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rfc:rfc7770

Internet Engineering Task Force (IETF) A. Lindem, Ed. Request for Comments: 7770 N. Shen Obsoletes: 4970 JP. Vasseur Category: Standards Track Cisco Systems ISSN: 2070-1721 R. Aggarwal

                                                                Arktan
                                                            S. Shaffer
                                                                Akamai
                                                         February 2016
  Extensions to OSPF for Advertising Optional Router Capabilities

Abstract

 It is useful for routers in an OSPFv2 or OSPFv3 routing domain to
 know the capabilities of their neighbors and other routers in the
 routing domain.  This document proposes extensions to OSPFv2 and
 OSPFv3 for advertising optional router capabilities.  The Router
 Information (RI) Link State Advertisement (LSA) is defined for this
 purpose.  In OSPFv2, the RI LSA will be implemented with an Opaque
 LSA type ID.  In OSPFv3, the RI LSA will be implemented with a unique
 LSA type function code.  In both protocols, the RI LSA can be
 advertised at any of the defined flooding scopes (link, area, or
 autonomous system (AS)).  This document obsoletes RFC 4970 by
 providing a revised specification that includes support for
 advertisement of multiple instances of the RI LSA and a TLV for
 functional capabilities.

Status of This Memo

 This is an Internet Standards Track document.
 This document is a product of the Internet Engineering Task Force
 (IETF).  It represents the consensus of the IETF community.  It has
 received public review and has been approved for publication by the
 Internet Engineering Steering Group (IESG).  Further information on
 Internet Standards is available in Section 2 of RFC 5741.
 Information about the current status of this document, any errata,
 and how to provide feedback on it may be obtained at
 http://www.rfc-editor.org/info/rfc7770.

Lindem, et al. Standards Track [Page 1] RFC 7770 OSPF Capability Extensions February 2016

Copyright Notice

 Copyright (c) 2016 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
 (http://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
   1.1.  Requirements Notation . . . . . . . . . . . . . . . . . .   3
   1.2.  Summary of Changes from RFC 4970  . . . . . . . . . . . .   3
 2.  OSPF Router Information (RI) LSA  . . . . . . . . . . . . . .   4
   2.1.  OSPFv2 Router Information (RI) Opaque LSA . . . . . . . .   4
   2.2.  OSPFv3 Router Information (RI) Opaque LSA . . . . . . . .   5
   2.3.  OSPF Router Information LSA TLV Format  . . . . . . . . .   6
   2.4.  OSPF Router Informational Capabilities TLV  . . . . . . .   6
   2.5.  Assigned OSPF Router Informational Capability Bits  . . .   7
   2.6.  OSPF Router Functional Capabilities TLV . . . . . . . . .   8
   2.7.  Flooding Scope of the Router Information LSA  . . . . . .   9
 3.  Backwards Compatibility . . . . . . . . . . . . . . . . . . .   9
 4.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
 5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  10
   5.1.  OSPFv2 Opaque LSA Type Assignment . . . . . . . . . . . .  10
   5.2.  OSPFv3 LSA Function Code Assignment . . . . . . . . . . .  10
   5.3.  OSPF RI LSA TLV Type Assignment . . . . . . . . . . . . .  11
   5.4.  Registry for OSPF Router Informational Capability Bits  .  12
   5.5.  Registry for OSPF Router Functional Capability Bits . . .  12
 6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  12
   6.1.  Normative References  . . . . . . . . . . . . . . . . . .  12
   6.2.  Informative References  . . . . . . . . . . . . . . . . .  13
 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .  14
 Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  15

Lindem, et al. Standards Track [Page 2] RFC 7770 OSPF Capability Extensions February 2016

1. Introduction

 It is useful for routers in an OSPFv2 [OSPF] or OSPFv3 [OSPFv3]
 routing domain to know the capabilities of their neighbors and other
 routers in the routing domain.  This can be useful for both the
 advertisement and discovery of OSPFv2 and OSPFv3 capabilities.
 Throughout this document, OSPF will be used when the specification is
 applicable to both OSPFv2 and OSPFv3.  Similarly, OSPFv2 or OSPFv3
 will be used when the text is protocol specific.
 OSPF uses the options field in LSAs and hello packets to advertise
 optional router capabilities.  In the case of OSPFv2, all the bits in
 this field have been allocated so additional optional capabilities
 cannot be advertised.  This document describes extensions to OSPF to
 advertise these optional capabilities via Opaque LSAs in OSPFv2 and
 LSAs with a unique type in OSPFv3.  For existing OSPF capabilities,
 backwards compatibility issues dictate that this advertisement is
 used primarily for informational purposes.  For future OSPF
 extensions, this advertisement MAY be used as the sole mechanism for
 advertisement and discovery.
 This document obsoletes RFC 4970 by providing a revised specification
 including support for advertisement of multiple instances of the RI
 LSA and a TLV for functional capabilities.

