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Versions: (draft-xu-ospf-encapsulation-cap) 00 01 02 03 04 05 06

OSPF Working Group                                            X. Xu, Ed.
Internet-Draft                                                    Huawei
Intended status: Standards Track                        B. Decraene, Ed.
Expires: January 17, 2018                                         Orange
                                                               R. Raszuk
                                                            Bloomberg LP
                                                            L. Contreras
                                                          Telefonica I+D
                                                                L. Jalil
                                                                 Verizon
                                                           July 16, 2017


                Advertising Tunneling Capability in OSPF
                  draft-ietf-ospf-encapsulation-cap-06

Abstract

   Networks use tunnels for a variety of reasons.  A large variety of
   tunnel types are defined and the ingress needs to select a type of
   tunnel which is supported by the egress and itself.  This document
   defines how to advertise egress tunnel capabilities in OSPF Router
   Information Link State Advertisement (LSAs).

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 http://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 January 17, 2018.





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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
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
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   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  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Advertising Encapsulation Capability  . . . . . . . . . . . .   3
   4.  Tunnel Encapsulation Type . . . . . . . . . . . . . . . . . .   4
   5.  Tunnel Encapsulation Attribute Sub-TLVs . . . . . . . . . . .   4
     5.1.  Encapsulation Sub-TLV . . . . . . . . . . . . . . . . . .   5
     5.2.  Protocol Type Sub-TLV . . . . . . . . . . . . . . . . . .   5
     5.3.  Endpoint Sub-TLV  . . . . . . . . . . . . . . . . . . . .   5
     5.4.  Color Sub-TLV . . . . . . . . . . . . . . . . . . . . . .   5
     5.5.  Load-Balancing Block Sub-TLV  . . . . . . . . . . . . . .   6
     5.6.  IP QoS Field  . . . . . . . . . . . . . . . . . . . . . .   6
     5.7.  UDP Destination Port  . . . . . . . . . . . . . . . . . .   6
   6.  Usage of the Tunnel Encapsulation attribute . . . . . . . . .   6
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
     7.1.  OSPF Router Information . . . . . . . . . . . . . . . . .   6
     7.2.  OSPF Tunnel Encapsulation Attribute Sub-TLVs Registry . .   7
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   9.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .   7
   10. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   8
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .   8
     11.1.  Normative References . . . . . . . . . . . . . . . . . .   8
     11.2.  Informative References . . . . . . . . . . . . . . . . .   8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   9

1.  Introduction

   Networks use tunnels for a variety of reasons, such as:

   o  Partial deployment of MPLS-SPRING as described in
      [I-D.xu-mpls-unified-source-routing-instruction], where IP tunnels




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      are used between MPLS-SPRING-enabled routers to traverse non-MPLS
      routers.

   o  Partial deployment of MPLS-BIER as described in
      [I-D.ietf-bier-architecture], where IP tunnels are used between
      MPLS-BIER-capable routers to traverse non MPLS-BIER
      [I-D.ietf-bier-mpls-encapsulation] routers.

   o  Partial deployment of IPv6 in IPv4 networks or IPv4 in IPv6
      networks as described in [RFC5565], where IPvx tunnels are used
      between IPvx-enabled routers so as to traverse non-IPvx routers.

   o  Remote Loop-Free Alternate (RLFA) repair tunnels as described in
      [RFC7490], where tunnels are used between the Point of Local
      Repair and the selected PQ node.

   The ingress needs to select a type of tunnel which is supported by
   the egress and itself.  This document describes how to use OSPF
   Router Information Link State Advertisements (LSAs) to advertise the
   egress tunneling capabilities of OSPF routers.  In this document,
   OSPF refers to both OSPFv2 [RFC2328] and OSPFv3 [RFC5340].

2.  Terminology

   This memo makes use of the terms defined in [RFC7770].

3.  Advertising Encapsulation Capability

   Routers advertise their supported encapsulation type(s) by
   advertising a new TLV of the OSPF Router Information (RI) Opaque LSA
   [RFC7770], referred to as the Encapsulation Capability TLV.  This TLV
   is applicable to both OSPFv2 and OSPFv3.  The Encapsulation
   Capability TLV SHOULD NOT appear more than once within a given OSPF
   Router Information (RI) Opaque LSA.  If the Encapsulation Capability
   TLV appears more than once in an OSPF Router Information LSA, only
   the first occurrence MUST be processed and others MUST be ignored.
   The scope of the advertisement depends on the application but it is
   recommended that it SHOULD be domain-wide.  The Type code of the
   Encapsulation Capability TLV is TBD1, the Length value is variable,
   and the Value field contains one or more Tunnel Encapsulation Type
   Sub-TLVs.  Each Encapsulation Type Sub-TLVs indicates a particular
   encapsulation format that the advertising router supports along with
   the parameters to be used for the tunnel.








