--- 1/draft-ietf-ipwave-vehicular-networking-07.txt 2019-03-24 05:13:43.057133171 -0700 +++ 2/draft-ietf-ipwave-vehicular-networking-08.txt 2019-03-24 05:13:43.137135106 -0700 @@ -1,153 +1,152 @@ IPWAVE Working Group J. Jeong, Ed. Internet-Draft Sungkyunkwan University -Intended status: Informational November 4, 2018 -Expires: May 8, 2019 +Intended status: Informational March 24, 2019 +Expires: September 25, 2019 IP Wireless Access in Vehicular Environments (IPWAVE): Problem Statement and Use Cases - draft-ietf-ipwave-vehicular-networking-07 + draft-ietf-ipwave-vehicular-networking-08 Abstract - This document discusses the problem statement and use cases on IP- - based vehicular networks, which are considered a key component of - Intelligent Transportation Systems (ITS). The main scenarios of - vehicular communications are vehicle-to-vehicle (V2V), vehicle-to- - infrastructure (V2I), and vehicle-to-everything (V2X) communications. - First, this document surveys use cases using V2V, V2I, and V2X - networking. Second, it analyzes proposed protocols for IP-based - vehicular networking and highlights the limitations and difficulties - found on those protocols. Third, it presents a problem exploration - for key aspects in IP-based vehicular networking, such as IPv6 - Neighbor Discovery, Mobility Management, and Security & Privacy. For - each key aspect, this document discusses a problem statement to - evaluate the gap between the state-of-the-art techniques and - requirements in IP-based vehicular networking. + This document discusses the problem statement and use cases of IP- + based vehicular networking for Intelligent Transportation Systems + (ITS). The main scenarios of vehicular communications are vehicle- + to-vehicle (V2V), vehicle-to-infrastructure (V2I), and vehicle-to- + everything (V2X) communications. First, this document surveys use + cases using V2V, V2I, and V2X networking. Second, it analyzes + proposed protocols for IP-based vehicular networking and highlights + the limitations and difficulties found on those protocols. Third, it + presents a problem exploration for key aspects in IP-based vehicular + networking, such as IPv6 Neighbor Discovery, Mobility Management, and + Security & Privacy. For each key aspect, this document discusses a + problem statement to evaluate the gap between the state-of-the-art + techniques and requirements in IP-based vehicular networking. 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 8, 2019. + This Internet-Draft will expire on September 25, 2019. Copyright Notice - Copyright (c) 2018 IETF Trust and the persons identified as the + 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 . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3.1. V2V . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 3.2. V2I . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 + 3.2. V2I . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3.3. V2X . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 4. Analysis for Existing Protocols . . . . . . . . . . . . . . . 8 4.1. Existing Protocols for Vehicular Networking . . . . . . . 8 - 4.1.1. IPv6 over 802.11-OCB . . . . . . . . . . . . . . . . 8 - 4.1.2. IP Address Autoconfiguration . . . . . . . . . . . . 8 - 4.1.3. Routing . . . . . . . . . . . . . . . . . . . . . . . 9 - 4.1.4. Mobility Management . . . . . . . . . . . . . . . . . 9 - 4.1.5. DNS Naming Service . . . . . . . . . . . . . . . . . 9 - 4.1.6. Service Discovery . . . . . . . . . . . . . . . . . . 9 - 4.1.7. Security and Privacy . . . . . . . . . . . . . . . . 10 - 4.2. General Problems . . . . . . . . . . . . . . . . . . . . 10 - 4.2.1. Vehicular Network Architecture . . . . . . . . . . . 11 - 4.2.2. Latency . . . . . . . . . . . . . . . . . . . . . . . 16 - 4.2.3. Security . . . . . . . . . . . . . . . . . . . . . . 16 - 4.2.4. Pseudonym Handling . . . . . . . . . . . . . . . . . 16 - 5. Problem Exploration . . . . . . . . . . . . . . . . . . . . . 17 - 5.1. Neighbor Discovery . . . . . . . . . . . . . . . . . . . 17 - 5.1.1. Link Model . . . . . . . . . . . . . . . . . . . . . 17 - 5.1.2. MAC Address Pseudonym . . . . . . . . . . . . . . . . 18 - 5.1.3. Prefix Dissemination/Exchange . . . . . . . . . . . . 18 - 5.1.4. Routing . . . . . . . . . . . . . . . . . . . . . . . 18 - 5.2. Mobility Management . . . . . . . . . . . . . . . . . . . 19 - 5.3. Security and Privacy . . . . . . . . . . . . . . . . . . 20 - 6. Security Considerations . . . . . . . . . . . . . . . . . . . 20 - 7. Informative References . . . . . . . . . . . . . . . . . . . 21 - Appendix A. Relevant Topics to IPWAVE Working Group . . . . . . 29 - A.1. Vehicle Identity Management . . . . . . . . . . . . . . . 29 - A.2. Multihop V2X . . . . . . . . . . . . . . . . . . . . . . 29 - A.3. Multicast . . . . . . . . . . . . . . . . . . . . . . . . 29 - A.4. DNS Naming Services and Service Discovery . . . . . . . . 30 - A.5. IPv6 over Cellular Networks . . . . . . . . . . . . . . . 30 - A.5.1. Cellular V2X (C-V2X) Using 4G-LTE . . . . . . . . . . 30 - A.5.2. Cellular V2X (C-V2X) Using 5G . . . . . . . . . . . . 31 + 4.1.1. IP Address Autoconfiguration . . . . . . . . . . . . 8 + 4.1.2. Routing Protocol . . . . . . . . . . . . . . . . . . 9 + 4.1.3. Mobility Management . . . . . . . . . . . . . . . . . 10 + 4.1.4. DNS Naming Service . . . . . . . . . . . . . . . . . 11 + 4.1.5. Service Discovery . . . . . . . . . . . . . . . . . . 12 + 4.1.6. Security and Privacy . . . . . . . . . . . . . . . . 12 + 4.2. General Problems . . . . . . . . . . . . . . . . . . . . 13 + 4.2.1. Vehicular Network Architecture . . . . . . . . . . . 14 + 4.2.2. Latency . . . . . . . . . . . . . . . . . . . . . . . 19 + 4.2.3. Security . . . . . . . . . . . . . . . . . . . . . . 20 + 4.2.4. Pseudonym Handling . . . . . . . . . . . . . . . . . 20 + 5. Problem Exploration . . . . . . . . . . . . . . . . . . . . . 20 + 5.1. Neighbor Discovery . . . . . . . . . . . . . . . . . . . 20 + 5.1.1. Link Model . . . . . . . . . . . . . . . . . . . . . 21 + 5.1.2. MAC Address Pseudonym . . . . . . . . . . . . . . . . 22 + 5.1.3. Prefix Dissemination/Exchange . . . . . . . . . . . . 22 + 5.1.4. Routing . . . . . . . . . . . . . . . . . . . . . . . 22 + 5.2. Mobility Management . . . . . . . . . . . . . . . . . . . 23 + 5.3. Security and Privacy . . . . . . . . . . . . . . . . . . 24 + 6. Security Considerations . . . . . . . . . . . . . . . . . . . 24 + 7. Informative References . . . . . . . . . . . . . . . . . . . 25 + Appendix A. Relevant Topics to IPWAVE Working Group . . . . . . 33 + A.1. Vehicle Identity Management . . . . . . . . . . . . . . . 33 + A.2. Multihop V2X . . . . . . . . . . . . . . . . . . . . . . 33 + A.3. Multicast . . . . . . . . . . . . . . . . . . . . . . . . 33 + A.4. DNS Naming Services and Service Discovery . . . . . . . . 34 + A.5. IPv6 over Cellular Networks . . . . . . . . . . . . . . . 34 + A.5.1. Cellular V2X (C-V2X) Using 4G-LTE . . . . . . . . . . 34 + A.5.2. Cellular V2X (C-V2X) Using 5G . . . . . . . . . . . . 35 Appendix B. Changes from draft-ietf-ipwave-vehicular- - networking-06 . . . . . . . . . . . . . . . . . . . 31 - Appendix C. Acknowledgments . . . . . . . . . . . . . . . . . . 31 - Appendix D. Contributors . . . . . . . . . . . . . . . . . . . . 32 - Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 34 + networking-07 . . . . . . . . . . . . . . . . . . . 35 + Appendix C. Acknowledgments . . . . . . . . . . . . . . . . . . 35 + Appendix D. Contributors . . . . . . . . . . . . . . . . . . . . 36 + Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 38 1. Introduction - Vehicular networking studies have mainly focused on driving safety, - driving efficiency, and entertainment in road networks. The Federal - Communications Commission (FCC) in the US allocated wireless channels - for Dedicated Short-Range Communications (DSRC) [DSRC], service in - the Intelligent Transportation Systems (ITS) Radio Service in the - 5.850 - 5.925 GHz band (5.9 GHz band). DSRC-based wireless - communications can support vehicle-to-vehicle (V2V), vehicle-to- - infrastructure (V2I), and vehicle-to-everything (V2X) networking. - Also, the European Union (EU) passed a decision to allocate radio - spectrum for safety-related and non-safety-related applications of - ITS with the frequency band of 5.875 - 5.905 GHz, which is called - Commission Decision 2008/671/EC [EU-2008-671-EC]. + Vehicular networking studies have mainly focused on improving safety + and efficiency, and also enabling entertainment in vehicular + networks. The Federal Communications Commission (FCC) in the US + allocated wireless channels for Dedicated Short-Range Communications + (DSRC) [DSRC], service in the Intelligent Transportation Systems + (ITS) Radio Service in the 5.850 - 5.925 GHz band (5.9 GHz band). + DSRC-based wireless communications can support vehicle-to-vehicle + (V2V), vehicle-to-infrastructure (V2I), and vehicle-to-everything + (V2X) networking. Also, the European Union (EU) passed a decision to + allocate radio spectrum for safety-related and non-safety-related + applications of ITS with the frequency band of 5.875 - 5.905 GHz, + which is called Commission Decision 2008/671/EC [EU-2008-671-EC]. For direct inter-vehicular wireless connectivity, IEEE has amended WiFi standard 802.11 to enable driving safety services based on the DSRC in terms of standards for the Wireless Access in Vehicular - Environments (WAVE) system. L1 and L2 issues are addressed in IEEE - 802.11p [IEEE-802.11p] for the PHY and MAC of the DSRC, while IEEE - 1609.2 [WAVE-1609.2] covers security aspects, IEEE 1609.3 - [WAVE-1609.3] defines related services at network and transport - layers, and IEEE 1609.4 [WAVE-1609.4] specifies the multi-channel - operation. Note that IEEE 802.11p has been published as IEEE 802.11 - Outside the Context of a Basic Service Set (OCB) called IEEE - 802.11-OCB [IEEE-802.11-OCB] in 2012. + Environments (WAVE) system. The Physical Layer (L1) and Data Link + Layer (L2) issues are addressed in IEEE 802.11p [IEEE-802.11p] for + the PHY and MAC of the DSRC, while IEEE 1609.2 [WAVE-1609.2] covers + security aspects, IEEE 1609.3 [WAVE-1609.3] defines related services + at network and transport layers, and IEEE 1609.4 [WAVE-1609.4] + specifies the multi-channel operation. Note that IEEE 802.11p was a + separate standard, but was later enrolled into the base 802.11 + standard (IEEE 802.11-2012) as IEEE 802.11 Outside the Context of a + Basic Service Set in 2012 [IEEE-802.11-OCB]. Along with these WAVE standards, IPv6 [RFC8200] and Mobile IP - protocols (e.g., MIPv4 [RFC5944] and MIPv6 [RFC6275]) can be applied - (or easily modified) to vehicular networks. In Europe, ETSI