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Versions: (draft-ppsenak-ospf-te-link-attr-reuse) 00 01 02

Network Working Group                                          P. Psenak
Internet-Draft                                                 A. Lindem
Intended status: Standards Track                             L. Ginsberg
Expires: April 30, 2018                                    Cisco Systems
                                                           W. Henderickx
                                                                   Nokia
                                                             J. Tantsura
                                                              Individual
                                                              H. Gredler
                                                            RtBrick Inc.
                                                                J. Drake
                                                        Juniper Networks
                                                        October 27, 2017


          OSPFv2 Link Traffic Engineering (TE) Attribute Reuse
               draft-ietf-ospf-te-link-attr-reuse-02.txt

Abstract

   Various link attributes have been defined in OSPFv2 in the context of
   the MPLS Traffic Engineering (TE) and GMPLS.  Many of these link
   attributes can be used for purposes other than MPLS Traffic
   Engineering or GMPLS.  This documents defines how to distribute such
   attributes in OSPFv2 for applications other than MPLS Traffic
   Engineering or GMPLS purposes.

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
   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 30, 2018.








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Copyright Notice

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Requirements notation . . . . . . . . . . . . . . . . . .   3
   2.  Link attributes examples  . . . . . . . . . . . . . . . . . .   3
   3.  Advertising Link Attributes . . . . . . . . . . . . . . . . .   4
     3.1.  TE Opaque LSA . . . . . . . . . . . . . . . . . . . . . .   4
     3.2.  Extended Link Opaque LSA  . . . . . . . . . . . . . . . .   5
     3.3.  Selected Approach . . . . . . . . . . . . . . . . . . . .   5
   4.  Reused TE link attributes . . . . . . . . . . . . . . . . . .   6
     4.1.  Shared Risk Link Group (SRLG) . . . . . . . . . . . . . .   6
     4.2.  Extended Metrics  . . . . . . . . . . . . . . . . . . . .   6
     4.3.  Administrative Group  . . . . . . . . . . . . . . . . . .   7
   5.  Advertisement of Application Specific Values  . . . . . . . .   7
   6.  Deployment Considerations . . . . . . . . . . . . . . . . . .  10
   7.  Attribute Advertisements and Enablement . . . . . . . . . . .  10
   8.  Backward Compatibility  . . . . . . . . . . . . . . . . . . .  11
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .  12
   10. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  12
   11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  12
   12. References  . . . . . . . . . . . . . . . . . . . . . . . . .  12



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     12.1.  Normative References . . . . . . . . . . . . . . . . . .  12
     12.2.  Informative References . . . . . . . . . . . . . . . . .  13
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  14

1.  Introduction

   Various link attributes have been defined in OSPFv2 [RFC2328] in the
   context of the MPLS traffic engineering and GMPLS.  All these
   attributes are distributed by OSPFv2 as sub-TLVs of the Link-TLV
   advertised in the OSPFv2 TE Opaque LSA [RFC3630].

   Many of these link attributes are useful outside of the traditional
   MPLS Traffic Engineering or GMPLS.  This brings its own set of
   problems, in particular how to distribute these link attributes in
   OSPFv2 when MPLS TE or GMPLS are not deployed or are deployed in
   parallel with other applications that use these link attributes.

   [RFC7855] discusses use cases/requirements for SR.  Included among
   these use cases is SRTE.  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 should
   minimize advertising duplicate link/attribute when possible.

1.1.  Requirements notation

   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].

2.  Link attributes examples

   This section lists some of the link attributes originally defined for
   MPLS Traffic Engineering that can be used for other purposes in
   OSPFv2.  The list doesn't necessarily contain all the required
   attributes.



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   1.  Remote Interface IP address [RFC3630] - OSPFv2 currently cannot
       distinguish between parallel links between two OSPFv2 routers.
       As a result, the two-way connectivity check performed during SPF
       may succeed when the two routers disagree on which of the links
       to use for data traffic.

