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6MAN working group                                            J. Dong
Internet-Draft                                                  Z. Li
Intended status: Standard Track                                Huawei
Expires: August 2020                                February 10, 2020




        Carrying Virtual Transport Network (VTN) Identifier in IPv6
                    Extensison Header for Enhanced VPN

                  draft-dong-6man-enhanced-vpn-vtn-id-00


Abstract

   This document proposes a new option type to carry virtual transport
   network identifier (VTN ID) in the IPv6 extensions headers to
   identify the virtual transport network the packet belongs to. The
   procedure of processing the VTN option is also specified. This
   provides a scalable solution for data plane encapsulation of
   enhanced VPN (VPN+) as described in I-D.ietf-teas-enhanced-vpn. One
   typical use case of VPN+ is to provide transport network slicing in
   5G, while it could also be used in more general cases.

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
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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on August 10, 2020.

Copyright Notice

   Copyright (c) 2020 IETF Trust and the persons identified as the
   document authors. All rights reserved.






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

Table of Contents


   1. Introduction ................................................ 2
   2. Requirements Language ....................................... 3
   3. New IPv6 Extension Header Option for VTN .................... 3
   4. Procedures .................................................. 4
      4.1. VTN Option Insertion ................................... 4
      4.2. VTN based Packet Forwarding ............................ 5
   5. Security Considerations ..................................... 5
   IANA Considerations ............................................ 5
   Contributors ................................................... 6
   Acknowledgments ................................................ 6
   References ..................................................... 6
      Normative References ........................................ 6
      Informative References ...................................... 6
   Authors' Addresses ............................................. 7

1. Introduction

   Virtual private networks (VPNs) have served the industry well as a
   means of providing different groups of users with logically isolated
   connectivity over a common network.  Some customers may request a
   connectivity services with advanced characteristics such as complete
   isolation from other services or guaranteed performance. These
   services are "enhanced VPNs" (known as VPN+). [I-D.ietf-teas-
   enhanced-vpn] describes the framework and candidate component
   technologies for providing enhanced VPN services. One typical use
   case of VPN+ is to provide transport network slicing in 5G, while it
   could also be used in more general cases.

   The enhanced properties of VPN+ require tighter coordination and
   integration between the underlay network resources and the overlay
   network. VPN+ service is built on a Virtual Transport Network (VTN)
   which has a customized network topology and a set of dedicated or
   shared network resources allocated from the underlay network. The



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   overlay VPN together with the corresponding VTN in the underlay
   provide the VPN+ service. In the network, traffic of different VPN+
   services need to be processed separately based on the topology and
   the network resources associated with the corresponding VTN.

   [I-D.dong-teas-enhanced-vpn-vtn-scalability] describes the
   scalability considerations of enhanced VPN, in which one approach
   to improve the data plane scalability is to introduce a dedicated
   identifier indata packet to identify the VTN the packet belongs to,
   so as to perform resource specific packet processing. This is called
   Resource Independent (RI) VTN.

   This document proposes a mechanism to carry the VTN Identifier (VTN
   ID) in the IPv6 extensions headers [RFC8200] of packet, so that the
   packet will be processed by network nodes using the network
   resources allocated to the corresponding VTN. The procedure of
   processing the VTN ID is also specified. This provides a scalable
   solution for enhanced VPN data plane, so that it could be used to
   support a large number of transport network slices in IPv6 network.

2. Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   BCP14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

3. New IPv6 Extension Header Option for VTN

   A new option type of IPv6 extension headers is defined to carry the
   Virtual Transport Network Identifier (VTN ID) in IPv6 packet header.
   Its format is shown as below:

          Option    Option       Option
           Type    Data Len       Data
         +--------+--------+--------+--------+
         |BBCTTTTT|00000100|  4-octet VTN ID |
         +--------+--------+--------+--------+

   Option Type: 8-bit identifier of the type of option. The type of VTN
   option is TBD by IANA. The highest-order bits of the type field are
   defined as below:





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       BB  00  The highest-order 2 bits are set to 00 to indicate that a
               node which does not recognize this type will skip over it
               and continue processing the header.

       C    0  The third highest-order bit are set to 0 to indicate this
               option does not change en route.

   Opt Data Len: 8-bit unsigned integer indicates the length of the
   option Data field of this option, in octets. The value of Opt Data
   Len of VTN option SHOULD be set to 4.

