Re: [ipwave] Review comments on draft-ietf-ipwave-ipv6-over-80211ocb-04.txt
"Sri Gundavelli (sgundave)" <sgundave@cisco.com> Tue, 29 August 2017 09:51 UTC
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From: "Sri Gundavelli (sgundave)" <sgundave@cisco.com>
To: François Simon <fygsimon@gmail.com>
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Thread-Topic: [ipwave] Review comments on draft-ietf-ipwave-ipv6-over-80211ocb-04.txt
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Subject: Re: [ipwave] Review comments on draft-ietf-ipwave-ipv6-over-80211ocb-04.txt
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Hi Francois, Thanks you for your response and also for clarification on the QoS aspects which are present in OCB. Hopefully, you can address these comments and my other comments in the next rev. Regards Sri From: François Simon <gsgsimon@gmail.com<mailto:fygsimon@gmail.com>> Date: Monday, August 28, 2017 at 11:08 AM To: Sri Gundavelli <sgundave@cisco.com<mailto:sgundave@cisco.com>> Cc: "its@ietf.org<mailto:its@ietf.org>" <its@ietf.org<mailto:its@ietf.org>>, "fygsimon@gmail.com<mailto:fygsimon@gmail.com>" <fygsimon@gmail.com<mailto:fygsimon@gmail.com>> Subject: RE: [ipwave] Review comments on draft-ietf-ipwave-ipv6-over-80211ocb-04.txt Mr. Gundaveli, I provided some comments and responses in the text below your comments identified by“[Fygs] and “bold”. If you have additional questions, please, let me know. Sincerely, Francois Simon From: its [mailto:its-bounces@ietf.org] On Behalf Of Sri Gundavelli (sgundave) Sent: Sunday, August 27, 2017 11:01 PM To: its@ietf.org<mailto:its@ietf.org> Subject: [ipwave] Review comments on draft-ietf-ipwave-ipv6-over-80211ocb-04.txt Attached is my review feedback. In general there is lot of good information in the document. But, there are also few areas where additional clarifications will greatly help. 1.) Its not clear, if the document makes any assumption on the operating environment/communication profile. There is not much discussion on that aspect; For example, Is it always a one-hop communication between RSU and OBU where the 802.11-OCB link? So, is the use of IPv6 only in that context of 1-hop communication? 2.) There is also no discussion on how these links get formed in vehicular environment and when they are attached/detached. 3.) How do nodes discover each other? How does ND resolution work? Are these messages received by a multiple RSU’s, or a single RSU? Whats the implication of that. Note that you don’t have that issue in 802.11, given the association to an access point, which in turn maps the links to a VLAN/subnet. 4.) What happens as a vehicle moves between RSU’s, how does it impact address configuration? Is DHCPv6 based address configuration relevant here? Please see inline for additional comments. ------------------------------------------------------------------ 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 [Sri] May be change to, “..in mode .." —> “..operating in mode ..” ? [Fygs] Agreed 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. [Sri] Is it “recommended MTU size", or "supported MTU size on the 802.11 OCB link? 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. [Sri] Minor comment. May be instead of using the “layer” terminology, you may want to present this as IPv6 support on "802.11 OCB" links. [Fygs] 802.11 OCB provides data link and PHY services to IPv6 An example of an IPv6 packet captured while transmitted over an IEEE 802.11 OCB link (802.11p) is given. [Sri] Last paragraph can be ommitted in my view. That’s too much of detail for Abstract. [Fygs] - Agree Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of https://tools.ietf.org/html/bcp78 and https://tools.ietf.org/html/bcp79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute Petrescu, et al. Expires February 18, 2018 [Page 1] ________________________________________ https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-2 Internet-Draft IPv6-over-80211ocb August 2017 working documents as Internet-Drafts. The list of current Internet- Drafts is at http://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. Copyright Notice Copyright (c) 2017 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to https://tools.ietf.org/html/bcp78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://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 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-3 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-5 3. Communication Scenarios where IEEE 802.11 OCB Links are Used 6 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-4. Aspects introduced by the OCB mode to 802.11 . . . . . . . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-6 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-5. Layering of IPv6 over 802.11-OCB as over Ethernet . . . . . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-10 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-5.1. Maximum Transmission Unit (MTU) . . . . . . . . . . . . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-10 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-5.2. Frame Format . . . . . . . . . . . . . . . . . . . . . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-11 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-5.2.1. Ethernet Adaptation Layer . . . . . . . . . . . . . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-12 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-5.3. Link-Local Addresses . . . . . . . . . . . . . . . . . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-13 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-5.4. Address Mapping . . . . . . . . . . . . . . . . . . . . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-14 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-5.4.1. Address Mapping -- Unicast . . . . . . . . . . . . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-14 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-5.4.2. Address Mapping -- Multicast . . . . . . . . . . . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-14 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-5.5. Stateless Autoconfiguration . . . . . . . . . . . . . . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-15 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-5.6. Subnet Structure . . . . . . . . . . . . . . . . . . . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-16 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-6. Example IPv6 Packet captured over a IEEE 802.11-OCB link . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-16 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-6.1. Capture in Monitor Mode . . . . . . . . . . . . . . . . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-17 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-6.2. Capture in Normal Mode . . . . . . . . . . . . . . . . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-19 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-7. Security Considerations . . . . . . . . . . . . . . . . . . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-21 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-22 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-22 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-22 Petrescu, et al. Expires February 18, 2018 [Page 2] ________________________________________ https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-3 Internet-Draft IPv6-over-80211ocb August 2017 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-11. References . . . . . . . . . . . . . . . . . . . . . . . . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-23 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-11.1. Normative References . . . . . . . . . . . . . . . . . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-23 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-11.2. Informative References . . . . . . . . . . . . . . . . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-24 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendix-A. ChangeLog . . . . . . . . . . . . . . . . . . . . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-26 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendix-B. Changes Needed on a software driver 802.11a to become a 802.11-OCB driver . . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-28 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendix-C. Design Considerations . . . . . . . . . . . . . . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-30 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendix-C.1. Vehicle ID . . . . . . . . . . . . . . . . . . . . . . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-30 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendix-C.2. Reliability Requirements . . . . . . . . . . . . . . . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-30 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendix-C.3. Multiple interfaces . . . . . . . . . . . . . . . . . . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-31 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendix-C.4. MAC Address Generation . . . . . . . . . . . . . . . . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-32 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendix-D. IEEE 802.11 Messages Transmitted in OCB mode . . . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-32 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-32 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-1. Introduction This document describes the transmission of IPv6 packets on IEEE Std 802.11 OCB networks (earlier known as 802.11p). [Sri] Please add a reference to the IEEE specification that defines the OCB mode. [Fygs] Since 2010 the OCB is defined in IEEE Std 802.11p, IEEE Std 802.11-2012, and IEEE 802.11-2016. 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. 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 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 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 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 [https://tools.ietf.org/html/rfc1042] and [https://tools.ietf.org/html/rfc2464]. The situation of IPv6 networking layer on Ethernet Adaptation Layer is illustrated below: Petrescu, et al. Expires February 18, 2018 [Page 3] ________________________________________ https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-4 Internet-Draft IPv6-over-80211ocb August 2017 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 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 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 +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ Boundary | EPD | | | | | MLME | | +-+-+-{ MAC_SAP }+-+-+-| MLME_SAP | | 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 [https://tools.ietf.org/html/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 [https://tools.ietf.org/html/rfc4301]). Petrescu, et al. Expires February 18, 2018 [Page 4] ________________________________________ https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-5 Internet-Draft IPv6-over-80211ocb August 2017 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 [https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-ieee1609.2] does provide security services for applications to use so that there can easily be data security over the air without invoking IPsec. We briefly introduce the vehicular communication scenarios where IEEE 802.11-OCB links are used. [Sri] I have not seen much discussion on the link / communication assumptions. [Fygs] Not sure of what is meant by assumptions in this context. 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 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#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 [https://tools.ietf.org/html/rfc2464]. 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 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#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. In the published literature, many documents describe aspects related to running IPv6 over 802.11 OCB: [https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-I-D.jeong-ipwave-vehicular-networking-survey]. https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-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 https://tools.ietf.org/html/rfc2119 [https://tools.ietf.org/html/rfc2119]. Petrescu, et al. Expires February 18, 2018 [Page 5] ________________________________________ https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-6 Internet-Draft IPv6-over-80211ocb August 2017 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. [Sri] RSU can be compared to an 802.11 access point; Or, WTP as defined in CAPWAP specification, RFC5415. [Fygs] While I am not familiar with “WTP as defined in CAPWAP specification, RFC5415”, I know that an RSU has no commonality with an 802.11 AP. Perhaps. rephrase as below?: "RSU: Road Side Unit. Its a wireless termination point (WTP), as defined in RFC5415 with one key difference, where the wireless physical and the mac layer is MAC layers 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.” [Fygs]: This seems reasonable and accurate. This would be for V2I mode. ** Also, since you are defining the RSU term, should you also not define OBU (On board Unit) in the vehicle which is the entity on the other end of the link? “RSU ----802.11-OCB——OBU” ? May be introduce the OCB definition separately, just as you did with RSU, and show the communication link as 802.11-OCB. [Fygs] Here is a definition of OBU (FCC): “An On-Board Unit is a DSRCS transceiver that is normally mounted in or on a vehicle, or which in some instances may be a portable unit. An OBU can be operational while a vehicle or person is either mobile or stationary.” 