--- 1/draft-ietf-ipwave-ipv6-over-80211ocb-01.txt 2017-03-12 13:13:45.189280948 -0700 +++ 2/draft-ietf-ipwave-ipv6-over-80211ocb-02.txt 2017-03-12 13:13:45.257282563 -0700 @@ -1,30 +1,30 @@ Network Working Group A. Petrescu Internet-Draft CEA, LIST Intended status: Standards Track N. Benamar -Expires: August 24, 2017 Moulay Ismail University +Expires: September 13, 2017 Moulay Ismail University J. Haerri Eurecom C. Huitema J. Lee Sangmyung University T. Ernst YoGoKo T. Li Peloton Technology - February 20, 2017 + March 12, 2017 Transmission of IPv6 Packets over IEEE 802.11 Networks in mode Outside the Context of a Basic Service Set (IPv6-over-80211ocb) - draft-ietf-ipwave-ipv6-over-80211ocb-01.txt + draft-ietf-ipwave-ipv6-over-80211ocb-02.txt Abstract In order to transmit IPv6 packets on IEEE 802.11 networks run outside the context of a basic service set (OCB, earlier "802.11p") there is a need to define a few parameters such as the recommended Maximum Transmission Unit size, the header format preceding the IPv6 header, the Type value within it, and others. This document describes these parameters for IPv6 and IEEE 802.11 OCB networks; it portrays the layering of IPv6 on 802.11 OCB similarly to other known 802.11 and @@ -47,21 +47,21 @@ Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. 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 August 24, 2017. + This Internet-Draft will expire on September 13, 2017. Copyright Notice Copyright (c) 2017 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents @@ -70,48 +70,48 @@ include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Communication Scenarios where IEEE 802.11 OCB Links are Used 6 4. Aspects introduced by the OCB mode to 802.11 . . . . . . . . 6 - 5. Layering of IPv6 over 802.11p as over Ethernet . . . . . . . 10 + 5. Layering of IPv6 over 802.11-OCB as over Ethernet . . . . . . 10 5.1. Maximum Transmission Unit (MTU) . . . . . . . . . . . . . 10 5.2. Frame Format . . . . . . . . . . . . . . . . . . . . . . 10 5.2.1. Ethernet Adaptation Layer . . . . . . . . . . . . . . 11 5.3. Link-Local Addresses . . . . . . . . . . . . . . . . . . 13 5.4. Address Mapping . . . . . . . . . . . . . . . . . . . . . 13 5.4.1. Address Mapping -- Unicast . . . . . . . . . . . . . 13 5.4.2. Address Mapping -- Multicast . . . . . . . . . . . . 13 5.5. Stateless Autoconfiguration . . . . . . . . . . . . . . . 14 5.6. Subnet Structure . . . . . . . . . . . . . . . . . . . . 15 - 6. Example IPv6 Packet captured over a IEEE 802.11p link . . . . 15 - 6.1. Capture in Monitor Mode . . . . . . . . . . . . . . . . . 15 + 6. Example IPv6 Packet captured over a IEEE 802.11-OCB link . . 15 + 6.1. Capture in Monitor Mode . . . . . . . . . . . . . . . . . 16 6.2. Capture in Normal Mode . . . . . . . . . . . . . . . . . 18 7. Security Considerations . . . . . . . . . . . . . . . . . . . 20 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21 9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 21 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 21 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 22 11.1. Normative References . . . . . . . . . . . . . . . . . . 22 11.2. Informative References . . . . . . . . . . . . . . . . . 23 Appendix A. ChangeLog . . . . . . . . . . . . . . . . . . . . . 26 Appendix B. Changes Needed on a software driver 802.11a to become a 802.11-OCB driver . . . 27 - Appendix C. Design Considerations . . . . . . . . . . . . . . . 28 - C.1. Vehicle ID . . . . . . . . . . . . . . . . . . . . . . . 28 + Appendix C. Design Considerations . . . . . . . . . . . . . . . 29 + C.1. Vehicle ID . . . . . . . . . . . . . . . . . . . . . . . 29 C.2. Reliability Requirements . . . . . . . . . . . . . . . . 29 - C.3. Multiple interfaces . . . . . . . . . . . . . . . . . . . 29 - C.4. MAC Address Generation . . . . . . . . . . . . . . . . . 30 + C.3. Multiple interfaces . . . . . . . . . . . . . . . . . . . 30 + C.4. MAC Address Generation . . . . . . . . . . . . . . . . . 31 Appendix D. IEEE 802.11 Messages Transmitted in OCB mode . . . . 