has - standardized a GeoNetworking (GN) protocol [ETSI-GeoNetworking] and a - protocol adaptation sub-layer from GeoNetworking to IPv6 - [ETSI-GeoNetwork-IP]. Note that a GN protocol is useful to route an - event or notification message to vehicles around a geographic - position, such as an acciendent area in a roadway. In addition, ISO - has approved a standard specifying the IPv6 network protocols and - services to be used for Communications Access for Land Mobiles (CALM) - [ISO-ITS-IPv6]. + protocols (e.g., MIPv4 [RFC5944], MIPv6 [RFC6275], and Proxy MIPv6 + (PMIPv6) [RFC5213][RFC5844]) can be applied (or easily modified) to + vehicular networks. In Europe, ETSI has standardized a GeoNetworking + (GN) protocol [ETSI-GeoNetworking] and a protocol adaptation sub- + layer from GeoNetworking to IPv6 [ETSI-GeoNetwork-IP]. Note that a + GN protocol is useful to route an event or notification message to + vehicles around a geographic position, such as an acciendent area in + a roadway. In addition, ISO has approved a standard specifying the + IPv6 network protocols and services to be used for Communications + Access for Land Mobiles (CALM) [ISO-ITS-IPv6]. This document discusses problem statements and use cases related to IP-based vehicular networking for Intelligent Transportation Systems (ITS), which is denoted as IP Wireless Access in Vehicular Environments (IPWAVE). First, it surveys the use cases for using V2V, V2I, and V2X networking in the ITS. Second, for literature review, it analyzes proposed protocols for IP-based vehicular networking and highlights the limitations and difficulties found on those protocols. Third, for problem statement, it presents a problem exploration with key aspects in IPWAVE, such as IPv6 Neighbor @@ -159,66 +158,76 @@ Multihop V2X Communications, Multicast, DNS Naming Services, Service Discovery, and IPv6 over Cellular Networks. Therefore, with the problem statement, this document will open a door to develop key protocols for IPWAVE that will be essential to IP-based vehicular networks. 2. Terminology This document uses the following definitions: - o WAVE: Acronym for "Wireless Access in Vehicular Environments" - [WAVE-1609.0]. - o DMM: Acronym for "Distributed Mobility Management" [RFC7333][RFC7429]. - o Road-Side Unit (RSU): A node that has physical communication - devices (e.g., DSRC, Visible Light Communication, 802.15.4, LTE- - V2X, etc.) for wireless communications with vehicles and is also - connected to the Internet as a router or switch for packet - forwarding. An RSU is typically deployed on the road - infrastructure, either at an intersection or in a road segment, - but may also be located in car parking area. + o LiDAR: Acronym for "Light Detection and Ranging". It is a + scanning device to measure a distance to an object by emitting + pulsed laser light and measuring the reflected pulsed light. - o On-Board Unit (OBU): A node that has a DSRC device for wireless - communications with other OBUs and RSUs, and may be connected to - in-vehicle devices or networks. An OBU is mounted on a vehicle. - It is assumed that a radio navigation receiver (e.g., Global - Positioning System (GPS)) is included in a vehicle with an OBU for - efficient navigation. + o Mobility Anchor (MA): A node that maintains IP addresses and + mobility information of vehicles in a road network to support + their address autoconfiguration and mobility management with a + binding table. It has end-to-end connections with RSUs under its + control. - o Vehicle Detection Loop (or Loop Detector): An inductive device - used for detecting vehicles passing or arriving at a certain - point, for instance approaching a traffic light or in motorway - traffic. The relatively crude nature of the loop's structure - means that only metal masses above a certain size are capable of - triggering the detection. + o On-Board Unit (OBU): A node that has (e.g., IEEE 802.11-OCB and + Cellular V2X (C-V2X) [TS-23.285-3GPP]) for wireless communications + with other OBUs and RSUs, and may be connected to in-vehicle + devices or networks. An OBU is mounted on a vehicle. It is + assumed that a radio navigation receiver (e.g., Global Positioning + System (GPS)) is included in a vehicle with an OBU for efficient + navigation. - o Mobility Anchor (MA): A node that maintains IP addresses and - mobility information of vehicles in a road network to support the - address autoconfiguration and mobility management of them. It has - end-to-end connections with RSUs under its control. It maintains - a DAD table having the IP addresses of the vehicles moving within - the communication coverage of its RSUs. + o OCB: Acronym for "Outside the Context of a Basic Service Set" + [IEEE-802.11-OCB]. - o Vehicular Cloud: A cloud infrastructure for vehicular networks, - having compute nodes, storage nodes, and network nodes. + o Road-Side Unit (RSU): A node that has physical communication + devices (e.g., IEEE 802.11-OCB and C-V2X) for wireless + communications with vehicles and is also connected to the Internet + as a router or switch for packet forwarding. An RSU is typically + deployed on the road infrastructure, either at an intersection or + in a road segment, but may also be located in car parking area. o Traffic Control Center (TCC): A node that maintains road infrastructure information (e.g., RSUs, traffic signals, and loop detectors), vehicular traffic statistics (e.g., average vehicle speed and vehicle inter-arrival time per road segment), and vehicle information (e.g., a vehicle's identifier, position, direction, speed, and trajectory as a navigation path). TCC is included in a vehicular cloud for vehicular networks. + o Vehicular Cloud: A cloud infrastructure for vehicular networks, + having compute nodes, storage nodes, and network nodes. + + o Vehicle Detection Loop (or Loop Detector): An inductive device + used for detecting vehicles passing or arriving at a certain + point, for instance approaching a traffic light or in motorway + traffic. The relatively crude nature of the loop's structure + means that only metal masses above a certain size are capable of + triggering the detection. + + o V2I2P: Acronym for "Vehicle to Infrastructure to Pedestrian". + + o V2I2V: Acronym for "Vehicle to Infrastructure to Vehicle". + + o WAVE: Acronym for "Wireless Access in Vehicular Environments" + [WAVE-1609.0]. + 3. Use Cases This section provides use cases of V2V, V2I, and V2X networking. The use cases of the V2X networking exclude the ones of the V2V and V2I networking, but include Vehicle-to-Pedestrian (V2P) and Vehicle-to- Device (V2D). 3.1. V2V The use cases of V2V networking discussed in this section include @@ -241,23 +249,23 @@ neighboring vehicles relevant to possible collisions in real-time through V2V networking. CASD provides vehicles with a class-based automatic safety action plan, which considers three situations, such as the Line-of-Sight unsafe, Non-Line-of-Sight unsafe and safe situations. This action plan can be performed among vehicles through V2V networking. Cooperative Adaptive Cruise Control (CACC) [CA-Cruise-Control] helps vehicles to adapt their speed autonomously through V2V communication among vehicles according to the mobility of their predecessor and - successor vehicles in an urban roadway or a highway. CACC can help - adjacent vehicles to efficiently adjust their speed in a cascade way - through V2V networking. + successor vehicles in an urban roadway or a highway. Thus, CACC can + help adjacent vehicles to efficiently adjust their speed in an + interactive way through V2V networking in order to avoid collision. Platooning [Truck-Platooning] allows a series of vehicles (e.g., trucks) to move together with a very short inter-distance. Trucks can use V2V communication in addition to forward sensors in order to maintain constant clearance between two consecutive vehicles at very short gaps (from 3 meters to 10 meters). This platooning can maximize the throughput of vehicular traffic in a highway and reduce the gas consumption because the leading vehicle can help the following vehicles to experience less air resistance. @@ -281,24 +289,24 @@ o Navigation service; o Energy-efficient speed recommendation service; o Accident notification service. A navigation service, such as the Self-Adaptive Interactive Navigation Tool (called SAINT) [SAINT], using V2I networking interacts with TCC for the large-scale/long-range road traffic optimization and can guide individual vehicles for appropriate - navigation paths in real time. The enhanced SAINT (called SAINT+) - [SAINTplus] can give the fast moving paths for emergency vehicles - (e.g., ambulance and fire engine) toward accident spots while - providing other vehicles with efficient detour paths. + navigation paths in real time. The enhanced version of SAINT + [SAINTplus] can give the fast moving paths to emergency vehicles + (e.g., ambulance and fire engine) to let them reach accident spots + while providing other vehicles with efficient detour paths. A TCC can recommend an energy-efficient speed to a vehicle driving in different traffic environments. [Fuel-Efficient] studies fuel- efficient route and speed plans for platooned trucks. The emergency communication between accident vehicles (or emergency vehicles) and TCC can be performed via either RSU or 4G-LTE networks. The First Responder Network Authority (FirstNet) [FirstNet] is provided by the US government to establish, operate, and maintain an interoperable public safety broadband network for safety and security @@ -333,553 +341,727 @@ for collision avoidance. 