   2.  Link Local/Remote Identifiers - [RFC4203] - Used for the two-way
       connectivity check for parallel unnumbered links.  Also used for
       identifying adjacencies for unnumbered links in Segment Routing
       traffic engineering.

   3.  Shared Risk Link Group (SRLG) [RFC4203]  - In IPFRR, the SRLG is
       used to compute diverse backup paths [RFC5714].

   4.  Unidirectional Link Delay/Loss Metrics [RFC7471] - Could be used
       for the shortest path first (SPF) computation using alternate
       metrics within an OSPF area.

3.  Advertising Link Attributes

   This section outlines possible approaches for advertising link
   attributes originally defined for MPLS Traffic Engineering purposes
   or GMPLS when they are used for other applications.

3.1.  TE Opaque LSA

   One approach for advertising link attributes is to continue to use TE
   Opaque LSA ([RFC3630]).  There are several problems with this
   approach:

   1.  Whenever the link is advertised in a TE Opaque LSA, the link
       becomes a part of the TE topology, which may not match IP routed
       topology.  By making the link part of the TE topology, remote
       nodes may mistakenly believe that the link is available for MPLS
       TE or GMPLS, when, in fact, MPLS is not enabled on the link.

   2.  The TE Opaque LSA carries link attributes that are not used or
       required by MPLS TE or GMPLS.  There is no mechanism in a TE
       Opaque LSA to indicate which of the link attributes are passed to
       MPLS TE application and which are used by other applications
       including OSPFv2 itself.

   3.  Link attributes used for non-TE purposes are partitioned across
       multiple LSAs - the TE Opaque LSA and the Extended Link Opaque
       LSA.  This partitioning will require implementations to lookup
       multiple LSAs to extract link attributes for a single link,
       bringing needless complexity to OSPFv2 implementations.




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   The advantage of this approach is that there is no additional
   standardization requirement to advertise the TE/GMPL attributes for
   other applications.  Additionally, link attributes are only
   advertised once when both OSPF TE and other applications are deployed
   on the same link.  This is not expected to be a common deployment
   scenario.

3.2.  Extended Link Opaque LSA

   An alternative approach for advertising link attributes is to use
   Extended Link Opaque LSAs as defined in [RFC7684].  This LSA was
   defined as a generic container for distribution of the extended link
   attributes.  There are several advantages in using Extended Link LSA:

   1.  Advertisement of the link attributes does not make the link part
       of the TE topology.  It avoids any conflicts and is fully
       compatible with the [RFC3630].

   2.  The TE Opaque LSA remains truly opaque to OSPFv2 as originally
       defined in [RFC3630].  Its content is not inspected by OSPFv2 and
       OSPFv2 acts as a pure transport.

   3.  There is clear distinction between link attributes used by TE and
       link attributes used by other OSPFv2 applications.

   4.  All link attributes that are used by OSPFv2 applications are
       advertised in a single LSA, the Extended Link Opaque LSA.

   The disadvantage of this approach is that in rare cases, the same
   link attribute is advertised in both the TE Opaque and Extended Link
   Attribute LSAs.  Additionally, there will be additional
   standardization effort.  However, this could also be viewed as an
   advantage as the non-TE use cases for the TE link attributes are
   documented and validated by the OSPF working group.

3.3.  Selected Approach

   It is RECOMMENDED to use the Extended Link Opaque LSA ([RFC7684] to
   advertise any link attributes used for non-TE purposes in OSPFv2,
   including those that have been originally defined for TE purposes.
   TE link attributes used for TE purposes continue to use TE Opaque LSA
   ([RFC3630]).

   It is also RECOMMENDED to keep the format of the link attribute TLVs
   that have been defined for TE purposes unchanged even when they are
   used for non-TE purposes.





