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Basic Support for IPv6 Networks Operating over 5G Vehicle-to-Everything Communications
draft-jeong-6man-ipv6-over-5g-v2x-00

Document Type Active Internet-Draft (individual)
Authors Jaehoon Paul Jeong , Bien Aime Mugabarigira , Yiwen Shen , Alexandre Petrescu , Sandra Cespedes
Last updated 2022-10-24
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draft-jeong-6man-ipv6-over-5g-v2x-00
6man Working Group                                         J. Jeong, Ed.
Internet-Draft                                           B. Mugabarigira
Intended status: Standards Track                 Sungkyunkwan University
Expires: 27 April 2023                                           Y. Shen
                                                    Kyungsung University
                                                             A. Petrescu
                                                                     CEA
                                                             S. Cespedes
                                                    Universidad de Chile
                                                         24 October 2022

Basic Support for IPv6 Networks Operating over 5G Vehicle-to-Everything
                             Communications
                  draft-jeong-6man-ipv6-over-5g-v2x-00

Abstract

   This document provides methods and settings for using IPv6 to
   communicate among nodes within range of one another over 5G V2X
   (i.e., the 5th generation vehicle-to-everything) links.  Support for
   these methods and settings require minimal changes to existing
   stacks.  This document also describes limitations associated with
   using these methods.  Optimizations and usage of IPv6 over more
   complex scenarios are not covered in this specification and are a
   subject for future work.

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 https://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 27 April 2023.

Copyright Notice

   Copyright (c) 2022 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 Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  Requirements Language . . . . . . . . . . . . . . . . . . . .   4
   4.  Overview of 5G V2X Communications . . . . . . . . . . . . . .   4
   5.  IPv6 over 5G V2X Links  . . . . . . . . . . . . . . . . . . .   6
     5.1.  Maximum Transmission Unit (MTU) . . . . . . . . . . . . .   6
     5.2.  Frame Format  . . . . . . . . . . . . . . . . . . . . . .   6
     5.3.  Link-Local Addresses  . . . . . . . . . . . . . . . . . .   6
     5.4.  Stateless Address Autoconfiguration . . . . . . . . . . .   7
     5.5.  Subnet Structure  . . . . . . . . . . . . . . . . . . . .   8
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   8
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   8
     8.2.  Informative References  . . . . . . . . . . . . . . . . .   9
   Appendix A.  Acknowledgments  . . . . . . . . . . . . . . . . . .  10
   Appendix B.  Contributors . . . . . . . . . . . . . . . . . . . .  10
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  10

1.  Introduction

   This document provides a baseline for using IPv6 in the hosts
   communicating with each other by the 5th generation new radio
   vehicle-to-everything (5G NR V2X) links [TS23303] [TS23304] defined
   by the 3rd generation partnership project (3GPP).  The baseline
   defined in this document has the minimal changes to existing stacks.
   Moreover, the document identifies the limitations of such usage.

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   The 3GPP has published the long-term evolution V2X (LTE V2X) in its
   Release 14 to support V2X communications using the Uu and PC5
   reference points for vehicle-to-infrastructure (V2I) and vehicle-to-
   vehicle (V2V), respectively.  In the recent development, the 5G NR
   V2X has also been proposed to enhance the existing and future V2X use
   cases.  Particularly, the 5G NR V2X improves the sidelink resource
   allocation and the handling of quality-of-service (QoS) in the
   current 5G networks, and beyond 5G networks, such as 6G networks.  It
   also extends the communication modes for UE over PC5 from broadcast
   mode to groupcast and unicast mode [TS24587].

   The motivation for this document is the service discovery that
   utilizes the specifications developed by 3GPP to enhance and broaden
   the connectivity in a vehicular environment.  As the 5G Core (5GC)
   and 5G New Radio (5G-NR) with 5G User Equipment (UE) are being
   deployed world wide, they can be of great importance in creating a
   connected network for moving objects such as automobiles,
   motorcycles, drones etc.

