--- 1/draft-ietf-ipwave-ipv6-over-80211ocb-04.txt 2017-09-10 07:13:46.389202916 -0700 +++ 2/draft-ietf-ipwave-ipv6-over-80211ocb-05.txt 2017-09-10 07:13:46.469204832 -0700 @@ -1,486 +1,509 @@ Network Working Group A. Petrescu Internet-Draft CEA, LIST Intended status: Standards Track N. Benamar -Expires: February 18, 2018 Moulay Ismail University +Expires: March 14, 2018 Moulay Ismail University J. Haerri Eurecom C. Huitema - + Private Octopus Inc. J. Lee Sangmyung University T. Ernst YoGoKo T. Li Peloton Technology - August 17, 2017 + September 10, 2017 - Transmission of IPv6 Packets over IEEE 802.11 Networks in mode Outside - the Context of a Basic Service Set (IPv6-over-80211ocb) - draft-ietf-ipwave-ipv6-over-80211ocb-04.txt +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-05.txt Abstract In order to transmit IPv6 packets on IEEE 802.11 networks run outside the context of a basic service set (OCB, earlier "802.11p") there is - a need to define a few parameters such as the recommended Maximum - Transmission Unit size, the header format preceding the IPv6 header, - the Type value within it, and others. This document describes these - parameters for IPv6 and IEEE 802.11 OCB networks; it portrays the - layering of IPv6 on 802.11 OCB similarly to other known 802.11 and - Ethernet layers - by using an Ethernet Adaptation Layer. - - In addition, the document attempts to list what is different in - 802.11 OCB (802.11p) compared to more 'traditional' 802.11a/b/g/n - layers, layers over which IPv6 protocols operates without issues. - Most notably, the operation outside the context of a BSS (OCB) has - impact on IPv6 handover behaviour and on IPv6 security. + a need to define a few parameters such as the supported Maximum + Transmission Unit size on the 802.11-OCB link, the header format + preceding the IPv6 header, the Type value within it, and others. + This document describes these parameters for IPv6 and IEEE 802.11-OCB + networks; it portrays the layering of IPv6 on 802.11-OCB similarly to + other known 802.11 and Ethernet layers - by using an Ethernet + Adaptation Layer. - An example of an IPv6 packet captured while transmitted over an IEEE - 802.11 OCB link (802.11p) is given. + In addition, the document lists what is different in 802.11-OCB + (802.11p) links compared to more 'traditional' 802.11a/b/g/n links, + where IPv6 protocols operate without issues. Most notably, the + operation outside the context of a BSS (OCB) has impact on IPv6 + handover behaviour and on IPv6 security. 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 http://datatracker.ietf.org/drafts/current/. + 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 February 18, 2018. + This Internet-Draft will expire on March 14, 2018. Copyright Notice Copyright (c) 2017 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 - (http://trustee.ietf.org/license-info) in effect on the date of + (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 . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 3. Communication Scenarios where IEEE 802.11 OCB Links are Used 6 - 4. Aspects introduced by the OCB mode to 802.11 . . . . . . . . 6 - 5. Layering of IPv6 over 802.11-OCB as over Ethernet . . . . . . 10 - 5.1. Maximum Transmission Unit (MTU) . . . . . . . . . . . . . 10 + 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6 + 3. Communication Scenarios where IEEE 802.11-OCB Links are Used 6 + 4. Aspects introduced by the OCB mode to 802.11 . . . . . . . . 7 + 5. Layering of IPv6 over 802.11-OCB as over Ethernet . . . . . . 11 + 5.1. Maximum Transmission Unit (MTU) . . . . . . . . . . . . . 11 5.2. Frame Format . . . . . . . . . . . . . . . . . . . . . . 11 - 5.2.1. Ethernet Adaptation Layer . . . . . . . . . . . . . . 12 - 5.3. Link-Local Addresses . . . . . . . . . . . . . . . . . . 13 + 5.2.1. Ethernet Adaptation Layer . . . . . . . . . . . . . . 13 + 5.3. Link-Local Addresses . . . . . . . . . . . . . . . . . . 14 5.4. Address Mapping . . . . . . . . . . . . . . . . . . . . . 14 5.4.1. Address Mapping -- Unicast . . . . . . . . . . . . . 14 - 5.4.2. Address Mapping -- Multicast . . . . . . . . . . . . 14 - 5.5. Stateless Autoconfiguration . . . . . . . . . . . . . . . 15 - 5.6. Subnet Structure . . . . . . . . . . . . . . . . . . . . 16 - 6. Example IPv6 Packet captured over a IEEE 802.11-OCB link . . 16 - 6.1. Capture in Monitor Mode . . . . . . . . . . . . . . . . . 17 - 6.2. Capture in Normal Mode . . . . . . . . . . . . . . . . . 19 - 7. Security Considerations . . . . . . . . . . . . . . . . . . . 21 - 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 22 - 9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 22 - 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 22 - 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 23 - 11.1. Normative References . . . . . . . . . . . . . . . . . . 23 - 11.2. Informative References . . . . . . . . . . . . . . . . . 24 - Appendix A. ChangeLog . . . . . . . . . . . . . . . . . . . . . 26 + 5.4.2. Address Mapping -- Multicast . . . . . . . . . . . . 15 + 5.5. Stateless Autoconfiguration . . . . . . . . . . . . . . . 16 + 5.6. Subnet Structure . . . . . . . . . . . . . . . . . . . . 17 + 6. Security Considerations . . . . . . . . . . . . . . . . . . . 17 + 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18 + 8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 18 + 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 18 + 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 19 + 10.1. Normative References . . . . . . . . . . . . . . . . . . 19 + 10.2. Informative References . . . . . . . . . . . . . . . . . 21 + Appendix A. ChangeLog . . . . . . . . . . . . . . . . . . . . . 24 Appendix B. Changes Needed on a software driver 802.11a to - become a 802.11-OCB driver . . . 28 - Appendix C. Design Considerations . . . . . . . . . . . . . . . 30 - C.1. Vehicle ID . . . . . . . . . . . . . . . . . . . . . . . 30 - C.2. Reliability Requirements . . . . . . . . . . . . . . . . 30 - C.3. Multiple interfaces . . . . . . . . . . . . . . . . . . . 31 - C.4. MAC Address Generation . . . . . . . . . . . . . . . . . 32 - Appendix D. IEEE 802.11 Messages Transmitted in OCB mode . . . . 32 - Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 32 + become a 802.11-OCB driver . . . 27 + + Appendix C. Design Considerations . . . . . . . . . . . . . . . 28 + C.1. Vehicle ID . . . . . . . . . . . . . . . . . . . . . . . 28 + C.2. Reliability Requirements . . . . . . . . . . . . . . . . 29 + C.3. Multiple interfaces . . . . . . . . . . . . . . . . . . . 30 + C.4. MAC Address Generation . . . . . . . . . . . . . . . . . 30 + Appendix D. IEEE 802.11 Messages Transmitted in OCB mode . . . . 31 + Appendix E. Implementation Status . . . . . . . . . . . . . . . 31 + E.1. Capture in Monitor Mode . . . . . . . . . . . . . . . . . 32 + E.2. Capture in Normal Mode . . . . . . . . . . . . . . . . . 34 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 36 1. Introduction This document describes the transmission of IPv6 packets on IEEE Std - 802.11 OCB networks (earlier known as 802.11p). This involves the - layering of IPv6 networking on top of the IEEE 802.11 MAC layer (with - an LLC layer). Compared to running IPv6 over the Ethernet MAC layer, - there is no modification required to the standards: IPv6 works fine - directly over 802.11 OCB too (with an LLC layer). + 802.11-OCB networks (earlier known as 802.11p) [IEEE-802.11-2012]. + This involves the layering of IPv6 networking on top of the IEEE + 802.11 MAC layer (with an LLC layer). Compared to running IPv6 over + the Ethernet MAC layer, there is no modification required to the + standards: IPv6 works fine directly over 802.11-OCB too (with an LLC + layer). The term "802.11p" is an earlier definition. As of year 2012, the behaviour of "802.11p" networks has been rolled in the document IEEE - Std 802.11-2012. In this document the term 802.11p disappears. + Std 802.11-2012. In that document the term 802.11p disappears. Instead, each 802.11p feature is conditioned by a flag in the Management Information Base. That flag is named "OCBActivated". - Whenever OCBActivated is set to true the feature it relates to - represents an earlier 802.11p feature. For example, an 802.11 + Whenever OCBActivated is set to true the feature it relates to, or + represents, an earlier 802.11p feature. For example, an 802.11 STAtion operating outside the context of a basic service set has the - OCBActivated flag set. Such a station, when it has the flag set, it + OCBActivated flag set. Such a station, when it has the flag set, uses a BSS identifier equal to ff:ff:ff:ff:ff:ff. - In the following text we use the term "802.11p" to mean 802.11-2012 - OCB. - - The IPv6 network layer operates on 802.11 OCB in the same manner as + The IPv6 network layer operates on 802.11-OCB in the same manner as it operates on 802.11 WiFi, with a few particular exceptions. The IPv6 network layer operates on WiFi by involving an Ethernet Adaptation Layer; this Ethernet Adaptation Layer maps 802.11 headers to Ethernet II headers. The operation of IP on Ethernet is described - in [RFC1042] and [RFC2464]. The situation of IPv6 networking layer - on Ethernet Adaptation Layer is illustrated below: + in [RFC1042], [RFC2464] and [I-D.hinden-6man-rfc2464bis]. The + situation of IPv6 networking layer on Ethernet Adaptation Layer is + illustrated below: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv6 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Ethernet Adaptation Layer | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 802.11 WiFi MAC | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 802.11 WiFi PHY | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ (in the above figure, a WiFi profile is represented; this is used also for OCB profile.) A more theoretical and detailed view of layer stacking, and - interfaces between the IP layer and 802.11 OCB layers, is illustrated + interfaces between the IP layer and 802.11-OCB layers, is illustrated below. The IP layer operates on top of the EtherType Protocol Discrimination (EPD); this Discrimination layer is described in IEEE Std 802.3-2012; the interface between IPv6 and EPD