wdiff draft-ietf-ipwave-ipv6-over-80211ocb-00.txt draft-ietf-ipwave-ipv6-over-80211ocb-01.txt

Network Working Group A. Petrescu
Internet-Draft CEA, LIST
Intended status: Standards Track N. Benamar
Expires: June 4, August 24, 2017 Moulay Ismail University
J. Haerri
Eurecom
C. Huitema

J. Lee
Sangmyung University
T. Ernst
YoGoKo
T. Li
Peloton Technology
December 1, 2016
February 20, 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-00.txt
draft-ietf-ipwave-ipv6-over-80211ocb-01.txt

Abstract

In order to transmit IPv6 packets on IEEE 802.11 networks run outside
the context of a basic service set (OCB, earlier "802.11p") there is
a need to define a few parameters such as the recommended Maximum
Transmission Unit size, the header format preceding the IPv6 header,
the Type value within it, and others. This document describes these
parameters for IPv6 and IEEE 802.11 OCB networks; it portrays the
layering of IPv6 on 802.11 OCB similarly to other known 802.11 and
Ethernet layers - by using an Ethernet Adaptation Layer.

In addition, the document attempts to list what is different in
802.11 OCB (802.11p) compared to more 'traditional' 802.11a/b/g/n
layers, layers over which IPv6 protocols operates without issues.
Most notably, the operation outside the context of a BSS (OCB) has
impact on IPv6 handover behaviour and on IPv6 security.

An example of an IPv6 packet captured while transmitted over an IEEE
802.11 OCB link (802.11p) is given.

Status of This Memo

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Table of Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Communication Scenarios where IEEE 802.11p 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 . . . . . . . 9 10
5.1. Maximum Transmission Unit (MTU) . . . . . . . . . . . . . 9 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. Handovers between OCB links . . . . . . . . . . . . . . . . . 15
7. Example IPv6 Packet captured over a IEEE 802.11p link . . . . 17
7.1. 15
6.1. Capture in Monitor Mode . . . . . . . . . . . . . . . . . 18
7.2. 15
6.2. Capture in Normal Mode . . . . . . . . . . . . . . . . . 21
8. 18
7. Security Considerations . . . . . . . . . . . . . . . . . . . 23
9. 20
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24
10. 21
9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 24
11. 21
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 24
12. 21
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 25
12.1. 22
11.1. Normative References . . . . . . . . . . . . . . . . . . 25
12.2. 22
11.2. Informative References . . . . . . . . . . . . . . . . . 26 23
Appendix A. ChangeLog . . . . . . . . . . . . . . . . . . . . . 30 26
Appendix B. Explicit Prohibition of IPv6 on Channels
Related to ITS Scenarios using 802.11p Networks
- an Analysis . . . . . . . . . . . . . . . . . . . 32
B.1. Interpretation of FCC and ETSI documents with
respect to running IP on particular channels . . . . . . 32
B.2. Interpretations of Latencies of IP datagrams . . . . . . 33
Appendix C. Changes Needed on a software driver 802.11a to
become a 802.11-OCB driver . . 33 . 27
Appendix D. C. Design Considerations . . . . . . . . . . . . . . . 34
D.1. 28
C.1. Vehicle ID . . . . . . . . . . . . . . . . . . . . . . . 35
D.2. Non IP Communications . . . . . . . . . . . . . . . . . . 35
D.3. 28
C.2. Reliability Requirements . . . . . . . . . . . . . . . . 36
D.4. Privacy requirements . . . . . . . . . . . . . . . . . . 37
D.5. Authentication requirements . . . . . . . . . . . . . . . 38
D.6. 29
C.3. Multiple interfaces . . . . . . . . . . . . . . . . . . . 38
D.7. 29
C.4. MAC Address Generation . . . . . . . . . . . . . . . . . 39
D.8. Security Certificate Generation . . . . . . . . . 30
Appendix D. IEEE 802.11 Messages Transmitted in OCB mode . . . . 39 31
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 40 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
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, and vice-versa.