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. [Sri] The text starting with. “This means” is not clear to me. Does it 802.11e is supported with 802.11OCB mode. Please clarify [Fygs]QoS is required for 802.11 OCB. https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-3. Communication Scenarios where IEEE 802.11 OCB Links are Used 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 [https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-I-D.petrescu-its-scenarios-reqs], about scenarios and requirements for IP in Intelligent Transportation Systems. [Sri] You can do bit more justice to this section. Explain the link model. “STA ----802.11-OCB——STA”. Then talk about the applicability in Vehicular networks, with STA's as RSU and OCB. You may also want to talk about, how links get formed/terminated; how nodes peer/discover and how mobility works ..etc. While 802.11-OCB is clearly specified and the use of IPv6 over such link is also not radically new, but the operating environment which is vehicular brings many new things. That description is not present any where. https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-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: [Sri] Can you add some text on how nodes (ST1 and STA2) discover each other on such links supporting 802.11 OCB mode. 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 authentication required o No association needed o No encryption provided [Fygs] All the nodes in the communication range (OBU and RSU) receivesall the messages transmitted (OBU and RSU) within the communications range. The conflicts are resolved by the MAC CDMA function. [Sri] Can you clarify what you mean when you say “No xxx required” / “No xxx needed” for the above capabilities. What does “needed” or “required” mean? Does it mean, “Authentication", “Association" and “Encryption” is optional on this link, or that its not supported on 802.11 OCB links. [Fygs]The original text in IEEE 802.11p specifies: “Change the lettered list items (a) through (c) of 5.3.1 as follows: a) Authentication (not used when dot11OCBEnabled is true) b) Deauthentication (not used when dot11OCBEnabled is true) c) Data confidentiality (not used when dot11OCBEnabled is true)” o Flag dot11OCBActivated set to true The following message exchange diagram illustrates a comparison between traditional 802.11 and 802.11 in OCB mode. The 'Data' Petrescu, et al. Expires February 18, 2018 [Page 6] ________________________________________ https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-7 Internet-Draft IPv6-over-80211ocb August 2017 messages can be IP messages such as the messages used in Stateless or Stateful Address Auto-Configuration, or other IP messages. [Sri] Lets separate the discussion on IP Address configuration using SLAAC/DHCP on such links from the above description. The Data packets here can be application packets such as HTTP or other packets. May be additional discussion is needed on the IP address configuration on 802.11-OCB links. 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 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#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 The link 802.11 OCB was specified in IEEE Std 802.11p (TM) -2010 [https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-ieee802.11p-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 [https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-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'). 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". Petrescu, et al. Expires February 18, 2018 [Page 7] ________________________________________ https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-8 Internet-Draft IPv6-over-80211ocb August 2017 In order to delineate the aspects introduced by 802.11 OCB to 802.11, we refer to the earlier [https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-ieee802.11p-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 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 offers practically the same interface to IP as the WiFi and Ethernet layers do (802.11a/b/g/n and 802.3). [Sri] A packet sent from a vehicle’s OBU is received by a single RSU, or multiple RSU’s? How does the link-layer resolution happen? [Fygs] Assuming that: a) If there aresingle or multiple RSUsin the communication range and it is amulticast message,the single RSU or RSUs in the comm. range will receive it (eventually). There is no resolution at the link layer. The RSU(s) will determine their “interest” based on the content of the message at the higher layers (application); b) If there are single or multiple RSUs in the communication rand and it isunicast message, then the link-layer resolves by thedestination MAC address. 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. 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. [Sri] I am really not sure how link throughput (12Mbps) relates to "IPv6 support on OCB links". [Fygs] First of all there is guarantee of 12 Mbps throughput because of collisions and other interferences, 12 Mbps data rate was probably intended. The data rates for 20 MHz channel spacingare6, 9, 12, 18, 24, 36,48, and 54 Mb/s with mandatory support of 6, 12, and 24 Mbps; Data rates for 10 MHz channel spacing are3, 4.5, 6, 9, 12, 18, 24, and 27 Mb/s.with mandatory support of 3, 6, and 12 Mb/s. 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 [https://tools.ietf.org/html/rfc6275] and on the protocols for IP layer security [https://tools.ietf.org/html/rfc4301]. [Sri] The document till now has been arguing heavily on how IPv6 operates so naturally on these links and now I see discussion on “Impact to a high-level protocol such as MIPv6”. You may want to fix the earlier text. In any case, the absence of link-layer security practically impacts every application, not just MIPv6. Also, MIPv6 does not make any assumptions on the link-layer security. Also, the the 0xFF-FF-FF-FF-FF-FF as the BSSID, makes the messages readable by all other RSU’s in proximity. I think the discussion on the nature of the link, who all see’s the messages.. how L2 addresses are resolved is not explained clearly. 