is the LLC_SAP (Link Layer Control Service Accesss Point). +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv6 | +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ - { LLC_SAP } 802.11 OCB + { LLC_SAP } 802.11-OCB +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ Boundary | EPD | | | | | MLME | | +-+-+-{ MAC_SAP }+-+-+-| MLME_SAP | - | MAC Sublayer | | | 802.11 OCB + | MAC Sublayer | | | 802.11-OCB | and ch. coord. | | SME | Services +-+-+-{ PHY_SAP }+-+-+-+-+-+-+-| | | | PLME | | | PHY Layer | PLME_SAP | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ In addition to the description of interface between IP and MAC using "Ethernet Adaptation Layer" and "Ethernet Protocol Discrimination (EPD)" it is worth mentioning that SNAP [RFC1042] is used to carry the IPv6 Ethertype. However, there may be some deployment considerations helping optimize the performances of running IPv6 over 802.11-OCB (e.g. in the case of - handovers between 802.11 OCB-enabled access routers, or the - consideration of using the IP security layer [RFC4301]). + handovers between 802.11-OCB-enabled access routers, or the + consideration of using the IP security architecture [RFC4301]). There are currently no specifications for handover between OCB links since these are currently specified as LLC-1 links (i.e. connectionless). Any handovers must be performed above the Data Link - Layer. Also, while there is no encryption applied below the network - layer using 802.11p, 1609.2 [ieee1609.2] does provide security - services for applications to use so that there can easily be data - security over the air without invoking IPsec. + Layer. To realize handovers between OCB links there is a need of + specific indicators to assist in the handover process. The + indicators may be IP Router Advertisements, or 802.11-OCB's Time + Advertisements, or higher layer messages such as the 'Basic Safety + Message' (in the US), or the 'Cooperative Awareness Message' (in the + EU), or the 'WAVE Routing Advertisement'. However, this document + does not describe handover behaviour. + + The OCB operation is stripping off all existing 802.11 link-layer + security mechanisms. There is no encryption applied below the + network layer running on 802.11-OCB. At application layer, the IEEE + 1609.2 document [IEEE-1609.2] does provide security services for + certain applications to use. A security mechanism provided at + networking layer, such as IPsec [RFC4301], may provide data security + protection to a wider range of applications. See the section + Security Considerations of this document, Section 6 We briefly introduce the vehicular communication scenarios where IEEE 802.11-OCB links are used. This is followed by a description of - differences in specification terms, between 802.11 OCB and - 802.11a/b/g/n (and the same differences expressed in terms of - requirements to software implementation are listed in Appendix B.) + differences in specification terms, between 802.11-OCB and + 802.11a/b/g/n - we answer the question of what are the aspects + introduced by OCB mode to 802.11; the same aspects, but expressed in + terms of requirements to implementation, are listed in Appendix B.) The document then concentrates on the parameters of layering IP over - 802.11 OCB as over Ethernet: value of MTU, the contents of Frame - Format, the rules for forming Interface Identifiers, the mechanism - for Address Mapping and for State-less Address Auto-configuration. - These are precisely the same as IPv6 over Ethernet [RFC2464]. + 802.11-OCB as over Ethernet: value of MTU, the Frame Format which + includes a description of an Ethernet Adaptation Layer, the forming + of Link-Local Addresses the rules for forming Interface Identifiers + for Stateless Autoconfiguration, the mechanisms for Address Mapping. + These are precisely the same as IPv6 over Ethernet [RFC2464]. A + reference is made to ad-hoc networking characteristics of the subnet + structure in OCB mode. As an example, these characteristics of layering IPv6 straight over - LLC over 802.11 OCB MAC are illustrated by dissecting an IPv6 packet - captured over a 802.11 OCB link; this is described in the section - Section 6. - - A couple of points can be considered as different, although they are - not required in order to have a working implementation of IPv6-over- - 802.11-OCB. These points are consequences of the OCB operation which - is particular to 802.11 OCB (Outside the Context of a BSS). First, - the handovers between OCB links need specific behaviour for IP Router - Advertisements, or otherwise 802.11 OCB's Time Advertisement, or of - higher layer messages such as the 'Basic Safety Message' (in the US) - or the 'Cooperative Awareness Message' (in the EU) or the 'WAVE - Routing Advertisement'; second, the IP security mechanisms are - necessary, since OCB means that 802.11 is stripped of all 802.11 - link-layer security; a small additional security aspect which is - shared between 802.11 OCB and other 802.11 links is the privacy - concerns related to the address formation mechanisms. + LLC over 802.11-OCB MAC are illustrated by dissecting an IPv6 packet + captured over a 802.11-OCB link; this is described in the section + Appendix E. In the published literature, many documents describe aspects related - to running IPv6 over 802.11 OCB: + to running IPv6 over 802.11-OCB: [I-D.jeong-ipwave-vehicular-networking-survey]. 2. Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119]. - RSU: Road Side Unit. A computer equipped with at least one IEEE - 802.11 interface operated in OCB mode. This definition applies to - this document. An RSU may be connected to the Internet, and may be - equipped with additional wired or wireless network interfaces running - IP. An RSU MAY be an IP Router. + OBU (On-Board Unit): contrary to an RSU, an OBU is almost always + situated in a vehicle; it is a computer with at least two IP + interfaces; also, at least one IP interface runs in OCB mode of + 802.11. It may be an IP router. - OCB: outside the context of a basic service set (BSS): A mode of + RSU (Road Side Unit): It is a Wireless Termination Point (WTP), as + defined in [RFC5415], or an Access Point (AP), or an Access Network + Router (ANR) defined in [RFC3753], with one key particularity: the + wireless PHY/MAC layer is configured to operate in 802.11-OCB mode. + The RSU communicates with the On board Unit (OBU) in the vehicle over + 802.11 wireless link operating in OCB mode. An RSU MAY be connected + to the Internet, and MAY be an IP router. When it is connected to + the Internet, the term V2I (Vehicle to Internet) is relevant. + + OCB (outside the context of a basic service set - BSS): A mode of operation in which a STA is not a member of a BSS and does not utilize IEEE Std 802.11 authentication, association, or data confidentiality. - 802.11-OCB, or 802.11 OCB: text in document IEEE 802.11-2012 that is - flagged by "dot11OCBActivated". This means: IEEE 802.11e for quality - of service; 802.11j-2004 for half-clocked operations; and (what was - known earlier as) 802.11p for operation in the 5.9 GHz band and in - mode OCB. + 802.11-OCB, or 802.11-OCB: text in document IEEE 802.11-2012 that is + flagged by "dot11OCBActivated". The text flagged "dot11OCBActivated" + includes IEEE 802.11e for quality of service, 802.11j-2004 for half- + clocked operations and (what was known earlier as) 802.11p for + operation in the 5.9 GHz band and in mode OCB. -3. Communication Scenarios where IEEE 802.11 OCB Links are Used +3. Communication Scenarios where IEEE 802.11-OCB Links are Used - The IEEE 802.11 OCB Networks are used for vehicular communications, + The IEEE 802.11-OCB Networks are used for vehicular communications, as 'Wireless Access in Vehicular Environments'. The IP communication scenarios for these environments have been described in several documents, among which we refer the reader to one recently updated [I-D.petrescu-its-scenarios-reqs], about scenarios and requirements for IP in Intelligent Transportation Systems. + The link model is the following: STA --- 802.11-OCB --- STA. In + vehicular networks, STAs can be RSUs and/or OBUs. While 802.11-OCB + is clearly specified, and the use of IPv6 over such link is not + radically new, the operating environment (vehicular networks) brings + in new perspectives. + + The 802.11-OCB links form and terminate; nodes connected to these + links peer, and discover each other; the nodes are mobile. However, + the precise description of how links discover each other, peer and + manage mobility is not given in this document. + 4. Aspects introduced by the OCB mode to 802.11 - In the IEEE 802.11 OCB mode, all nodes in the wireless range can - directly communicate with each other without authentication/ - association procedures. Briefly, the IEEE 802.11 OCB mode has the - following properties: + In the IEEE 802.11-OCB mode, all nodes in the wireless range can + directly communicate with each other without involving authentication + or association procedures. At link layer, it is necessary to set a + same channel number (or frequency) on two stations that need to + communicate with each other. Stations STA1 and STA2 can exchange IP + packets if they are set on the same channel. At IP layer, they then + discover each other by using the IPv6 Neighbor Discovery protocol. + + Briefly, the IEEE 802.11-OCB mode has the following properties: o The use by each node of a 'wildcard' BSSID (i.e., each bit of the BSSID is set to 1) - o No IEEE 802.11 Beacon frames transmitted + o No IEEE 802.11 Beacon frames are transmitted - o No authentication required + o No authentication is required in order to be able to communicate - o No association needed + o No association is needed in order to be able to communicate - o No encryption provided + o No encryption is provided in order to be able to communicate - o Flag dot11OCBActivated set to true + o Flag dot11OCBActivated is set to true + + All the nodes in the radio communication range (OBU and RSU) receive + all the messages transmitted (OBU and RSU) within the radio + communications range. The eventual conflict(s) are resolved by the + MAC CDMA function. The following message exchange diagram