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. Jeong, et al. Expires 27 April 2023 [Page 1] Internet-Draft IPv6 over 5G V2X October 2022 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. Jeong, et al. Expires 27 April 2023 [Page 2] Internet-Draft IPv6 over 5G V2X October 2022 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 Jeong, et al. Expires 27 April 2023 [Page 3] Internet-Draft IPv6 over 5G V2X October 2022 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 Jeong, et al. Expires 27 April 2023 [Page 4] Internet-Draft IPv6 over 5G V2X October 2022 +-------------------+ | 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. Jeong, et al. Expires 27 April 2023 [Page 5] Internet-Draft IPv6 over 5G V2X October 2022 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. Jeong, et al. Expires 27 April 2023 [Page 6] Internet-Draft IPv6 over 5G V2X October 2022 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. Jeong, et al. Expires 27 April 2023 [Page 7] Internet-Draft IPv6 over 5G V2X October 2022 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, . [RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet Networks", RFC 2464, DOI 10.17487/RFC2464, December 1998, . [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing Architecture", RFC 4291, DOI 10.17487/RFC4291, February 2006, . [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, . [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless Address Autoconfiguration", RFC 4862, DOI 10.17487/RFC4862, September 2007, . Jeong, et al. Expires 27 April 2023 [Page 8] Internet-Draft IPv6 over 5G V2X October 2022 [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, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6) Specification", STD 86, RFC 8200, DOI 10.17487/RFC8200, July 2017, . [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, . 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, . [TS23303] 3GPP, "Proximity-based services (ProSe); Stage 2", TS 23.303 V17.0.0, December 2021, . [TS23304] 3GPP, "Proximity based Services (ProSe) in the 5G System (5GS)", TS 23.304 V17.4.0, September 2022, . [TS23501] 3GPP, "System Architecture for the 5G System (5GS); Stage 2", TS 23.501 V17.6.0, September 2022, . [TS24587] 3GPP, "Vehicle-to-Everything (V2X) services in 5G System (5GS); Stage 3", TS 24.587 V17.3.0, September 2022, . [TS38300] 3GPP, "NR; NR and NG-RAN Overall description; Stage 2", TS 38.300 V17.2.0, September 2022, . Jeong, et al. Expires 27 April 2023 [Page 9] Internet-Draft IPv6 over 5G V2X October 2022 [RFC4193] Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast Addresses", RFC 4193, DOI 10.17487/RFC4193, October 2005, . [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, . [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, . 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 Jeong, et al. Expires 27 April 2023 [Page 10] Internet-Draft IPv6 over 5G V2X October 2022 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 Jeong, et al. Expires 27 April 2023 [Page 11] Internet-Draft IPv6 over 5G V2X October 2022 Sandra Cespedes Universidad de Chile Av. Tupper 2007 8370451 Santiago Chile Phone: +56 2 29784093 Email: scespede@niclabs.cl URI: http://scespedes.cl Jeong, et al. Expires 27 April 2023 [Page 12]