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 Petrescu, et al. Expires February 18, 2018 [Page 8] ________________________________________ https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-9 Internet-Draft IPv6-over-80211ocb August 2017 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.) [Sri] The first part explaining Timing Advertisement messages is great, but the rest of the commentary is unnecessary and not needed. We don’t speculate the protocol adoption success in IETF specifications, or about the experience level of the “reviewer" :) [Fygs]: Absolutely agree. 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). 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. Petrescu, et al. Expires February 18, 2018 [Page 9] ________________________________________ https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-10 Internet-Draft IPv6-over-80211ocb August 2017 * 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. * 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 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-7. A relevant function is described in IEEE 1609.3-2016 [https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-ieee1609.3], clause 5.5.1 and IEEE 1609.4-2016 [https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-ieee1609.4], 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 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. [Sri] Per my earlier comment, the link model, addressing ..etc needs to be explained in more detail. It is not clear what exactly the “subnet structure” that is assumed in 802.11-OCB. https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-5. Layering of IPv6 over 802.11-OCB as over Ethernet https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-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 [https://tools.ietf.org/html/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 [https://tools.ietf.org/html/rfc2460], 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. Petrescu, et al. Expires February 18, 2018 [Page 10] ________________________________________ https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-11 Internet-Draft IPv6-over-80211ocb August 2017 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. [Sri] The last paragraph needs some additional context. Did 802.11-OCB introduce ETTC concept? [Fygs] NO ! https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-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 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-5.2.1. The Ethernet Type code (EtherType) for IPv6 is 0x86DD (hexadecimal 86DD, or otherwise #86DD). The Frame format for transmitting IPv6 on 802.11-OCB networks is the same as transmitting IPv6 on Ethernet networks, and is described in https://tools.ietf.org/html/rfc2464#section-3. The frame format for transmitting IPv6 packets over Ethernet is illustrated below: 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination | +- -+ | Ethernet | +- -+ | Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source | +- -+ | Ethernet | +- -+ | Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv6 | +- -+ | header | +- -+ | and | +- -+ / payload ... / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ (Each tic mark represents one bit.) Petrescu, et al. Expires February 18, 2018 [Page 11] ________________________________________ https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-12 Internet-Draft IPv6-over-80211ocb August 2017 Ethernet II Fields: Destination Ethernet Address the MAC destination address. Source Ethernet Address the MAC source address. 1 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1 binary representation of the EtherType value 0x86DD. IPv6 header and payload the IPv6 packet containing IPv6 header and payload. https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-5.2.1. Ethernet Adaptation Layer In general, an 'adaptation' layer is inserted between a MAC layer and the Networking layer. This is used to transform some parameters between their form expected by the IP stack and the form provided by the MAC layer. For example, an 802.15.4 adaptation layer may perform fragmentation and reassembly operations on a MAC whose maximum Packet Data Unit size is smaller than the minimum MTU recognized by the IPv6 Networking layer. Other examples involve link-layer address transformation, packet header insertion/removal, and so on. An Ethernet Adaptation Layer makes an 802.11 MAC look to IP Networking layer as a more traditional Ethernet layer. At reception, this layer takes as input the IEEE 802.11 Data Header and the Logical-Link Layer Control Header and produces an Ethernet II Header. At sending, the reverse operation is performed. +--------------------+------------+-------------+---------+-----------+ | 802.11 Data Header | LLC Header | IPv6 Header | Payload |.11 Trailer| +--------------------+------------+-------------+---------+-----------+ \ / \ / ----------------------------- -------- ^---------------------------------------------/ | 802.11-to-Ethernet Adaptation Layer | v +---------------------+-------------+---------+ | Ethernet II Header | IPv6 Header | Payload | +---------------------+-------------+---------+ Petrescu, et al. Expires February 18, 2018 [Page 12] ________________________________________ https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-13 Internet-Draft IPv6-over-80211ocb August 2017 The Receiver and Transmitter Address fields in the 802.11 Data Header contain the same values as the Destination and the Source Address fields in the Ethernet II Header, respectively. The value of the Type field in the LLC Header is the same as the value of the Type 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 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#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: +--------------------+-------------+-------------+---------+-----------+ | 802.11 Data Header | LLC Header | IPv6 Header | Payload |.11 Trailer| +--------------------+-------------+-------------+---------+-----------+ or +--------------------+-------------+-------------+---------+-----------+ | 802.11 QoS Data Hdr| LLC Header | IPv6 Header | Payload |.11 Trailer| +--------------------+-------------+-------------+---------+-----------+ The distinction between the two formats is given by the value of the field "Type/Subtype". The value of the field "Type/Subtype" in the 802.11 Data header is 0x0020. The value of the field "Type/Subtype" in the 802.11 QoS header is 0x0028. The mapping between qos-related fields in the IPv6 header (e.g. "Traffic Class", "Flow label") and fields in the "802.11 QoS Data Header" (e.g. "QoS Control") are not specified in this document. Guidance for a potential mapping is provided in [https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-I-D.ietf-tsvwg-ieee-802-11], although