31 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 31 1. Introduction This document describes the transmission of IPv6 packets on IEEE Std 802.11 OCB networks (earlier known as 802.11p). This involves the layering of IPv6 networking on top of the IEEE 802.11 MAC layer (with an LLC layer). Compared to running IPv6 over the Ethernet MAC layer, there is no modification required to the standards: IPv6 works fine @@ -122,21 +122,21 @@ 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, and vice-versa. + OCB. The IPv6 network layer operates on 802.11 OCB in the same manner as it operates on 802.11 WiFi. The IPv6 network layer operates on WiFi by involving an Ethernet Adaptation Layer; this Ethernet Adaptation Layer converts between 802.11 Headers and Ethernet II headers. The operation of IP on Ethernet is described in [RFC1042] and [RFC2464]. The situation of IPv6 networking layer on Ethernet Adaptation Layer is illustrated below: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ @@ -169,34 +169,39 @@ +-+-+-{ PHY_SAP }+-+-+-+-+-+-+-| | | | PLME | | | PHY Layer | PLME_SAP | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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). + 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 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. This is followed by a description of differences in specification terms, between 802.11 OCB and 802.11a/b/g/n (and the same differences expressed in terms of requirements to software implementation are listed in Appendix B.) The document then concentrates on the parameters of layering IP over - 802.11 OCB as over Ethernet: MTU, Frame Format, Interface Identifier, - Address Mapping, State-less Address Auto-configuration. The values - of these parameters are precisely the same as IPv6 over Ethernet - [RFC2464]: the recommended value of MTU to be 1500 octets, the Frame - Format containing the Type 0x86DD, the rules for forming an Interface - Identifier, the Address Mapping mechanism and the Stateless Address - Auto-Configuration. + 802.11 OCB as over Ethernet: value of MTU, the contents of Frame + Format, the rules for forming Interface Identifiers, the mechanism + for Address Mapping and for State-less Address Auto-configuration. + These are precisely the same as IPv6 over Ethernet [RFC2464]. As an example, these characteristics of layering IPv6 straight over LLC over 802.11 OCB MAC are illustrated by dissecting an IPv6 packet captured over a 802.11 OCB link; this is described in the section Section 6. A couple of points can be considered as different, although they are not required in order to have a working implementation of IPv6-over- 802.11-OCB. These points are consequences of the OCB operation which is particular to 802.11 OCB (Outside the Context of a BSS). First, @@ -222,24 +227,25 @@ RSU: Road Side Unit. An IP router equipped with, or connected to, at least one interface that is 802.11 and that is an interface that operates in OCB mode. 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: 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 802.11p for - operation in the 5.9 GHz band and in mode OCB. + 802.11-OCB, or 802.11 OCB: text in document IEEE 802.11-2012 that is + flagged by "dot11OCBActivated". 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. 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 [I-D.petrescu-its-scenarios-reqs], about scenarios and requirements for IP in Intelligent Transportation Systems. @@ -286,34 +292,36 @@ |<--- Asso Res. -------| |<------ Data -------->| | | |<------ Data -------->| |------- Data -------->| |<------ Data -------->| |------- Data -------->| |<------ Data -------->| (a) Traditional IEEE 802.11 (b) IEEE 802.11 OCB mode The link 802.11 OCB was specified in IEEE Std 802.11p(TM)-2010 [ieee802.11p-2010] as an amendment to the 802.11 specifications, titled "Amendment 6: Wireless Access in Vehicular Environments". - Since then, these 802.11p amendments have been included in IEEE - 802.11(TM)-2012 [ieee802.11-2012], titled "IEEE Standard for - Information technology--Telecommunications and information exchange - between systems Local and metropolitan area networks--Specific - requirements Part 11: Wireless LAN Medium Access Control (MAC) and - Physical Layer (PHY) Specifications"; the modifications are diffused - throughout various sections (e.g. 802.11p's Time Advertisement - message is described in section 'Frame formats', and the operation - outside the context of a BSS described in section 'MLME'). + Since then, this amendment has been included in IEEE 802.11(TM)-2012 + [ieee802.11-2012], titled "IEEE Standard for Information technology-- + Telecommunications and information exchange between systems Local and + metropolitan area networks--Specific requirements Part 11: Wireless + LAN Medium Access Control (MAC) and Physical Layer (PHY) + Specifications"; the modifications are diffused throughout various + sections (e.g. the Time Advertisement message described in the + earlier 802.11p ammendment 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 - in earlier 802.11p documents the term "OCBEnabled" was used instead. + that in earlier 802.11p documents the term "OCBEnabled" was used + instead of te current "OCBActivated". In order to delineate the aspects introduced by 802.11 OCB