illustrates a comparison between traditional 802.11 and 802.11 in OCB mode. The 'Data' - messages can be IP messages such as the messages used in Stateless or - Stateful Address Auto-Configuration, or other IP messages. Other - 802.11 management and control frames (non IP) may be transmitted, as + messages can be IP packets such as HTTP or others. Other 802.11 + management and control frames (non IP) may be transmitted, as specified in the 802.11 standard. For information, the names of these messages as currently specified by the 802.11 standard are listed in Appendix D. STA AP STA1 STA2 | | | | |<------ Beacon -------| |<------ Data -------->| | | | | |---- Probe Req. ----->| |<------ Data -------->| |<--- Probe Res. ------| | | | | |<------ Data -------->| |---- Auth Req. ------>| | | |<--- Auth Res. -------| |<------ Data -------->| | | | | |---- Asso Req. ------>| |<------ Data -------->| |<--- Asso Res. -------| | | | | |<------ Data -------->| |<------ Data -------->| | | |<------ Data -------->| |<------ Data -------->| - (a) 802.11 Infrastructure mode (b) 802.11 OCB mode + (a) 802.11 Infrastructure mode (b) 802.11-OCB mode - The link 802.11 OCB was specified in IEEE Std 802.11p (TM) -2010 - [ieee802.11p-2010] as an amendment to IEEE Std 802.11 (TM) -2007, + The link 802.11-OCB was specified in IEEE Std 802.11p (TM) -2010 + [IEEE-802.11p-2010] as an amendment to IEEE Std 802.11 (TM) -2007, titled "Amendment 6: Wireless Access in Vehicular Environments". Since then, this amendment has been included in IEEE 802.11(TM)-2012 - [ieee802.11-2012], titled "IEEE Standard for Information technology-- - Telecommunications and information exchange between systems Local and - metropolitan area networks--Specific requirements Part 11: Wireless - LAN Medium Access Control (MAC) and Physical Layer (PHY) - Specifications"; the modifications are diffused throughout various - sections (e.g. the Time Advertisement message described in the - earlier 802.11 (TM) p amendment is now described in section 'Frame - formats', and the operation outside the context of a BSS described in - section 'MLME'). + [IEEE-802.11-2012], titled "IEEE Standard for Information + technology--Telecommunications and information exchange between + systems Local and metropolitan area networks--Specific requirements + Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer + (PHY) Specifications"; the modifications are diffused throughout + various sections (e.g. the Time Advertisement message described in + the earlier 802.11 (TM) p amendment is now described in section + 'Frame formats', and the operation outside the context of a BSS + described in section 'MLME'). In document 802.11-2012, specifically anything referring "OCBActivated", or "outside the context of a basic service set" is - actually referring to the 802.11p aspects introduced to 802.11. Note - that in earlier 802.11p documents the term "OCBEnabled" was used - instead of te current "OCBActivated". + actually referring to OCB aspects introduced to 802.11. Note that in + earlier 802.11p documents the term "OCBEnabled" was used instead of + the current "OCBActivated". - In order to delineate the aspects introduced by 802.11 OCB to 802.11, - we refer to the earlier [ieee802.11p-2010]. The amendment is + In order to delineate the aspects introduced by 802.11-OCB to 802.11, + we refer to the earlier [IEEE-802.11p-2010]. The amendment is concerned with vehicular communications, where the wireless link is similar to that of Wireless LAN (using a PHY layer specified by 802.11a/b/g/n), but which needs to cope with the high mobility factor inherent in scenarios of communications between moving vehicles, and between vehicles and fixed infrastructure deployed along roads. While 'p' is a letter just like 'a, b, g' and 'n' are, 'p' is concerned more with MAC modifications, and a little with PHY modifications; the others are mainly about PHY modifications. It is possible in practice to combine a 'p' MAC with an 'a' PHY by operating outside the context of a BSS with OFDM at 5.4GHz. - The 802.11 OCB links are specified to be compatible as much as + The 802.11-OCB links are specified to be compatible as much as possible with the behaviour of 802.11a/b/g/n and future generation - IEEE WLAN links. From the IP perspective, an 802.11 OCB MAC layer + IEEE WLAN links. From the IP perspective, an 802.11-OCB MAC layer offers practically the same interface to IP as the WiFi and Ethernet - layers do (802.11a/b/g/n and 802.3). + layers do (802.11a/b/g/n and 802.3). A packet sent by an OBU may be + received by one or multiple RSUs. The link-layer resolution is + performed by using the IPv6 Neighbor Discovery protocol. To support this similarity statement (IPv6 is layered on top of LLC - on top of 802.11 OCB similarly as on top of LLC on top of - 802.11a/b/g/n, and as on top of LLC on top of 802.3) it is useful to - analyze the differences between 802.11 OCB and 802.11 specifications. - Whereas the 802.11p amendment specifies relatively complex and - numerous changes to the MAC layer (and very little to the PHY layer), - we note there are only a few characteristics which may be important - for an implementation transmitting IPv6 packets on 802.11 OCB links. + on top of 802.11-OCB, in the same way that IPv6 is layered on top of + LLC on top of 802.11a/b/g/n (for WLAN) or layered on top of LLC on + top of 802.3 (for Ethernet)) it is useful to analyze the differences + between 802.11-OCB and 802.11 specifications. During this analysis, + we note that whereas 802.11-OCB lists relatively complex and numerous + changes to the MAC layer (and very little to the PHY layer), there + are only a few characteristics which may be important for an + implementation transmitting IPv6 packets on 802.11-OCB links. - In the list below, the only 802.11 OCB fundamental points which - influence IPv6 are the OCB operation and the 12Mbit/s maximum which - may be afforded by the IPv6 applications. + The most important 802.11-OCB point which influences the IPv6 + functioning is the OCB characteristic; an additional, less direct + influence, is the maximum bandwidth afforded by the PHY modulation/ + demodulation methods and channel access specified by 802.11-OCB. The + maximum bandwidth possible in 802.11-OCB is 12Mbit/s; this bandwidth + allows the operation of a wide range of protocols relying on IPv6. o Operation Outside the Context of a BSS (OCB): the (earlier 802.11p) 802.11-OCB links are operated without a Basic Service Set (BSS). This means that the frames IEEE 802.11 Beacon, Association Request/Response, Authentication Request/Response, and similar, are not used. The used identifier of BSS (BSSID) has a hexadecimal value always 0xffffffffffff (48 '1' bits, represented as MAC address ff:ff:ff:ff:ff:ff, or otherwise the 'wildcard' BSSID), as opposed to an arbitrary BSSID value set by administrator (e.g. 'My-Home-AccessPoint'). The OCB operation - namely the lack of beacon-based scanning and lack of - authentication - has a potentially strong impact on the use of the - Mobile IPv6 protocol [RFC6275] and on the protocols for IP layer - security [RFC4301]. + authentication - should be taken into account when the Mobile IPv6 + protocol [RFC6275] and the protocols for IP layer security + [RFC4301] are used. The way these protocols adapt to OCB is not + described in this document. o Timing Advertisement: is a new message defined in 802.11-OCB, which does not exist in 802.11a/b/g/n. This message is used by stations to inform other stations about the value of time. It is similar to the time as delivered by a GNSS system (Galileo, GPS, ...) or by a cellular system. This message is optional for - implementation. At the date of writing, an experienced reviewer - considers that currently no field testing has used this message. - Another implementor considers this feature implemented in an - initial manner. In the future, it is speculated that this message - may be useful for very simple devices which may not have their own - hardware source of time (Galileo, GPS, cellular network), or by - vehicular devices situated in areas not covered by such network - (in tunnels, underground, outdoors but shaded by foliage or - buildings, in remote areas, etc.) + implementation. o Frequency range: this is a characteristic of the PHY layer, with almost no impact to the interface between MAC and IP. However, it is worth considering that the frequency range is regulated by a regional authority (ARCEP, ETSI, FCC, etc.); as part of the regulation process, specific applications are associated with specific frequency ranges. In the case of 802.11-OCB, the regulator associates a set of frequency ranges, or slots within a band, to the use of applications of vehicular communications, in a - band known as "5.9GHz". This band is "5.9GHz" which is different - from the bands "2.4GHz" or "5GHz" used by Wireless LAN. However, - as with Wireless LAN, the operation of 802.11-OCB in "5.9GHz" - bands is exempt from owning a license in EU (in US the 5.9GHz is a - licensed band of spectrum; for the the fixed infrastructure an - explicit FCC autorization is required; for an onboard device a - 'licensed-by-rule' concept applies: rule certification conformity - is required); however technical conditions are different than - those of the bands "2.4GHz" or "5GHz". On one hand, the allowed - power levels, and implicitly the maximum allowed distance between - vehicles, is of 33dBm for 802.11-OCB (in Europe), compared to 20 - dBm for Wireless LAN 802.11a/b/g/n; this leads to a maximum - distance of approximately 1km, compared to approximately 50m. On - the other hand, specific conditions related to congestion - avoidance, jamming avoidance, and radar detection are imposed on - the use of DSRC (in US) and on the use of frequencies for - Intelligent Transportation Systems (in EU), compared to Wireless - LAN (802.11a/b/g/n). + band known as "5.9GHz". The 5.9GHz band is different from the + 2.4GHz and 5GHz bands used by Wireless LAN. However, as with + Wireless LAN, the operation of 802.11-OCB in "5.9GHz" bands is + exempt from owning a license in EU (in US the 5.9GHz is a licensed + band of spectrum; for the the fixed infrastructure