As an overview, we illustrate how an IPv6 stack runs over 802.11p by
layering different protocols on top of each other.

The IPv6
Networking is layered network layer operates on top of 802.11 OCB in the IEEE 802.2 Logical-Link Control
(LLC) layer; this is itself layered same manner as
it operates on top of the 802.11p MAC; this
layering illustration 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 similar to that described in [RFC1042] and [RFC2464].
The situation of running IPv6 over 802.2
LLC over the 802.11 MAC, or over networking layer on Ethernet MAC.

+-----------------+ +-----------------+ Adaptation Layer
is illustrated below:

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... IPv6 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... Ethernet Adaptation Layer |
+-----------------+ +-----------------+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 Networking 802.11 WiFi MAC |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 802.11 WiFi PHY |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

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 Networking |
+-----------------+ +-----------------+
+-+-+-+-+-+-{ }+-+-+-+-+-+-+-+
{ LLC_SAP } 802.11 OCB
+-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ Boundary
| 802.2 LLC EPD | vs. | 802.2 LLC |
+-----------------+ +-----------------+
| 802.11p MAC | MLME | |
+-+-+-{ MAC_SAP }+-+-+-| MLME_SAP |
| 802.11b MAC Sublayer |
+-----------------+ +-----------------+ | 802.11p PHY | 802.11 OCB
| and ch. coord. | | SME | Services
+-+-+-{ PHY_SAP }+-+-+-+-+-+-+-| |
| | PLME | |
| 802.11b PHY Layer |
+-----------------+ +-----------------+ PLME_SAP |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

However, there are several may be some deployment considerations to helping optimize
the performances of running IPv6 over 802.11p 802.11-OCB (e.g. in the case of
handovers between 802.11p Access Points, 802.11 OCB-enabled access routers, or the
consideration of using the IP security layer).

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 802.11p 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 C.) B.)

The document then concentrates on the parameters of layering IP over
802.11p
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.

As an example, these characteristics of layering IPv6 straight over
LLC over 802.11p 802.11 OCB MAC are illustrated by dissecting an IPv6 packet
captured over a 802.11p 802.11 OCB link; this is described in the section titled
"Example of IPv6 Packet captured over an IEEE 802.11p link".
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-
802.11p.
802.11-OCB. These points are consequences of the OCB operation which
is particular to 802.11p 802.11 OCB (Outside the Context of a BSS). First,
the handovers between OCB links need specific behaviour for IP Router
Advertisements, or otherwise 802.11p's 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 802.11p 802.11 is stripped of all 802.11
link-layer security; a small additional security aspect which is
shared between 802.11p 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:
[I-D.jeong-ipwave-vehicular-networking-survey].

2. Terminology

The OCB handovers key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and
security "OPTIONAL" in this
document are to be interpreted as described each in section Section 6 RFC 2119 [RFC2119].

RSU: Road Side Unit. An IP router equipped with, or connected to, at
least one interface that is 802.11 and Section 8
respectively.

In standards, the operation of IPv6 as a 'data plane' over 802.11p that is
specified at IEEE P1609 in [ieeep1609.3-D9-2010]. For example, it
mentions an interface that "Networking services also specifies
operates in OCB mode.

OCB: outside the use context of the
Internet protocol IPv6, and supports transport protocols such as UDP
and TCP. [...] a basic service set (BSS): A Networking Services implementation shall support
either IPv6 or WSMP or both." and "IP traffic is sent and received
through the LLC sublayer as specified in [...]". The layered stacks
depicted in the "Architecture" document P1609.0 [ieeep1609.0-D2]
suggest that WSMP messages may not be transmitted as payload mode of IPv6
datagrams; WSMP and IPv6 are parallel (not stacked) layers.

Also, the
operation of IPv6 over in which a GeoNetworking layer and over G5 STA is
described in [etsi-302663-v1.2.1p-2013].

In the published literature, three documents describe aspects related
to running IPv6 over 802.11p: [vip-wave], [ipv6-80211p-its] and
[ipv6-wave].