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 [RFC-KEYWORDS].

1.2. Summary of Changes from RFC 4970

 This document includes the following changes from RFC 4970 [RFC4970]:
 1. The main change is that an OSPF router will be able to advertise
    multiple instances of the OSPF Router Information LSA.  This
    change permeates through much of the document.
 2. Additionally, Section 2.6 includes an additional TLV for
    functional capabilities.  This is in contrast to the existing TLV
    that is used to advertise capabilities for informational purposes
    only.

Lindem, et al. Standards Track [Page 3] RFC 7770 OSPF Capability Extensions February 2016

 3. The IANA allocation policy has been changed from "Standards
    Action" to "IETF Review" [IANA-GUIDE] for the following
    registries:
    o  OSPFv3 LSA Function Codes
    o  OSPF Router Information (RI) TLVs
    o  OSPF Router Informational Capability Bits
    o  OSPF Router Functional Capability Bits
 4. Finally, references have been updated for documents that have
    become RFCs and RFCs that have been obsoleted since the
    publication of RFC 4970.

2. OSPF Router Information (RI) LSA

2.1. OSPFv2 Router Information (RI) Opaque LSA

 OSPFv2 routers will advertise a link scoped, area-scoped, or AS-
 scoped Opaque LSA [OPAQUE].  The OSPFv2 RI LSA has an Opaque type of
 4 and the Opaque ID is the RI LSA Instance ID.  The first Opaque ID,
 i.e., 0, SHOULD always contain the Router Informational Capabilities
 TLV and, if advertised, the Router Functional Capabilities TLV.  RI
 LSA instances subsequent to the first can be used for information
 that doesn't fit in the first instance.
 OSPFv2 routers will advertise a link-scoped, area-scoped, or AS-
 scoped Opaque LSA [OPAQUE].  The OSPFv2 Router Information LSA has an
 Opaque type of 4.  The Opaque ID specifies the LSA Instance ID with
 the first instance always having an Instance ID of 0.
     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
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |            LS age             |     Options   |  9, 10, or 11 |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |       4       |     Opaque ID (Instance ID)                   |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+d-+-+-+-+-+-+-+-+-+-+-+
    |                     Advertising Router                        |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                     LS sequence number                        |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |         LS checksum           |             length            |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                                                               |
    +-                            TLVs                             -+
    |                             ...                               |
              Figure 1.  OSPFv2 Router Information Opaque LSA

Lindem, et al. Standards Track [Page 4] RFC 7770 OSPF Capability Extensions February 2016

 The format of the TLVs within the body of an RI LSA is as defined in
 Section 2.3.

2.2. OSPFv3 Router Information (RI) Opaque LSA

 The OSPFv3 Router Information LSA has a function code of 12 while the
 S1/S2 bits are dependent on the desired flooding scope for the LSA.
 The U bit will be set indicating that the OSPFv3 RI LSA should be
 flooded even if it is not understood.  The Link State ID (LSID) value
 for this LSA is the Instance ID.  The first Instance ID, i.e., 0,
 SHOULD always contain the Router Informational Capabilities TLV and,
 if advertised, the Router Functional Capabilities TLV.  OSPFv3 Router
 Information LSAs subsequent to the first can be used for information
 that doesn't fit in the first instance.  OSPFv3 routers MAY advertise
 multiple RI LSAs per flooding scope.
     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
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |            LS age             |1|S12|          12             |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                       Link State ID (Instance ID)             |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                       Advertising Router                      |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                       LS sequence number                      |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |        LS checksum            |            Length             |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                                                               |
    +-                            TLVs                             -+
    |                             ...                               |
                Figure 2.  OSPFv3 Router Information LSA
 The format of the TLVs within the body of an RI LSA is as defined in
 Section 2.3

Lindem, et al. Standards Track [Page 5] RFC 7770 OSPF Capability Extensions February 2016