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   Finally, it is RECOMMENDED to allocate unique code points for link
   attribute TLVs that have been defined for TE purposes for the OSPFv2
   Extended Link TLV Sub-TLV Registry as defined in [RFC7684].  For each
   reused TLV, the code point will be defined in an IETF document along
   with the expected usecase(s).

4.  Reused TE link attributes

   This section defines the use case and code points for the OSPFv2
   Extended Link TLV Sub-TLV Registry for some of the link attributes
   that have been originally defined for TE or GMPLS purposes.

   Remote interface IP address and Link Local/Remote Identifiers have
   been added as sub-TLVs of OSPFv2 Extended Link TLV by
   [I-D.ietf-ospf-link-overload].

4.1.  Shared Risk Link Group (SRLG)

   The SRLG of a link can be used in IPFRR to compute a backup path that
   does not share any SRLG group with the protected link.

   To advertise the SRLG of the link in the OSPFv2 Extended Link TLV,
   the same format of the sub-TLV as defined in section 1.3. of
   [RFC4203] is used and TLV type TBD1 is used.

4.2.  Extended Metrics

   [RFC3630] defines several link bandwidth types.  [RFC7471] defines
   extended link metrics that are based on link bandwidth, delay and
   loss characteristics.  All these can be used to compute best paths
   within an OSPF area to satisfy requirements for bandwidth, delay
   (nominal or worst case) or loss.

   To advertise extended link metrics in the OSPFv2 Extended Link TLV,
   the same format of the sub-TLVs as defined in [RFC7471] is used with
   following TLV types:

      TBD2 - Unidirectional Link Delay

      TBD3 - Min/Max Unidirectional Link Delay

      TBD4 - Unidirectional Delay Variation

      TBD5 - Unidirectional Link Loss

      TBD6 - Unidirectional Residual Bandwidth

      TBD7 - Unidirectional Available Bandwidth



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      TBD8 - Unidirectional Utilized Bandwidth

4.3.  Administrative Group

   [RFC3630] and [RFC7308] define Administrative Group and Extended
   Administrative Group sub-TLVs.

   One use case where advertisement of the Extended Administrative
   Group(s) for a link is required is described in
   [I-D.hegdeppsenak-isis-sr-flex-algo].

   To advertise Administrative Group and Extended Administrative Group
   in the OSPFv2 Extended Link TLV, the same format of the sub-TLVs as
   defined in [RFC3630] and [RFC7308] is used with following TLV types:

      TBD9 - Administrative Group

      TBD10 - Extended Administrative Group

5.  Advertisement of Application Specific Values

   Multiple applications can utilize link attributes that are flooded by
   OSPFv2.  Some examples of applications using the link attributes are
   Segment Routing Traffic Engineering and LFA [RFC5286].

   In some cases the link attribute only has a single value that is
   applicable to all applications.  An example is a Remote interface IP
   address or Link Local/Remote Identifiers
   [I-D.ietf-ospf-link-overload].

   In some cases the link attribute MAY have different values for
   different applications.  An example could be SRLG [Section 4.1],
   where values used by LFA could be different then the values used by
   Segment Routing Traffic Engineering.

   To allow advertisement of the application specific values of the link
   attribute, a new Extended Link Attribute sub-TLV of the Extended Link
   TLV [RFC7471] is defined.  The Extended Link Attribute sub-TLV is an
   optional sub-TLV and can appear multiple times in the Extended Link
   TLV.  It has following format:











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    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            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     SABML     |     UDABML    |            Reserved           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                Standard Application Bit-Mask                  |
   +-                                                             -+
   |                            ...                                |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                User Defined Application Bit-Mask              |
   +-                                                             -+
   |                            ...                                |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                      Link Attribute sub-sub-TLVs              |
   +-                                                             -+
   |                            ...                                |

   where:

      Type: TBD11, suggested value 8

      Length: variable

      SABML: Standard Application Bit-Mask Length.  If the Standard
      Application Bit-Mask is not present, the Standard Application Bit-
      Mask Length MUST be set to 0.

