Encapsulation of End-to-End IETF Network Slice Information in IPv6
draft-li-6man-e2e-ietf-network-slicing-00

Document Type Active Internet-Draft (individual)
Authors Zhenbin Li  , Jie Dong 
Last updated 2021-04-14
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Network Working Group                                              Z. Li
Internet-Draft                                                   J. Dong
Intended status: Standards Track                     Huawei Technologies
Expires: October 16, 2021                                 April 14, 2021

   Encapsulation of End-to-End IETF Network Slice Information in IPv6
               draft-li-6man-e2e-ietf-network-slicing-00

Abstract

   Network slicing can be used to meet the connectivity and performance
   requirement of different services or customers in a shared network.
   An IETF network slice may span multiple network domains.  In the
   context of 5G, the 5G end-to-end network slices consist of three
   major types of network segments: Radio Access Network (RAN),
   Transport Network (TN) and Core Network (CN).

   In order to facilitate the mapping between network slices in
   different network segments and network domains, it is beneficial to
   carry the identifiers of the 5G end-to-end network slice, the multi-
   domain IETF network slice together with the intra-domain network
   slice identifier in the data packet.

   This document defines the mechanism of encapsulating the end-to-end
   network slice related information in IPv6 data plane.

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
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   Internet-Drafts are draft documents valid for a maximum of six months
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   This Internet-Draft will expire on October 16, 2021.

Copyright Notice

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   This document is subject to BCP 78 and the IETF Trust's Legal
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  End-to-End Network Slice Identifiers in IPv6  . . . . . . . .   3
     2.1.  IPv6 Global VTN-ID Option . . . . . . . . . . . . . . . .   4
     2.2.  IPv6 5G Network Slice ID Option . . . . . . . . . . . . .   4
   3.  Procedures  . . . . . . . . . . . . . . . . . . . . . . . . .   5
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   6
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   6
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   The definition and the characteristics of IETF are introduced in
   [I-D.ietf-teas-ietf-network-slice-definition], and
   [I-D.ietf-teas-ietf-network-slice-framework] describes a general
   framework of IETF network slice.

   [I-D.ietf-teas-enhanced-vpn] describes the framework and the
   candidate component technologies for providing enhanced VPN services.
   VPN+ can be built from a VPN overlay and an underlying Virtual
   Transport Network (VTN) which has a customized network topology and a
   set of dedicated or shared resources in the underlay network.
   Enhanced VPN (VPN+) can be used for the realization of IETF network
   slices.

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   [I-D.dong-teas-enhanced-vpn-vtn-scalability] describes the
   scalability considerations in the control plane and data plane to
   enable VPN+ services, and provides several suggestions to improve the
   scalability of VTN.  In the control plane, It proposes the approach
   of decoupling the topology and resource attributes of VTN, so that
   multiple VTNs may share the same topology and the result of topology
   based path computation.  In the data plane, it proposes to carry a
   VTN-ID in the data packet to determine the set of resources reserved
   for the corresponding VTN.

   An IETF network slice may span multiple network domains.  Further in
   the context of 5G, there can be end-to-end network slices which
   consists of three major types of network segments: Radio Access
   Network (RAN), Transport Network (TN) and Core Network (CN).  In
   order to facilitate the mapping between network slices in different
   network segments and network domains, it may be beneficial to carry
   the identifiers of the 5G end-to-end network slice and the multi-
   domain IETF network slice together with the intra-domain network
   slice identifier in the data packet.

   [I-D.li-teas-e2e-ietf-network-slicing] describes the framework of
   carrying end-to-end network slice related identifiers in the data
   plane, each of the identifiers may span a different network scope.

   With IPv6 data plane, [I-D.dong-6man-enhanced-vpn-vtn-id] specifies
   the extensions and mechanisms to carry the VTN-ID of a single network
   domain in IPv6 extension header, so as to improve the scalability of
   VTN [I-D.dong-teas-enhanced-vpn-vtn-scalability].  This document
   further specifies the extensions and mechanisms of encapsulating the
   identifiers of the 5G end-to-end network slice and the multi-domain
   IETF network slice in IPv6 data plane to support the end-to-end
   network slicing.

2.  End-to-End Network Slice Identifiers in IPv6

   This section describes the approach of encapsulating the end-to-end
   network slice identifiers in IPv6 data plane.  Two new IPv6 options
   are defined for the global VTN-ID and the 5G end-to-end network slice
   ID (i.e.  S-NSSAI) respectively.  This way, the network slice
   identifiers with different network scopes are carried in separate
   IPv6 options.

   The Global VTN-ID and the 5G network slice ID are optional in the
   data packet, depending on whether a IETF network slice spans multiple
   domains and whether it is used as part of the 5G end-to-end network
   slice.

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   Editor's note: Another option is to define a new network slice option
   to carry all the network slicing related information, each network
   slice related identifier can be defined as a separate TLV in the new
   option.  Since the end-to-end network slice related identifiers are
   optional information, it is more practical to define them as separate
   options of IPv6 extension header for better incremental evolution.