2.3. OSPF Router Information LSA TLV Format

 The format of the TLVs within the body of an RI LSA is the same as
 the format used by the Traffic Engineering Extensions to OSPF [TE].
 The LSA payload consists of one or more nested Type/Length/Value
 (TLV) triplets.  The format of each TLV is:
     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...                           |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                           Figure 3.  TLV Format
 The Length field defines the length of the value portion in octets
 (thus a TLV with no value portion would have a length of 0).  The TLV
 is padded to 4-octet alignment; padding is not included in the length
 field (so a 3-octet value would have a length of 3, but the total
 size of the TLV would be 8 octets).  Nested TLVs are also 4-octet
 aligned.  For example, a 1-octet value would have the length field
 set to 1, and 3 octets of padding would be added to the end of the
 value portion of the TLV.  The padding is composed of undefined bits.
 Unrecognized types are ignored.
 When a new Router Information LSA TLV is defined, the specification
 MUST explicitly state whether the TLV is applicable to OSPFv2 only,
 OSPFv3 only, or both OSPFv2 and OSPFv3.

2.4. OSPF Router Informational Capabilities TLV

 An OSPF router advertising an OSPF RI LSA MAY include the Router
 Informational Capabilities TLV.  If included, it MUST be the first
 TLV in the first instance, i.e., Instance 0, of the OSPF RI LSA.
 Additionally, the TLV MUST accurately reflect the OSPF router's
 capabilities in the scope advertised.  However, the informational
 capabilities advertised have no impact on OSPF protocol operation;
 they are advertised purely for informational purposes.

Lindem, et al. Standards Track [Page 6] RFC 7770 OSPF Capability Extensions February 2016

 The format of the Router Informational Capabilities TLV is 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            |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |             Informational Capabilities                        |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    Type     A 16-bit field set to 1.
    Length   A 16-bit field that indicates the length of the value
             portion in octets and will be a multiple of 4 octets
             dependent on the number of capabilities advertised.
             Initially, the length will be 4, denoting 4 octets of
             informational capability bits.
    Value    A variable-length sequence of capability bits rounded to
             a multiple of 4 octets padded with undefined bits.
             Initially, there are 4 octets of capability bits.  Bits
             are numbered left to right starting with the most
             significant bit being bit 0.
         Figure 4.  OSPF Router Informational Capabilities TLV
 The Router Informational Capabilities TLV MAY be followed by optional
 TLVs that further specify a capability.

2.5. Assigned OSPF Router Informational Capability Bits

 The following informational capability bits have been assigned:
    Bit       Capabilities
    0         OSPF graceful restart capable [GRACE]
    1         OSPF graceful restart helper  [GRACE]
    2         OSPF Stub Router support [STUB]
    3         OSPF Traffic Engineering support [TE]
    4         OSPF point-to-point over LAN [P2PLAN]
    5         OSPF Experimental TE [EXP-TE]
    6-31      Unassigned (IETF Review)
    Figure 5.  OSPF Router Informational Capabilities Bits
 References for [GRACE], [STUB], [TE], [P2PLAN], and [EXP-TE] are
 included herein.

Lindem, et al. Standards Track [Page 7] RFC 7770 OSPF Capability Extensions February 2016

2.6. OSPF Router Functional Capabilities TLV

 This specification also defines the Router Functional Capabilities
 TLV for advertisement in the OSPF Router Information LSA.  An OSPF
 router advertising an OSPF RI LSA MAY include the Router Functional
 Capabilities TLV.  If included, it MUST be the included in the first
 instance of the LSA.  Additionally, the TLV MUST reflect the
 advertising OSPF router's actual functional capabilities since the
 information will be used to dictate OSPF protocol operation in the
 flooding scope of the containing OSPF RI LSA.  If the TLV is not
 included or the length doesn't include the assigned OSPF functional
 capability bit, the corresponding OSPF functional capability is
 implicitly advertised as not being supported by the advertising OSPF
 router.
 The format of the Router Functional Capabilities TLV is 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            |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |             Functional Capabilities                           |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    Type     A 16-bit field set to 2.
    Length   A 16-bit field that indicates the length of the value
             portion in octets and will be a multiple of 4 octets
             dependent on the number of capabilities advertised.
             Initially, the length will be 4, denoting 4 octets of
             informational capability bits.
    Value    A variable-length sequence of capability bits rounded
             to a multiple of 4 octets padded with undefined bits.
             Initially, there are 4 octets of capability bits.  Bits
             are numbered left to right starting with the most
             significant bit being bit 0.
           Figure 6.  OSPF Router Functional Capabilities TLV
 The Router Functional Capabilities TLV MAY be followed by optional
 TLVs that further specify a capability.  In contrast to the Router
 Informational Capabilities TLV, the OSPF extensions advertised in
 this TLV MAY be used by other OSPF routers to dictate protocol
 operation.  The specifications for functional capabilities advertised
 in this TLV MUST describe protocol behavior and address backwards
 compatibility.