   However, for IPv6-based 5G V2X communications based on the 3GPP
   documents [TS23287] [TS24587] it is still not clear how the IPv6
   addresses are well configured for multi-hop 5G V2X networks.
   Particularly, when the Stateless Address Autoconfiguration (SLAAC)
   process is used in IPv6-based 5G V2X communications, a vehicle as an
   IPv6 router, which assigns an IPv6 prefix to another vehicle in
   SLAAC, shall be selected or determined.  For a scenario having ground
   moving vehicles, how to determine the IPv6 router for SLAAC is still
   not clear.  In addition, the 3GPP 5G V2X specifications discourage
   the use of the Duplicate Address Detection (DAD) [RFC4862] [RFC7527]
   and Neighbor Discover (ND) messages [RFC4861], which arises the
   concern of unusable IPv6-based 5G V2X services in the future.

   Thus this document offers the basic support for IPv6-based 5G NR V2X
   communications to enable application services such as infotainment
   and cooperative driving safety through the driving context
   information sharing.

                              +------------+
                              |   NG-RAN   |  Base Station
                              +------------+ (e.g., gNodeB)
                                    ^
                                    |
                                    Uu
                                    |
       +------------+         +------------+         +------------+
       | IP-VehUE A |<--PC5-->| IP-VehUE B |<--PC5-->|    UE C    |
       +------------+         +------------+         +------------+
            Car A                  Car B                Pedestrian

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                   Figure 1: 3GPP 5G NR V2X Architecture

2.  Terminology

   This document uses the terminology described in [RFC8691].  In
   addition, the following terms are defined below:

   *  IP-VehUE (Internet Protocol Vehicle User Equipment): It is a UE
      device mounted on a vehicle such as car, motorcycle, and scooter
      that operates based on 5G NR V2X services to transmit IPv6 data
      packets.  It can connect to the vehicle's internal networks.

   *  NG-RAN (Next Generation Radio Access Network) node: It is a base
      station node that provides user plane and control plane functions
      toward IP-VehUEs, and it also connects to 5GC networks.  It can be
      a gNodeB (gNB) in 5G NR or an ng-eNobdB (ng-eNB) in E-UTRA per the
      5G network definition [TS23501] [TS38300].

   *  5G NR-PC5 RP (5G New Radio PC5 Reference Point): The 5G NR-PC5 RP
      is referred to as communication links among IP-VehUEs (i.e., V2V).

   *  5G NR-Uu RP(5G New Radio Uu Reference Point): The 5G NR-Uu RP is
      referred to as communication links between an IP-VehUE and an NG-
      RAN node.

3.  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 BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

4.  Overview of 5G V2X Communications

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                           +-------------------+
                           |  UDP/TCP V2X App  |
                           +-------------------+
                                     |
                           +===================+
                           |       IPv6        |
                           +===================+
                                     |
                         +-----------------------+
                         |3GPP Underlying Layers |
                         |   +--------------+    |
                         |   |      SDAP    |    |
                         |   +--------------+    |
                         |           |           |
                         |   +--------------+    |
                         |   |      PDCP    |    |
                         |   +--------------+    |
                         |           |           |
                         |   +--------------+    |
                         |   |      RLC     |    |
                         |   +--------------+    |
                         |           |           |
                         |   +--------------+    |
                         |   |      MAC     |    |
                         |   +--------------+    |
                         |           |           |
                         |   +--------------+    |
                         |   |      PHY     |    |
                         |   +--------------+    |
                         +-----------------------+

     Figure 2: 3GPP IPv6-based 5G NR V2X Communications Protocol Stack

   A high-level system architecture for V2X communication over PC5 and
   Uu reference points is shown in Figure 1.  A modified sidelink
   interface allows IP-VehUEs to communicate with each other by the PC5
   RP.  An IP-VehUE can connect with a stationary NG-RAN through Uu
   interface.  Both communications among IP-VehUEs and between IP-VehUEs
   and NG-RAN mainly rely on the lower layers shown in Figure 2.