4. Analysis for Existing Protocols 4.1. Existing Protocols for Vehicular Networking We describe some currently existing protocols and proposed solutions with respect to the following aspects that are relevant and essential for vehicular networking: - o IPv6 over 802.11-OCB; - o IP address autoconfiguration; - o Routing; + o Routing protocol; o Mobility management; o DNS naming service; o Service discovery; o Security and privacy. -4.1.1. IPv6 over 802.11-OCB - - For IPv6 packets transporting over IEEE 802.11-OCB, - [IPv6-over-802.11-OCB] specifies several details, such as Maximum - Transmission Unit (MTU), frame format, link-local address, address - mapping for unicast and multicast, stateless autoconfiguration, and - subnet structure. Especially, an Ethernet Adaptation (EA) layer is - in charge of transforming some parameters between IEEE 802.11 MAC - layer and IPv6 network layer, which is located between IEEE - 802.11-OCB's logical link control layer and IPv6 network layer. - -4.1.2. IP Address Autoconfiguration +4.1.1. IP Address Autoconfiguration For IP address autoconfiguration, Fazio et al. proposed a vehicular address configuration (VAC) scheme using DHCP where elected leader- vehicles provide unique identifiers for IP address configurations in vehicles [Address-Autoconf]. Kato et al. proposed an IPv6 address assignment scheme using lane and position information [Address-Assignment]. Baldessari et al. proposed an IPv6 scalable address autoconfiguration scheme called GeoSAC for vehicular networks [GeoSAC]. Wetterwald et al. conducted for heterogeneous vehicular networks (i.e., employing multiple access technologies) a - comprehensive study of the cross-layer identities management, which + comprehensive study of the cross-layer identity management, which constitutes a fundamental element of the ITS architecture [Identity-Management]. -4.1.3. Routing + A server-based address autoconfiguration such as VAC + [Address-Autoconf] takes some delay for a vehicle to join a new + cluster (i.e., a connected VANET) and communicate with neighboring + vehicles. This delay may prevent vehicles from exchaning safety + messages with each other in a prompty way. It will be good for a + vehicle to maintain its IP address even when it joins another + cluster. A geographical-position-based address autoconfiguration, + such as a prefix allocation per lane [Address-Assignment] and a + prefix allocation per geographic region [GeoSAC], causes the frequent + change of a vehicle's IP address and requires the DAD for the + uniqueness test of a new IP address. This is significant overhead + for high-speed moving vehicles. It will be efficient for a vehicle + to be able to use its IP address while moving across the clusters and + geographical regions. For the cross-layer identity management with + multiple wireless interfaces [Identity-Management], it will be + necessary to maintain an upper-layer session (e.g., TCP session) of a + vehicle with multiple IP addresses corresponing to the multiple + wireless interfaces. - For routing, Tsukada et al. presented a work that aims at combining - IPv6 networking and a Car-to-Car Network routing protocol (called - C2CNet) proposed by the Car2Car Communication Consortium (C2C-CC), - which is an architecture using a geographic routing protocol - [VANET-Geo-Routing]. Abrougui et al. presented a gateway discovery - scheme for VANET, called Location-Aided Gateway Advertisement and - Discovery (LAGAD) mechanism [LAGAD]. +4.1.2. Routing Protocol -4.1.4. Mobility Management + For vehicular routing, Abboud et al. proposed a cluster-based routing + [Cluster-Based-Routing]. Vehicles construct clusters along with + their location and speed information for fast data dissemination + among the clusters. They consist of cluster headers, cluster + gateways and cluster members for intra-cluster and inter-cluster + communications. Tsukada et al. presented a work that aims at + combining IPv6 networking and a Car-to-Car Network (called C2CNet) + routing protocol proposed by the Car-to-Car Communication Consortium + (C2C-CC). Note that C2CNet is the network layer of the C2C-CC + communication system and uses a geographic routing protocol for + vehicular networks [VANET-Geo-Routing]. Abrougui et al. presented a + gateway discovery scheme for vehicles to access the Internet via a + gateway, called Location-Aided Gateway Advertisement and Discovery + (LAGAD) mechanism [LAGAD]. A vehicle (as a packet source) multihop + away from a gateway can discover the gateway and deliver its packets + to the gateway through the packet forwarding of intermediate vehicles + (as relay vehicles) in a connected VANET. Those intermediate + vehicles are located between the packet source vehicle and the + gateway. + + For data packet routing in vehicular networks, multihop V2V and + multihop V2I communications are required. For multihop V2V + communications within a connected VANET, a cluster-based routing like + [Cluster-Based-Routing] can play a role of efficient data forwarding + through a virtual backbone of cluster headers and cluster gateways. + For this, an efficient cluster formation is performed through sharing + the mobility information (e.g., position, direction, and speed) of + vehicles. But the pure VANET-based clustering will cause significant + control messages and need some delay for cluster formation, so + vehicles can perform clustering through infrastructure nodes (e.g., + RSUs and base stations) via cellular links, which guarantees always- + network-connection. + + For multihop V2I communications, a gateway discovery scheme like + LAGAD [LAGAD] can be used through a connected VANET having a + connection with an Internet gateway. However, this reactive gateway + discovery causes much control messages for the discovery and need + some delay until a packet source vehicle can transmit its packets + toward the gateway. Thus, a proactive gateway discovery is required + over a connected VANET where vehicles share routes towards gateways + (e.g., distance vector information to gateways) in a proactive + manner. + +4.1.3. Mobility Management For mobility management, Chen et al. tackled the issue of network fragmentation in VANET environments [IP-Passing-Protocol] by proposing a protocol that can postpone the time to release IP addresses to the DHCP server and select a faster way to get the vehicle's new IP address, when the vehicle density is low or the speeds of vehicles are highly variable. Nguyen et al. proposed a hybrid centralized-distributed mobility management called H-DMM to - support highly mobile vehicles [H-DMM]. [NEMO-LMS] proposed an - architecture to enable IP mobility for moving networks using a - network-based mobility scheme based on PMIPv6. Chen et al. proposed - a network mobility protocol to reduce handoff delay and maintain - Internet connectivity to moving vehicles in a highway [NEMO-VANET]. - Lee et al. proposed P-NEMO, which is a PMIPv6-based IP mobility - management scheme to maintain the Internet connectivity at the - vehicle as a mobile network, and provides a make-before-break + support the mobility of high-speed mobile vehicles, which is based on + both DMM and PMIPv6 [H-DMM]. They also proposed a hybrid + centralized-distributed mobility management for network mobility + called H-NEMO to support the efficient mobility of mobile nodes and + mobile routers between different subnets, which is based on both DMM + and PMIPv6 [H-NEMO]. + + [NEMO-LMS] proposed an architecture to enable IP mobility for moving + networks using a network-based mobility scheme based on PMIPv6. Chen + et al. proposed a network mobility protocol to reduce handoff delay + and maintain Internet connectivity to moving vehicles in a highway + [NEMO-VANET]. Lee et al. proposed P-NEMO, which is a PMIPv6-based IP + mobility management scheme to maintain the Internet connectivity at + the vehicle as a mobile network, and provides a make-before-break mechanism when vehicles switch to a new access network [PMIP-NEMO-Analysis]. Peng et al. proposed a novel mobility management scheme for integration of VANET and fixed IP networks - [VNET-MM]. Nguyen et al. extended their previous works on a - vehicular adapted DMM considering a Software-Defined Networking (SDN) - architecture [SDN-DMM]. + [VNET-MM]. This scheme uses both a road network layout and the + wireless coverage of multiple base stations in order to improve the + connectivity of vehicles to the Internet and decrease the overhead of + mobility management. Nguyen et al. extended their previous works + (i.e., H-DMM [H-DMM] and H-NEMO [H-NEMO]) on a vehicular DMM by using + a Software-Defined Networking (SDN) architecture, which separates the + control plane and the data plane in network functionality [SDN-DMM]. -4.1.5. DNS Naming Service + A vehicle can have an internal network for its in-vehicle devices and + passengers' mobile devices. In this case, vehicular networks need to + support not only the host mobility for the vehicle, but also the + network mobility of such an internet network within the vehicle. The + current mobility management schemes, such as [H-DMM] and [H-NEMO], + are not enough to support both the host mobility and network mobility + in an efficient way. An efficient mobility management scheme can + take advantage of a vehicle's mobility information (e.g., position, + direction, and speed) and partial or full trajectory (i.e., a + navigation path in a road network) in order to perform operations for + mobility management proactively. For this proactive mobility + management, an SDN-based mobility management scheme like [SDN-DMM] + will be promising because SDN controllers can proactively set up + forwarding tables for traffic flows of vehicles with their mobility + and trajectory information. + +4.1.4. DNS Naming Service For DNS naming service, Multicast DNS (mDNS) [RFC6762] allows devices in one-hop communication range to resolve each other's DNS name into the corresponding IP address in multicast. DNS Name Autoconfiguration (DNSNA) [ID-DNSNA] proposes a DNS naming service for Internet-of-Things (IoT) devices in a large-scale network. -4.1.6. Service Discovery + A DNS name resolution service needs to support DNS name resolution + for in-vehicle devices and passengers' mobile devices within a + vehicle's internal network, which can be called intra-vehicle DNS + name resolution. Also, it needs to support DNS name resolution + between devices (e.g., cooperative cruise control device) existing in + different vehicles, which can be called inter-vehicle DNS name + resolution. In addition, it need to support DNS name resolution in + hosts or servers as corresponding nodes in the Internet, which can be + called global DNS name resolution. + + For the intra-vehicle DNS name resolution and inter-vehicle DNS name + resolution, both mDNS [RFC6762] and DNSNA [ID-DNSNA] can be used, but + they perform DNS name resolution in a reactive way. That is, when a + DNS query is given by a querier, it will be multicasted to devices + through mDNS or be unicasted to a dedicated DNS server through DNSNA, + respectively. + + For the inter-vehicle DNS name resolution in fast-moving vehicles, a + proactive DNS resolution can be performed by the help of an RSU that + collects the DNS information of vehicles and disseminate it to + vehicles under its coverage. + + For the global DNS name resolution, a vehicle can use an RSU's DNS + server (or a DNS server close to an RSU in the wired network) to + perform a DNS resolution for the sake of the vehicle's device during + its travel. When the DNS resolution is finished by the RSU's DNS + server, the DNS server can forward the DNS resolution result to the + vehicle through the current RSU providing the vehicle with the + Internet connectivity. + +4.1.5. Service Discovery To