The Tunnel Encapsulations OSPF Router Information
draft-ietf-ospf-encapsulation-cap-09

Versions: (draft-xu-ospf-encapsulation-cap)   00         Standards Track
          01 02 03 04 05 06 07 08 09                                    
OSPF Working Group                                            X. Xu, Ed.
Internet-Draft                                                    Huawei
Intended status: Standards Track                        B. Decraene, Ed.
Expires: March 14, 2018                                           Orange
                                                               R. Raszuk
                                                            Bloomberg LP
                                                            L. Contreras
                                                          Telefonica I+D
                                                                L. Jalil
                                                                 Verizon
                                                      September 10, 2017


         Advertising Tunnel Encapsulation Capabilities in OSPF
                  draft-ietf-ospf-encapsulation-cap-07

Abstract

   Networks use tunnels for a variety of reasons.  A large variety of
   tunnel types are defined and the ingress tunnel router needs to
   select a type of tunnel which is supported by the egress tunnel
   router and itself.  This document defines how to advertise the tunnel
   encapsulation capabilities of egress tunnel routers 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
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   This Internet-Draft will expire on March 14, 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 (https://trustee.ietf.org/license-info)
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   and are provided without warranty as described in the Simplified
   BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Tunnel Encapsulation Capabilities TLV . . . . . . . . . . . .   3
   4.  Tunnel Encapsulation Type Sub-TLVs  . . . . . . . . . . . . .   3
   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.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
     6.1.  OSPF Router Information . . . . . . . . . . . . . . . . .   6
     6.2.  Tunnel Encapsulation Attribute Sub-TLVs Registry  . . . .   6
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   8.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .   7
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   7
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .   8
     10.1.  Normative References . . . . . . . . . . . . . . . . . .   8
     10.2.  Informative References . . . . . . . . . . . . . . . . .   8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   9

1.  Introduction

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

   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.




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   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 tunnel router needs to select a type of tunnel which is
   supported by the egress tunnel router and itself.  This document
   describes how to use OSPF Router Information Link State
   Advertisements (LSAs) to advertise the tunneling capabilities of OSPF
   routers acting as egress tunnel 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.  Tunnel Encapsulation Capabilities TLV

   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 Tunnel Encapsulation Capabilities TLV.
   This TLV is applicable to both OSPFv2 and OSPFv3.  The Tunnel
   Encapsulation Capabilities TLV SHOULD NOT appear more than once
   within a given OSPF Router Information (RI) Opaque LSA.  If the
   Tunnel Encapsulation Capabilities TLV appears more than once in an
   OSPF Router Information LSA, only the first occurrence MUST be
   processed and others SHOULD 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 Tunnel Encapsulation
   Capabilities TLV is TBD1, the Length value is variable, and the Value
   field contains one or more Tunnel Encapsulation Type Sub-TLVs (see
   Section 4).  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.

4.  Tunnel Encapsulation Type Sub-TLVs

   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)      |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                                                               |
      |         Tunnel Encapsulation Attribute Sub-TLVs               |
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+




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      Tunnel Type (2 octets): Identifies the type of tunneling
      technology being signaled.  Tunnel types are shared with the BGP
      extension [I-D.ietf-idr-tunnel-encaps] 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.  Note that this is a padding
      to be ignored if the length field is longer than the field
      indicated by the sub-TLVs.

      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 6.2.

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

      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 deemed as invalid Sub-TLVs and therefore
   MUST be ignored and skipped upon receipt.  When a reserved value (See
   Section 6.2) is seen in an LSA, it SHOULD be treated as an invalid
   Sub-TLV.  If a Sub-TLV is invalid, its Tunnel Encapsulation Type TLV
   MUST be ignored and skipped.  However, other Tunnel Encapsulation
   Type TLVs MUST be considered.

   The advertisement of an Encapsulation Type Sub-TLV (See Section 5.1)
   indicates that the advertising router support a particular tunnel



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   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 (See Section 5.4) 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 (See
   Section 5.3) or if the route is not advertised by the router
   advertising the Tunnel Encapsulation Attribute Sub-TLVs for the
   tunnel.

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.

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 tunnel 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.  IANA Considerations

6.1.  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 Encapsulation Capabilities      This document

6.2.  Tunnel Encapsulation Attribute Sub-TLVs Registry

   This document requests IANA to create a new registry "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.












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  Registry Name: OSPF Tunnel Encapsulation Attribute Sub-TLVs

Value          Name                   Reference
-----------    --------------------   --------------------------------------------
          0    Reserved               This document
          1    Encapsulation          This document & [I-D.ietf-idr-tunnel-encaps]
          2    Protocol Type          This document & [I-D.ietf-idr-tunnel-encaps]
          3    Endpoint               This document
          4    Color                  This document
          5    Load-Balancing Block   This document & [RFC5640]
          6    IP QoS                 This document & [I-D.ietf-idr-tunnel-encaps]
          7    UDP Destination Port   This document & [I-D.ietf-idr-tunnel-encaps]
    8-65499    Unassigned
65500-65534    Experimental           This document
      65535    Reserved               This document

7.  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.
   However, since an OSPF routing domain is usually well-controlled and
   well-managed network, the possiblity of the above risk is very low.

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

8.  Contributors

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

9.  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.  The authors
   would like to thank Pete Resnick, Joe Touch, David Mandelberg,



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   Sabrina Tanamal, Tim Wicinski, Amanda Baber for their Last Call
   reviews and thank Spencer Dawkins, Mirja Kuehlewind, Ben Campbell,
   Benoit Claise, Alvaro Retana, Adam Roach and Suresh Krishnan for
   their AD reviews.

10.  References

10.1.  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-07
              (work in progress), July 2017.

   [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>.

   [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", RFC 5226,
              DOI 10.17487/RFC5226, May 2008,
              <https://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,
              <https://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, <https://www.rfc-editor.org/info/rfc7770>.

10.2.  Informative References

   [RFC2328]  Moy, J., "OSPF Version 2", STD 54, RFC 2328,
              DOI 10.17487/RFC2328, April 1998,
              <https://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,
              <https://www.rfc-editor.org/info/rfc5340>.








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

Authors' Addresses

   Xiaohu Xu (editor)
   Huawei

   Email: xuxiaohu@huawei.com


   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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