to 802.11, we refer to the earlier [ieee802.11p-2010]. The amendment is 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 @@ -333,104 +341,106 @@ 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. - o Operation Outside the Context of a BSS (OCB): the 802.11p links - are operated without a Basic Service Set (BSS). This means that - the messages Beacon, Association Request/Response, Authentication - Request/Response, and similar, are not used. The used identifier - of BSS (BSSID) has a hexadecimal value always ff:ff:ff:ff:ff:ff - (48 '1' bits, or 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 and on the protocols for IP layer - security. + 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 messages Beacon, Association Request/ + Response, Authentication Request/Response, and similar, are not + used. The used identifier of BSS (BSSID) has a hexadecimal value + always ff:ff:ff:ff:ff:ff (48 '1' bits, or 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 + and on the protocols for IP layer security. - o Timing Advertisement: is a new message defined in 802.11p, which - does not exist in 802.11a/b/g/n. This message is used by stations - to inform other stations about the value of time. It is similar - to the time as delivered by a GNSS system (Galileo, GPS, ...) or - by a cellular system. This message is optional for + o Timing Advertisement: is a new message defined in 802.11-OCB, + which does not exist in 802.11a/b/g/n. This message is used by + stations to inform other stations about the value of time. It is + similar to the time as delivered by a GNSS system (Galileo, GPS, + ...) or by a cellular system. This message is optional for implementation. At the date of writing, an experienced reviewer considers that currently no field testing has used this message. Another implementor considers this feature implemented in an initial manner. In the future, it is speculated that this message may be useful for very simple devices which may not have their own hardware source of time (Galileo, GPS, cellular network), or by vehicular devices situated in areas not covered by such network (in tunnels, underground, outdoors but shaded by foliage or buildings, in remote areas, etc.) 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 802.11p, 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 802.11p 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 802.11p (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 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). + 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 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 the PHY of IEEE 802.11-OCB, as opposed to IPv6 not being prohibited on any channel on which 802.11a/b/g/n runs; at the time of writing, this prohibition is explicit in IEEE 1609 documents. 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 802.11p links, there are strong - privacy concerns with respect to addressing. While the 802.11p - standard does not specify anything in particular with respect to - MAC addresses, in these settings there exists a strong need for - dynamic change of these addresses (as opposed to the non-vehicular - settings - real wall protection - where fixed MAC addresses do not - currently pose some privacy risks). This is further described in - section Section 7. A relevant function is described in IEEE - 1609.3, clause 5.5.1 and IEEE 1609.4, clause 6.7. + o In vehicular communications using 802.11-OCB links, there are + strong privacy concerns with respect to addressing. While the + 802.11-OCB standard does not specify anything in particular with + respect to MAC addresses, in these settings there exists a strong + need for dynamic change of these addresses (as opposed to the non- + vehicular settings - real wall protection - where fixed MAC + addresses do not currently pose some privacy risks). This is + further described in section Section 7. A relevant function is + described in IEEE 1609.3, clause 5.5.1 and IEEE 1609.4, clause + 6.7. - Other aspects particular to 802.11p which are also particular to + 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 802.11p networks. The - subnet structure which may be assumed in 802.11p networks is strongly - influenced by the mobility of vehicles. + 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. -5. Layering of IPv6 over 802.11p as over Ethernet +5. Layering of IPv6 over 802.11-OCB as over Ethernet 5.1. Maximum Transmission Unit (MTU) - The default MTU for IP packets on 802.11p is 1500 octets. It is the - same value as IPv6 packets on Ethernet links, as specified in + The default MTU for IP packets on 802.11-OCB is 1500 octets. It is + the same value