it is not specific to OCB mode. [Sri] The applicability of the QoS mapping draft to 802.11-OCB needs further investigation, IMO. [Fygs] I am not familiar with QoS control of IPv6. As for the OCB MAC QoS it is somewhat involved. It is based ontransmission priority of MAC frames. A higher priority frame is intended to be transmitted ahead of lower priority frames. If a detail process is required, please, let me know and I would provide the text. https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-5.3. Link-Local Addresses The link-local address of an 802.11-OCB interface is formed in the same manner as on an Ethernet interface. This manner is described in https://tools.ietf.org/html/rfc2464#section-5. [Sri] Does this go against the 8064 recommendation on Interface identifier generation? May be RFC7217 for interface identifier generation in conjunction with the link-local address generation per RFC2464 Petrescu, et al. Expires February 18, 2018 [Page 13] ________________________________________ https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-14 Internet-Draft IPv6-over-80211ocb August 2017 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-5.4. Address Mapping For unicast as for multicast, there is no change from the unicast and multicast address mapping format of Ethernet interfaces, as defined by sections https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-6 and https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-7 of [https://tools.ietf.org/html/rfc2464]. [Sri] RFC6085 specified mapping is also relevant; If the communication peers are aware that there is only one peer, it should apply 6085 specified mapping. That mode is relevant for 802.11-OCB types links as well. https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-5.4.1. Address Mapping -- Unicast The procedure for mapping IPv6 unicast addresses into Ethernet link- layer addresses is described in [https://tools.ietf.org/html/rfc4861]. The Source/Target Link- layer Address option has the following form when the link-layer is Ethernet. [Sri] I thought, mapping of IPv6 unicast addresses to Ethernet link-layer addresses is specified in section 6, of RFC2464 and not in RFC4861. 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | +- Ethernet -+ | | +- Address -+ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Option fields: Type 1 for Source Link-layer address. 2 for Target Link-layer address. Length 1 (in units of 8 octets). Ethernet Address The 48 bit Ethernet IEEE 802 address, in canonical bit order. https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-5.4.2. Address Mapping -- Multicast IPv6 protocols often make use of IPv6 multicast addresses in the destination field of IPv6 headers. For example, an ICMPv6 link- scoped Neighbor Advertisement is sent to the IPv6 address ff02::1 denoted "all-nodes" address. When transmitting these packets on 802.11-OCB links it is necessary to map the IPv6 address to a MAC address. Petrescu, et al. Expires February 18, 2018 [Page 14] ________________________________________ https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-15 Internet-Draft IPv6-over-80211ocb August 2017 The same mapping requirement applies to the link-scoped multicast addresses of other IPv6 protocols as well. In DHCPv6, the "All_DHCP_Servers" IPv6 multicast address ff02::1:2, and in OSPF the "All_SPF_Routers" IPv6 multicast address ff02::5, need to be mapped on a multicast MAC address. An IPv6 packet with a multicast destination address DST, consisting of the sixteen octets DST[1] through DST[16], is transmitted to the IEEE 802.11-OCB MAC multicast address whose first two octets are the value 0x3333 and whose last four octets are the last four octets of DST. [Sri] Please add a reference to Section 7, RFC4861 and also RFC6085. In general, for both unicast and multicast, you may want to clearly say that this is per the existing specs and duplicated here for convenience. +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |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 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 [https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-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. https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-5.5. Stateless Autoconfiguration 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 https://tools.ietf.org/html/rfc2464#section-4. No changes are needed, but some care must be taken when considering the use of the SLAAC procedure. [Sri] Per my earlier comment, please refer to the current recommendation on interface-identifier generation and its use in link-local, global or other addresses. 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 [https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-I-D.ietf-6man-ug]. Petrescu, et al. Expires February 18, 2018 [Page 15] ________________________________________ https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-16 Internet-Draft IPv6-over-80211ocb August 2017 As with all Ethernet and 802.11 interface identifiers ([https://tools.ietf.org/html/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 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendix-C. [Sri] I think there are other security issues here; the absence of link-layer security opens up Mac-spoofing and IP address hijacking. That should be mentioned. 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 [https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#ref-I-D.ietf-6man-default-iids]. https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-5.6. Subnet Structure The 802.11 networks in OCB mode may be considered as 'ad-hoc' networks. The addressing model for such networks is described in [https://tools.ietf.org/html/rfc5889]. [Sri] Per my earlier comment, there is no system level view of the network where 802.11-OCB links are used. So, in the absence of such discussion So, I am not sure what part of RFC5889 is applicable here. For example, link-local addresses may just work fine. https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-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, Petrescu, et al. Expires February 18, 2018 [Page 16] ________________________________________ https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-17 Internet-Draft IPv6-over-80211ocb August 2017 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. [Sri] I suggest moving this discussion under the section “Implementation Status”, which will eventually be removed from the RFC. There is nothing new here. This are details on experimentation. But, if you think there is some useful information such as discussion on Capture mode ..etc, you may want to move this entire section to Appendix. Implementors may use these tools for verification. https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Petrescu, et al. Expires February 18, 2018 [Page 17] ________________________________________ https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-18 Internet-Draft IPv6-over-80211ocb August 2017 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. Petrescu, et al. Expires February 18, 2018 [Page 18] ________________________________________ https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-19 Internet-Draft IPv6-over-80211ocb August 2017 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 [https://tools.ietf.org/html/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. [Sri] Not sure, why all of this text should be in the specification. 