      UDABML: User Defined Application Bit-Mask Length.  If the User
      Defined Application Bit-Mask is not present, the User Defined
      Application Bit-Mask Length MUST be set to 0.

      Standard Application Bit-Mask: Optional set of bits, where each
      bit represents a single standard application.  The following bits
      are defined by this document:

         Bit-0: RSVP Traffic Engineering

         Bit-1: Segment Routing Traffic Engineering

         Bit-2: Loop Free Alternate (LFA).  Includes all LFA types.

         Bit-3: Flexible Algorithm as describe in
         [I-D.hegdeppsenak-isis-sr-flex-algo].

      User Defined Application Bit-Mask: Optional set of bits, where
      each bit represents a single user defined application.



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   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.

   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 of them.

   Undefined bits in both Bit-Masks 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.

   If the link attribute advertisement is limited to be used by a
   specific set of applications, corresponding Bit-Masks MUST be present
   and application specific bit(s) MUST be set for all applications that
   use the link attributes advertised in the Extended Link Attribute
   sub-TLV.

   Application Bit-Masks apply to all link attributes that support
   application specific values and are advertised in the Extended Link
   Attribute sub-TLV.

   The advantage of not making the Application Bit-Masks part of the
   attribute advertisement itself is that we can keep the format of the
   link attributes that have been defined previously and reuse the same
   format when advertising them in the Extended Link Attribute sub-TLV.

   If the link attribute is advertised and there is no Application Bit-
   Mask present in the Extended Link Attribute Sub-TLV, the link
   attribute advertisement MAY be used by any application.  If, however,
   another advertisement of the same link attribute includes any
   Application Bit-Mask in the Extended Link Attribute sub-TLV,
   applications that are listed in the Application Bit-Masks of such
   Extended Link Attribute sub-TLV SHOULD use the attribute
   advertisement which has the application specific bit set in the
   Application Bit-Masks.

   If the same application is listed in the Application Bit-Masks of
   more then one Extended Link Attribute sub-TLV, the application SHOULD
   use the first advertisement and ignore any subsequent advertisements
   of the same attribute.  This situation SHOULD be logged as an error.

   This document defines the set of link attributes for which the
   Application Bit-Masks may be advertised.  If any of the Application
   Bit-Masks is included in the Extended Link Attribute sub-TLV that
   advertises any link attribute(s) NOT listed below, the Application



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   Bit-Masks MUST NOT be used for such link attribute(s).  It MUST be
   used for those attribute(s) that support application specific values.
   Documents which define new link attributes MUST state whether the new
   attributes support application specific values.  The link attributes
   to which the Application Bit-Masks may apply are:

      - Shared Risk Link Group

      - Unidirectional Link Delay

      - Min/Max Unidirectional Link Delay

      - Unidirectional Delay Variation

      - Unidirectional Link Loss

      - Unidirectional Residual Bandwidth

      - Unidirectional Available Bandwidth

      - Unidirectional Utilized Bandwidth

      - Administrative Group

      - Extended Administrative Group

6.  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
   with an explicit set of applications specified before a new
   application is introduced.

7.  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.



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   In the case of RSVP-TE, the advertisement of application specific
   link attributes 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 application specific link
   attributes does NOT indicate enablement of LFA on that link.
   Enablement is controlled by local configuration.

   In the case of Flexible Algorithm, advertisement of application
   specific link attributes does NOT indicate enablement of Flexible
   Algorithm on that link.  Rather the attributes are used to determine
   what links are included/excluded in the algorithm specific
   constrained SPF.  This is fully specified in
   [I-D.hegdeppsenak-isis-sr-flex-algo].

   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.

8.  Backward Compatibility

   Link attributes may be concurrently advertised in both the TE Opaque
   LSA [RFC3630] and the Extended Link Opaque LSA [RFC7684].