   Option Data: 4-octet VTN which uniquely identifies a virtual
   transport network.



   Editor's note: The length of the VTN ID is defined as 4-octet
   partially for the matching with the 4-octet network slice identifier
   defined in 3GPP [TS23501].

                   8-bit              24-bit
               +------------+-------------------------+
               |    SST     |   Slice Differentiator  |
               +------------+-------------------------+


4. Procedures

4.1. VTN Option Insertion

   The VTN option is inserted at the edge of the IPv6 network which
   provides enhanced VPN service. On receipt of a data packet, the
   ingress node determines the associated enhanced VPN based on traffic
   classification or local policies, then it SHOULD insert the
   corresponding VTN ID option into the IPv6 extension header of the
   packet. If SRv6 is enabled, the VTN option SHOULD be included in the
   outer IPv6 header which MAY optionally include the SRH [I-D.ietf-
   6man-segment-routing-header].

   In order to make the VTN option be processed by each node along the
   path, it is RECOMMENDED that the VTN option be carried in the Hop-
   by-Hop option header of the IPv6 packet.







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4.2. VTN based Packet Forwarding

   On receipt of a packet with the VTN option, each network node which
   can support the VTN option SHOULD use the VTN ID to identify the
   virtual network the packet belongs to, and the set of local network
   resources allocated the processing of the packet. This means the
   forwarding behavior is based on both the destination IP address and
   the VTN option.

   There can be different implementations of allocating local network
   resources to the VTNs. On each interface, the resources allocated to
   a particular VTN can be considered as a virtual sub-interface with
   dedicated bandwidth. In packet forwarding, the IPv6 destination
   address of the received packet is used to identify the next-hop and
   the outgoing interface, and the VTN ID is used to further identify
   the virtual sub-interface which is associated with the VTN on the
   outgoing interface.

   Routers which do not support Hop-by-Hop options SHOULD ignore this
   option and SHOULD forward the packet. Routers which support Hop-by-
   Hop Options, but do not recognize the VTN option SHOULD ignore the
   option and continue to forward the packet merely based on the
   destination IP address.

5. Security Considerations

   TBD

IANA Considerations

   This document requests IANA to assign a new option type from
   "Destination Options and Hop-by-Hop Options" registry.

   Value   Description                            Reference
   ------------------------------------------------------------
   TBD     Virtual Transport Network Identifier   this document












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Contributors

   Zhibo Hu
   Email: huzhibo@huawei.com

   Juhua Xu
   Email: xujuhua@huawei.com

Acknowledgments

   The authors would like to thank XXX for the review and valuable
   comments.

References

Normative References

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

   [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
             2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
             May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6
             (IPv6) Specification", STD 86, RFC 8200, DOI 10.17487/
             RFC8200, July 2017, <https://www.rfc-editor.org/info/
             rfc8200>.

Informative References

   I-D.ietf-teas-enhanced-vpn] Dong, J., Bryant, S., Li, Z., Miyasaka,
             T., and Y. Lee, "A Framework for Enhanced Virtual Private
             Networks (VPN+) Service", draft-ietf-teas-enhanced-vpn-04
             (work in progress), January 2020.

   [I-D.dong-teas-enhanced-vpn-vtn-scalability] Dong, J., Li, Z., Qin,
             F., "Scalability Considerations of Enhanced VPN",
             draft-dong-teas-enhanced-vpn-vtn-scalability-00
                         (work in progress), February 2020.






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   [I-D.ietf-6man-segment-routing-header] Filsfils, C., Dukes, D.,
             Previdi, S., Leddy, J., Matsushima, S., and D. Voyer,
             "IPv6 Segment Routing Header (SRH)", draft-ietf-6man-
             segment-routing-header-26 (work in progress), October 2019.

   [I-D.ietf-spring-srv6-network-programming] Filsfils, C., Camarillo,
             P., Leddy, J., Voyer, D., Matsushima, S., and Z. Li, "SRv6
             Network Programming", draft-ietf-spring-srv6-network-
             programming-07 (work in progress), December 2019.

   [TS23501] "3GPP TS23.501", 2019,
             <https://portal.3gpp.org/desktopmodules/Specifications/Spe
             cificationDetails.aspx?specificationId=3144>.

Authors' Addresses

   Jie Dong
   Huawei

   Email: jie.dong@huawei.com

   Zhenbin Li
   Huawei

   Email: lizhenbin@huawei.com























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