an explicit FCC + autorization is required; for an onboard device a 'licensed-by- + rule' concept applies: rule certification conformity is required); + however technical conditions are different than those of the bands + "2.4GHz" or "5GHz". On one hand, the allowed power levels, and + implicitly the maximum allowed distance between vehicles, is of + 33dBm for 802.11-OCB (in Europe), compared to 20 dBm for Wireless + LAN 802.11a/b/g/n; this leads to a maximum distance of + approximately 1km, compared to approximately 50m. On the other + hand, specific conditions related to congestion avoidance, jamming + avoidance, and radar detection are imposed on the use of DSRC (in + US) and on the use of frequencies for Intelligent Transportation + Systems (in EU), compared to Wireless LAN (802.11a/b/g/n). o Prohibition of IPv6 on some channels relevant for IEEE 802.11-OCB, as opposed to IPv6 not being prohibited on any channel on which 802.11a/b/g/n runs: * Some channels are reserved for safety communications; the IPv6 packets should not be sent on these channels. * At the time of writing, the prohibition is explicit at higher layer protocols providing services to the application; these - higher layer protocols are specified in IEEE 1609 documents. + higher layer protocols are specified in IEEE 1609 documents, + i.e. the "WAVE" stack. * National or regional specifications and regulations specify the use of different channels; these regulations must be followed. o 'Half-rate' encoding: as the frequency range, this parameter is related to PHY, and thus has not much impact on the interface between the IP layer and the MAC layer. o In vehicular communications using 802.11-OCB links, there are strong privacy requirements with respect to addressing. While the 802.11-OCB standard does not specify anything in particular with respect to MAC addresses, in these settings there exists a strong need for dynamic change of these addresses (as opposed to the non- vehicular settings - real wall protection - where fixed MAC addresses do not currently pose some privacy risks). This is - further described in section Section 7. A relevant function is - described in IEEE 1609.3-2016 [ieee1609.3], clause 5.5.1 and IEEE - 1609.4-2016 [ieee1609.4], clause 6.7. + further described in section Section 6. A relevant function is + described in IEEE 1609.3-2016 [IEEE-1609.3], clause 5.5.1 and IEEE + 1609.4-2016 [IEEE-1609.4], clause 6.7. - Other aspects particular to 802.11-OCB which are also particular to - 802.11 (e.g. the 'hidden node' operation) may have an influence on + Other aspects particular to 802.11-OCB, which are also particular to + 802.11 (e.g. the 'hidden node' operation), may have an influence on the use of transmission of IPv6 packets on 802.11-OCB networks. The - subnet structure which may be assumed in 802.11-OCB networks is - strongly influenced by the mobility of vehicles. + OCB subnet structure is described in section Section 5.6. 5. Layering of IPv6 over 802.11-OCB as over Ethernet 5.1. Maximum Transmission Unit (MTU) The default MTU for IP packets on 802.11-OCB is 1500 octets. It is the same value as IPv6 packets on Ethernet links, as specified in [RFC2464]. This value of the MTU respects the recommendation that every link in the Internet must have a minimum MTU of 1280 octets - (stated in [RFC2460], and the recommendations therein, especially + (stated in [RFC8200], and the recommendations therein, especially with respect to fragmentation). If IPv6 packets of size larger than 1500 bytes are sent on an 802.11-OCB interface card then the IP stack will fragment. In case there are IP fragments, the field "Sequence number" of the 802.11 Data header containing the IP fragment field is increased. Non-IP packets such as WAVE Short Message Protocol (WSMP) can be delivered on 802.11-OCB links. Specifications of these packets are out of scope of this document, and do not impose any limit on the MTU size, allowing an arbitrary number of 'containers'. Non-IP packets - such as ETSI 'geonet' packets have an MTU of 1492 bytes. - - The Equivalent Transmit Time on Channel is a concept that may be used - as an alternative to the MTU concept. A rate of transmission may be - specified as well. The ETTC, rate and MTU may be in direct - relationship. + such as ETSI GeoNetworking packets have an MTU of 1492 bytes. The + operation of IPv6 over GeoNetworking is specified at + [ETSI-IPv6-GeoNetworking]. 5.2. Frame Format IP packets are transmitted over 802.11-OCB as standard Ethernet packets. As with all 802.11 frames, an Ethernet adaptation layer is used with 802.11-OCB as well. This Ethernet Adaptation Layer performing 802.11-to-Ethernet is described in Section 5.2.1. The Ethernet Type code (EtherType) for IPv6 is 0x86DD (hexadecimal 86DD, or otherwise #86DD). @@ -567,21 +591,22 @@ field in the Ethernet II Header. The ".11 Trailer" contains solely a 4-byte Frame Check Sequence. The Ethernet Adaptation Layer performs operations in relation to IP fragmentation and MTU. One of these operations is briefly described in section Section 5.1. In OCB mode, IPv6 packets can be transmitted either as "IEEE 802.11 Data" or alternatively as "IEEE 802.11 QoS Data", as illustrated in - the following figure: + the figure below. Some commercial OCB products use 802.11 Data, and + others 802.11 QoS data. In the future, both could be used. +--------------------+-------------+-------------+---------+-----------+ | 802.11 Data Header | LLC Header | IPv6 Header | Payload |.11 Trailer| +--------------------+-------------+-------------+---------+-----------+ or +--------------------+-------------+-------------+---------+-----------+ | 802.11 QoS Data Hdr| LLC Header | IPv6 Header | Payload |.11 Trailer| +--------------------+-------------+-------------+---------+-----------+ @@ -663,21 +688,21 @@ DST. +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 1 1 0 0 1 1|0 0 1 1 0 0 1 1| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | DST[13] | DST[14] | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | DST[15] | DST[16] | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - A Group ID TBD of length 112bits may be requested from IANA; this + A Group ID named TBD, of length 112bits is requested to IANA; this Group ID signifies "All 80211OCB Interfaces Address". Only the least 32 significant bits of this "All 80211OCB Interfaces Address" will be mapped to and from a MAC multicast address. Transmitting IPv6 packets to multicast destinations over 802.11 links proved to have some performance issues [I-D.perkins-intarea-multicast-ieee802]. These issues may be exacerbated in OCB mode. Solutions for these problems should consider the OCB mode of operation. @@ -686,521 +711,418 @@ The Interface Identifier for an 802.11-OCB interface is formed using the same rules as the Interface Identifier for an Ethernet interface; this is described in section 4 of [RFC2464]. No changes are needed, but some care must be taken when considering the use of the SLAAC procedure. The bits in the the interface identifier have no generic meaning and the identifier should be treated as an opaque value. The bits 'Universal' and 'Group' in the identifier of an 802.11-OCB interface are significant, as this is an IEEE link-layer address. The details - of this significance are described in [I-D.ietf-6man-ug]. + of this significance are described in [RFC7136]. As with all Ethernet and 802.11 interface identifiers ([RFC7721]), - the identifier of an 802.11-OCB interface may involve privacy risks. - A vehicle embarking an On-Board Unit whose egress interface is - 802.11-OCB may expose itself to eavesdropping and subsequent - correlation of data; this may reveal data considered private by the - vehicle owner; there is a risk of being tracked; see the privacy - considerations described in Appendix C. + the identifier of an 802.11-OCB interface may involve privacy, MAC + address spoofing and IP address hijacking risks. A vehicle embarking + an On-Board Unit whose egress interface is 802.11-OCB may expose + itself to eavesdropping and subsequent correlation of data; this may + reveal data considered private by the vehicle owner; there is a risk + of being tracked; see the privacy considerations described in + Appendix C. If stable Interface Identifiers are needed in order to form IPv6 addresses on 802.11-OCB links, it is recommended to follow the - recommendation in [I-D.ietf-6man-default-iids]. + recommendation in [RFC8064]. 5.6. Subnet Structure + A subnet is formed by the external 802.11-OCB interfaces of vehicles + that are in close range (not their on-board interfaces). This + ephemeral subnet structure is strongly influenced by the mobility of + vehicles: the 802.11 hidden node effects appear. On another hand, + the structure of the internal subnets in each car is relatively + stable. + + For routing purposes, a prefix exchange mechanism could be needed + between neighboring vehicles. + The 802.11 networks in OCB mode may be considered as 'ad-hoc' networks. The addressing model for such networks is described in [RFC5889]. -6. Example IPv6 Packet captured over a IEEE 802.11-OCB link - - We remind that a main goal of this document is to make the case that - IPv6 works fine over 802.11-OCB networks. Consequently, this section - is an illustration of this concept and thus can help the implementer - when it comes to running IPv6 over IEEE 802.11-OCB. By way of - example we show that there is no modification in the headers when - transmitted over 802.11-OCB networks - they are transmitted like any - other 802.11 and Ethernet packets. - - We describe an experiment of capturing an IPv6 packet on an - 802.11-OCB link. In this experiment, the packet is an IPv6 Router - Advertisement. This packet is emitted by a Router on its 802.11-OCB - interface. The packet is captured on the Host, using a network - protocol analyzer (e.g. Wireshark); the capture is performed in two - different modes: direct mode and 'monitor' mode. The topology used - during the capture is depicted below. - - +--------+ +-------+ - | | 802.11-OCB Link | | - ---| Router |--------------------------------| Host | - | | | | - +--------+ +-------+ - - During several capture