2. Terminology

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].

RSU: Road Side Unit.

OCB: Outside the Context of not a Basic Service Set identifier.

OCB - Outside the Context member of a Basic-Service Set ID (BSSID).

802.11-OCB - BSS and does not
utilize IEEE 802.11-2012 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.

3. Communication Scenarios where IEEE 802.11p 802.11 OCB Links are Used

The IEEE 802.11p 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.

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:

o Wildcard The use by each node of a 'wildcard' BSSID (i.e., all bits are each bit of the
BSSID is set to 1) used by each node

o No beacons Beacons transmitted

o No authentication required

o No association needed

o No encryption provided

o Flag dot11OCBActivated OID set to true

The link 802.11p is specified following message exchange diagram illustrates a comparison
between traditional 802.11 and 802.11 in IEEE Std 802.11p(TM)-2010
[ieee802.11p-2010] OCB mode. The 'Data'
messages can be IP messages such as an amendment to the 802.11 specifications,
titled "Amendment 6: Wireless Access messages used in Vehicular Environments".
Since then, these Stateless or
Stateful Address Auto-Configuration, or other IP messages. Other
802.11 management and control frames (non IP) may be transmitted, as
specified in the 802.11 standard. For information, the names of
these messages as currently specified by the 802.11 standard are
listed in Appendix D.

STA AP STA1 STA2
| | | |
|<------ Beacon -------| |<------ Data -------->|
| | |<------ Data -------->|
|---- Probe Req. ----->| |<------ Data -------->|
|<--- Probe Res. ------| |<------ Data -------->|
| | |<------ Data -------->|
|---- Auth Req. ------>| |<------ Data -------->|
|<--- Auth Res. -------| |<------ Data -------->|
| | |<------ Data -------->|
|---- Asso Req. ------>| |<------ Data -------->|
|<--- 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').

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.

In order to delineate the aspects introduced by 802.11p 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
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 802.11p 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 802.11p 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).

To support this similarity statement (IPv6 is layered on top of LLC
on top of 802.11p 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 802.11p 802.11 OCB and non-p 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 802.11p 802.11 OCB links.

In the list below, the only 802.11p 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 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
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).

o Explicit prohibition Prohibition of IPv6 on some channels relevant for the PHY of IEEE 802.11p,
802.11-OCB, as opposed to IPv6 not being prohibited on any channel
on which 802.11a/b/g/n runs; for example, IPv6 is
prohibited on the 'Control Channel' (number 178 at FCC/IEEE, and
180 at ETSI); for a detailed analysis the time of IEEE and ETSI writing, this
prohibition
of IP is explicit in particular channels see Appendix B. 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. The standard IEEE 802.11p
uses OFDM encoding at PHY, as other non-b 802.11 variants do.
This considers 20MHz encoding to be 'full-rate' encoding, as the
earlier 20MHz encoding which is used extensively by 802.11b.

o In
addition vehicular communications using 802.11p links, there are strong
privacy concerns with respect to addressing. While the full-rate encoding, the OFDM rates also involve
5MHz and 10MHz. The 10MHz encoding is named 'half-rate'. The
encoding dictates the bandwidth and latency characteristics that
can be afforded by the higher-layer applications of IP
communications. The half-rate means that each symbol takes twice
the time to be transmitted; for this 802.11p
standard does not specify anything in particular with respect to work, all 802.11 software
timer values are doubled. With this,
MAC addresses, in certain channels of the
"5.9GHz" band, a maximum bandwidth of 12Mbit/s is possible,
whereas in other "5.9GHz" channels a minimal bandwidth of 1Mbit/s
may be used. It is worth mentioning the half-rate encoding is an
optional feature characteristic of OFDM PHY (compared to 802.11b's
full-rate 20MHz), used by 802.11a before 802.11p used it. In
addition to the half-rate (10MHz) used by 802.11p in some
channels, some other 802.11p channels may use full-rate (20MHz) or
quarter-rate(?) (5MHz) encoding instead.

o It is worth mentioning that more precise interpretations of the
'half-rate' term suggest that a maximum throughput be 27Mbit/s
(which is half of 802.11g's 54Mbit/s), whereas 6Mbit/s or 12Mbit/s
throughputs represent effects of further 802.11p-specific PHY
reductions in the throughput necessary to better accommodate
vehicle-class speeds and distance ranges.