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   The 5G V2X communications support both IP and non-IP based message
   exchanges in unicast, broadcast, and groupcast modes per 3GPP
   documents [TS23287] [TS24587].  For the IPv6-based 5G V2X
   communications via PC5 RP, only IPv6 is used for the communications.
   In the unicast mode of IPv6-based 5G V2X by PC5 RP, an IP-VehUE uses
   either the IPv6 Stateless Address Autoconfiguration (SLAAC) process
   or the IPv6 link-local addresses to generate usable IP addresses
   [RFC4862].

   *  When using SLAAC, an IP-VehUE uses an IPv6 prefix sent by another
      IP-VehUE acting as an IPv6 default router.

   *  When using IPv6 link-local addresses, an IP-VehUE forms the link-
      local addresses locally without Duplicate Address Detection (DAD)
      [TS23287].

   In the broadcast and groupcast modes of 5G V2X over PC5 RP, an IP-
   VehUE configures a link-local IPv6 address as the source IP address.
   The configuration of the link-local IPv6 address does not send
   Neighbor Solicitation (NS) and Neighbor Advertisement (NA) messages
   for DAD per the 3GPP document [TS23287].

5.  IPv6 over 5G V2X Links

5.1.  Maximum Transmission Unit (MTU)

   The V2X standard based on the 5G NR air interface introduced advanced
   functionalities to support connected and automated driving.  The
   default MTU for IP packets on 5G NR V2X links over both PC5 and Uu
   RPs is inherited from [RFC2464], which is 1500 octets.  Also as
   defined in [RFC8200], the 5G NR V2X links must offer a minimum MTU of
   1280 octets to the IP layer and IP packets on those links must follow
   other IPv6 recommendations, especially with regard to fragmentation.

5.2.  Frame Format

   As shown in Figure 2, the IP packets over 5G V2X links follow the
   general frame format according to the protocol stack defined by 3GPP.

5.3.  Link-Local Addresses

   The IPv6-based 5G V2X communications use link-local addresses for IP
   packets.  IPv6 addresses are assigned enabling the establishment of
   communication in and out of the subnet.  To avoid conflicts between
   link local address in wireless vehicle networks, the interface
   identifier used by each IP-VehUE is ensured to be unique through
   addressing.  There are several types of IPv6 addresses [RFC4291]
   [RFC4193] that may be assigned to a 5G NR V2X interface.

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5.4.  Stateless Address Autoconfiguration

   This section suggests the extension over 5G V2X links to enable SLAAC
   process for a multi-hop communication scenario.

                           +---------------------+
                           |  Mobility Function  |
                           +---------------------+
                                  ^
                                  |
                                  Un
                                  |
    +------------+        +------------+        +---------------+
    |  NG-RAN  A |<--Xn-->|  NG-RAN  B |<--Xn-->|  NG-RAN  C    |
    +------------+        +------------+        +---------------+
          |                       |                      |
          Uu                      Uu                     Uu
          |                       |                      |
    +-----------------------------------------+   +------------------+
    |                                         |   |                  |
    |  +------------+         +------------+  |   |  +------------+  |
    |  | IP-VehUE A |<--PC5-->| IP-VehUE B |<--PC5-->|   UE C     |  |
    |  +------------+         +------------+  |   |  +------------+  |
    |     Car A                  Car B        |   |    Pedestrian    |
    +-----------------------------------------+   +------------------+
                     Subnet 1                           Subnet 2

              Figure 3: 3GPP 5G NR V2X Networking Architecture

   To enable a reachability of moving nodes across different subnets, an
   address registration is defined [RFC4862].  Links among moving IP-
   VehUEs (i.e., electric scooter, unmanned aerial vehicles, and
   connected cars) through optimized address registration and a multi-
   hop DAD mechanism need to be conducted.