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. https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-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. Petrescu, et al. Expires February 18, 2018 [Page 19] ________________________________________ https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-20 Internet-Draft IPv6-over-80211ocb August 2017 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 ... +-+-+-+-+-+-+-+-+-+-+-+- Petrescu, et al. Expires February 18, 2018 [Page 20] ________________________________________ https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-21 Internet-Draft IPv6-over-80211ocb August 2017 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). https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-7. 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). [Sri] Per my earlier comment, there is more than one attack vector possible 1.) Absence of link-layer security and the potential for mac address spoofing 2.) IP address / Session hijacking 3.) Data privacy per your text At the IP layer, IPsec can be used to protect unicast communications, and SeND can be used for multicast communications. [Sri] IPSec can be used for protecting both multicast or unicast communication; RFC-5374 with GDOI. 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. Petrescu, et al. Expires February 18, 2018 [Page 21] ________________________________________ https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-22 Internet-Draft IPv6-over-80211ocb August 2017 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. https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-8. IANA Considerations https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-9. 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. https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-10. 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. Pierre Pfister, Rostislav Lisovy, and others, wrote 802.11-OCB drivers for linux and described how. Petrescu, et al. Expires February 18, 2018 [Page 22] ________________________________________ https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-23 Internet-Draft IPv6-over-80211ocb August 2017 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. https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-11. References https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-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", https://tools.ietf.org/html/draft-ietf-6man-default-iids-16 (work in progress), September 2016. [I-D.ietf-6man-ug] Carpenter, B. and S. Jiang, "Significance of IPv6 Interface Identifiers", https://tools.ietf.org/html/draft-ietf-6man-ug-06 (work in progress), December 2013. [I-D.ietf-tsvwg-ieee-802-11] Szigeti, T., Henry, J., and F. Baker, "Diffserv to IEEE 802.11 Mapping", https://tools.ietf.org/html/draft-ietf-tsvwg-ieee-802-11-06 (work in progress), August 2017. [RFC1042] Postel, J. and J. Reynolds, "Standard for the transmission of IP datagrams over IEEE 802 networks", STD 43, https://tools.ietf.org/html/rfc1042, DOI 10.17487/RFC1042, February 1988, <https://www.rfc-editor.org/info/rfc1042 https://www.rfc-editor.org/info/rfc1042>. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", https://tools.ietf.org/html/bcp14, https://tools.ietf.org/html/rfc2119, DOI 10.17487/RFC2119, March 1997, <https://www.rfc-editor.org/info/rfc2119 https://www.rfc-editor.org/info/rfc2119>. [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6) Specification", https://tools.ietf.org/html/rfc2460, DOI 10.17487/RFC2460, December 1998, <https://www.rfc-editor.org/info/rfc2460>. [RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet Networks", https://tools.ietf.org/html/rfc2464, DOI 10.17487/RFC2464, December 1998, <https://www.rfc-editor.org/info/rfc2464>. Petrescu, et al. Expires February 18, 2018 [Page 23] ________________________________________ https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-24 Internet-Draft IPv6-over-80211ocb August 2017 [RFC3963] Devarapalli, V., Wakikawa, R., Petrescu, A., and P. Thubert, "Network Mobility (NEMO) Basic Support Protocol", https://tools.ietf.org/html/rfc3963, DOI 10.17487/RFC3963, January 2005, <https://www.rfc-editor.org/info/rfc3963>. [RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker, "Randomness Requirements for Security", https://tools.ietf.org/html/bcp106, https://tools.ietf.org/html/rfc4086, DOI 10.17487/RFC4086, June 2005, <https://www.rfc-editor.org/info/rfc4086 https://www.rfc-editor.org/info/rfc4086>. [RFC4301] Kent, S. and K. Seo, "Security Architecture for the Internet Protocol", https://tools.ietf.org/html/rfc4301, DOI 10.17487/RFC4301, December 2005, <https://www.rfc-editor.org/info/rfc4301>. [RFC4429] Moore, N., "Optimistic Duplicate Address Detection (DAD) for IPv6", https://tools.ietf.org/html/rfc4429, DOI 10.17487/RFC4429, April 2006, <https://www.rfc-editor.org/info/rfc4429>. [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, "Neighbor Discovery for IP version 6 (IPv6)", https://tools.ietf.org/html/rfc4861, DOI 10.17487/RFC4861, September 2007, <https://www.rfc-editor.org/info/rfc4861 https://www.rfc-editor.org/info/rfc4861>. [RFC5889] Baccelli, E., Ed. and M. Townsley, Ed., "IP Addressing Model in Ad Hoc Networks", https://tools.ietf.org/html/rfc5889, DOI 10.17487/RFC5889, September 2010, <https://www.rfc-editor.org/info/rfc5889>. [RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility Support in IPv6", https://tools.ietf.org/html/rfc6275, DOI 10.17487/RFC6275, July 2011, <https://www.rfc-editor.org/info/rfc6275>. [RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C. Bormann, "Neighbor Discovery Optimization for IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs)", https://tools.ietf.org/html/rfc6775, DOI 10.17487/RFC6775, November 2012, <https://www.rfc-editor.org/info/rfc6775>. [RFC7721] Cooper, A., Gont, F., and