   In fact, there is at least one OSPF implementation that utilizes the
   link attributes advertised in TE Opaque LSAs [RFC3630] for Non-RSVP
   TE applications.  For example, this implementation of LFA and remote
   LFA utilizes links attributes such as Shared Risk Link Groups (SRLG)
   [RFC4203] and Admin Group [[RFC3630]advertised in TE Opaque LSAs.
   These applications are described in [RFC5286], [RFC7490],
   [I-D.ietf-rtgwg-lfa-manageability] and
   [I-D.psarkar-rtgwg-rlfa-node-protection].

   When an OSPF routing domain includes routers using link attributes
   from TE Opaque LSAs for Non-RSVP TE applications such as LFA, OSPF
   routers in that domain should continue to advertise such TE Opaque
   LSAs.  If there are also OSPF routers using the link attributes
   described herein for any application, OSPF routers in the routing
   domain will also need to advertise these attributes in OSPF Extended
   Link Attributes LSAs [RFC7684].  In such a deployment, the advertised




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   attributes SHOULD be the same and Non-RSVP application access to link
   attributes is a matter of local policy.

9.  Security Considerations

   Implementations must assure that malformed TLV and Sub-TLV
   permutations do not result in errors that cause hard OSPFv2 failures.

10.  IANA Considerations

   OSPFv2 Extended Link TLV Sub-TLVs registry [RFC7684] defines sub-TLVs
   at any level of nesting for OSPFv2 Extended Link TLVs.  This
   specification updates OSPFv2 Extended Link TLV sub-TLVs registry with
   the following TLV types:

      TBD1 (9 Recommended) - Shared Risk Link Group

      TBD2 (10 Recommended) - Unidirectional Link Delay

      TBD3 (11 Recommended) - Min/Max Unidirectional Link Delay

      TBD4 (12 Recommended) - Unidirectional Delay Variation

      TBD5 (13 Recommended) - Unidirectional Link Loss

      TBD6 (14 Recommended) - Unidirectional Residual Bandwidth

      TBD7 (15 Recommended) - Unidirectional Available Bandwidth

      TBD8 (16 Recommended) - Unidirectional Utilized Bandwidth

      TBD9 (17 Recommended) - Administrative Group

      TBD10 (18 Recommended) - Extended Administrative Group

      TBD11 (8 Recommended) - Extended Link Attribute

11.  Acknowledgments

   Thanks to Chris Bowers for his review and comments.

12.  References

12.1.  Normative References







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   [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>.

   [RFC3630]  Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
              (TE) Extensions to OSPF Version 2", RFC 3630,
              DOI 10.17487/RFC3630, September 2003,
              <https://www.rfc-editor.org/info/rfc3630>.

   [RFC5714]  Shand, M. and S. Bryant, "IP Fast Reroute Framework",
              RFC 5714, DOI 10.17487/RFC5714, January 2010,
              <https://www.rfc-editor.org/info/rfc5714>.

   [RFC7308]  Osborne, E., "Extended Administrative Groups in MPLS
              Traffic Engineering (MPLS-TE)", RFC 7308,
              DOI 10.17487/RFC7308, July 2014,
              <https://www.rfc-editor.org/info/rfc7308>.

   [RFC7684]  Psenak, P., Gredler, H., Shakir, R., Henderickx, W.,
              Tantsura, J., and A. Lindem, "OSPFv2 Prefix/Link Attribute
              Advertisement", RFC 7684, DOI 10.17487/RFC7684, November
              2015, <https://www.rfc-editor.org/info/rfc7684>.

12.2.  Informative References

   [I-D.hegdeppsenak-isis-sr-flex-algo]
              Psenak, P., Hegde, S., Filsfils, C., and a.
              arkadiy.gulko@thomsonreuters.com, "ISIS Segment Routing
              Flexible Algorithm", draft-hegdeppsenak-isis-sr-flex-
              algo-01 (work in progress), October 2017.