discover instances of a demanded service in vehicular networks, DNS-based Service Discovery (DNS-SD) [RFC6763] with either DNSNA [ID-DNSNA] or mDNS [RFC6762] provides vehicles with service discovery by using standard DNS queries. Vehicular ND [ID-Vehicular-ND] proposes an extension of IPv6 ND for the prefix and service discovery - with new ND options [ID-VND-Discovery]. Note that a DNS query for - service discovery is unicasted in DNSNA, but it is multicasted in + with new ND options. + + For vehicular networks, DNSNA can use a dedicated DNS server residing + in an RSU or close to an RSU in the wired network [ID-DNSNA]. In + this case, in-vehicle devices can register their services (e.g., + cooperative cruise control service and navigation service) into the + DNS server. When the DNS server can receive a service discovery + query from vehicles via an RSU, it can resolve it quickly for them. + In DNSNA, these DNS query and response messages are delivered in + unicast rather than multicast, so the wireless channel will be + utilized efficiently for DNS resolution including service discovery. + Thus, DNSNA will provide a more efficient service discovery to + vehicles in a high-vehicle-density environment than mDNS [RFC6762] + and Vehicular ND [ID-Vehicular-ND]. This is because a DNS query for + service discovery is unicasted by DNSNA, but it is multicasted by both mDNS and Vehicular ND. -4.1.7. Security and Privacy + In a V2V scenario such as the case where a dedicated DNS server in an + RSU is not available for the registration and sharing of service + information, Vehicular ND can provide vehicles with rapid service + discovery by letting vehicles proactively advertise their service + information with Neighbor Advertisement (NA) messages. Thus, + considering both V2I and V2V scenarios, an efficient service + discovery scheme can be designed. + +4.1.6. Security and Privacy For security and privacy, Fernandez et al. proposed a secure vehicular IPv6 communication scheme using Internet Key Exchange - version 2 (IKEv2) and Internet Protocol Security (IPsec) - [Securing-VCOMM]. Moustafa et al. proposed a security scheme - providing authentication, authorization, and accounting (AAA) - services in vehicular networks [VNET-AAA]. + version 2 (IKEv2) and Internet Protocol Security (IPsec) for + vehiculer networks. This scheme provides the secure communication + channel between a home agent and a mobile router to support the + network mobility of a vehicle's internal network [Securing-VCOMM]. + Moustafa et al. proposed a security scheme providing authentication, + authorization, and accounting (AAA) services in vehicular networks + + [VNET-AAA]. The vehicular networks consist of VANETs as a front end + and an access network as a back end via an access point. The + security scheme provides vehicles with an efficient AAA service for + the network connectivity during their movement in the road network. + + Security services in vehicular networks need to support an efficient + AAA for the accommodation of only valid vehicles and a secure + communication with IKEv2 and IPsec between vehicles or between a + vehicle and the corresponding node in the Internet. For the + efficiency, these security services need to take advantage of a + vehicular network architecture having a TCC and RSUs as well as a + vehicle's mobility and trajectory information. 4.2. General Problems This section describes a possible vehicular network architecture for V2V, V2I, and V2X communications. Then it analyzes the limitations of the current protocols for vehicular networking. Traffic Control Center in Vehicular Cloud *-----------------------------------------* * * * +----------------+ * * | Mobility Anchor| * * +----------------+ * * ^ * * | * *--------------------v--------------------* ^ ^ ^ | | | -+------------------ | -------------|-------------+ +------------------+ + | | | + v v v + +--------+ Ethernet +--------+ +--------+ + | RSU1 |<-------->| RSU2 |<---------->| RSU3 | + +--------+ +--------+ +--------+ + ^ ^ ^ + : : : + +--------------------------------------+ +------------------+ + | : V2I V2I : | | V2I : | | v v | | v | -| +--------+ Ethernet +--------+ | | +--------+ | -| | RSU1 |<----------->| RSU2 |<---------->| RSU3 | | -| +--------+ +--------+ | | +--------+ | -| ^ ^ ^ | | ^ | -| : : : | | : | -| V2I : : V2I V2I : | | V2I : | -| v v v | | v | -| +--------+ +--------+ +--------+ | | +--------+ | -| |Vehicle1|===> |Vehicle2|===> |Vehicle3|===>| | |Vehicle4|===>| -| | |<....>| |<....>| | | | | | | -| +--------+ V2V +--------+ V2V +--------+ | | +--------+ | ++--------+ | +--------+ +--------+ | | +--------+ | +|Vehicle1|===> |Vehicle2|===> |Vehicle3|===> | | |Vehicle4|===>| +| |<...>| |<........>| | | | | | | ++--------+ V2V +--------+ V2V +--------+ | | +--------+ | | | | | -+-------------------------------------------------+ +------------------+ + +--------------------------------------+ +------------------+ Subnet1 Subnet2 <----> Wired Link <....> Wireless Link ===> Moving Direction Figure 1: A Vehicular Network Architecture for V2I and V2V Networking 4.2.1. Vehicular Network Architecture - Figure 1 shows a possible architecture for V2I and V2V networking in - a road network. It is assumed that RSUs as routers and vehicles with - OBU have wireless media interfaces (e.g., IEEE 802.11-OCB, LTE Uu and - Device-to-Device (D2D) (also known as PC5 [TS-23.285-3GPP]), - Bluetooth, and Light Fidelity (Li-Fi)) for V2I and V2V communication. - Also, it is assumed that such the wireless media interfaces are - autoconfigured with a global IPv6 prefix (e.g., 2001:DB8:1:1::/64) to - support both V2V and V2I networking. Three RSUs (RSU1, RSU2, and - RSU3) are deployed in the road network and are connected to a - Vehicular Cloud through the Internet. A Traffic Control Center (TCC) - is connected to the Vehicular Cloud for the management of RSUs and - vehicles in the road network. A Mobility Anchor (MA) is located in - the TCC as its key component for the mobility management of vehicles. - Two vehicles (Vehicle1 and Vehicle2) are wirelessly connected to - RSU1, and one vehicle (Vehicle3) is wirelessly connected to RSU2. - The wireless networks of RSU1 and RSU2 belong to a multi-link subnet - (denoted as Subnet1) with the same network prefix. Thus, these three - vehicles are within the same subnet. On the other hand, another - vehicle (Vehicle4) is wireless connected to RSU4, belonging to - another subnet (denoted as Subnet2). That is, the first three - vehicles (i.e., Vehicle1, Vehicle2, and Vehicle3) and the last - vehicle (i.e., Vehicle4) are located in the two different subnets. - Vehicle1 can communicate with Vehicle2 via V2V communication, and - Vehicle2 can communicate with Vehicle3 via V2V communication because - they are within the same subnet along their IPv6 addresses, which are - based on the same prefix. On the other hand, Vehicle3 can - communicate with Vehicle4 via RSU2 and RSU3 employing V2I (i.e., - V2I2V) communication because they are within the two different - subnets along with their IPv6 addresses, which are based on the two - different prefixes. + Figure 1 shows an architecture for V2I and V2V networking in a road + network. As shown in this figure, RSUs as routers and vehicles with + OBU have wireless media interfaces for VANET. Also, it is assumed + that such the wireless media interfaces are autoconfigured with a + global IPv6 prefix (e.g., 2001:DB8:1:1::/64) to support both V2V and + V2I networking. + + Especially, for IPv6 packets transporting over IEEE 802.11-OCB, + [IPv6-over-802.11-OCB] specifies several details, such as Maximum + Transmission Unit (MTU), frame format, link-local address, address + mapping for unicast and multicast, stateless autoconfiguration, and + subnet structure. Especially, an Ethernet Adaptation (EA) layer is + in charge of transforming some parameters between IEEE 802.11 MAC + layer and IPv6 network layer, which is located between IEEE + 802.11-OCB's logical link control layer and IPv6 network layer. This + IPv6 over 802.11-OCB can be used for both V2V and V2I in IP-based + vehicular networks. + + In Figure 1, three RSUs (RSU1, RSU2, and RSU3) are deployed in the + road network and are connected to a Vehicular Cloud through the + Internet. A Traffic Control Center (TCC) is connected to the + Vehicular Cloud for the management of RSUs and vehicles in the road + network. A Mobility Anchor (MA) is located in the TCC as its key + component for the mobility management of vehicles. Two vehicles + (Vehicle1 and Vehicle2) are wirelessly connected to RSU1, and one + vehicle (Vehicle3) is wirelessly connected to RSU2. The wireless + networks of RSU1 and RSU2 belong to a multi-link subnet (denoted as + Subnet1) with the same network prefix. Thus, these three vehicles + are within the same subnet. On the other hand, another vehicle + (Vehicle4) is wireless connected to RSU4, belonging to another subnet + (denoted as Subnet2). That is, the first three vehicles (i.e., + Vehicle1, Vehicle2, and Vehicle3) and the last vehicle (i.e., + Vehicle4) are located in the two different subnets. + + In wireless subnets in vehicular networks (e.g., Subnet 1 and Subnet + 2 in Figure 1), vehicles can construct a connected VANET (as an + arbitrary graph topology) and can communicate with each other via V2V + communication. Vehicle1 can communicate with Vehicle2 via V2V + communication, and Vehicle2 can communicate with Vehicle3 via V2V + communication because they are within the same subnet along their + IPv6 addresses, which are based on the same prefix. On the other + hand, Vehicle3 can communicate with Vehicle4 via RSU2 and RSU3 + employing V2I (i.e., V2I2V) communication because they are within the + two different subnets along with their IPv6 addresses, which are + based on the two different prefixes. In vehicular networks, unidirectional links exist and must be considered for wireless communications. Also, in the vehicular networks, control plane must be separated from data plane for efficient mobility management and data forwarding using Software- - Defined Networking (SDN) [SDN-DMM]. ID/Pseudonym change for privacy - requires a lightweight DAD. IP tunneling over the wireless link - should be avoided for performance efficiency. The mobility - information of a mobile (e.g., vehicle-mounted) device through a GPS - receiver in its vehicle, such as trajectory, position, speed, and - direction, can be used by the mobile device and infrastructure nodes - (e.g., TCC and RSU) for the accommodation of mobility-aware proactive - protocols. Vehicles can use the TCC as their Home Network having a - home agent for mobility management as in MIPv6 [RFC6275] and Proxy - Mobile IPv6 (PMIPv6) [RFC5213], so the TCC maintains the mobility - information of vehicles for location management. + Defined Networking (SDN) [SDN-DMM]. The mobility information of a + GPS receiver mounted in its vehicle (e.g., trajectory, position, + speed, and direction) can be used for the accommodation of mobility- + aware proactive protocols. Vehicles can use the TCC as their Home + Network having a home agent for mobility management as in MIPv6 + [RFC6275] and PMIPv6 [RFC5213], so the TCC maintains the mobility + information of vehicles for location management. Also, IP tunneling + over the wireless link should be avoided for performance efficiency. Cespedes et al. proposed a vehicular IP in WAVE called VIP-WAVE for I2V and V2I networking [VIP-WAVE]. The standard WAVE does not support both seamless communications for Internet services and multi- hop communications between a vehicle and an infrastructure node (e.g., RSU), either. To overcome these limitations of the standard WAVE, VIP-WAVE enhances the standard WAVE by the following three - schemes: (i) an efficient mechanism for the IPv6 address assignment - and DAD, (ii) on-demand IP mobility based on PMIPv6 [RFC5213], and - (iii) one-hop and two-hop communications for I2V and V2I networking. + schemes: + + 1. An efficient mechanism for the IPv6 address assignment and DAD + + 2. An on-demand IP mobility management based on PMIPv6 [RFC5213] + + 3. One-hop and two-hop communication scheme for V2I networking + + Note that VIP-WAVE supports at most two-hop V2I communication for + simple forwarding operations in VANET. This is because the multi-hop + V2I communication with more than two hops requires an additional + VANET routing protocol. Such a multi-hop V2I communication will be + required for vehicles in a highway with sparsely deployed RSUs in + order to provide them with the Internet connectivity via V2I. Baccelli et al. provided an analysis of the operation of IPv6 as it has been described by the IEEE WAVE standards 1609 [IPv6-WAVE]. This analysis confirms that the use of the standard IPv6 protocol stack in WAVE is not sufficient. It recommends that the IPv6 addressing assignment should follow considerations for ad-hoc link models, defined in [RFC5889] for nodes' mobility and link variability. + However, this ad-hoc link model is not clearly defined to support the + efficient V2V and V2I for vehicles with a wireless interface + configured with an IPv6 address. Petrescu et al. proposed the joint IP networking and radio architecture for V2V and V2I communication in [Joint-IP-Networking]. - The proposed architecture considers an IP topology in a similar way - as a radio link topology, in the sense that an IP subnet would - correspond to the range of 1-hop vehicular communication. This + The radio architecture uses Wi-Fi for wireless link rather than IEEE + 802.11-OCB. The proposed architecture considers an IP topology in a + similar way as a radio link topology, in the sense that an IP subnet + would correspond to the range of 1-hop vehicular communication. This architecture defines three types of vehicles: Leaf Vehicle, Range - Extending Vehicle, and Internet Vehicle. + Extending Vehicle, and Internet Vehicle. Leaf Vehicle is like a + vehicle with OBU and has one external WiFi interface along with an + MR. This MR supports the network mobility of a user's mobile device + and in-vehicle devices in the vehicle's internal network. Range + Extending Vehicles has two external Wi-Fi interfaces to connect two + Wi-Fi subnets of cars in a train. Internet Vehicle has one Wi-Fi + interface for a car's subnet and one Wireless Metropolitan Area + Network (WMAN) interface for the Internet connectivity. However, + this architecture is not suitable for vehicles with a small size and + with a wireless interface for V2V and V2I in vehicular links. - +----------------+ +4.2.1.1. V2I-based Internetworking + + This section discusses the internetworking between a vehicle's moving + network and an RSU's fixed network via V2I communication. + + +-----------------+ (*)<........>(*) +----->| Vehicular Cloud| - 2001:DB8:1:1::/64 | | | +----------------+ + 2001:DB8:1:1::/64 | | | +-----------------+ +------------------------------+ +---------------------------------+ | v | | v v | - | .-------. .------. .-------. | | .-------. .------. .-------. | - | | Host1 | |RDNSS1| |Router1| | | |Router3| |RDNSS2| | Host3 | | - | ._______. .______. ._______. | | ._______. .______. ._______. | + | +-------+ +------+ +-------+ | | +-------+ +------+ +-------+ | + | | Host1 | | DNS1 | |Router1| | | |Router3| | DNS2 | | Host3 | | + | +-------+ +------+ +-------+ | | +-------+ +------+ +-------+ | | ^ ^ ^ | | ^ ^ ^ | | | | | | | | | | | | v v v | | v v v | | ---------------------------- | | ------------------------------- | | 2001:DB8:10:1::/64 ^ | | ^ 2001:DB8:20:1::/64 | | | | | | | | v | | v | - | .-------. .-------. | | .-------. .-------. .-------. | + | +-------+ +-------+ | | +-------+ +-------+ +-------+ | | | Host2 | |Router2| | | |Router4| |Server1|...|ServerN| | - | ._______. ._______. | | ._______. ._______. ._______. | + | +-------+ +-------+ | | +-------+ +-------+ +-------+ | | ^ ^ | | ^ ^ ^ | | | | | | | | | | | v v | | v v v | | ---------------------------- | | ------------------------------- | | 2001:DB8:10:2::/64 | | 2001:DB8:20:2::/64 | - +______________________________+ +_________________________________+ + +------------------------------+ +---------------------------------+ Vehicle1 (Moving Network1) RSU1 (Fixed Network1) <----> Wired Link <....> Wireless Link (*) Antenna Figure 2: Internetworking between Vehicle Network and RSU Network -4.2.1.1. V2I-based Internetworking - - This section discusses the internetworking between a vehicle's moving - network and an RSU's fixed network via V2I communication. - As shown in Figure 2, the vehicle's moving network and the RSU's fixed network are self-contained networks having multiple subnets and having an edge router for the communication with another vehicle or - RSU. The method of prefix assignment for each subnet inside the - vehicle's mobile network and the RSU's fixed network is out of scope - for this document. Internetworking between two internal networks via - V2I communication requires an exchange of network prefix and other + RSU. Internetworking between two internal networks via V2I + communication requires an exchange of network prefix and other parameters through a prefix discovery mechanism, such as ND-based - prefix discovery [ID-VND-Discovery]. For the ND-based prefix + prefix discovery [ID-Vehicular-ND]. For the ND-based prefix discovery, network prefixs and parameters should be registered into a vehicle's router and an RSU router with an external network interface in advance. The network parameter discovery collects networking information for an IP communication between a vehicle and an RSU or between two neighboring vehicles, such as link layer, MAC layer, and IP layer information. The link layer information includes wireless link layer - parameters, such as wireless media (e.g., IEEE 802.11-OCB, LTE Uu and - D2D, Bluetooth, and LiFi) and a transmission power level. Note that - LiFi is a technology for light-based wireless communication between - devices in order to transmit both data and position. The MAC layer - information includes the MAC address of an external network interface - for the internetworking with another vehicle or RSU. The IP layer + parameters, such as wireless media (e.g., IEEE 802.11-OCB and LTE- + V2X) and a transmission power level. The MAC layer information + includes the MAC address of an external network interface for the + internetworking with another vehicle or RSU. The IP layer information includes the IP address and prefix of an external network interface for the internetworking with another vehicle or RSU. Once the network parameter discovery and prefix exchange operations have been performed, packets can be transmitted between the vehicle's moving network and the RSU's fixed network. DNS services should be supported to enable name resolution for hosts or servers residing either in the vehicle's moving network or the RSU's fixed network. It is assumed that the DNS names of in-vehicle devices and their - service names are registered into a DNS server (i.e., recursive DNS - server called RDNSS) in a vehicle or an RSU, as shown in Figure 2. - For service discovery, those DNS names and service names can be - advertised to neighboring vehicles through either DNS-based service - discovery mechanisms [RFC6762][RFC6763][ID-DNSNA] and ND-based - service discovery [ID-Vehicular-ND][ID-VND-Discovery]. For the ND- - based service discovery, service names should be registered into a - vehicle's router and an RSU router with an external network interface - in advance. Refer to Section 4.1.5 and Section 4.1.6 for detailed - information. For these DNS services, an RDNSS within each internal - network of a vehicle or RSU can be used for the hosts or servers. + service names are registered into a DNS server in a vehicle or an + RSU, as shown in Figure 2. For service discovery, those DNS names + and service names can be advertised to neighboring vehicles through + either DNS-based service discovery mechanisms + [RFC6762][RFC6763][ID-DNSNA] and ND-based service discovery + [ID-Vehicular-ND]. For the ND-based service discovery, service names + should be registered into a vehicle's router and an RSU router with + an external network interface in advance. For this service + discovery, each vehicle and each RSU should have its dedicated DNS + server within its internal network, respectively, as shown in + Figure 2. Figure 2 shows internetworking between the vehicle's moving network and the RSU's fixed network. There exists an internal network (Moving Network1) inside Vehicle1. Vehicle1 has the DNS Server - (RDNSS1), the two hosts (Host1 and Host2), and the two routers - (Router1 and Router2). There exists another internal network (Fixed - Network1) inside RSU1. RSU1 has the DNS Server (RDNSS2), one host - (Host3), the two routers (Router3 and Router4), and the collection of - servers (Server1 to ServerN) for various services in the road - networks, such as the emergency notification and navigation. - Vehicle1's Router1 (called mobile router) and RSU1's Router3 (called - fixed router) use 2001:DB8:1:1::/64 for an external link (e.g., DSRC) - for I2V networking. + (DNS1), the two hosts (Host1 and Host2), and the two routers (Router1 + and Router2). There exists another internal network (Fixed Network1) + inside RSU1. RSU1 has the DNS Server (DNS2), one host (Host3), the + two routers (Router3 and Router4), and the collection of servers + (Server1 to ServerN) for various services in the road networks, such + as the emergency notification and navigation. Vehicle1's Router1 + (called mobile router) and RSU1's Router3 (called fixed router) use + 2001:DB8:1:1::/64 for an external link (e.g., DSRC) for I2V + networking. + +4.2.1.2. V2V-based Internetworking + + This section discusses the internetworking between the moving + networks of two neighboring vehicles via V2V communication. (*)<..........