement
              and Requirements", RFC 7855, DOI 10.17487/RFC7855, May
              2016, <https://www.rfc-editor.org/info/rfc7855>.

   [SR-POLICY]
              "Segment Routing Policy for Traffic Engineering, draft-
              filsfils-spring-segment-routing-policy-01(work in
              progress)", July 2017.

Authors' Addresses

   Les Ginsberg
   Cisco Systems
   821 Alder Drive
   Milpitas, CA  95035
   USA

   Email: ginsberg@cisco.com





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Internet-Draft           draft-ietf-isis-te-app             October 2017


   Peter Psenak
   Cisco Systems
   Apollo Business Center Mlynske nivy 43
   Bratislava  821 09
   Slovakia

   Email: ppsenak@cisco.com


   Stefano Previdi
   Individual

   Email: stefano@previdi.net


   Wim Henderickx
   Nokia
   Copernicuslaan 50
   Antwerp  2018 94089
   Belgium

   Email: wim.henderickx@nokia.com


   John Drake
   Juniper Networks

   Email: jdrake@juniper.net























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