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4.  Tunnel Encapsulation Type

   The Tunnel Encapsulation Type Sub-TLV is structured 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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |    Tunnel Type (2 Octets)     |        Length (2 Octets)      |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                                                               |
      |                            Sub-TLVs                           |
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      Tunnel Type (2 octets): Identifies the type of tunneling
      technology being signaled.  Tunnel types are shared with the BGP
      extension [RFC5512] and hence are defined in the IANA registry
      "BGP Tunnel Encapsulation Attribute Tunnel Types".  Unknown types
      are to be ignored and skipped upon receipt.

      Length (2 octets): Unsigned 16-bit integer indicating the total
      number of octets of the value field.

      Value (variable): Zero or more Tunnel Encapsulation Attribute Sub-
      TLVs as defined in Section 5.

5.  Tunnel Encapsulation Attribute Sub-TLVs

   Tunnel Encapsulation Attribute Sub-TLV are structured as follows:

              +-----------------------------------+
              |     Sub-TLV Type   (2 Octets)     |
              +-----------------------------------+
              |     Sub-TLV Length (2 Octets)     |
              +-----------------------------------+
              |     Sub-TLV Value  (Variable)     |
              |                                   |
              +-----------------------------------+

      Sub-TLV Type (2 octets): Each Sub-TLV type defines a certain
      property of the tunnel TLV that contains this Sub-TLV.  Types are
      registered in the IANA registry "OSPF Tunnel Encapsulation
      Attribute Sub-TLVs" Section 7.2.

      Sub-TLV Length (2 octets): Unsigned 16-bit integer indicating the
      total number of octets of the Sub-TLV value field.





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      Sub-TLV Value (variable): Encodings of the value field depend on
      the Sub-TLV type as enumerated above.  The following sub-sections
      define the encoding in detail.

   Any unknown Sub-TLVs MUST be ignored and skipped upon receipt.

   If a Sub-TLV is invalid, its Tunnel Encapsulation TLV MUST be ignored
   and skipped.  However, other Tunnel Encapsulation TLVs MUST be
   considered.

5.1.  Encapsulation Sub-TLV

   This Sub-TLV of type 1 is defined in section 3.2 "Encapsulation Sub-
   TLVs for Particular Tunnel Types" of [I-D.ietf-idr-tunnel-encaps]
   from both a syntax and semantic standpoint.  Usage is defined in
   Section 6.

5.2.  Protocol Type Sub-TLV

   This Sub-TLV of type 2 is defined in section 3.4.1 "Protocol Type
   sub-TLV" of [I-D.ietf-idr-tunnel-encaps] from a syntactic, semantic,
   and usage standpoint.

5.3.  Endpoint Sub-TLV

   Type is 3.  The value field carries the Network Address to be used as
   tunnel destination address.

   If length is 4, the tunnel endpoint is an IPv4 address.

   If length is 16, the tunnel endpoint is an IPv6 address.

5.4.  Color Sub-TLV

   Type is 4.  The value field is a 4-octet opaque unsigned integer.

   The color value is user-defined and configured locally on the
   advertising routers.  It may be used by service providers to define
   policies on the ingress routers, for example, to control the
   selection of the tunnel to use.

   This color value can be referenced by BGP routes carrying Color
   Extended Community [I-D.ietf-idr-tunnel-encaps].  If the tunnel is
   used to reach the BGP Next-Hop of BGP routes, then attaching a Color
   Extended Community attached to those routes express the willingness
   of the BGP speaker to use a tunnel of the same color.





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5.5.  Load-Balancing Block Sub-TLV

   This Sub-TLV of type 5 is defined in [RFC5640] from a syntactic,
   semantic and usage standpoint.

5.6.  IP QoS Field

   This Sub-TLV of type 6 is defined in section 3.3.1 "IPv4 DS Field" of
   [I-D.ietf-idr-tunnel-encaps] from a syntactic, semantic and usage
   standpoint.

5.7.  UDP Destination Port

   This Sub-TLV of type 7 is defined in section 3.3.2 "UDP Destination
   Port" of [I-D.ietf-idr-tunnel-encaps] from a syntactic, semantic and
   usage standpoint.

6.  Usage of the Tunnel Encapsulation attribute

   The advertisement of an Encapsulation Type Sub-TLVs indicates that
   the advertising router support a particular tunnel encapsulation
   along with the parameters to be used for the tunnel.  The decision to
   use that tunnel is driven by the capability of the ingress router to
   support the encapsulation type and the policy on the ingress router.
   The color sub-TLV may be used as an input to this policy.  Note that
   some tunnel types may require the execution of an explicit tunnel
   setup protocol before they can be used to carry data.

   A tunnel MUST NOT be used if there is no route toward the IP address
   specified in the Endpoint Sub-TLV or if the route is not advertised
   by the router advertising the Tunnel Encapsulation attribute for the
   tunnel.

7.  IANA Considerations

7.1.  OSPF Router Information

   This document requests IANA to allocate a new code point from the
   OSPF Router Information (RI) registry.

       Value   TLV Name                               Reference
       -----   ------------------------------------   -------------
       TBD1    Tunnel Capabilities                    This document








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7.2.  OSPF Tunnel Encapsulation Attribute Sub-TLVs Registry

   This document requests IANA to create a new registry "OSPF Tunnel
   Encapsulation Attribute Sub-TLVs" with the following registration
   procedure:

      The values in the range 1-255 are to be allocated using the
      "Standards Action" registration procedure as defined in [RFC5226].

