IPWAVE Working Group Z. Yan Internet-Draft CNNIC Intended status: Standards Track J. Lee Expires: May 20, 2020 Sangmyung University J. Jeong Sungkyunkwan University November 17, 2019 Neighbor Vehicle Discovery and Service in IP-Based Vehicular Networks draft-yan-ipwave-nd-05.txt Abstract For Cooperative Adaptive Cruise Control (C-ACC), platooning and other typical use cases in ITS, direct IP communication between neighbor vehicles poses the following two issues: 1) how to discover a neighbor vehicle and the demanded service; and 2) how to discover the link-layer address of the neighbor vehicle and selected server. This document presents a solution to these problems based on DNS-SD/mDNS [RFC6762][RFC6763]. 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. 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 May 20, 2020. Yan, et al. Expires May 20, 2020 [Page 1] Internet-Draft ITS ND November 2019 Copyright Notice Copyright (c) 2019 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) 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. Prefix management . . . . . . . . . . . . . . . . . . . . . . 3 3. Name configuration . . . . . . . . . . . . . . . . . . . . . 3 4. Address configuration . . . . . . . . . . . . . . . . . . . . 4 5. Neighbor vehicle and service discovery . . . . . . . . . . . 4 6. Mobility support . . . . . . . . . . . . . . . . . . . . . . 5 7. Signaling messages . . . . . . . . . . . . . . . . . . . . . 6 8. Security considerations . . . . . . . . . . . . . . . . . . . 6 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 9.1. Normative References . . . . . . . . . . . . . . . . . . 6 9.2. Informative References . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 1. Introduction As illustrated in [DNS-Autoconf], a naming scheme is needed for the vehicle devices to support the unique name auto-configuration. This can support the location based communicaton and scalable information organization in Intelligent Transportation Systems (ITS). Based on the naming scheme like this and the widely-used DNS-SD/mDNS protocol, this document illustrates how to discover a neighbor vehicle or the required services with DNS resolution logic. Before this, we make the following assumptions: o Name: A vehicle SHOULD have a temporary name which is related to its geo-location. o Address: A vehicle SHOULD have a global IP address which is routeable for the IP communications. Yan, et al. Expires May 20, 2020 [Page 2] Internet-Draft ITS ND November 2019 In this way, a standardized, efficient and scalable scheme can be used to retrieve the necessary information of the corresponding node (domain name, IP address, goe-location, link-local address and so on) for the further communications based on the DNS-SD/mDNS function. In addition, the IPv6 Neighbor Discovery (ND)'s messages (e.g., RA and RS messages) can also be used to exchange some required information (e.g., mobile network prefixes and link-local address) in ITS in combination with DNS-SD/mDNS [MNPP]. 2. Prefix management The network architecture which illustrates the prefix management of name and address is shown in Figure 1. +------------+ +**********+ +------------+ | Router1 |--------* Internet *--------| Router2 | |[IP-Prefix1]| +**********+ |[IP-Prefix2]| +------------+ +------------+ | | | | ----------- ----------- | | | | | | | | +-------+ +-------+ +-------+ +-------+ | RSU1 | | RSU2 | | RSU3 | | RSU4 | |[Name1]| |[Name2]| |[Name3]| |[Name4]| +-------+ +-------+ +-------+ +-------+ +-------+ |Vehicle|--------moving----------> +-------+ Figure 1: Name and address management architecture As shown in Figure 1, Router1 and Router2 are two routers which can connect to the Internet and they hold different IP prefixes. RSU1 and RSU2 are two Road-Side Units (RSUs) under Router1 but hold different name prefixes, while RSU3 and RSU4 are two RSUs under Router2 but hold different name prefixes. 3. Name configuration The RSU acts as an access router for the static and moving vehicles which want to be connected with the Internet. Based on [RFC3646], [RFC6106] or extended WAVE Service Announcement (WSA) message, the RSU can announce its location based name prefix to the vehicles covered by the RSU. This location based prefix may contain information such as country, city, street and so on, which will act Yan, et al. Expires May 20, 2020 [Page 3] Internet-Draft ITS ND November 2019 as the "domain_name" of the vehicle device name as spefified in [DNS- Autoconf]. 4. Address configuration The RSU may advertise the IP prefix to support the IPv6 Stateless Address Autoconfiguration (SLAAC) operation of vehicle devices and movement detection (in the IP layer). If the DHCP is used for the address configuration, RSU also acts as functional entity such as a DHCP proxy and DHCP server. 5. Neighbor vehicle and service discovery (1) RSU based Vehicles may have direct connection with the serving RSU and join the same link with the serving RSU. Then the RSU can maintain the registered vehicle or service in its serving domain. Otherwise, the RSU acts as a relay node for discovering in a proxy manner. When a vehicle wants to locate the potential nearby neighbor and further establish the communication, the vehicle will trigger the direct unicast query to port 5353 or legacy unicast DNS query to the RSU. RSU may respond directly if it has the related information, otherwise, the RSU multicasts the DNS query to the multicast group to retrieve the related information. A unicast response is the first recommendation here because it can suppress the flooding, but of course, the DNS response message can also be multicasted as an active announcement of the verhicle or service existence. (2) Ad-hoc based Vehicles may communicate with each other or sense the front