D. Thaler, "Security and Privacy Considerations for IPv6 Address Generation Mechanisms", https://tools.ietf.org/html/rfc7721, DOI 10.17487/RFC7721, March 2016, <https://www.rfc-editor.org/info/rfc7721>. https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#section-11.2. Informative References Petrescu, et al. Expires February 18, 2018 [Page 24] ________________________________________ https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-25 Internet-Draft IPv6-over-80211ocb August 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.". [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 http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-06-110A1.pdf downloaded on June 5th, 2014.". [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", https://tools.ietf.org/html/draft-jeong-ipwave-vehicular-networking-survey-03 https://tools.ietf.org/html/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", https://tools.ietf.org/html/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", https://tools.ietf.org/html/draft-petrescu-its-scenarios-reqs-03 https://tools.ietf.org/html/draft-petrescu-its-scenarios-reqs-03 (work in progress), October 2013. [ieee1609.2] "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 SA - 1609.3-2016 - IEEE Standard for Wireless Access in Vehicular Environments (WAVE) -- Networking Services. Example URL http://ieeexplore.ieee.org/document/7458115/accessed http://ieeexplore.ieee.org/document/7458115/accessed on August 17th, 2017.". Petrescu, et al. Expires February 18, 2018 [Page 25] ________________________________________ https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-26 Internet-Draft IPv6-over-80211ocb August 2017 [ieee1609.4] "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] "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 http://standards.ieee.org/findstds/standard/802.11-2012.html retrieved on October 17th, 2013.". [ieee802.11p-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 http://standards.ieee.org/getieee802/download/802.11p-2010.pdf retrieved on September 20th, 2013.". https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendix-A. ChangeLog The changes are listed in reverse chronological order, most recent changes appearing at the top of the list. From https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-03 to https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04 https://tools.ietf.org/html/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. o Minor textual issues. Petrescu, et al. Expires February 18, 2018 [Page 26] ________________________________________ https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-27 Internet-Draft IPv6-over-80211ocb August 2017 From https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-02 to https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-03 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-03 o Keep the previous text on multiple addresses, so remove talk about MIP6, NEMOv6 and MCoA. o Clarified that a 'Beacon' is an IEEE 802.11 frame Beacon. o Clarified the figure showing Infrastructure mode and OCB mode side by side. o Added a reference to the IP Security Architecture RFC. o Detailed the IPv6-per-channel prohibition paragraph which reflects the discussion at the last IETF IPWAVE WG meeting. o Added section "Address Mapping -- Unicast". o Added the ".11 Trailer" to pictures of 802.11 frames. o Added text about SNAP carrying the Ethertype. o New RSU definition allowing for it be both a Router and not necessarily a Router some times. o Minor textual issues. From https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-01 to https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-02 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-02 o Replaced almost all occurences of 802.11p with 802.11-OCB, leaving only when explanation of evolution was necessary. o Shortened by removing parameter details from a paragraph in the Introduction. o Moved a reference from Normative to Informative. o Added text in intro clarifying there is no handover spec at IEEE, and that 1609.2 does provide security services. o Named the contents the fields of the EthernetII header (including the Ethertype bitstring). o Improved relationship between two paragraphs describing the increase of the Sequence Number in 802.11 header upon IP fragmentation. Petrescu, et al. Expires February 18, 2018 [Page 27] ________________________________________ https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-28 Internet-Draft IPv6-over-80211ocb August 2017 o Added brief clarification of "tracking". From https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-00 to https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-01 https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-01 o Introduced message exchange diagram illustrating differences between 802.11 and 802.11 in OCB mode. o Introduced an appendix listing for information the set of 802.11 messages that may be transmitted in OCB mode. o Removed appendix sections "Privacy Requirements", "Authentication Requirements" and "Security Certificate Generation". o Removed appendix section "Non IP Communications". o Introductory phrase in the Security Considerations section. o Improved the definition of "OCB". o Introduced theoretical stacked layers about IPv6 and IEEE layers including EPD. o Removed the appendix describing the details of prohibiting IPv6 on certain channels relevant to 802.11-OCB. o Added a brief reference in the privacy text about a precise clause in IEEE 1609.3 and .4. o Clarified the definition of a Road Side Unit. o Removed the discussion about security of WSA (because is non-IP). o Removed mentioning of the GeoNetworking discussion. o Moved references to scientific articles to a separate 'overview' draft, and referred to it. https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendix-B. Changes Needed on a software driver 802.11a to become a 802.11-OCB driver The 802.11p amendment modifies both the 802.11 stack's physical and MAC layers but all the induced modifications can be quite easily obtained by modifying an existing 802.11a ad-hoc stack. Conditions for a 802.11a hardware to be 802.11-OCB compliant: Petrescu, et al. Expires February 18, 2018 [Page 28] ________________________________________ https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-29 Internet-Draft IPv6-over-80211ocb August 2017 o The chip must support the frequency bands on which the regulator recommends the use of ITS communications, for example using IEEE 802.11-OCB layer, in France: 5875MHz to 5925MHz. o The chip must support the half-rate mode (the internal clock should be able to be divided by