2.1.  IPv6 Global VTN-ID Option

   The format of the Global VTN-ID option is shown as below:

             Option   Option                Option
              Type   Data Len                Data
           +--------+--------+--------+--------+--------+--------+
           |BBCTTTTT|00000100|           Global VTN-ID           |
           +--------+--------+--------+--------+--------+--------+
                Figure 1. The format of Global VTN-ID Option

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

   o  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.

   o  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 the Global VTN-ID option SHOULD be set to 4.

   Option Data: 4-octet identifier which uniquely identifies a global
   VTN.

2.2.  IPv6 5G Network Slice ID Option

   The format of the 5G network slice ID option is shown as below:

             Option   Option                Option
              Type   Data Len                Data
           +--------+--------+--------+--------+--------+--------+
           |BBCTTTTT|00000100|              S-NSSAI              |
           +--------+--------+--------+--------+--------+--------+
            Figure 2. The format of 5G network slice ID Option

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   Option Type: 8-bit identifier of the type of option.  The type of 5G
   network slice ID option is to be assigned by IANA.  The highest-order
   bits of the type field are defined as below:

   o  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.

   o  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 the 5G network slice ID option SHOULD be set to 4.  This
   aligns with the length of the S-NSSAI defined in 3GPP.

   Option Data: 4-octet identifier which uniquely identifies a 5G end-
   to-end network slice.

3.  Procedures

   The ingress node of a multi-domain IETF network slice SHOULD
   encapsulate the received packet in an outer IPv6 header, the Global
   VTN-ID the packet mapped to MAY be carried in the IPv6 HBH options
   header of the outer IPv6 header.

   The edge nodes of each domain MAY parse the Global VTN-ID in the IPv6
   HBH options header and maps it to a local VTN.  When the mechanism as
   defined in [I-D.dong-6man-enhanced-vpn-vtn-id] is used in the local
   domain, the Local VTN-ID is obtained from the mapping relationship
   between the Global VTN-ID and Local VTN-ID maintained on the edge
   node, and the Local VTN-ID SHOULD be encapsulated in the HBH header
   of the outer IPv6 header.  The Local VTN-ID is used to identify the
   local network resources reserved for the VTN in the local domain.
   The local VTN-ID in the packet MAY be updated on the edge nodes of
   each domain.

   When the multi-domain IETF network slice is part of a 5G end-to-end
   network slice, the 5G Network Slice ID option MAY be carried in the
   IPv6 HBH options header of the outer IPv6 header.  The S-NSSAI MAY be
   used for the collection and report of the performance information of
   the 5G end-to-end network slice based on the mechanism defined in
   [I-D.ietf-6man-ipv6-alt-mark].

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4.  IANA Considerations

   IANA is requested to allocate two new option types from "Destination
   Options and Hop-by-Hop Options" registry.

         Value        Description            Reference
         -------------------------------------------------
         TBD1    Global VTN-ID Option       this document
         TBD2   5G Network Slice ID Option  this document

5.  Security Considerations

   TBD

6.  Acknowledgements

   TBD

7.  References

7.1.  Normative References

   [I-D.dong-6man-enhanced-vpn-vtn-id]
              Dong, J., Li, Z., Xie, C., and C. Ma, "Carrying Virtual
              Transport Network Identifier in IPv6 Extension Header",
              draft-dong-6man-enhanced-vpn-vtn-id-02 (work in progress),
              November 2020.

   [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-06 (work in
              progress), July 2020.

   [I-D.ietf-teas-ietf-network-slice-definition]
              Rokui, R., Homma, S., Makhijani, K., Contreras, L., and J.
              Tantsura, "Definition of IETF Network Slices", draft-ietf-
              teas-ietf-network-slice-definition-00 (work in progress),
              January 2021.

   [I-D.ietf-teas-ietf-network-slice-framework]
              Gray, E. and J. Drake, "Framework for IETF Network
              Slices", March 2021, <https://tools.ietf.org/html/draft-
              ietf-teas-ietf-network-slice-framework>.

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   [I-D.li-teas-e2e-ietf-network-slicing]
              Li, Z. and J. Dong, "Framework for End-to-End IETF Network
              Slicing", April 2021, <https://tools.ietf.org/html/draft-
              li-teas-e2e-ietf-network-slicing>.

   [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>.

7.2.  Informative References

   [I-D.dong-teas-enhanced-vpn-vtn-scalability]
              Dong, J., Li, Z., Qin, F., and G. Yang, "Scalability
              Considerations for Enhanced VPN (VPN+)", draft-dong-teas-
              enhanced-vpn-vtn-scalability-01 (work in progress),
              November 2020.

   [I-D.ietf-6man-ipv6-alt-mark]
              Fioccola, G., Zhou, T., Cociglio, M., Qin, F., and R.
              Pang, "IPv6 Application of the Alternate Marking Method",
              draft-ietf-6man-ipv6-alt-mark-02 (work in progress),
              October 2020.

Authors' Addresses

   Zhenbin Li
   Huawei Technologies
   Huawei Campus, No. 156 Beiqing Road
   Beijing  100095
   China

   Email: lizhenbin@huawei.com

   Jie Dong
   Huawei Technologies
   Huawei Campus, No. 156 Beiqing Road
   Beijing  100095
   China

   Email: jie.dong@huawei.com

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