>(*) 2001:DB8:1:1::/64 | | - +------------------------------+ +---------------------------------+ + +------------------------------+ +------------------------------+ | v | | v | - | .-------. .------. .-------. | | .-------. .------. .-------. | - | | Host1 | |RDNSS1| |Router1| | | |Router5| |RDNSS3| | Host4 | | - | ._______. .______. ._______. | | ._______. .______. ._______. | + | +-------+ +------+ +-------+ | | +-------+ +------+ +-------+ | + | | Host1 | | DNS1 | |Router1| | | |Router5| | DNS3 | | Host4 | | + | +-------+ +------+ +-------+ | | +-------+ +------+ +-------+ | | ^ ^ ^ | | ^ ^ ^ | | | | | | | | | | | | v v v | | v v v | - | ---------------------------- | | ------------------------------- | + | ---------------------------- | | ---------------------------- | | 2001:DB8:10:1::/64 ^ | | ^ 2001:DB8:30:1::/64 | | | | | | | | v | | v | - | .-------. .-------. | | .-------. .-------. | + | +-------+ +-------+ | | +-------+ +-------+ | | | Host2 | |Router2| | | |Router6| | Host5 | | - | ._______. ._______. | | ._______. ._______. | + | +-------+ +-------+ | | +-------+ +-------+ | | ^ ^ | | ^ ^ | | | | | | | | | | v v | | v v | - | ---------------------------- | | ------------------------------- | + | ---------------------------- | | ---------------------------- | | 2001:DB8:10:2::/64 | | 2001:DB8:30:2::/64 | - +______________________________+ +_________________________________+ + +------------------------------+ +------------------------------+ Vehicle1 (Moving Network1) Vehicle2 (Moving Network2) <----> Wired Link <....> Wireless Link (*) Antenna Figure 3: Internetworking between Two Vehicle Networks -4.2.1.2. V2V-based Internetworking - - This section discusses the internetworking between the moving - networks of two neighboring vehicles via V2V communication. - Figure 3 shows internetworking between the moving networks of two neighboring vehicles. There exists an internal network (Moving - Network1) inside Vehicle1. Vehicle1 has the DNS Server (RDNSS1), the + Network1) inside Vehicle1. Vehicle1 has the DNS Server (DNS1), the two hosts (Host1 and Host2), and the two routers (Router1 and Router2). There exists another internal network (Moving Network2) - inside Vehicle2. Vehicle2 has the DNS Server (RDNSS3), the two hosts + inside Vehicle2. Vehicle2 has the DNS Server (DNS3), the two hosts (Host4 and Host5), and the two routers (Router5 and Router6). - Vehicle1's Router1 (called mobile router) and Vehicle2's Router5 (called mobile router) use 2001:DB8:1:1::/64 for an external link (e.g., DSRC) for V2V networking. - The differences between IPWAVE (including Vehicular Ad Hoc Networks - (VANET)) and Mobile Ad Hoc Networks (MANET) are as follows: - - o IPWAVE is not power-constrained operation; - - o Traffic can be sourced or sinked outside of IPWAVE; - - o IPWAVE shall support both distributed and centralized operations; - - o No "sleep" period operation is required for energy saving. - 4.2.2. Latency - The communication delay (i.e., latency) between two vehicular nodes - (vehicle and RSU) should be bounded to a certain threshold. For IP- - based safety applications (e.g., context-aware navigation, adaptive - cruise control, and platooning) in vehicular network, this bounded - data delivery is critical. The real implementations for such - applications are not available, so the feasibility of IP-based safety - applications is not tested yet. + The communication delay (i.e., latency) between two vehicles should + be bounded to a certain threshold (e.g., 500 ms) for collision- + avoidance message exchange [CASD]. For IP-based safety applications + (e.g., context-aware navigation, adaptive cruise control, and + platooning) in vehicular network, this bounded data delivery is + critical. The real implementations for such applications are not + available yet. Thus, the feasibility of IP-based safety applications + is not tested yet in the real world. 4.2.3. Security Strong security measures shall protect vehicles roaming in road networks from the attacks of malicious nodes, which are controlled by hackers. For safety applications, the cooperation among vehicles is assumed. Malicious nodes may disseminate wrong driving information (e.g., location, speed, and direction) to make driving be unsafe. Sybil attack, which tries to illude a vehicle with multiple false - identities, disturbs a vehicle in taking a safe maneuver. - Applications on IP-based vehicular networking, which are resilient to - such a sybil attack, are not developed and tested yet. + identities, disturbs a vehicle in taking a safe maneuver. This sybil + attack should be prevented through the cooperation between good + vehicles and RSUs. Applications on IP-based vehicular networking, + which are resilient to such a sybil attack, are not developed and + tested yet. 4.2.4. Pseudonym Handling - For the protection of drivers' privacy, pseudonym for a vehicle's - network interface should be used, with the help of which the - interface's identifier can be changed periodically. Such a pseudonym - affects an IPv6 address based on the network interface's identifier, - and a transport-layer (e.g., TCP) session with an IPv6 address pair. - The pseudonym handling is not implemented and tested yet for - applications on IP-based vehicular networking. + For the protection of drivers' privacy, the pseudonym of a MAC + address of a vehicle's network interface should be used, with the + help of which the MAC address can be changed periodically. The + pseudonym of a MAC address affects an IPv6 address based on the MAC + address, and a transport-layer (e.g., TCP) session with an IPv6 + address pair. However, the pseudonym handling is not implemented and + tested yet for applications on IP-based vehicular networking. 5. Problem Exploration This section discusses key topics for IPWAVE WG, such as neighbor discovery, mobility management, and security & privacy. 5.1. Neighbor Discovery Neighbor Discovery (ND) [RFC4861] is a core part of the IPv6 protocol suite. This section discusses the need for modifying ND for use with vehicular networking (e.g., V2V, V2I, and V2X). The vehicles are moving fast within the communication coverage of a vehicular node (e.g., vehicle and RSU). The external wireless link between two vehicular nodes can be used for vehicular networking, as shown in Figure 2 and Figure 3. ND time-related parameters such as router lifetime and Neighbor Advertisement (NA) interval should be adjusted for high-speed vehicles and vehicle density. As vehicles move faster, the NA - interval should decrease for the NA messages to reach the neighboring - vehicles promptly. Also, as vehicle density is higher, the NA - interval should increase for the NA messages to reduce collision + interval should decrease (e.g., from 1 sec to 0.5 sec) for the NA + messages to reach the neighboring vehicles promptly. Also, as + vehicle density is higher, the NA interval should increase (e.g., + from 0.5 sec to 1 sec) for the NA messages to reduce collision probability with other NA messages. 5.1.1. Link Model IPv6 protocols work under certain assumptions for the link model that do not necessarily hold in a vehicular wireless link [VIP-WAVE]. For instance, some IPv6 protocols assume symmetry in the connectivity among neighboring interfaces. However, interference and different levels of transmission power may cause unidirectional links to appear in vehicular wireless links. As a result, a new vehicular link model - is required for the vehicular wireless link. + is required for a dynamically changing vehicular wireless link. There is a relationship between a link and prefix, besides the different scopes that are expected from the link-local and global types of IPv6 addresses. In an IPv6 link, it is assumed that all interfaces which are configured with the same subnet prefix and with on-link bit set can communicate with each other on an IP link or extended IP links via ND proxy. Note that a subnet prefix can be - used by spanning multiple links as a multi-link subnet [RFC6775]. - Also, note that IPv6 Stateless Address Autoconfiguration can be - performed in the multiple links where each of them is not assigned - with a unique subnet prefix, that is, all of them are configured with - the same subnet prefix [RFC4861][RFC4862]. A vehicular link model - needs to consider a multi-hop VANET over a multi-link subnet. Such a - VANET is usually a multi-link subnet consisting of multiple vehicles - interconnected by wireless communication range. Such a subnet has a - highly dynamic topology over time due to node mobility. + used by spanning multiple links into a multi-link subnet with an + extended subnet concept [RFC6775]. Also, note that IPv6 Stateless + Address Autoconfiguration (SLAAC) can be performed in the multiple + links where each of them is not assigned with a unique subnet prefix, + that is, all of them are configured with the same subnet prefix + [RFC4861][RFC4862]. + + A vehicular link model needs to consider a multi-hop V2V (or V2I) + over a multi-link subnet as shown in Figure 1. In this figure, + vehicles in Subnet1 having RSU1 and RSU2 construct a multi-link + subnet called Subnet1 with VANETs and RSUs. Vehicle1 and Vehicle3 + can communicate with each other via multi-hop V2V or multi-hop V2I2V. + When two vehicles (e.g., Vehicle1 and Vehicle3 in Figure 1) are + connected in a VANET, they can communicate with each other via VANET + rather than RSUs. On the other hand, when two vehicles (e.g., + Vehicle1 and Vehicle3) are far away from the communication range in + separate VANETs and under two different RSUs, they can communicate + with each other through the relay of RSUs via V2I2V. Thus, IPv6 ND should be extended into a Vehicular Neighbor Discovey (VND) [ID-Vehicular-ND] to support the concept of an IPv6 link corresponding to an IPv6 prefix even in a multi-link subnet consisting of multiple vehicles and RSUs that are interconnected with wireless communication range in IP-based vehicular networks. 