      The values in the range 256-65499 are to be allocated using the
      "First Come, First Served" registration procedure.

    Registry Name: OSPF Tunnel Encapsulation Attribute Sub-TLVs

  Value          Name                                      Reference
  -----------    ------------------------------------      -------------
            0    Reserved                                  This document
            1    Encapsulation                             This document
            2    Protocol Type                             This document
            3    Endpoint                                  This document
            4    Color                                     This document
            5    Load-Balancing Block                      This document
            6    IP QoS                                    This document
            7    UDP Destination Port                      This document
      8-65499    Unassigned
  65500-65535    Experimental                              This document
        65535    Reserved                                  This document

8.  Security Considerations

   Security considerations applicable to softwires can be found in the
   mesh framework [RFC5565].  In general, security issues of the tunnel
   protocols signaled through this OSPF capability extension are
   inherited.

   If a third-party is able to modify any of the information that is
   used to form encapsulation headers, to choose a tunnel type, or to
   choose a particular tunnel for a particular payload type, user data
   packets may end up getting misrouted, misdelivered, and/or dropped.

   Security considerations for the base OSPF protocol are covered in
   [RFC2328] and [RFC5340].

9.  Contributors

   Uma Chunduri
   Huawei
   Email: uma.chunduri@gmail.com



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10.  Acknowledgements

   This document is partially inspired by [RFC5512].

   The authors would like to thank Greg Mirsky, John E Drake, Carlos
   Pignataro and Karsten Thomann for their valuable comments on this
   document.  Special thanks should be given to Acee Lindem for his
   multiple detailed reviews of this document and help.

11.  References

11.1.  Normative References

   [I-D.ietf-idr-tunnel-encaps]
              Rosen, E., Patel, K., and G. Velde, "The BGP Tunnel
              Encapsulation Attribute", draft-ietf-idr-tunnel-encaps-06
              (work in progress), June 2017.

   [RFC2119]  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>.

   [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", RFC 5226,
              DOI 10.17487/RFC5226, May 2008,
              <http://www.rfc-editor.org/info/rfc5226>.

   [RFC5640]  Filsfils, C., Mohapatra, P., and C. Pignataro, "Load-
              Balancing for Mesh Softwires", RFC 5640,
              DOI 10.17487/RFC5640, August 2009,
              <http://www.rfc-editor.org/info/rfc5640>.

   [RFC7770]  Lindem, A., Ed., Shen, N., Vasseur, JP., Aggarwal, R., and
              S. Shaffer, "Extensions to OSPF for Advertising Optional
              Router Capabilities", RFC 7770, DOI 10.17487/RFC7770,
              February 2016, <http://www.rfc-editor.org/info/rfc7770>.

11.2.  Informative References

   [I-D.ietf-bier-architecture]
              Wijnands, I., Rosen, E., Dolganow, A., Przygienda, T., and
              S. Aldrin, "Multicast using Bit Index Explicit
              Replication", draft-ietf-bier-architecture-07 (work in
              progress), June 2017.






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   [I-D.ietf-bier-mpls-encapsulation]
              Wijnands, I., Rosen, E., Dolganow, A., Tantsura, J.,
              Aldrin, S., and I. Meilik, "Encapsulation for Bit Index
              Explicit Replication in MPLS and non-MPLS Networks",
              draft-ietf-bier-mpls-encapsulation-07 (work in progress),
              June 2017.

   [I-D.xu-mpls-unified-source-routing-instruction]
              Xu, X., Bryant, S., Raszuk, R., Chunduri, U., Contreras,
              L., Jalil, L., Assarpour, H., Velde, G., Tantsura, J., and
              S. Ma, "Unified Source Routing Instruction using MPLS
              Label Stack", draft-xu-mpls-unified-source-routing-
              instruction-02 (work in progress), June 2017.

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

   [RFC5340]  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>.

   [RFC5512]  Mohapatra, P. and E. Rosen, "The BGP Encapsulation
              Subsequent Address Family Identifier (SAFI) and the BGP
              Tunnel Encapsulation Attribute", RFC 5512,
              DOI 10.17487/RFC5512, April 2009,
              <http://www.rfc-editor.org/info/rfc5512>.

   [RFC5565]  Wu, J., Cui, Y., Metz, C., and E. Rosen, "Softwire Mesh
              Framework", RFC 5565, DOI 10.17487/RFC5565, June 2009,
              <http://www.rfc-editor.org/info/rfc5565>.

   [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,
              <http://www.rfc-editor.org/info/rfc7490>.

Authors' Addresses

   Xiaohu Xu (editor)
   Huawei

   Email: xuxiaohu@huawei.com








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   Bruno Decraene  (editor)
   Orange

   Email: bruno.decraene@orange.com


   Robert Raszuk
   Bloomberg LP

   Email: robert@raszuk.net


   Luis M. Contreras
   Telefonica I+D

   Email: luismiguel.contrerasmurillo@telefonica.com


   Luay Jalil
   Verizon

   Email: luay.jalil@verizon.com





























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