operations running from a few moments to - several hours, no message relevant to the BSSID contexts were - captured (no Association Request/Response, Authentication Req/Resp, - Beacon). This shows that the operation of 802.11-OCB is outside the - context of a BSSID. - - Overall, the captured message is identical with a capture of an IPv6 - packet emitted on a 802.11b interface. The contents are precisely - similar. - -6.1. Capture in Monitor Mode - - The IPv6 RA packet captured in monitor mode is illustrated below. - The radio tap header provides more flexibility for reporting the - characteristics of frames. The Radiotap Header is prepended by this - particular stack and operating system on the Host machine to the RA - packet received from the network (the Radiotap Header is not present - on the air). The implementation-dependent Radiotap Header is useful - for piggybacking PHY information from the chip's registers as data in - a packet understandable by userland applications using Socket - interfaces (the PHY interface can be, for example: power levels, data - rate, ratio of signal to noise). - - The packet present on the air is formed by IEEE 802.11 Data Header, - Logical Link Control Header, IPv6 Base Header and ICMPv6 Header. - - Radiotap Header v0 - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - |Header Revision| Header Pad | Header length | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Present flags | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Data Rate | Pad | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - - IEEE 802.11 Data Header - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Type/Subtype and Frame Ctrl | Duration | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Receiver Address... - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - ... Receiver Address | Transmitter Address... - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - ... Transmitter Address | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | BSS Id... - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - ... BSS Id | Frag Number and Seq Number | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - Logical-Link Control Header - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | DSAP |I| SSAP |C| Control field | Org. code... - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - ... Organizational Code | Type | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - - IPv6 Base Header - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - |Version| Traffic Class | Flow Label | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Payload Length | Next Header | Hop Limit | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | | - + + - | | - + Source Address + - | | - + + - | | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | | - + + - | | - + Destination Address + - | | - + + - | | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - - Router Advertisement - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Type | Code | Checksum | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Cur Hop Limit |M|O| Reserved | Router Lifetime | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Reachable Time | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Retrans Timer | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Options ... - +-+-+-+-+-+-+-+-+-+-+-+- - - The value of the Data Rate field in the Radiotap header is set to 6 - Mb/s. This indicates the rate at which this RA was received. - - The value of the Transmitter address in the IEEE 802.11 Data Header - is set to a 48bit value. The value of the destination address is - 33:33:00:00:00:1 (all-nodes multicast address). The value of the BSS - Id field is ff:ff:ff:ff:ff:ff, which is recognized by the network - protocol analyzer as being "broadcast". The Fragment number and - sequence number fields are together set to 0x90C6. - - The value of the Organization Code field in the Logical-Link Control - Header is set to 0x0, recognized as "Encapsulated Ethernet". The - value of the Type field is 0x86DD (hexadecimal 86DD, or otherwise - #86DD), recognized as "IPv6". - - A Router Advertisement is periodically sent by the router to - multicast group address ff02::1. It is an icmp packet type 134. The - IPv6 Neighbor Discovery's Router Advertisement message contains an - 8-bit field reserved for single-bit flags, as described in [RFC4861]. - - The IPv6 header contains the link local address of the router - (source) configured via EUI-64 algorithm, and destination address set - to ff02::1. Recent versions of network protocol analyzers (e.g. - Wireshark) provide additional informations for an IP address, if a - geolocalization database is present. In this example, the - geolocalization database is absent, and the "GeoIP" information is - set to unknown for both source and destination addresses (although - the IPv6 source and destination addresses are set to useful values). - This "GeoIP" can be a useful information to look up the city, - country, AS number, and other information for an IP address. - - The Ethernet Type field in the logical-link control header is set to - 0x86dd which indicates that the frame transports an IPv6 packet. In - the IEEE 802.11 data, the destination address is 33:33:00:00:00:01 - which is he corresponding multicast MAC address. The BSS id is a - broadcast address of ff:ff:ff:ff:ff:ff. Due to the short link - duration between vehicles and the roadside infrastructure, there is - no need in IEEE 802.11-OCB to wait for the completion of association - and authentication procedures before exchanging data. IEEE - 802.11-OCB enabled nodes use the wildcard BSSID (a value of all 1s) - and may start communicating as soon as they arrive on the - communication channel. - -6.2. Capture in Normal Mode - - The same IPv6 Router Advertisement packet described above (monitor - mode) is captured on the Host, in the Normal mode, and depicted - below. - - Ethernet II Header - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Destination... - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - ...Destination | Source... - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - ...Source | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Type | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - - IPv6 Base Header - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - |Version| Traffic Class | Flow Label | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Payload Length | Next Header | Hop Limit | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | | - + + - | | - + Source Address + - | | - + + - | | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | | - + + - | | - + Destination Address + - | | - + + - | | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - - Router Advertisement - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Type | Code | Checksum | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Cur Hop Limit |M|O| Reserved | Router Lifetime | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Reachable Time | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Retrans Timer | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Options ... - +-+-+-+-+-+-+-+-+-+-+-+- - - One notices that the Radiotap Header is not prepended, and that the - IEEE 802.11 Data Header and the Logical-Link Control Headers are not - present. On another hand, a new header named Ethernet II Header is - present. - - The Destination and Source addresses in the Ethernet II header - contain the same values as the fields Receiver Address and - Transmitter Address present in the IEEE 802.11 Data Header in the - "monitor" mode capture. - - The value of the Type field in the Ethernet II header is 0x86DD - (recognized as "IPv6"); this value is the same value as the value of - the field Type in the Logical-Link Control Header in the "monitor" - mode capture. - - The knowledgeable experimenter will no doubt notice the similarity of - this Ethernet II Header with a capture in normal mode on a pure - Ethernet cable interface. - - It may be interpreted that an Adaptation layer is inserted in a pure - IEEE 802.11 MAC packets in the air, before delivering to the - applications. In detail, this adaptation layer may consist in - elimination of the Radiotap, 802.11 and LLC headers and insertion of - the Ethernet II header. In this way, it can be stated that IPv6 runs - naturally straight over LLC over the 802.11-OCB MAC layer, as shown - by the use of the Type 0x86DD, and assuming an adaptation layer - (adapting 802.11 LLC/MAC to Ethernet II header). + An addressing model involves several types of addresses, like + Globally-unique Addresses (GUA), Link-Local Addresses (LL) and Unique + Local Addresses (ULA). The subnet structure in 'ad-hoc' networks may + have characteristics that lead to difficulty of using GUAs derived + from a received prefix, but the LL addresses may be easier to use + since the prefix is constant. -7. Security Considerations +6. Security Considerations Any security mechanism at the IP layer or above that may be carried out for the general case of IPv6 may also be carried out for IPv6 operating over 802.11-OCB. 802.11-OCB does not provide any cryptographic protection, because it operates outside the context of a BSS (no Association Request/ Response, no Challenge messages). Any attacker can therefore just sit in the near range of vehicles, sniff the network (just set the interface card's frequency to the proper range) and perform attacks - without needing to physically break any wall. Such a link is way - less protected than commonly used links (wired link or protected - 802.11). + without needing to physically break any wall. Such a link is less + protected than commonly used links (wired link or protected 802.11). - At the IP layer, IPsec can be used to protect unicast communications, - and SeND can be used for multicast communications. If no protection - is used by the IP layer, upper layers should be protected. - Otherwise, the end-user or system should be warned about the risks - they run. + The potential attack vectors are: MAC address spoofing, IP address + and session hijacking and privacy violation. + + Within the IPsec Security Architecture [RFC4301], the