   A dynamic IPv6 address given by the stateless address
   autoconfiguration is used for forwarding the packet domain and packet
   forwarding in a subnetwork.  The hight mobility features in a 5G-NR
   vehicular network requires a persistent connection to ensure
   communication.  In the highway scenario, vehicular ad hoc networks
   (VANET) where IP-VehUEs wirelessly interconnect, improve
   communication efficiency.  The details of neighbor discovery are
   addressed in [I-D.jeong-ipwave-vehicular-neighbor-discovery] and the
   mobility management handling strategies are address in
   [I-D.jeong-ipwave-vehicular-mobility-management] as well.

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5.5.  Subnet Structure

   The network structure stated in Figure 3 follows the specifications
   defined in [I-D.jeong-ipwave-vehicular-neighbor-discovery].  Among
   the three NG-RAN deployed, two are deployed in same the subnet 1 and
   NG-RAN C is in a different subnet 2.  An IP-VehUE establishes a
   connection in the coverage of an NG-RAN, and to enable a handover
   between two NG-RANs, a multi-link subnet is involved.  The
   internetworking within subnetworks is done through IP router (i.e.,
   NG-RAN).

   IP-VehUE addresses with IPV6 prefixes belonging to the same
   subnetwork are specified using SLAAC.

6.  Security Considerations

   This section will be expanded in future versions of the draft.

7.  IANA Considerations

   This document does not require any IANA actions.

8.  References

8.1.  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>.

   [RFC2464]  Crawford, M., "Transmission of IPv6 Packets over Ethernet
              Networks", RFC 2464, DOI 10.17487/RFC2464, December 1998,
              <https://www.rfc-editor.org/info/rfc2464>.

   [RFC4291]  Hinden, R. and S. Deering, "IP Version 6 Addressing
              Architecture", RFC 4291, DOI 10.17487/RFC4291, February
              2006, <https://www.rfc-editor.org/info/rfc4291>.

   [RFC4861]  Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
              "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
              DOI 10.17487/RFC4861, September 2007,
              <https://www.rfc-editor.org/info/rfc4861>.

   [RFC4862]  Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
              Address Autoconfiguration", RFC 4862,
              DOI 10.17487/RFC4862, September 2007,
              <https://www.rfc-editor.org/info/rfc4862>.

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   [RFC7527]  Asati, R., Singh, H., Beebee, W., Pignataro, C., Dart, E.,
              and W. George, "Enhanced Duplicate Address Detection",
              RFC 7527, DOI 10.17487/RFC7527, April 2015,
              <https://www.rfc-editor.org/info/rfc7527>.

   [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>.

   [RFC8691]  Benamar, N., Härri, J., Lee, J., and T. Ernst, "Basic
              Support for IPv6 Networks Operating Outside the Context of
              a Basic Service Set over IEEE Std 802.11", RFC 8691,
              DOI 10.17487/RFC8691, December 2019,
              <https://www.rfc-editor.org/info/rfc8691>.

8.2.  Informative References

   [TS23287]  3GPP, "Architecture enhancements for 5G System (5GS) to
              support Vehicle-to-Everything (V2X) services", TS 23.287
              V17.1.0, September 2022,
              <https://www.3gpp.org/DynaReport/23287.htm>.

   [TS23303]  3GPP, "Proximity-based services (ProSe); Stage 2",
              TS 23.303 V17.0.0, December 2021,
              <https://www.3gpp.org/DynaReport/23303.htm>.

   [TS23304]  3GPP, "Proximity based Services (ProSe) in the 5G System
              (5GS)", TS 23.304 V17.4.0, September 2022,
              <https://www.3gpp.org/DynaReport/23304.htm>.

   [TS23501]  3GPP, "System Architecture for the 5G System (5GS); Stage
              2", TS 23.501 V17.6.0, September 2022,
              <https://www.3gpp.org/DynaReport/23501.htm>.

   [TS24587]  3GPP, "Vehicle-to-Everything (V2X) services in 5G System
              (5GS); Stage 3", TS 24.587 V17.3.0, September 2022,
              <https://www.3gpp.org/DynaReport/24587.htm>.