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 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 8. 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
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.

5. Layering of IPv6 over 802.11p 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
[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
delivered on 802.11-OCB links. Specifications of these packets are
out of scope of this document, and do not impose any limit on the MTU
size, allowing an arbitrary number of 'containers'. Non-IP packets
such as ETSI 'geonet' packets have an MTU of 1492 bytes.

The Equivalent Transmit Time on Channel is a concept that may be used
as an alternative to the MTU concept. A rate of transmission may be
specified as well. The ETTC, rate and MTU may be in direct
relationship.

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).

The Frame format for transmitting IPv6 on 802.11p 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 |
+- -+
| 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.)

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.

+---------------------+-------------+---------+
| 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.

In OCB mode, IPv6 packets can be transmitted either as "IEEE 802.11
Data" or alternatively as "IEEE 802.11 QoS Data", as illustrated in
the following figure:

The 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
[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
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

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
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.

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|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
[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;
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].

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.

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. Handovers between OCB links

A station operating Example IPv6 Packet captured over a IEEE 802.11p in the 5.9 GHz band in US or EU is
required to send data frames outside the context of link

We remind that a BSS. In main goal of this
case, the station does not utilize the IEEE 802.11 authentication,
association, or data confidentiality services. This avoids the
latency associated with establishing a BSS and document is particularly suited to communications between mobile stations or between a mobile station
and a fixed one playing make the role case that
IPv6 works fine over 802.11p networks. Consequently, this section is
an illustration of this concept and thus can help the default router (e.g. a fixed
Road-Side Unit a.k.a RSU acting as an infrastructure router).

The process implementer
when it comes to running IPv6 over IEEE 802.11p. By way of movement detection example
we show that there is described no modification in section 11.5.1 of
[RFC6275]. In the context of 802.11p deployments, detecting
movements between two adjacent RSUs becomes harder for the moving
stations: they cannot rely on Layer-2 triggers (such as L2
association/de-association phases) to detect headers when transmitted
over 802.11p networks - they leave the
vicinity of an RSU are transmitted like any other 802.11
and move within coverage Ethernet packets.

We describe an experiment of another RSU. capturing an IPv6 packet on an 802.11p
link. In such
case, the movement detection algorithms require other triggers. We
detail below this experiment, the potential other indications that can be used packet is an IPv6 Router
Advertisement. This packet is emitted by a
moving station in order to detect handovers between OCB ("Outside Router on its 802.11p
interface. The packet is captured on the
Context of a BSS") links.

A movement detection mechanism may take advantage of positioning data
(latitude and longitude).

Mobile IPv6 [RFC6275] specifies Host, using a new Router Advertisement option
called network
protocol analyzer (e.g. Wireshark); the "Advertisement Interval Option". It can be capture is performed in two
different modes: direct mode and 'monitor' mode. The topology used by an RSU
to indicate
during the maximum interval between two consecutive unsolicited capture is depicted below.

+--------+ +-------+
| | 802.11-OCB Link | |
---| Router Advertisement messages sent by this RSU. With this option, |--------------------------------| Host |
| | | |
+--------+ +-------+

During several capture operations running from a
moving station can learn when it is supposed few moments to
several hours, no message relevant to receive the next RA
from the same RSU. BSSID contexts were
captured (no Association Request/Response, Authentication Req/Resp,
Beacon). This can help movement detection: if the
specified amount of time elapses without the moving station receiving
any RA from that RSU, this means shows that the RA has been lost. It operation of 802.11p is up
to outside the moving node to determine how many lost RAs from that RSU
constitutes
context of a handover trigger.