IPsec AH and + ESP headers [RFC4302] and [RFC4303] respectively, its multicast + extensions [RFC5374], HTTPS [RFC2818] and SeND [RFC3971] protocols + can be used to protect communications. Further, the assistance of + proper Public Key Infrastructure (PKI) protocols [RFC4210] is + necessary to establish credentials. More IETF protocols are + available in the toolbox of the IP security protocol designer. + + Certain ETSI protocols related to security protocols in Intelligent + Transportation Systems are described in [ETSI-sec-archi]. As with all Ethernet and 802.11 interface identifiers, there may exist privacy risks in the use of 802.11-OCB interface identifiers. Moreover, in outdoors vehicular settings, the privacy risks are more important than in indoors settings. New risks are induced by the possibility of attacker sniffers deployed along routes which listen for IP packets of vehicles passing by. For this reason, in the 802.11-OCB deployments, there is a strong necessity to use protection tools such as dynamically changing MAC addresses. This may help mitigate privacy risks to a certain level. On another hand, it may have an impact in the way typical IPv6 address auto-configuration is performed for vehicles (SLAAC would rely on MAC addresses amd would hence dynamically change the affected IP address), in the way the IPv6 Privacy addresses were used, and other effects. -8. IANA Considerations +7. IANA Considerations -9. Contributors + A Group ID named TBD, of length 112bits is requested to IANA; this + Group ID signifies "All 80211OCB Interfaces Address". + +8. Contributors Romain Kuntz contributed extensively about IPv6 handovers between links running outside the context of a BSS (802.11-OCB links). Tim Leinmueller contributed the idea of the use of IPv6 over 802.11-OCB for distribution of certificates. Marios Makassikis, Jose Santa Lozano, Albin Severinson and Alexey Voronov provided significant feedback on the experience of using IP messages over 802.11-OCB in initial trials. Michelle Wetterwald contributed extensively the MTU discussion, offered the ETSI ITS perspective, and reviewed other parts of the document. -10. Acknowledgements +9. Acknowledgements The authors would like to thank Witold Klaudel, Ryuji Wakikawa, Emmanuel Baccelli, John Kenney, John Moring, Francois Simon, Dan Romascanu, Konstantin Khait, Ralph Droms, Richard 'Dick' Roy, Ray Hunter, Tom Kurihara, Michal Sojka, Jan de Jongh, Suresh Krishnan, Dino Farinacci, Vincent Park, Jaehoon Paul Jeong, Gloria Gwynne, Hans-Joachim Fischer, Russ Housley, Rex Buddenberg, Erik Nordmark, - Bob Moskowitz, Andrew (Dryden?), Georg Mayer, Dorothy Stanley and - William Whyte. Their valuable comments clarified certain issues and - generally helped to improve the document. + Bob Moskowitz, Andrew (Dryden?), Georg Mayer, Dorothy Stanley, Sandra + Cespedes, Mariano Falcitelli, Sri Gundavelli and William Whyte. + + Their valuable comments clarified particular issues and generally + helped to improve the document. Pierre Pfister, Rostislav Lisovy, and others, wrote 802.11-OCB drivers for linux and described how. For the multicast discussion, the authors would like to thank Owen DeLong, Joe Touch, Jen Linkova, Erik Kline, Brian Haberman and participants to discussions in network working groups. The authours would like to thank participants to the Birds-of- a-Feather "Intelligent Transportation Systems" meetings held at IETF in 2016. -11. References - -11.1. Normative References - - [I-D.ietf-6man-default-iids] - Gont, F., Cooper, A., Thaler, D., and S. LIU, - "Recommendation on Stable IPv6 Interface Identifiers", - draft-ietf-6man-default-iids-16 (work in progress), - September 2016. +10. References - [I-D.ietf-6man-ug] - Carpenter, B. and S. Jiang, "Significance of IPv6 - Interface Identifiers", draft-ietf-6man-ug-06 (work in - progress), December 2013. +10.1. Normative References [I-D.ietf-tsvwg-ieee-802-11] Szigeti, T., Henry, J., and F. Baker, "Diffserv to IEEE - 802.11 Mapping", draft-ietf-tsvwg-ieee-802-11-06 (work in - progress), August 2017. + 802.11 Mapping", draft-ietf-tsvwg-ieee-802-11-07 (work in + progress), September 2017. [RFC1042] Postel, J. and J. Reynolds, "Standard for the transmission of IP datagrams over IEEE 802 networks", STD 43, RFC 1042, - DOI 10.17487/RFC1042, February 1988, . + DOI 10.17487/RFC1042, February 1988, + . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, - DOI 10.17487/RFC2119, March 1997, . - - [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 - (IPv6) Specification", RFC 2460, DOI 10.17487/RFC2460, - December 1998, . + DOI 10.17487/RFC2119, March 1997, + . [RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet Networks", RFC 2464, DOI 10.17487/RFC2464, December 1998, . + [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, + DOI 10.17487/RFC2818, May 2000, + . + + [RFC3753] Manner, J., Ed. and M. Kojo, Ed., "Mobility Related + Terminology", RFC 3753, DOI 10.17487/RFC3753, June 2004, + . + [RFC3963] Devarapalli, V., Wakikawa, R., Petrescu, A., and P. Thubert, "Network Mobility (NEMO) Basic Support Protocol", RFC 3963, DOI 10.17487/RFC3963, January 2005, . + [RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander, + "SEcure Neighbor Discovery (SEND)", RFC 3971, + DOI 10.17487/RFC3971, March 2005, + . + [RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker, "Randomness Requirements for Security", BCP 106, RFC 4086, - DOI 10.17487/RFC4086, June 2005, . + DOI 10.17487/RFC4086, June 2005, + . + + [RFC4210] Adams, C., Farrell, S., Kause, T., and T. Mononen, + "Internet X.509 Public Key Infrastructure Certificate + Management Protocol (CMP)", RFC 4210, + DOI 10.17487/RFC4210, September 2005, + . [RFC4301] Kent, S. and K. Seo, "Security Architecture for the Internet Protocol", RFC 4301, DOI 10.17487/RFC4301, December 2005, . + [RFC4302] Kent, S., "IP Authentication Header", RFC 4302, + DOI 10.17487/RFC4302, December 2005, + . + + [RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", + RFC 4303, DOI 10.17487/RFC4303, December 2005, + . + [RFC4429] Moore, N., "Optimistic Duplicate Address Detection (DAD) for IPv6", RFC 4429, DOI 10.17487/RFC4429, April 2006, . [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, - DOI 10.17487/RFC4861, September 2007, . + DOI 10.17487/RFC4861, September 2007, + . + + [RFC5374] Weis, B., Gross, G., and D. Ignjatic, "Multicast + Extensions to the Security Architecture for the Internet + Protocol", RFC 5374, DOI 10.17487/RFC5374, November 2008, + . + + [RFC5415] Calhoun, P., Ed., Montemurro, M., Ed., and D. Stanley, + Ed., "Control And Provisioning of Wireless Access Points + (CAPWAP) Protocol Specification", RFC 5415, + DOI 10.17487/RFC5415, March 2009, + . [RFC5889] Baccelli, E., Ed. and M. Townsley, Ed., "IP Addressing Model in Ad Hoc Networks", RFC 5889, DOI 10.17487/RFC5889, September 2010, . [RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July 2011, . [RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C. Bormann, "Neighbor Discovery Optimization for IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs)", RFC 6775, DOI 10.17487/RFC6775, November 2012, . + [RFC7136] Carpenter, B. and S. Jiang, "Significance of IPv6 + Interface Identifiers", RFC 7136, DOI 10.17487/RFC7136, + February 2014, . + [RFC7721] Cooper, A., Gont, F., and D. Thaler, "Security and Privacy Considerations for IPv6 Address Generation Mechanisms", RFC 7721, DOI 10.17487/RFC7721, March 2016, . -11.2. Informative References + [RFC8064] Gont, F., Cooper, A., Thaler, D., and W. Liu, + "Recommendation on Stable IPv6 Interface Identifiers", + RFC 8064, DOI 10.17487/RFC8064, February 2017, + . - [fcc-cc] "'Report and Order, Before the Federal Communications - Commission Washington, D.C. 20554', FCC 03-324, Released - on February 10, 2004, document FCC-03-324A1.pdf, document - freely available at URL - http://www.its.dot.gov/exit/fcc_edocs.htm downloaded on - October 17th, 2013.". + [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 + (IPv6) Specification", STD 86, RFC 8200, + DOI 10.17487/RFC8200, July 2017, + . - [fcc-cc-172-184] - "'Memorandum Opinion and Order, Before the Federal - Communications Commission Washington, D.C. 20554', FCC - 06-10, Released on July 26, 2006, document FCC- - 06-110A1.pdf, document freely available at URL - http://hraunfoss.fcc.gov/edocs_public/attachmatch/ - FCC-06-110A1.pdf downloaded on June 5th, 2014.". +10.2. Informative References + + [ETSI-IPv6-GeoNetworking] + "ETSI EN 302 636-6-1 v1.2.1 (2014-05), ETSI, European + Standard, Intelligent Transportation Systems (ITS); + Vehicular Communications; Geonetworking; Part 6: Internet + Integration; Sub-part 1: Transmission of IPv6 Packets over + Geonetworking Protocols. Downloaded on September 9th, + 2017, freely available from ETSI website at URL + http://www.etsi.org/deliver/ + etsi_en/302600_302699/30263601/01.02.01_60/ + en_30263601v010201p.pdf". + + [ETSI-sec-archi] + "ETSI TS 102 940 V1.2.1 (2016-11), ETSI Technical + Specification, Intelligent Transport Systems (ITS); + Security; ITS communications security architecture and + security management, November 2016. Dowloaded on + September 9th, 2017, freely available from ETSI website at + URL http://www.etsi.org/deliver/ + etsi_ts/102900_102999/102940/01.02.01_60/ + ts_102940v010201p.pdf". + + [I-D.hinden-6man-rfc2464bis] + Crawford, M. and R. Hinden, "Transmission of IPv6 Packets + over Ethernet Networks", draft-hinden-6man-rfc2464bis-02 + (work in progress), March 2017. [I-D.jeong-ipwave-vehicular-networking-survey] Jeong, J., Cespedes, S., Benamar, N., Haerri, J., and M. Wetterwald, "Survey on IP-based Vehicular Networking for Intelligent Transportation Systems", draft-jeong-ipwave- vehicular-networking-survey-03 (work in progress), June 2017. [I-D.perkins-intarea-multicast-ieee802] Perkins, C., Stanley, D., Kumari, W., and J. Zuniga, "Multicast Considerations over IEEE 802 Wireless Media", draft-perkins-intarea-multicast-ieee802-03 (work in progress), July 2017. [I-D.petrescu-its-scenarios-reqs] Petrescu, A., Janneteau, C., Boc, M., and W. Klaudel, "Scenarios and Requirements for IP in Intelligent Transportation Systems", draft-petrescu-its-scenarios- reqs-03 (work in