   [TS38300]  3GPP, "NR; NR and NG-RAN Overall description; Stage 2",
              TS 38.300 V17.2.0, September 2022,
              <https://www.3gpp.org/DynaReport/38300.htm>.

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   [RFC4193]  Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast
              Addresses", RFC 4193, DOI 10.17487/RFC4193, October 2005,
              <https://www.rfc-editor.org/info/rfc4193>.

   [I-D.jeong-ipwave-vehicular-neighbor-discovery]
              Jeong, J. P., Shen, Y. C., Kwon, J., and S. Cespedes,
              "Vehicular Neighbor Discovery for IP-Based Vehicular
              Networks", Work in Progress, Internet-Draft, draft-jeong-
              ipwave-vehicular-neighbor-discovery-14, 25 July 2022,
              <https://www.ietf.org/archive/id/draft-jeong-ipwave-
              vehicular-neighbor-discovery-14.txt>.

   [I-D.jeong-ipwave-vehicular-mobility-management]
              Jeong, J. P., Mugabarigira, B. A., Shen, Y. C., and H.
              Jung, "Vehicular Mobility Management for IP-Based
              Vehicular Networks", Work in Progress, Internet-Draft,
              draft-jeong-ipwave-vehicular-mobility-management-08, 25
              July 2022, <https://www.ietf.org/archive/id/draft-jeong-
              ipwave-vehicular-mobility-management-08.txt>.

Appendix A.  Acknowledgments

   This work was supported by Institute of Information & Communications
   Technology Planning & Evaluation (IITP) grant funded by the Korea
   Ministry of Science and ICT (MSIT)(No. 2022-0-01015, Development of
   Candidate Element Technology for Intelligent 6G Mobile Core Network).

   This work was supported in part by Institute of Information &
   Communications Technology Planning & Evaluation (IITP) grant funded
   by the Korea Ministry of Science and ICT (MSIT) (No. 2022-0-01199,
   Regional strategic industry convergence security core talent training
   business).

Appendix B.  Contributors

   The following are co-authors of this document:

   Hyeongah Jung - Department of Computer Science & Engineering,
   Sungkyunkwan University, 2066 Seobu-Ro, Jangan-Gu, Suwon, Gyeonggi-Do
   16419, Republic of Korea.  Phone: +82 31 299 4106, Fax: +82 31 290
   7996, EMail: hyeonah214@skku.edu, URI: http://iotlab.skku.edu/people-
   Hyeonah-Jung.php

Authors' Addresses

   Jaehoon Paul Jeong (editor)
   Department of Computer Science and Engineering
   Sungkyunkwan University

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   2066 Seobu-Ro, Jangan-Gu
   Suwon
   Gyeonggi-Do
   16419
   Republic of Korea
   Phone: +82 31 299 4957
   Email: pauljeong@skku.edu
   URI:   http://iotlab.skku.edu/people-jaehoon-jeong.php

   Bien Aime Mugabarigira
   Department of Electical and Computer Engineering
   Sungkyunkwan University
   2066 Seobu-Ro, Jangan-Gu
   Suwon
   Gyeonggi-Do
   16419
   Republic of Korea
   Phone: +82 31 299 4106
   Email: bienaime@skku.edu
   URI:   http://iotlab.skku.edu/people-Bien-Aime.php

   Yiwen Chris Shen
   School of Global Studies
   Kyungsung University
   309, Suyeong-ro, Nam-gu
   Busan
   48434
   Republic of Korea
   Phone: +82 51 663 5270
   Email: chrisshen@ks.ac.kr
   URI:   https://chrisshen.github.io/

   Alexandre Petrescu
   CEA
   CEA Saclay
   Gif-sur-Yvette, Ile-de-France
   91190 Paris
   France
   Phone: +33 169089223
   Email: Alexandre.Petrescu@cea.fr

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   Sandra Cespedes
   Universidad de Chile
   Av. Tupper 2007
   8370451 Santiago
   Chile
   Phone: +56 2 29784093
   Email: scespede@niclabs.cl
   URI:   http://scespedes.cl

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