two). o The chip transmit spectrum mask must be compliant to the "Transmit spectrum mask" from the IEEE 802.11p amendment (but experimental environments tolerate otherwise). o The chip should be able to transmit up to 44.8 dBm when used by the US government in the United States, and up to 33 dBm in Europe; other regional conditions apply. Changes needed on the network stack in OCB mode: o Physical layer: * The chip must use the Orthogonal Frequency Multiple Access (OFDM) encoding mode. * The chip must be set in half-mode rate mode (the internal clock frequency is divided by two). * The chip must use dedicated channels and should allow the use of higher emission powers. This may require modifications to the regulatory domains rules, if used by the kernel to enforce local specific restrictions. Such modifications must respect the location-specific laws. MAC layer: * All management frames (beacons, join, leave, and others) emission and reception must be disabled except for frames of subtype Action and Timing Advertisement (defined below). * No encryption key or method must be used. * Packet emission and reception must be performed as in ad-hoc mode, using the wildcard BSSID (ff:ff:ff:ff:ff:ff). * The functions related to joining a BSS (Association Request/ Response) and for authentication (Authentication Request/Reply, Challenge) are not called. * The beacon interval is always set to 0 (zero). Petrescu, et al. Expires February 18, 2018 [Page 29] ________________________________________ https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-30 Internet-Draft IPv6-over-80211ocb August 2017 * Timing Advertisement frames, defined in the amendment, should be supported. The upper layer should be able to trigger such frames emission and to retrieve information contained in received Timing Advertisements. https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#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 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. https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendix-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. 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. https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendix-C.2. Reliability Requirements 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- 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. Petrescu, et al. Expires February 18, 2018 [Page 30] ________________________________________ https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-31 Internet-Draft IPv6-over-80211ocb August 2017 Channel scanning being disabled, IPv6 over IEEE 802.11-OCB MUST implement a mechanism for transmitter and receiver to converge to a common channel. 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 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. https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendix-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 clearly defined yet. One possibility is to consider each card as an independent network interface, with a specific MAC Address and a set 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. Petrescu, et al. Expires February 18, 2018 [Page 31] ________________________________________ https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#page-32 Internet-Draft IPv6-over-80211ocb August 2017 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. https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendix-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 the following characteristics: o Bit "Local/Global" set to "locally admninistered". o Bit "Unicast/Multicast" set to "Unicast". o 46 remaining bits set to a random value, using a random number generator that meets the requirements of [https://tools.ietf.org/html/rfc4086]. The way to meet the randomization requirements is to retain 46 bits from the output of a strong hash function, such as SHA256, taking as input a 256 bit local secret, the "nominal" MAC Address of the interface, and a representation of the date and time of the renumbering event. https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-04#appendix-D. IEEE 802.11 Messages Transmitted in OCB mode For information, at the time of writing, this is the list of IEEE 802.11 messages that may be transmitted in OCB mode, i.e. when dot11OCBActivated is true in a STA: 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. Authors' Addresses
- [ipwave] Review comments on draft-ietf-ipwave-ipv… Sri Gundavelli (sgundave)
- Re: [ipwave] Review comments on draft-ietf-ipwave… Russ Housley
- Re: [ipwave] Review comments on draft-ietf-ipwave… Sri Gundavelli (sgundave)
- Re: [ipwave] Review comments on draft-ietf-ipwave… François Simon
- Re: [ipwave] Review comments on draft-ietf-ipwave… Sri Gundavelli (sgundave)
- Re: [ipwave] Review comments on draft-ietf-ipwave… Alexandre Petrescu
- Re: [ipwave] Review comments on draft-ietf-ipwave… Sri Gundavelli (sgundave)
- Re: [ipwave] Review comments on draft-ietf-ipwave… Alexandre Petrescu
- Re: [ipwave] Review comments on draft-ietf-ipwave… Alexandre Petrescu
- Re: [ipwave] Review comments on draft-ietf-ipwave… Alexandre Petrescu
- Re: [ipwave] Review comments on draft-ietf-ipwave… Sri Gundavelli (sgundave)
- Re: [ipwave] Review comments on draft-ietf-ipwave… Sri Gundavelli (sgundave)
- Re: [ipwave] Review comments on draft-ietf-ipwave… William Whyte
- Re: [ipwave] Review comments on draft-ietf-ipwave… Alexandre Petrescu
- Re: [ipwave] Review comments on draft-ietf-ipwave… William Whyte
- Re: [ipwave] Review comments on draft-ietf-ipwave… Alexandre Petrescu
- Re: [ipwave] Review comments on draft-ietf-ipwave… Sri Gundavelli (sgundave)
- Re: [ipwave] Review comments on draft-ietf-ipwave… William Whyte
- Re: [ipwave] Review comments on draft-ietf-ipwave… Alexandre Petrescu
- Re: [ipwave] Review comments on draft-ietf-ipwave… Alexandre Petrescu
- Re: [ipwave] Review comments on draft-ietf-ipwave… Alexandre Petrescu
- Re: [ipwave] Review comments on draft-ietf-ipwave… Alexandre Petrescu
- Re: [ipwave] Review comments on draft-ietf-ipwave… Sri Gundavelli (sgundave)
- Re: [ipwave] Review comments on draft-ietf-ipwave… Alexandre Petrescu
- Re: [ipwave] Review comments on draft-ietf-ipwave… Sri Gundavelli (sgundave)
- Re: [ipwave] Review comments on draft-ietf-ipwave… Sri Gundavelli (sgundave)
- Re: [ipwave] Review comments on draft-ietf-ipwave… Alexandre Petrescu
- Re: [ipwave] Review comments on draft-ietf-ipwave… Sri Gundavelli (sgundave)
- Re: [ipwave] Review comments on draft-ietf-ipwave… Tony Li
- Re: [ipwave] Review comments on draft-ietf-ipwave… Sri Gundavelli (sgundave)
- Re: [ipwave] Review comments on draft-ietf-ipwave… Alexandre Petrescu