In addition to the Mobile IPv6 "Advertisement Interval Option", the
Neighbor Unreachability Detection (NUD) [RFC4861] can be used to
determine whether BSSID.

Overall, the RSU captured message is still reachable or not. In this
context, reachability confirmation would basically consist in
receiving a Neighbor Advertisement message from identical with a RSU, in response to capture of an IPv6
packet emitted on a Neighbor Solicitation message sent by the moving station. 802.11b interface. The RSU
should also configure a low Reachable Time value contents are precisely
similar.

6.1. Capture in its Monitor Mode

The IPv6 RA packet captured in order
to ensure that a moving station does not assume an RSU to be
reachable for too long. monitor mode is illustrated below.
The Mobile IPv6 "Advertisement Interval Option" as well as the NUD
procedure only help knowing if radio tap header provides more flexibility for reporting the RSU
characteristics of frames. The Radiotap Header is still reachable prepended by the
moving station. It does not provide the moving station with
information about other potential RSUs that might be in range. For this purpose, it is by increasing the RA frequency that
particular stack and operating system on the delay
could be reduced Host machine to discover the next RSU. The Neighbor Discovery
protocol [RFC4861] limits the unsolicited multicast RA interval to a
minimum of 3 seconds
packet received from the network (the MinRtrAdvInterval variable). This value Radiotap Header is
too high for dense deployments of Access Routers deployed along fast
roads. not present
on the air). The protocol Mobile IPv6 [RFC6275] allows routers to send
such RA more frequently, with a minimum possible of 0.03 seconds (the
same MinRtrAdvInterval variable): this should be preferred to ensure
a faster detection of implementation-dependent Radiotap Header is useful
for piggybacking PHY information from the potential RSUs chip's registers as data in range.

However, frequent RAs (every 0.03 seconds) may occupy the channel
with too many packets leading to other significant packets being
lost. There is
a tradeoff to be established: the more frequent the
RAs the better handover performance but the more risks 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
loss.

If multiple RSUs are in present on the vicinity of a moving station at air is formed by IEEE 802.11 Data Header,
Logical Link Control Header, IPv6 Base Header and ICMPv6 Header.

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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

IPv6 Base Header
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Version| Traffic Class | Flow Label |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Payload Length | Next Header | Hop Limit |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Source Address +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Destination Address +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

The value of the same
time, Data Rate field in the station may not be able Radiotap header is set to choose the "best" one (i.e. the
one that would afford 6
Mb/s. This indicates the moving station spending rate at which this RA was received.

The value of the longest time in
its vicinity, Transmitter address in order to avoid too frequent handovers). In this
case, it would be helpful to base the decision on the signal quality
(e.g. the RSSI of the received RA provided by the radio driver). A
better signal would probably offer a longer coverage. If, in terms
of RA frequency, it IEEE 802.11 Data Header
is not possible set to adopt the recommendations a 48bit value. The value of
protocol Mobile IPv6 (but only the Neighbor Discovery specification
ones, for whatever reason), then another message than destination address is
33:33:00:00:00:1 (all-nodes multicast address). The value of the RA could be
emitted periodically BSS
Id field is ff:ff:ff:ff:ff:ff, which is recognized by the Access Router (provided its specification
allows to send it very often), in order network
protocol analyzer as being "broadcast". The Fragment number and
sequence number fields are together set to help the Host determine 0x90C6.

The value of the signal quality. One such message may be Organization Code field in the 802.11p's Time
Advertisement, or higher layer messages such Logical-Link Control
Header is set to 0x0, recognized as "Encapsulated Ethernet". The
value of the "Basic Safety
Message" (in the US) Type field is 0x86DD (hexadecimal 86DD, or the "Cooperative Awareness Message " (in the
EU), that are usually sent several times per second. Another
alternative replacement for the IPv6 otherwise
#86DD), recognized as "IPv6".