Lindem, et al. Standards Track [Page 8] RFC 7770 OSPF Capability Extensions February 2016

2.7. Flooding Scope of the Router Information LSA

 The flooding scope for a Router Information LSA is determined by the
 LSA type.  For OSPFv2, a type 9 (link-scoped), type 10 (area-scoped),
 or type 11 (AS-scoped) Opaque LSA may be flooded.  For OSPFv3, the S1
 and S2 bits in the LSA type determine the flooding scope.  If AS-wide
 flooding scope is chosen, the originating router should also
 advertise area-scoped LSA(s) into any attached Not-So-Stubby Area
 (NSSA) area(s).  An OSPF router MAY advertise different capabilities
 when both NSSA area-scoped LSA(s) and an AS-scoped LSA are
 advertised.  This allows functional capabilities to be limited in
 scope.  For example, a router may be an area border router but only
 support traffic engineering (TE) in a subset of its attached areas.
 The choice of flooding scope is made by the advertising router and is
 a matter of local policy.  The originating router MAY advertise
 multiple RI LSAs with the same Instance ID as long as the flooding
 scopes differ.  TLV flooding-scope rules will be specified on a per-
 TLV basis and MUST be specified in the accompanying specifications
 for future Router Information LSA TLVs.

3. Backwards Compatibility

 For backwards compatibility, previously advertised Router Information
 TLVs SHOULD continue to be advertised in the first instance, i.e., 0,
 of the Router Information LSA.  If a Router Information TLV is
 advertised in multiple Router Information LSA instances and the
 multiple instance processing is not explicitly specified in the RFC
 defining that Router Information TLV, the Router Instance TLV in the
 Router Information LSA with the numerically smallest Instance ID will
 be used and subsequent instances will be ignored.

4. Security Considerations

 This document describes both a generic mechanism for advertising
 router capabilities and TLVs for advertising informational and
 functional capabilities.  The capability TLVs are less critical than
 the topology information currently advertised by the base OSPF
 protocol.  The security considerations for the generic mechanism are
 dependent on the future application and, as such, should be described
 as additional capabilities are proposed for advertisement.  Security
 considerations for the base OSPF protocol are covered in [OSPF] and
 [OSPFv3].

Lindem, et al. Standards Track [Page 9] RFC 7770 OSPF Capability Extensions February 2016

5. IANA Considerations

5.1. OSPFv2 Opaque LSA Type Assignment

 [RFC4970] defined the Router Information Opaque LSA as type 4 in the
 "Opaque Link-State Advertisements (LSA) Option Types" registry.  IANA
 has updated the reference for that entry to point to this RFC.

5.2. OSPFv3 LSA Function Code Assignment

 [RFC4970] created the registry for "OSPFv3 LSA Function Codes".  IANA
 has updated the reference for that registry to point to this RFC.
 References within that registry to [RFC4970] have been updated to
 point to this RFC; references to other RFCs are unchanged.
 The definition and assignment policy has been updated as follows.
 This registry is now comprised of the fields Value, LSA Function Code
 Name, and Reference.  The OSPFv3 LSA function code is defined in
 Appendix A.4.2.1 of [OSPFv3].  Values 1-11 and 13-15 have already
 been assigned.  The OSPFv3 LSA function code 12 has been assigned to
 the OSPFv3 Router Information (RI) LSA as defined herein.
       +-----------+-------------------------------------+
       | Range     | Assignment Policy                   |
       +-----------+-------------------------------------+
       | 0         | Reserved (not to be assigned)       |
       |           |                                     |
       | 16-255    | Unassigned (IETF Review)            |
       |           |                                     |
       | 256-8175  | Reserved (No assignments)           |
       |           |                                     |
       | 8176-8183 | Experimentation (No assignments)    |
       |           |                                     |
       | 8184-8190 | Vendor Private Use (No assignments) |
       |           |                                     |
       | 8191      | Reserved (not to be assigned)       |
       +-----------+-------------------------------------+
              Figure 7.  OSPFv3 LSA Function Codes
 o  The assignment policy for OSPFv3 LSA function codes in the range
    16-255 has changed and are now assigned subject to IETF Review.
    New values are assigned through RFCs that have been shepherded
    through the IESG as AD-Sponsored or IETF WG documents
    [IANA-GUIDE].