progress), October 2013. - [ieee1609.2] + [IEEE-1609.2] "IEEE SA - 1609.2-2016 - IEEE Standard for Wireless Access in Vehicular Environments (WAVE) -- Security Services for Applications and Management Messages. Example URL http://ieeexplore.ieee.org/document/7426684/ accessed on August 17th, 2017.". - [ieee1609.3] + [IEEE-1609.3] "IEEE SA - 1609.3-2016 - IEEE Standard for Wireless Access in Vehicular Environments (WAVE) -- Networking Services. Example URL http://ieeexplore.ieee.org/document/7458115/ accessed on August 17th, 2017.". - [ieee1609.4] + [IEEE-1609.4] "IEEE SA - 1609.4-2016 - IEEE Standard for Wireless Access in Vehicular Environments (WAVE) -- Multi-Channel Operation. Example URL http://ieeexplore.ieee.org/document/7435228/ accessed on August 17th, 2017.". - [ieee802.11-2012] + [IEEE-802.11-2012] "802.11-2012 - IEEE Standard for Information technology-- Telecommunications and information exchange between systems Local and metropolitan area networks--Specific requirements Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications. Downloaded on October 17th, 2013, from IEEE Standards, document freely available at URL http://standards.ieee.org/findstds/ standard/802.11-2012.html retrieved on October 17th, 2013.". - [ieee802.11p-2010] + [IEEE-802.11p-2010] "IEEE Std 802.11p (TM)-2010, IEEE Standard for Information Technology - Telecommunications and information exchange between systems - Local and metropolitan area networks - Specific requirements, Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications, Amendment 6: Wireless Access in Vehicular Environments; document freely available at URL http://standards.ieee.org/getieee802/ download/802.11p-2010.pdf retrieved on September 20th, 2013.". Appendix A. ChangeLog The changes are listed in reverse chronological order, most recent changes appearing at the top of the list. + From draft-ietf-ipwave-ipv6-over-80211ocb-04 to draft-ietf-ipwave- + ipv6-over-80211ocb-05 + + o Lengthened the title and cleanded the abstract. + + o Added text suggesting LLs may be easy to use on OCB, rather than + GUAs based on received prefix. + + o Added the risks of spoofing and hijacking. + + o Removed the text speculation on adoption of the TSA message. + + o Clarified that the ND protocol is used. + + o Clarified what it means "No association needed". + + o Added some text about how two STAs discover each other. + + o Added mention of external (OCB) and internal network (stable), in + the subnet structure section. + + o Added phrase explaining that both .11 Data and .11 QoS Data + headers are currently being used, and may be used in the future. + + o Moved the packet capture example into an Appendix Implementation + Status. + + o Suggested moving the reliability requirements appendix out into + another document. + + o Added a IANA Consiserations section, with content, requesting for + a new multicast group "all OCB interfaces". + + o Added new OBU term, improved the RSU term definition, removed the + ETTC term, replaced more occurences of 802.11p, 802.11 OCB with + 802.11-OCB. + + o References: + + * Added an informational reference to ETSI's IPv6-over- + GeoNetworking. + + * Added more references to IETF and ETSI security protocols. + + * Updated some references from I-D to RFC, and from old RFC to + new RFC numbers. + + * Added reference to multicast extensions to IPsec architecture + RFC. + + * Added a reference to 2464-bis. + + * Removed FCC informative references, because not used. + + o Updated the affiliation of one author. + + o Reformulation of some phrases for better readability, and + correction of typographical errors. + From draft-ietf-ipwave-ipv6-over-80211ocb-03 to draft-ietf-ipwave- ipv6-over-80211ocb-04 o Removed a few informative references pointing to Dx draft IEEE 1609 documents. o Removed outdated informative references to ETSI documents. o Added citations to IEEE 1609.2, .3 and .4-2016. @@ -1353,46 +1275,53 @@ be supported. The upper layer should be able to trigger such frames emission and to retrieve information contained in received Timing Advertisements. Appendix C. Design Considerations The networks defined by 802.11-OCB are in many ways similar to other networks of the 802.11 family. In theory, the encapsulation of IPv6 over 802.11-OCB could be very similar to the operation of IPv6 over other networks of the 802.11 family. However, the high mobility, - strong link asymetry and very short connection makes the 802.11-OCB + strong link asymmetry and very short connection makes the 802.11-OCB link significantly different from other 802.11 networks. Also, the automotive applications have specific requirements for reliability, security and privacy, which further add to the particularity of the 802.11-OCB link. C.1. Vehicle ID - Automotive networks require the unique representation of each of - their node. Accordingly, a vehicle must be identified by at least - one unique identifier. The current specification at ETSI and at IEEE - 1609 identifies a vehicle by its MAC address uniquely obtained from - the 802.11-OCB NIC. + In automotive networks it is required that each node is represented + uniquely. Accordingly, a vehicle must be identified by at least one + unique identifier. The current specification at ETSI and at IEEE + 1609 identifies a vehicle by its MAC address, which is obtained from + the 802.11-OCB Network Interface Card (NIC). - A MAC address uniquely obtained from a IEEE 802.11-OCB NIC - implicitely generates multiple vehicle IDs in case of multiple - 802.11-OCB NICs. A mechanims to uniquely identify a vehicle - irrespectively to the different NICs and/or technologies is required. + In case multiple 802.11-OCB NICs are present in one car, implicitely + multiple vehicle IDs will be generated. Additionally, some software + generates a random MAC address each time the computer boots; this + constitutes an additional difficulty. + + A mechanim to uniquely identify a vehicle irrespectively to the + multiplicity of NICs, or frequent MAC address generation, is + necessary. C.2. Reliability Requirements + This section may need to be moved out into a separate requirements + document. + The dynamically changing topology, short connectivity, mobile transmitter and receivers, different antenna heights, and many-to- many communication types, make IEEE 802.11-OCB links significantly different from other IEEE 802.11 links. Any IPv6 mechanism operating - on IEEE 802.11-OCB link MUST support strong link asymetry, spatio- + on IEEE 802.11-OCB link MUST support strong link asymmetry, spatio- temporal link quality, fast address resolution and transmission. IEEE 802.11-OCB strongly differs from other 802.11 systems to operate outside of the context of a Basic Service Set. This means in practice that IEEE 802.11-OCB does not rely on a Base Station for all Basic Service Set management. In particular, IEEE 802.11-OCB SHALL NOT use beacons. Any IPv6 mechanism requiring L2 services from IEEE 802.11 beacons MUST support an alternative service. Channel scanning being disabled, IPv6 over IEEE 802.11-OCB MUST @@ -1401,26 +1330,26 @@ Authentication not being possible, IPv6 over IEEE 802.11-OCB MUST implement an distributed mechanism to authenticate transmitters and receivers without the support of a DHCP server. Time synchronization not being available, IPv6 over IEEE 802.11-OCB MUST implement a higher layer mechanism for time synchronization between transmitters and receivers without the support of a NTP server. - The IEEE 802.11-OCB link being asymetic, IPv6 over IEEE 802.11-OCB + The IEEE 802.11-OCB link being asymmetric, IPv6 over IEEE 802.11-OCB MUST disable management mechanisms requesting acknowledgements or replies. The IEEE 802.11-OCB link having a short duration time, IPv6 over IEEE - 802.11-OCB MUST implement fast IPv6 mobility management mechanisms. + 802.11-OCB SHOULD implement fast IPv6 mobility management mechanisms. C.3. Multiple interfaces There are considerations for 2 or more IEEE 802.11-OCB interface cards per vehicle. For each vehicle taking part in road traffic, one IEEE 802.11-OCB interface card could be fully allocated for Non IP safety-critical communication. Any other IEEE 802.11-OCB may be used for other type of traffic. The mode of operation of these other wireless interfaces is not @@ -1429,26 +1358,26 @@ of IPv6 addresses. Another possibility is to consider the set of these wireless interfaces as a single network interface (not including the IEEE 802.11-OCB interface used by Non IP safety critical communications). This will require specific logic to ensure, for example, that packets meant for a vehicle in front are actually sent by the radio in the front, or that multiple copies of the same packet received by multiple interfaces are treated as a single packet. Treating each wireless interface as a separate network interface pushes such issues to the application layer. - The privacy requirements of [] imply that if these multiple - interfaces are represented by many network interface, a single - renumbering event SHALL cause renumbering of all these interfaces. - If one MAC changed and another stayed constant, external observers - would be able to correlate old and new values, and the privacy - benefits of randomization would be lost. + Certain privacy requirements imply that if these multiple interfaces + are represented by many network interface, a single renumbering event + SHALL cause renumbering of all these interfaces. If one MAC changed + and another stayed constant, external observers would be able to + correlate old and new values, and the privacy benefits of + randomization would be lost. The privacy requirements of Non IP safety-critical communications imply that if a change of pseudonyme occurs, renumbering of all other interfaces SHALL also occur. C.4. MAC Address Generation When designing the IPv6 over 802.11-OCB address mapping, we will assume that the MAC Addresses will change during well defined "renumbering events". The 48 bits randomized MAC addresses will have @@ -1475,21 +1404,260 @@ o The STA may send management frames of subtype Action and, if the STA maintains a TSF Timer, subtype Timing Advertisement; o The STA may send control frames, except those of