as IPv6 packets on Ethernet links, as specified in [RFC2464]. This value of the MTU respects the recommendation that every link in the Internet must have a minimum MTU of 1280 octets (stated in [RFC2460], and the recommendations therein, especially with respect to fragmentation). If IPv6 packets of size larger than 1500 bytes are sent on an 802.11-OCB interface 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 @@ -439,27 +449,28 @@ size, allowing an arbitrary number of 'containers'. Non-IP packets such as ETSI 'geonet' packets have an MTU of 1492 bytes. The Equivalent Transmit Time on Channel is a concept that may be used as an alternative to the MTU concept. A rate of transmission may be specified as well. The ETTC, rate and MTU may be in direct relationship. 5.2. Frame Format - IP packets are transmitted over 802.11p as standard Ethernet packets. - As with all 802.11 frames, an Ethernet adaptation layer is used with - 802.11p as well. This Ethernet Adaptation Layer 802.11-to-Ethernet - is described in Section 5.2.1. The Ethernet Type code (EtherType) - for IPv6 is 0x86DD (hexadecimal 86DD, or otherwise #86DD). + IP packets are transmitted over 802.11-OCB as standard Ethernet + packets. As with all 802.11 frames, an Ethernet adaptation layer is + used with 802.11-OCB as well. This Ethernet Adaptation Layer + performing 802.11-to-Ethernet is described in Section 5.2.1. The + Ethernet Type code (EtherType) for IPv6 is 0x86DD (hexadecimal 86DD, + or otherwise #86DD). - The Frame format for transmitting IPv6 on 802.11p networks is the + The Frame format for transmitting IPv6 on 802.11-OCB networks is the same as transmitting IPv6 on Ethernet networks, and is described in section 3 of [RFC2464]. 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 | @@ -477,20 +488,32 @@ | IPv6 | +- -+ | header | +- -+ | and | +- -+ / payload ... / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ (Each tic mark represents one bit.) + Ethernet II Fields: + + o Destination Ethernet Address: the MAC destination address. + + o Source Ethernet Address: the MAC source address. + + o "1 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1": binary representation of the + EtherType value 0x86DD. + + o IPv6 header and payload: the IPv6 packet containing IPv6 header + and payload. + 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. @@ -513,24 +536,23 @@ +---------------------+-------------+---------+ | Ethernet II Header | IPv6 Header | Payload | +---------------------+-------------+---------+ 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. - When the MTU value is smaller than the size of the IP packet to be - sent, the IP layer fragments the packet into multiple IP fragments. - During this operation, the "Sequence number" field of the 802.11 Data - Header is increased. + The Ethernet Adaptation Layer performs operations in relation to IP + fragmentation and MTU. One of these operations is briefly described + in section Section 5.1. In OCB mode, IPv6 packets can be transmitted either as "IEEE 802.11 Data" or alternatively as "IEEE 802.11 QoS Data", as illustrated in the following figure: +--------------------+-------------+-------------+---------+ | 802.11 Data Header | LLC Header | IPv6 Header | Payload | +--------------------+-------------+-------------+---------+ or @@ -546,32 +568,35 @@ 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 [I-D.ietf-tsvwg-ieee-802-11], although it is not specific to OCB mode. 5.3. Link-Local Addresses - The link-local address of an 802.11p interface is formed in the same - manner as on an Ethernet interface. This manner is described in + 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 section 5 of [RFC2464]. 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 6 and 7 of [RFC2464]. 5.4.1. Address Mapping -- Unicast + The procedure for mapping IPv6 unicast addresses into Ethernet link- + layer addresses is described in + 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. The same mapping requirement applies to the link-scoped multicast @@ -600,76 +625,78 @@ mapped to and from a MAC multicast address. Transmitting IPv6 packets to multicast destinations over 802.11 links proved to have some performance issues [I-D.perkins-intarea-multicast-ieee802]. These issues may be exacerbated in OCB mode. Solutions for these problems should consider the OCB mode of operation. 