5.1.2. MAC Address Pseudonym In the ETSI standards, for the sake of security and privacy, an ITS station (e.g., vehicle) can use pseudonyms for its network interface identities (e.g., MAC address) and the corresponding IPv6 addresses [Identity-Management]. Whenever the network interface identifier changes, the IPv6 address based on the network interface identifier - should be updated. For the continuity of an end-to-end (E2E) - transport-layer (e.g., TCP, UDP, and SCTP) session, with a mobility - management scheme (e.g., MIPv6 and PMIPv6), the new IP address for - the transport-layer session should be notified to an appropriate end - point, and the packets of the session should be forwarded to their - destinations with the changed network interface identifier and IPv6 - address. + should be updated, and the uniqueness of the address should be + performed through the DAD procedure. For vehicular networks with + high-mobility, this DAD should be performed efficiently with minimum + overhead. + + For the continuity of an end-to-end (E2E) transport-layer (e.g., TCP, + UDP, and SCTP) session, with a mobility management scheme (e.g., + MIPv6 and PMIPv6), the new IP address for the transport-layer session + can be notified to an appropriate end point, and the packets of the + session should be forwarded to their destinations with the changed + network interface identifier and IPv6 address. This mobiliy + management overhead for pseudonyms should be minimized for efficient + operations in vehicular networks having lots of vehicles. 5.1.3. Prefix Dissemination/Exchange A vehicle and an RSU can have their internal network, as shown in Figure 2 and Figure 3. In this case, nodes in within the internal networks of two vehicular nodes (e.g., vehicle and RSU) want to communicate with each other. For this communication on the wireless link, the network prefix dissemination or exchange is required. It is assumed that a vehicular node has an external network interface - and its internal network. The legacy IPv6 ND [RFC4861] needs to be - extended to a vehicular ND (VND) [ID-Vehicular-ND] for the - communication between the internal-network nodes (e.g., an in-vehicle - device in a vehicle and a server in an RSU) of vehicular nodes by - letting each of them know the other side's prefix with a new ND - option [ID-VND-Discovery]. Thus, this ND extension for routing + and its internal network, as shown in Figure 2 and Figure 3. The + vehicular ND (VND) [ID-Vehicular-ND] can support the communication + between the internal-network nodes (e.g., an in-vehicle device in a + vehicle and a server in an RSU) of vehicular nodes with a vehicular + prefix information option. Thus, this ND extension for routing functionality can reduce control traffic for routing in vehicular - networks without an additional vehicular ad hoc routing protocol - [VANET-Geo-Routing]. + networks without a vehicular ad hoc routing protocol (e.g., AODV + [RFC3561] and OLSRv2 [RFC7181]). 5.1.4. Routing For multihop V2V communications in a multi-link subnet (as a - connected VANET), a vehicular ad hoc routing protocol (e.g., - geographic routing) may be required to support both unicast and - multicast in the links of the subnet with the same IPv6 prefix - [VANET-Geo-Routing]. Instead of the vehicular ad hoc routing - protocol, Vehicular ND along with a prefix discovery option can be - used to let vehicles exchange their prefixes in a multihop fashion + connected VANET), a vehicular ad hoc routing protocol (e.g., AODV and + OLSRv2) may be required to support both unicast and multicast in the + links of the subnet with the same IPv6 prefix. Instead of the + vehicular ad hoc routing protocol, Vehicular ND along with a prefix + discovery option can be used to let vehicles exchange their prefixes + in a multihop fashion [ID-Vehicular-ND]. With the exchanged + prefixes, they can compute their routing table (or IPv6 ND's neighbor + cache) for the multi-link subnet with a distance-vector algorithm + [Intro-to-Algorithms]. - [ID-Vehicular-ND][ID-VND-Discovery]. With the exchanged prefixes, - they can compute their routing table (or IPv6 ND's neighbor cache) - for the multi-link subnet with a distance-vector algorithm - [Intro-to-Algorithms]. Also, an efficient, rapid DAD should be - supported to prevent or reduce IPv6 address conflicts in the multi- - link subnet by using a DAD optimization [ID-Vehicular-ND][RFC6775] or + Also, an efficient, rapid DAD should be supported in a multi-link + subnet to prevent or reduce IPv6 address conflicts in such a subnet + by using a multi-hop DAD optimization [ID-Vehicular-ND][RFC6775] or an IPv6 geographic-routing-based address autoconfiguration [GeoSAC]. 5.2. Mobility Management The seamless connectivity and timely data exchange between two end points requires an efficient mobility management including location management and handover. Most of vehicles are equipped with a GPS receiver as part of a dedicated navigation system or a corresponding - smartphone App. In the case where the provided location information - is precise enough, well-known temporary degradations in precision may - occur due to system configuration or the adverse local environment. - This precision is improved thanks to assistance by the RSUs or a - cellular system with this navigation system. With this GPS - navigator, an efficient mobility management is possible by vehicles - periodically reporting their current position and trajectory (i.e., - navigation path) to RSUs and a Mobility Anchor (MA) in TCC. The RSUs - and MA can predict the future positions of the vehicles with their - mobility information (i.e., the current position, speed, direction, - and trajectory) for the efficient mobility management (e.g., - proactive handover). For a better proactive handover, link-layer - parameters, such as the signal strength of a link-layer frame (e.g., - Received Channel Power Indicator (RCPI) [VIP-WAVE]), can be used to - determine the moment of a handover between RSUs along with mobility - information [ID-Vehicular-ND]. + smartphone App. The GPS receiver may not provide vehicles with + accurate location information in adverse, local environments such as + building area and tunnel. The location precision can be improved by + the assistance from the RSUs or a cellular system with a navigation + system. + + With this GPS navigator, an efficient mobility management is possible + by vehicles periodically reporting their current position and + trajectory (i.e., navigation path) to RSUs and a Mobility Anchor (MA) + in TCC. The RSUs and MA can predict the future positions of the + vehicles with their mobility information (i.e., the current position, + speed, direction, and trajectory) for the efficient mobility + management (e.g., proactive handover). For a better proactive + handover, link-layer parameters, such as the signal strength of a + link-layer frame (e.g., Received Channel Power Indicator (RCPI) + [VIP-WAVE]), can be used to determine the moment of a handover + between RSUs along with mobility information [ID-Vehicular-ND]. With the prediction of the vehicle mobility, MA can support RSUs to perform DAD, data packet routing, horizontal handover (i.e., handover in wireless links using a homogeneous radio technology), and vertical handover (i.e., handover in wireless links using heterogeneous radio technologies) in a proactive manner. Even though a vehicle moves into the wireless link under another RSU belonging to a different subnet, the RSU can proactively perform the DAD for the sake of the vehicle, reducing IPv6 control traffic overhead in the wireless link - [ID-Vehicular-ND]. + [ID-Vehicular-ND]. To prevent a hacker from impersonating RSUs as + bogus RSUs, RSUs and MA should have secure channels via IPsec. Therefore, with a proactive handover and a multihop DAD in vehicular networks [ID-Vehicular-ND], RSUs can efficiently forward data packets from the wired network (or the wireless network) to a moving destination vehicle along its trajectory along with the MA. Thus, a moving vehicle can communicate with its corresponding vehicle in the vehicular network or a host/server in the Internet along its trajectory. 5.3. Security and Privacy @@ -958,20 +1140,26 @@ Available: http://www.path.berkeley.edu/research/automated-and- connected-vehicles/cooperative-adaptive-cruise-control, 2017. [CASD] Shen, Y., Jeong, J., Oh, T., and S. Son, "CASD: A Framework of Context-Awareness Safety Driving in Vehicular Networks", International Workshop on Device Centric Cloud (DC2), March 2016. + [Cluster-Based-Routing] + Abboud, K. and W. Zhuang, "Impact of Microscopic Vehicle + Mobility on Cluster-Based Routing Overhead in VANETs", + IEEE Transactions on Vehicular Technology, Vol. 64, No. + 12, December 2015. + [DSRC] ASTM International, "Standard Specification for Telecommunications and Information Exchange Between Roadside and Vehicle Systems - 5 GHz Band Dedicated Short Range Communications (DSRC) Medium Access Control (MAC) and Physical Layer (PHY) Specifications", ASTM E2213-03(2010), October 2010. [ETSI-GeoNetwork-IP] ETSI Technical Committee Intelligent Transport Systems, "Intelligent Transport Systems (ITS); Vehicular @@ -1016,72 +1204,71 @@ Scalable Address Autoconfiguration for VANET Using Geographic Networking Concepts", IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, September 2008. [H-DMM] Nguyen, T. and C. Bonnet, "A Hybrid Centralized- Distributed Mobility Management for Supporting Highly Mobile Users", IEEE International Conference on Communications, June 2015. + [H-NEMO] Nguyen, T. and C. Bonnet, "A Hybrid Centralized- + Distributed Mobility Management Architecture for Network + Mobility", IEEE International Symposium on A World of + Wireless, Mobile and Multimedia Networks, June 2015. + [ID-DNSNA] Jeong, J., Ed., Lee, S., and J. Park, "DNS Name Autoconfiguration for Internet of Things Devices", draft- jeong-ipwave-iot-dns-autoconf-04 (work in progress), October 2018. [ID-Vehicular-ND] - Xiang, Zhong., Jeong, J., Ed., and Y. Shen, "IPv6 Neighbor - Discovery for IP-Based Vehicular Networks", draft-xiang- - ipwave-vehicular-neighbor-discovery-00 (work in progress), - November 2018. - - [ID-VND-Discovery] - Jeong, J., Ed., Shen, Y., Jo, Y., Jeong, J., and J. Lee, - "IPv6 Neighbor Discovery for Prefix and Service Discovery - in Vehicular Networks", draft-jeong-ipwave-vehicular- - neighbor-discovery-04 (work in progress), October 2018. + Jeong, J., Ed., Shen, Y., and Z. Xiang, "IPv6 Neighbor + Discovery for IP-Based Vehicular Networks", draft-jeong- + ipwave-vehicular-neighbor-discovery-06 (work in progress), + March 2019. [Identity-Management] Wetterwald, M., Hrizi, F., and P. Cataldi, "Cross-layer Identities Management in ITS Stations", The 10th International Conference on ITS Telecommunications, November 2010. [IEEE-802.11-OCB] - IEEE 802.11 Working Group, "Part 11: Wireless LAN Medium - Access Control (MAC) and Physical Layer (PHY) - Specifications", IEEE