and rear neighbor vehicles with DSRC, WiFi, Bluetooth or other short-distance communication technologies, connecting each other in the Ad-hoc manner. Then the discovery can be executed in an infrastructure-less manner with the following phases, as specified in mDNS. o Probing: When a vehicle starts up, wakes up from sleeping mode or the Vehicular Ad Hoc Networks (VANET) topology changes (after configuration of the name and address), it should probe the availability of the service with which it can provide other vehicles. Then the vehicle periodically announces the service and its existence with unsolicited multicast DNS response containing, in the Answer Section, all of its service name, DNS name, IP address and other information. The vehicle also updates the related information actively if there is any change. Yan, et al. Expires May 20, 2020 [Page 4] Internet-Draft ITS ND November 2019 o Discovering: To support the service and neighbor vehicle discovery in the dynamic and fragmentation-possible environment in VANET, different query modes of mDNS can be used for different scenarios: 1) One-Short Multicast DNS Query can be used to locate a specific vehicle. 2) Continuous Multicast DNS Query can be used to locate the nearby vehicles which are moving. o Refreshing: After the neighbor discovery as illustrated above, the vehicles should continually exchange their DNS name, IP address, geo-location and other information in order to refresh the established communications. For example, the Multiple Questions Multicast Responses can be used to update the caches of receivers efficiently and Multiple Questions Unicast Responses can be used to support the fast bootstrapping when a new vehicle joins. o Goodbye: When the vehicle arrives at its destination, stops temporarily or shuts down its communication or sensing devices, it will announce the service suspending and its inexistence with an unsolicited multicast DNS response packet, giving the same Resource Records (RRs) (containing its DNS name and IP address), but with zero Time-To-Live (TTL). 6. Mobility support During the movement of the vehicle, it may cross different RSUs. When a vehicle enters the communication coverage of a new RSU, the new domain prefix and new IP prefix may be learned. Generally, there are two main cases for the mobility: o The domain name changes and the IP prefix remains, as shown in Figure 1, the vehicle moves from the coverage of RSU1 to the coverage of RSU2. The vehicle will configure a new DNS name from RSU2 and may update the new DNS name in the local database (e.g., RSU). But the vehicle should keep its previous DNS name for a while until that all the communicating neighbors have learned its new DNS name. During this duration, the vehicle will contain both the previous and new DNS names in the DNS response message. o Both the domain name and IP prefix change, as shown in Figure 1, the vehicle performs a handover from RSU2 to RSU3. The vehicle will configure both its new DNS name and new IP address from RSU3 and update them in the local database. Then the above scheme can also be used or with IP-layer mobility management protocols (e.g., Mobile IPv6 [RFC6275] and Proxy Mobile IPv6 [RFC5213]). Yan, et al. Expires May 20, 2020 [Page 5] Internet-Draft ITS ND November 2019 7. Signaling messages To facilitate the further communication, the link-layer address and geo-information may be included in the DNS message in a piggyback manner. Otherwise, this information may be obtained through the following IPv6 Neighbor Discovery Protocol (NDP) or other procedures (e.g., DHCP and WSA). 8. Security considerations In order to reduce the DNS traffic on the wireless link and avoid the unnecessary flooding, the related schemes in mDNS can be used, such as: Known-Answer Suppression, Multipacket Known-Answer Suppression, Duplicate Question Suppression and Duplicate Answer Suppression. In order to guarantee the origination of the DNS message and avoid the DNS message tampering, the security consideration in mDNS should also be adopted. 9. References 9.1. 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, . [RFC3646] Droms, R., Ed., "DNS Configuration options for Dynamic Host Configuration Protocol for IPv6 (DHCPv6)", RFC 3646, DOI 10.17487/RFC3646, December 2003, . [RFC5213] Gundavelli, S., Ed., Leung, K., Devarapalli, V., Chowdhury, K., and B. Patil, "Proxy Mobile IPv6", RFC 5213, DOI 10.17487/RFC5213, August 2008, . [RFC6106] Jeong, J., Park, S., Beloeil, L., and S. Madanapalli, "IPv6 Router Advertisement Options for DNS Configuration", RFC 6106, DOI 10.17487/RFC6106, November 2010, . [RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July 2011, . Yan, et al. Expires May 20, 2020 [Page 6] Internet-Draft ITS ND November 2019 [RFC6762] Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762, DOI 10.17487/RFC6762, February 2013, . [RFC6763] Cheshire, S. and M. Krochmal, "DNS-Based Service Discovery", RFC 6763, DOI 10.17487/RFC6763, February 2013, . 9.2. Informative References [DNS-Autoconf] Jeong, J., Lee, S., and J. Park, "DNS Name Autoconfiguration for Internet-of-Things Devices in IP- Based Vehicular Networks", draft-jeong-ipwave-iot-dns- autoconf-07, November 2019. [MNPP] Lee, J., Tsukada, M., and T. Ernst, "Mobile Network Prefix Provisioning", draft-jhlee-mext-mnpp-00, October 2009. Authors' Addresses Zhiwei Yan CNNIC No.4 South 4th Street, Zhongguancun Beijing 100190 China EMail: yan@cnnic.cn Jong-Hyouk Lee Sangmyung University 31, Sangmyeongdae-gil, Dongnam-gu Cheonan Republic of Korea EMail: jonghyouk@smu.ac.kr Jaehoon Paul Jeong Department of Computer Science and Engineering Sungkyunkwan University 2066 Seobu-Ro, Jangan-Gu Suwon, Gyeonggi-Do Republic of Korea EMail: pauljeong@skku.edu Yan, et al. Expires May 20, 2020 [Page 7]