5.5. Stateless Autoconfiguration - The Interface Identifier for an 802.11p interface is formed using the - same rules as the Interface Identifier for an Ethernet interface; + The Interface Identifier for an 802.11-OCB interface is formed using + the same rules as the Interface Identifier for an Ethernet interface; this is described in section 4 of [RFC2464]. No changes are needed, but some care must be taken when considering the use of the SLAAC procedure. The bits in the the interface identifier have no generic meaning and the identifier should be treated as an opaque value. The bits - 'Universal' and 'Group' in the identifier of an 802.11p interface are - significant, as this is a IEEE link-layer address. The details of - this significance are described in [I-D.ietf-6man-ug]. + 'Universal' and 'Group' in the identifier of an 802.11-OCB interface + are significant, as this is an IEEE link-layer address. The details + of this significance are described in [I-D.ietf-6man-ug]. As with all Ethernet and 802.11 interface identifiers ([RFC7721]), - the identifier of an 802.11p interface may involve privacy risks. A - vehicle embarking an On-Board Unit whose egress interface is 802.11p - may expose itself to eavesdropping and subsequent correlation of - data; this may reveal data considered private by the vehicle owner. + 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 fo being tracked; see the privacy + considerations described in Appendix C. If stable Interface Identifiers are needed in order to form IPv6 addresses on 802.11-OCB links, it is recommended to follow the recommendation in [I-D.ietf-6man-default-iids]. 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 [RFC5889]. -6. Example IPv6 Packet captured over a IEEE 802.11p link +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 802.11p networks. Consequently, this section is - an illustration of this concept and thus can help the implementer - when it comes to running IPv6 over IEEE 802.11p. By way of example - we show that there is no modification in the headers when transmitted - over 802.11p networks - they are transmitted like any other 802.11 - and Ethernet packets. + 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 802.11p - link. In this experiment, the packet is an IPv6 Router - Advertisement. This packet is emitted by a Router on its 802.11p + We describe an experiment of capturing an IPv6 packet on an + 802.11-OCB link. In this experiment, the packet is an IPv6 Router + Advertisement. This packet is emitted by a Router on its 802.11-OCB interface. The packet is captured on the Host, using a network protocol analyzer (e.g. Wireshark); the capture is performed in two different modes: direct mode and 'monitor' mode. The topology used during the capture is depicted below. +--------+ +-------+ | | 802.11-OCB Link | | ---| Router |--------------------------------| Host | | | | | +--------+ +-------+ During several capture operations running from a few moments to several hours, no message relevant to the BSSID contexts were captured (no Association Request/Response, Authentication Req/Resp, - Beacon). This shows that the operation of 802.11p is outside the + Beacon). This shows that the operation of 802.11-OCB is outside the context of a BSSID. Overall, the captured message is identical with a capture of an IPv6 packet emitted on a 802.11b interface. The contents are precisely similar. 6.1. Capture in Monitor Mode The IPv6 RA packet captured in monitor mode is illustrated below. The radio tap header provides more flexibility for reporting the @@ -782,25 +808,25 @@ the IPv6 source and destination addresses are set to useful values). This "GeoIP" can be a useful information to look up the city, country, AS number, and other information for an IP address. The Ethernet Type field in the logical-link control header is set to 0x86dd which indicates that the frame transports an IPv6 packet. In the IEEE 802.11 data, the destination address is 33:33:00:00:00:01 which is he corresponding multicast MAC address. The BSS id is a broadcast address of ff:ff:ff:ff:ff:ff. Due to the short link duration between vehicles and the roadside infrastructure, there is - no need in IEEE 802.11p to wait for the completion of association and - authentication procedures before exchanging data. IEEE 802.11p - enabled nodes use the wildcard BSSID (a value of all 1s) and may - start communicating as soon as they arrive on the communication - channel. + no need in IEEE 802.11-OCB to wait for the completion of association + and authentication procedures before exchanging data. IEEE + 802.11-OCB enabled nodes use the wildcard BSSID (a value of all 1s) + and may start communicating as soon as they arrive on the + communication channel. 6.2. Capture in Normal Mode The same IPv6 Router Advertisement packet described above (monitor mode) is captured on the Host, in the Normal mode, and depicted below. Ethernet II Header +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination... @@ -865,75 +891,75 @@ 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 802.11p MAC layer, as shown by - the use of the Type 0x86DD, and assuming an adaptation layer + 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). 