Std 802.11-2016, December 2016. + "Part 11: Wireless LAN Medium Access Control (MAC) and + Physical Layer (PHY) Specifications", IEEE Std + 802.11-2016, December 2016. [IEEE-802.11p] - IEEE 802.11 Working Group, "Part 11: Wireless LAN Medium - Access Control (MAC) and Physical Layer (PHY) - Specifications - Amendment 6: Wireless Access in Vehicular - Environments", IEEE Std 802.11p-2010, June 2010. + "Part 11: Wireless LAN Medium Access Control (MAC) and + Physical Layer (PHY) Specifications - Amendment 6: + Wireless Access in Vehicular Environments", IEEE Std + 802.11p-2010, June 2010. [Intro-to-Algorithms] H. Cormen, T., E. Leiserson, C., L. Rivest, R., and C. Stein, "Introduction to Algorithms, 3rd ed.", The MIT Press, July 2009. [IP-Passing-Protocol] Chen, Y., Hsu, C., and W. Yi, "An IP Passing Protocol for Vehicular Ad Hoc Networks with Network Fragmentation", Elsevier Computers & Mathematics with Applications, January 2012. [IPv6-over-802.11-OCB] Petrescu, A., Benamar, N., Haerri, J., Lee, J., and T. Ernst, "Transmission of IPv6 Packets over IEEE 802.11 Networks operating in mode Outside the Context of a Basic Service Set (IPv6-over-80211-OCB)", draft-ietf-ipwave- - ipv6-over-80211ocb-30 (work in progress), September 2018. + ipv6-over-80211ocb-34 (work in progress), December 2018. [IPv6-WAVE] Baccelli, E., Clausen, T., and R. Wakikawa, "IPv6 Operation for WAVE - Wireless Access in Vehicular Environments", IEEE Vehicular Networking Conference, December 2010. [ISO-ITS-IPv6] ISO/TC 204, "Intelligent Transport Systems - Communications Access for Land Mobiles (CALM) - IPv6 @@ -1122,59 +1309,70 @@ Protocol for Vehicular Ad Hoc Networks", Wiley International Journal of Communication Systems, November 2014. [PMIP-NEMO-Analysis] Lee, J., Ernst, T., and N. Chilamkurti, "Performance Analysis of PMIPv6-Based Network Mobility for Intelligent Transportation Systems", IEEE Transactions on Vehicular Technology, January 2012. + [RFC3561] Perkins, C., Belding-Royer, E., and S. Das, "Ad hoc On- + Demand Distance Vector (AODV) Routing", RFC 3561, July + 2003. + [RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker, "Randomness Requirements for Security", RFC 4086, June 2005. [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, "Neighbor Discovery for IP Version 6 (IPv6)", RFC 4861, September 2007. [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless Address Autoconfiguration", RFC 4862, September 2007. [RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy Extensions for Stateless Address Autoconfiguration in IPv6", RFC 4941, September 2007. [RFC5213] Gundavelli, S., Ed., Leung, K., Devarapalli, V., Chowdhury, K., and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008. + [RFC5844] Wakikawa, R. and S. Gundavelli, "IPv4 Support for Proxy + Mobile IPv6", RFC 5844, May 2010. + [RFC5889] Baccelli, E. and M. Townsley, "IP Addressing Model in Ad Hoc Networks", RFC 5889, September 2010. [RFC5944] Perkins, C., Ed., "IP Mobility Support in IPv4, Revised", RFC 5944, November 2010. [RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility Support in IPv6", RFC 6275, July 2011. [RFC6762] Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762, February 2013. [RFC6763] Cheshire, S. and M. Krochmal, "DNS-Based Service Discovery", RFC 6763, February 2013. [RFC6775] Shelby, Z., Chakrabarti, S., Nordmark, E., and C. Bormann, "Neighbor Discovery Optimization for IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs)", RFC 6775, November 2012. + [RFC7181] Clausen, T., Dearlove, C., Jacquet, P., and U. Herberg, + "The Optimized Link State Routing Protocol Version 2", + RFC 7181, April 2014. + [RFC7333] Chan, H., Liu, D., Seite, P., Yokota, H., and J. Korhonen, "Requirements for Distributed Mobility Management", RFC 7333, August 2014. [RFC7429] Liu, D., Zuniga, JC., Seite, P., Chan, H., and CJ. Bernardos, "Distributed Mobility Management: Current Practices and Gap Analysis", RFC 7429, January 2015. [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6) Specification", RFC 8200, July 2017. @@ -1315,92 +1513,91 @@ functions based on IPv6 use multicast for control-plane messages, such as Neighbor Discovery (ND) and Service Discovery, [Multicast-802] describes that the ND process may fail due to unreliable wireless link, causing failure of the DAD process. Also, the Router Advertisement messages can be lost in multicasting. A.4. DNS Naming Services and Service Discovery When two vehicular nodes communicate with each other using the DNS name of the partner node, DNS naming service (i.e., DNS name - resolution) is required. As shown in Figure 2 and Figure 3, a - recursive DNS server (RDNSS) within an internal network can perform - such DNS name resolution for the sake of other vehicular nodes. + resolution) is required. As shown in Figure 2 and Figure 3, a DNS + server within an internal network can perform such DNS name + resolution for the sake of other vehicular nodes. A service discovery service is required for an application in a vehicular node to search for another application or server in another vehicular node, which resides in either the same internal network or the other internal network. In V2I or V2V networking, as shown in Figure 2 and Figure 3, such a service discovery service can be provided by either DNS-based Service Discovery (DNS-SD) [RFC6763] with mDNS [RFC6762] or the vehicular ND with a new option for service - discovery [ID-Vehicular-ND][ID-VND-Discovery]. + discovery [ID-Vehicular-ND]. A.5. IPv6 over Cellular Networks Recently, 3GPP has announced a set of new technical specifications, - such as Release 14 (3GPP-R14), which proposes an architecture - enhancements for V2X services using the modified sidelink interface - that originally is designed for the LTE-D2D communications. 3GPP-R14 - specifies that the V2X services only support IPv6 implementation. - 3GPP is also investigating and discussing the evolved V2X services in - the next generation cellular networks, i.e., 5G new radio (5G-NR), - for advanced V2X communications and automated vehicles' applications. + such as Release 14 (3GPP-R14) [TS-23.285-3GPP], which proposes an + architecture enhancements for V2X services using the modified + sidelink interface that originally is designed for the LTE-Device-to- + Device (D2D) communications. 3GPP-R14 specifies that the V2X + services only support IPv6 implementation. 3GPP is also + investigating and discussing the evolved V2X services in the next + generation cellular networks, i.e., 5G new radio (5G-NR), for + advanced V2X communications and automated vehicles' applications. A.5.1. Cellular V2X (C-V2X) Using 4G-LTE Before 3GPP-R14, some researchers have studied the potential usage of C-V2X communications. For example, [VMaSC-LTE] explores a multihop cluster-based hybrid architecture using both DSRC and LTE for safety message dissemination. Most of the research considers a short message service for safety instead of IP datagram forwarding. In other C-V2X research, the standard IPv6 is assumed. - The 3GPP technical specification [TS-23.285-3GPP] states that both IP - based and non-IP based V2X messages are supported, and only IPv6 is - supported for IP based messages. Moreover, [TS-23.285-3GPP] + The 3GPP technical specification of [TS-23.285-3GPP] states that both + IP based and non-IP based V2X messages are supported, and only IPv6 + is supported for IP based messages. Moreover, [TS-23.285-3GPP] instructs that a UE autoconfigures a link-local IPv6 address by - following [RFC4862], but without sending Neighbor Solicitation and - Neighbor Advertisement messages for DAD. This is because a unique - prefix is allocated to each node by the 3GPP network, so the IPv6 - addresses cannot be duplicate. + following SLAAC in [RFC4862], but without sending Neighbor + Solicitation and Neighbor Advertisement messages for DAD. This is + because a unique prefix is allocated to each node by the 3GPP + network, so the IPv6 addresses cannot be duplicate. A.5.2. Cellular V2X (C-V2X) Using 5G The emerging services, functions, and applications, which are developped in automotive industry, demand reliable and efficient - communication infrastructure for road networks. Correspondingly, the - support of enhanced V2X (eV2X)-based services by future converged and - interoperable 5G systems is required. The 3GPP Technical Report - [TR-22.886-3GPP] is studying new use cases and the corresponding - service requirements for V2X (including V2V and V2I) using 5G in both - infrastructure mode and the sidelink variations in the future. + communication infrastructure for road networks. Correspondingly, + enhanced V2X (eV2X)-based services can be supported by 5G systems. + The 3GPP Technical Report of [TR-22.886-3GPP] is studying new use + cases and the corresponding service requirements for V2X (including + V2V and V2I) using 5G in both infrastructure mode and the sidelink + variations in the future. -Appendix B. Changes from draft-ietf-ipwave-vehicular-networking-06 +Appendix B. Changes from draft-ietf-ipwave-vehicular-networking-07 The following changes are made from draft-ietf-ipwave-vehicular- - networking-06: + networking-07: - o In Figure 1, a vehicular network architecture is modified to show - a vehicular link model in a multi-link subnet with vehicular - wireless links. + o This version is revised based on the comments from Charlie Perkins + and Sri Gundavelli. - o In Section 5.1, a Vehicular Neighbor Discovery (VND) - [ID-Vehicular-ND] is introduced along with a vehicular link model - in a multi-link subnet. In such a subnet, the description of MAC - Address Pseudonym, Prefix Dissemination/Exchange, and Routing is - clarified. + o In Section 4.1, the existing protocols relevant to IP vehicular + networking are summarized and analyzed with pros and cons. This + subsection addresses the requirements for IP vehicular networking. - o In Section 5.2, a proactive handover is introduced for an - efficient mobility management with the cooperation among vehicles, - RSUs, and MA along with link-layer parameters, such as Received - Channel Power Indicator (RCPI). + o In Figure 1, a vehicular network architecture is modified to + clarify a multi-link subnet consisting of vehicular wireless + links, and to provide efficient vehicular communications for V2I & + V2V to vehicles whose wireless interface is configured with a + global IP address. Appendix C. Acknowledgments This work was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2017R1D1A1B03035885). This work was supported in part by Global Research Laboratory Program through the NRF funded by the Ministry of Science and ICT (MSIT) (NRF-2013K1A1A2A02078326) and by the DGIST R&D Program of the MSIT