Lindem, et al. Standards Track [Page 10] RFC 7770 OSPF Capability Extensions February 2016

 o  OSPFv3 LSA function codes in the range 8176-8183 are for
    experimental use; these will not be registered with IANA and MUST
    NOT be mentioned by RFCs.
 o  OSPFv3 LSAs with an LSA Function Code in the Vendor Private Use
    range 8184-8190 MUST include the Enterprise Code [ENTERPRISE-CODE]
    as the first 4 octets following the 20 octets of LSA header.
 o  If a new LSA Function Code is documented, the documentation MUST
    include the valid combinations of the U, S2, and S1 bits for the
    LSA.  It SHOULD also describe how the Link State ID is to be
    assigned.

5.3. OSPF RI LSA TLV Type Assignment

 [RFC4970] created the registry for "OSPF Router Information (RI)
 TLVs".  IANA has updated the reference for this registry to point to
 this RFC.  References within that registry to [RFC4970] have been
 updated to point to this RFC; references to other RFCs are unchanged.
 The definition and assignment policy has been updated as follows.
 The registry is now comprised of the fields Value, TLV Name, and
 Reference.  Values 3-9 have already been assigned.  Value 1 has been
 assigned to the Router Informational Capabilities TLV and value 2 has
 been assigned to the Router Functional Capabilities TLV as defined
 herein.
          +-------------+-----------------------------------+
          | Range       | Assignment Policy                 |
          +-------------+-----------------------------------+
          | 0           | Reserved (not to be assigned)     |
          |             |                                   |
          | 10-32767    | Unassigned (IETF Review)          |
          |             |                                   |
          | 32768-32777 | Experimentation (No assignments)  |
          |             |                                   |
          | 32778-65535 | Reserved (Not to be assigned)     |
          +-------------+-----------------------------------+
                       Figure 8.  OSPF RI TLVs
 o  Types in the range 10-32767 are to be assigned subject to IETF
    Review.  New values are assigned through RFCs that have been
    shepherded through the IESG as AD-Sponsored or IETF WG documents
    [IANA-GUIDE].

Lindem, et al. Standards Track [Page 11] RFC 7770 OSPF Capability Extensions February 2016

 o  Types in the range 32778-65535 are reserved and are not to be
    assigned at this time.  Before any assignments can be made in this
    range, there MUST be a Standards Track RFC that specifies IANA
    Considerations that cover the range being assigned.

5.4. Registry for OSPF Router Informational Capability Bits

 [RFC4970] created the registry for "OSPF Router Informational
 Capability Bits".  IANA has updated the reference for this registry
 to point to this RFC.  The definition and assignment policy has been
 updated as follows.
 o  This registry is now comprised of the fields Bit Number,
    Capability Name, and Reference.
 o  The values are defined in Section 2.6.  All Router Informational
    Capability TLV additions are to be assigned through IETF Review
    [IANA-GUIDE].

5.5. Registry for OSPF Router Functional Capability Bits

 IANA has created a subregistry for "OSPF Router Functional Capability
 Bits" within the "Open Shortest Path First v2 (OSPFv2) Parameters"
 registry.  This subregistry is comprised of the fields Bit Number,
 Capability Name, and Reference.  Initially, the subregistry will be
 empty but will be available for future capabilities.  All Router
 Functional Capability TLV additions are to be assigned through IETF
 Review [IANA-GUIDE].

6. References

6.1. Normative References

 [OPAQUE]  Berger, L., Bryskin, I., Zinin, A., and R. Coltun, "The
           OSPF Opaque LSA Option", RFC 5250, DOI 10.17487/RFC5250,
           July 2008, <http://www.rfc-editor.org/info/rfc5250>.
 [OSPF]    Moy, J., "OSPF Version 2", STD 54, RFC 2328,
           DOI 10.17487/RFC2328, April 1998,
           <http://www.rfc-editor.org/info/rfc2328>.
 [OSPFv3]  Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF for
           IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008,
           <http://www.rfc-editor.org/info/rfc5340>.