subtype PS-Poll, CF-End, and CF-End plus CFAck; o The STA may send data frames of subtype Data, Null, QoS Data, and QoS Null. +Appendix E. Implementation Status + + This section describese an example of an IPv6 Packet captured over a + IEEE 802.11-OCB link. + + By way of example we show that there is no modification in the + headers when transmitted over 802.11-OCB networks - they are + transmitted like any other 802.11 and Ethernet packets. + + We describe an experiment of capturing an IPv6 packet on an + 802.11-OCB link. In this experiment, the packet is an IPv6 Router + Advertisement. This packet is emitted by a Router on its 802.11-OCB + interface. The packet is captured on the Host, using a network + protocol analyzer (e.g. Wireshark); the capture is performed in two + different modes: direct mode and 'monitor' mode. The topology used + during the capture is depicted below. + + +--------+ +-------+ + | | 802.11-OCB Link | | + ---| Router |--------------------------------| Host | + | | | | + +--------+ +-------+ + + During several capture operations running from a few moments to + several hours, no message relevant to the BSSID contexts were + captured (no Association Request/Response, Authentication Req/Resp, + Beacon). This shows that the operation of 802.11-OCB is outside the + context of a BSSID. + + Overall, the captured message is identical with a capture of an IPv6 + packet emitted on a 802.11b interface. The contents are precisely + similar. + +E.1. Capture in Monitor Mode + + The IPv6 RA packet captured in monitor mode is illustrated below. + The radio tap header provides more flexibility for reporting the + characteristics of frames. The Radiotap Header is prepended by this + particular stack and operating system on the Host machine to the RA + packet received from the network (the Radiotap Header is not present + on the air). The implementation-dependent Radiotap Header is useful + for piggybacking PHY information from the chip's registers as data in + a packet understandable by userland applications using Socket + interfaces (the PHY interface can be, for example: power levels, data + rate, ratio of signal to noise). + + The packet present on the air is formed by IEEE 802.11 Data Header, + Logical Link Control Header, IPv6 Base Header and ICMPv6 Header. + + Radiotap Header v0 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |Header Revision| Header Pad | Header length | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Present flags | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Data Rate | Pad | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + IEEE 802.11 Data Header + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Type/Subtype and Frame Ctrl | Duration | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Receiver Address... + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + ... Receiver Address | Transmitter Address... + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + ... Transmitter Address | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | BSS Id... + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + ... BSS Id | Frag Number and Seq Number | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + Logical-Link Control Header + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | DSAP |I| SSAP |C| Control field | Org. code... + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + ... Organizational Code | Type | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + IPv6 Base Header + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |Version| Traffic Class | Flow Label | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Payload Length | Next Header | Hop Limit | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | | + + + + | | + + Source Address + + | | + + + + | | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | | + + + + | | + + Destination Address + + | | + + + + | | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + Router Advertisement + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Type | Code | Checksum | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Cur Hop Limit |M|O| Reserved | Router Lifetime | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Reachable Time | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Retrans Timer | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Options ... + +-+-+-+-+-+-+-+-+-+-+-+- + + The value of the Data Rate field in the Radiotap header is set to 6 + Mb/s. This indicates the rate at which this RA was received. + + The value of the Transmitter address in the IEEE 802.11 Data Header + is set to a 48bit value. The value of the destination address is + 33:33:00:00:00:1 (all-nodes multicast address). The value of the BSS + Id field is ff:ff:ff:ff:ff:ff, which is recognized by the network + protocol analyzer as being "broadcast". The Fragment number and + sequence number fields are together set to 0x90C6. + + The value of the Organization Code field in the Logical-Link Control + Header is set to 0x0, recognized as "Encapsulated Ethernet". The + value of the Type field is 0x86DD (hexadecimal 86DD, or otherwise + #86DD), recognized as "IPv6". + + A Router Advertisement is periodically sent by the router to + multicast group address ff02::1. It is an icmp packet type 134. The + IPv6 Neighbor Discovery's Router Advertisement message contains an + 8-bit field reserved for single-bit flags, as described in [RFC4861]. + + The IPv6 header contains the link local address of the router + (source) configured via EUI-64 algorithm, and destination address set + to ff02::1. Recent versions of network protocol analyzers (e.g. + Wireshark) provide additional informations for an IP address, if a + geolocalization database is present. In this example, the + geolocalization database is absent, and the "GeoIP" information is + set to unknown for both source and destination addresses (although + the IPv6 source and destination addresses are set to useful values). + This "GeoIP" can be a useful information to look up the city, + country, AS number, and other information for an IP address. + + The Ethernet Type field in the logical-link control header is set to + 0x86dd which indicates that the frame transports an IPv6 packet. In + the IEEE 802.11 data, the destination address is 33:33:00:00:00:01 + which is the corresponding multicast MAC address. The BSS id is a + broadcast address of ff:ff:ff:ff:ff:ff. Due to the short link + duration between vehicles and the roadside infrastructure, there is + no need in IEEE 802.11-OCB to wait for the completion of association + and authentication procedures before exchanging data. IEEE + 802.11-OCB enabled nodes use the wildcard BSSID (a value of all 1s) + and may start communicating as soon as they arrive on the + communication channel. + +E.2. Capture in Normal Mode + + The same IPv6 Router Advertisement packet described above (monitor + mode) is captured on the Host, in the Normal mode, and depicted + below. + + Ethernet II Header + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Destination... + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + ...Destination | Source... + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + ...Source | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Type | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + IPv6 Base Header + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |Version| Traffic Class | Flow Label | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Payload Length | Next Header | Hop Limit | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | | + + + + | | + + Source Address + + | | + + + + | | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | | + + + + | | + + Destination Address + + | | + + + + | | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + Router Advertisement + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Type | Code | Checksum | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Cur Hop Limit |M|O| Reserved | Router Lifetime | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Reachable Time | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Retrans Timer | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Options ... + +-+-+-+-+-+-+-+-+-+-+-+- + + One notices that the Radiotap Header, the IEEE 802.11 Data Header and + the Logical-Link Control Headers are not present. On the other hand, + a new header named Ethernet II Header is present. + + The Destination and Source addresses in the Ethernet II header + contain the same values as the fields Receiver Address and + Transmitter Address present in the IEEE 802.11 Data Header in the + "monitor" mode capture. + + The value of the Type field in the Ethernet II header is 0x86DD + (recognized as "IPv6"); this value is the same value as the value of + the field Type in the Logical-Link Control Header in the "monitor" + mode capture. + + The knowledgeable experimenter will no doubt notice the similarity of + this Ethernet II Header with a capture in normal mode on a pure + Ethernet cable interface. + + An Adaptation layer is inserted on top of a pure IEEE 802.11 MAC + layer, in order to adapt packets, before delivering the payload data + to the applications. It adapts 802.11 LLC/MAC headers to Ethernet II + headers. In further detail, this adaptation consists in the + elimination of the Radiotap, 802.11 and LLC headers, and in the + insertion of the Ethernet II header. In this way, IPv6 runs straight + over LLC over the 802.11-OCB MAC layer; this is further confirmed by + the use of the unique Type 0x86DD. + Authors' Addresses + Alexandre Petrescu CEA, LIST CEA Saclay Gif-sur-Yvette , Ile-de-France 91190 France Phone: +33169089223 Email: Alexandre.Petrescu@cea.fr Nabil Benamar @@ -1491,30 +1659,30 @@ Phone: +33169089223 Email: Alexandre.Petrescu@cea.fr Nabil Benamar Moulay Ismail University Morocco Phone: +212670832236 Email: benamar73@gmail.com - Jerome Haerri Eurecom Sophia-Antipolis 06904 France Phone: +33493008134 Email: Jerome.Haerri@eurecom.fr Christian Huitema + Private Octopus Inc. Friday Harbor, WA 98250 U.S.A. Email: huitema@huitema.net Jong-Hyouk Lee Sangmyung University 31, Sangmyeongdae-gil, Dongnam-gu Cheonan 31066 Republic of Korea