   [I-D.ietf-idr-ls-distribution]
              Gredler, H., Medved, J., Previdi, S., Farrel, A., and S.
              Ray, "North-Bound Distribution of Link-State and TE
              Information using BGP", draft-ietf-idr-ls-distribution-13
              (work in progress), October 2015.

   [I-D.ietf-ospf-link-overload]
              Hegde, S., Sarkar, P., Gredler, H., Nanduri, M., and L.
              Jalil, "OSPF Link Overload", draft-ietf-ospf-link-
              overload-09 (work in progress), August 2017.

   [I-D.ietf-ospf-segment-routing-extensions]
              Psenak, P., Previdi, S., Filsfils, C., Gredler, H.,
              Shakir, R., Henderickx, W., and J. Tantsura, "OSPF
              Extensions for Segment Routing", draft-ietf-ospf-segment-
              routing-extensions-21 (work in progress), October 2017.



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   [I-D.ietf-rtgwg-lfa-manageability]
              Litkowski, S., Decraene, B., Filsfils, C., Raza, K., and
              M. Horneffer, "Operational management of Loop Free
              Alternates", draft-ietf-rtgwg-lfa-manageability-11 (work
              in progress), June 2015.

   [I-D.psarkar-rtgwg-rlfa-node-protection]
              psarkar@juniper.net, p., Gredler, H., Hegde, S., Bowers,
              C., Litkowski, S., and H. Raghuveer, "Remote-LFA Node
              Protection and Manageability", draft-psarkar-rtgwg-rlfa-
              node-protection-05 (work in progress), June 2014.

   [RFC2328]  Moy, J., "OSPF Version 2", STD 54, RFC 2328,
              DOI 10.17487/RFC2328, April 1998,
              <https://www.rfc-editor.org/info/rfc2328>.

   [RFC4203]  Kompella, K., Ed. and Y. Rekhter, Ed., "OSPF Extensions in
              Support of Generalized Multi-Protocol Label Switching
              (GMPLS)", RFC 4203, DOI 10.17487/RFC4203, October 2005,
              <https://www.rfc-editor.org/info/rfc4203>.

   [RFC5286]  Atlas, A., Ed. and A. Zinin, Ed., "Basic Specification for
              IP Fast Reroute: Loop-Free Alternates", RFC 5286,
              DOI 10.17487/RFC5286, September 2008,
              <https://www.rfc-editor.org/info/rfc5286>.

   [RFC7471]  Giacalone, S., Ward, D., Drake, J., Atlas, A., and S.
              Previdi, "OSPF Traffic Engineering (TE) Metric
              Extensions", RFC 7471, DOI 10.17487/RFC7471, March 2015,
              <https://www.rfc-editor.org/info/rfc7471>.

   [RFC7490]  Bryant, S., Filsfils, C., Previdi, S., Shand, M., and N.
              So, "Remote Loop-Free Alternate (LFA) Fast Reroute (FRR)",
              RFC 7490, DOI 10.17487/RFC7490, April 2015,
              <https://www.rfc-editor.org/info/rfc7490>.

   [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>.

Authors' Addresses








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Internet-Draft       OSPFv2 Link TE Attributes Reuse        October 2017


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

   Email: ppsenak@cisco.com


   Acee Lindem
   Cisco Systems
   301 Midenhall Way
   Cary, NC  27513
   USA

   Email: acee@cisco.com


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

   Email: ginsberg@cisco.com


   Wim Henderickx
   Nokia
   Copernicuslaan 50
   Antwerp, 2018  94089
   Belgium

   Email: wim.henderickx@nokia.com


   Jeff Tantsura
   Individual
   USA

   Email: jefftant.ietf@gmail.com


   Hannes Gredler
   RtBrick Inc.

   Email: hannes@rtbrick.com



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Internet-Draft       OSPFv2 Link TE Attributes Reuse        October 2017


   John Drake
   Juniper Networks

   Email: jdrake@juniper.net















































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