Lindem, et al. Standards Track [Page 12] RFC 7770 OSPF Capability Extensions February 2016

 [RFC-KEYWORDS]
           Bradner, S., "Key words for use in RFCs to Indicate
           Requirement Levels", BCP 14, RFC 2119,
           DOI 10.17487/RFC2119, March 1997,
           <http://www.rfc-editor.org/info/rfc2119>.
 [RFC4970] Lindem, A., Ed., Shen, N., Vasseur, JP., Aggarwal, R., and
           S. Shaffer, "Extensions to OSPF for Advertising Optional
           Router Capabilities", RFC 4970, DOI 10.17487/RFC4970,
           July 2007, <http://www.rfc-editor.org/info/rfc4970>.
 [TE]      Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
           (TE) Extensions to OSPF Version 2", RFC 3630,
           DOI 10.17487/RFC3630, September 2003,
           <http://www.rfc-editor.org/info/rfc3630>.

6.2. Informative References

 [ENTERPRISE-CODE]
           Eronen, P. and D. Harrington, "Enterprise Number for
           Documentation Use", RFC 5612, DOI 10.17487/RFC5612,
           August 2009, <http://www.rfc-editor.org/info/rfc5612>.
 [EXP-TE]  Srisuresh, P. and P. Joseph, "OSPF-xTE: Experimental
           Extension to OSPF for Traffic Engineering", RFC 4973,
           DOI 10.17487/RFC4973, July 2007,
           <http://www.rfc-editor.org/info/rfc4973>.
 [GRACE]   Moy, J., Pillay-Esnault, P., and A. Lindem, "Graceful OSPF
           Restart", RFC 3623, DOI 10.17487/RFC3623, November 2003,
           <http://www.rfc-editor.org/info/rfc3623>.
 [IANA-GUIDE]
           Narten, T. and H. Alvestrand, "Guidelines for Writing an
           IANA Considerations Section in RFCs", BCP 26, RFC 5226,
           DOI 10.17487/RFC5226, May 2008,
           <http://www.rfc-editor.org/info/rfc5226>.
 [P2PLAN]  Shen, N., Ed., and A. Zinin, Ed., "Point-to-Point Operation
           over LAN in Link State Routing Protocols", RFC 5309,
           DOI 10.17487/RFC5309, October 2008,
           <http://www.rfc-editor.org/info/rfc5309>.
 [STUB]    Retana, A., Nguyen, L., Zinin, A., White, R., and D.
           McPherson, "OSPF Stub Router Advertisement", RFC 6987,
           DOI 10.17487/RFC6987, September 2013,
           <http://www.rfc-editor.org/info/rfc6987>.

Lindem, et al. Standards Track [Page 13] RFC 7770 OSPF Capability Extensions February 2016

Acknowledgments

 The idea for this work grew out of a conversation with Andrew Partan
 and we thank him for his contribution.  The authors thank Peter
 Psenak for his review and helpful comments on early draft versions of
 the document.
 Special thanks to Tom Petch for providing the updated IANA text in
 this document.
 Comments from Abhay Roy, Vishwas Manral, Vivek Dubey, and Adrian
 Farrel have been incorporated into later draft versions of this
 document.
 Thanks to Yingzhen Qu for acting as document shepherd.
 Thanks to Chris Bowers, Alia Atlas, Shraddha Hegde, Dan Romascanu,
 and Victor Kuarsingh for review of this document.

Lindem, et al. Standards Track [Page 14] RFC 7770 OSPF Capability Extensions February 2016

Authors' Addresses

 Acee Lindem (editor)
 Cisco Systems
 301 Midenhall Way
 Cary, NC  27513
 United States
 Email: acee@cisco.com
 Naiming Shen
 Cisco Systems
 225 West Tasman Drive
 San Jose, CA  95134
 United States
 Email: naiming@cisco.com
 Jean-Philippe Vasseur
 Cisco Systems
 1414 Massachusetts Avenue
 Boxborough, MA  01719
 United States
 Email: jpv@cisco.com
 Rahul Aggarwal
 Arktan
 Email: raggarwa_1@yahoo.com
 Scott Shaffer
 Akamai
 8 Cambridge Center
 Cambridge, MA  02142
 United States
 Email: sshaffer@akamai.com

Lindem, et al. Standards Track [Page 15]

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