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. - 802.11p does not provide any cryptographic protection, because it + 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). At the IP layer, IPsec can be used to protect unicast communications, and SeND can be used for multicast communications. If no protection is used by the IP layer, upper layers should be protected. Otherwise, the end-user or system should be warned about the risks they run. As with all Ethernet and 802.11 interface identifiers, there may - exist privacy risks in the use of 802.11p interface identifiers. - However, in outdoors vehicular settings, the privacy risks are more + 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 - 802.11p deployments, there is a strong necessity to use protection + 802.11-OCB deployments, there is a strong necessity to use protection tools such as dynamically changing MAC addresses. This may help mitigate privacy risks to a certain level. On another hand, it may have an impact in the way typical IPv6 address auto-configuration is performed for vehicles (SLAAC would rely on MAC addresses amd would hence dynamically change the affected IP address), in the way the IPv6 Privacy addresses were used, and other effects. 8. IANA Considerations 9. Contributors Romain Kuntz contributed extensively about IPv6 handovers between - links running outside the context of a BSS (802.11p links). + 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 - offering the ETSI ITS perspective, as well as other parts of the + Michelle Wetterwald contributed extensively the MTU discussion, + offeried the ETSI ITS perspective, and reviewed other parts of the document. 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, and William @@ -964,26 +990,20 @@ [I-D.ietf-6man-ug] Carpenter, B. and S. Jiang, "Significance of IPv6 Interface Identifiers", draft-ietf-6man-ug-06 (work in progress), December 2013. [I-D.ietf-tsvwg-ieee-802-11] Szigeti, T. and F. Baker, "DiffServ to IEEE 802.11 Mapping", draft-ietf-tsvwg-ieee-802-11-01 (work in progress), November 2016. - [I-D.jeong-ipwave-vehicular-networking-survey] - Jeong, J., Cespedes, S., Benamar, N., and J. Haerri, - "Survey on IP-based Vehicular Networking for Intelligent - Transportation Systems", draft-jeong-ipwave-vehicular- - networking-survey-00 (work in progress), October 2016. - [RFC1042] Postel, J. and J. Reynolds, "Standard for the transmission of IP datagrams over IEEE 802 networks", STD 43, RFC 1042, DOI 10.17487/RFC1042, February 1988, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . @@ -1060,20 +1080,26 @@ 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 downloaded on June 5th, 2014.". + [I-D.jeong-ipwave-vehicular-networking-survey] + Jeong, J., Cespedes, S., Benamar, N., and J. Haerri, + "Survey on IP-based Vehicular Networking for Intelligent + Transportation Systems", draft-jeong-ipwave-vehicular- + networking-survey-00 (work in progress), October 2016. + [I-D.perkins-intarea-multicast-ieee802] Perkins, C., Stanley, D., Kumari, W., and J. Zuniga, "Multicast Considerations over IEEE 802 Wireless Media", draft-perkins-intarea-multicast-ieee802-01 (work in progress), September 2016. [I-D.petrescu-its-scenarios-reqs] Petrescu, A., Janneteau, C., Boc, M., and W. Klaudel, "Scenarios and Requirements for IP in Intelligent Transportation Systems", draft-petrescu-its-scenarios- @@ -1142,20 +1168,43 @@ header and certificate formats; document freely available at URL http://www.etsi.org/deliver/ etsi_ts/103000_103099/103097/01.01.01_60/ ts_103097v010101p.pdf retrieved on July 08th, 2016.". Appendix A. ChangeLog The changes are listed in reverse chronological order, most recent changes appearing at the top of the list. + From draft-ietf-ipwave-ipv6-over-80211ocb-01 to 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. + + o Added brief clarification of "tracking". + From draft-ietf-ipwave-ipv6-over-80211ocb-00 to 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 @@ -1185,25 +1234,25 @@ o Moved references to scientific articles to a separate 'overview' draft, and referred to it. 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 802.11p compliant: + Conditions for a 802.11a hardware to be 802.11-OCB compliant: o The chip must support the frequency bands on which the regulator recommends the use of ITS communications, for example using IEEE - 802.11p layer, in France: 5875MHz to 5925MHz. + 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