A Router Advertisement may be the
message 'WAVE Routing Advertisement' (WRA), which is part of periodically sent by the WAVE
Service router to
multicast group address ff02::1. It is an icmp packet type 134. The
IPv6 Neighbor Discovery's Router Advertisement and which may contain optionally the
transmitter location; this message is contains an
8-bit field reserved for single-bit flags, as described in section 8.2.5 of
[ieeep1609.3-D9-2010].

Once [RFC4861].

The IPv6 header contains the choice link local address of the default router has been performed by the
moving node, it can be interesting to use Optimistic DAD [RFC4429] in
order to speed-up the address auto-configuration
(source) configured via EUI-64 algorithm, and ensure the
fastest possible Layer-3 handover.

To summarize, efficient handovers between OCB links can be performed
by using a combination destination address set
to ff02::1. Recent versions of existing mechanisms. network protocol analyzers (e.g.
Wireshark) provide additional informations for an IP address, if a
geolocalization database is present. In order to improve
the default router unreachability detection, this example, the RSU
geolocalization database is absent, and moving
stations should use the Mobile IPv6 "Advertisement Interval Option"
as well as rely on the NUD mechanism. In order to allow the moving
station to detect potential default router faster, the RSU should
also be able "GeoIP" information is
set to be configured with a smaller minimum RA interval such
as unknown for both source and destination addresses (although
the one recommended by Mobile IPv6. When multiple RSUs IPv6 source and destination addresses are
available at the same time, the moving station should perform the
handover decision based on the signal quality. Finally, optimistic
DAD set to useful values).
This "GeoIP" can be used a useful information to reduce look up the handover delay. city,
country, AS number, and other information for an IP address.

The Received Frame Power Level (RCPI) defined Ethernet Type field in IEEE Std
802.11-2012, conditioned by the dotOCBActived flag, logical-link control header is an information
element which contains a value expressing the power level at set to
0x86dd which indicates that the frame was received. This value may be used in comparing power
levels when triggering IP handovers.

7. Example transports an IPv6 Packet captured over a packet. In
the IEEE 802.11p link

We remind that 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 main goal
broadcast address of this document is ff:ff:ff:ff:ff:ff. Due to make the case that
IPv6 works fine over 802.11p networks. Consequently, this section is
an illustration of this concept short link
duration between vehicles and thus can help the implementer
when it comes to running IPv6 over IEEE 802.11p. By way of example
we show that roadside infrastructure, there is
no modification need in the headers when transmitted
over IEEE 802.11p networks - they are transmitted like any other 802.11 to wait for the completion of association and Ethernet packets.

We describe an experiment
authentication procedures before exchanging data. IEEE 802.11p
enabled nodes use the wildcard BSSID (a value of capturing an IPv6 packet captured all 1s) and may
start communicating as soon as they arrive on an
802.11p link. In this experiment, the packet is an communication
channel.

6.2. Capture in Normal Mode

The same IPv6 Router
Advertisement. This packet is emitted by a Router on its 802.11p
interface. The Advertisement packet described above (monitor
mode) 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 Normal mode, and depicted
below.

+--------+ +-------+

Ethernet II Header
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
...Destination | 802.11-OCB Link Source...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
...Source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
---| Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Router |--------------------------------| Host Advertisement
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Code | Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
+--------+ +-------+

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 Cur Hop Limit |M|O| Reserved | Router Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reachable Time |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Retrans Timer |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Options ...
+-+-+-+-+-+-+-+-+-+-+-+-

One notices that the Radiotap Header is outside not prepended, and that the
context of a BSSID.

Overall,
IEEE 802.11 Data Header and the captured message is identical with a capture of an IPv6
packet emitted on a 802.11b interface. The contents Logical-Link Control Headers are precisely
similar.

The popular wireshark network protocol analyzer is not
present. On another hand, a free software
tool for Windows new header named Ethernet II Header is
present.

The Destination and Unix. It includes a dissector for 802.11p
features along with all other 802.11 features (i.e. it displays these
features Source addresses in a human-readable format).

7.1. Capture the Ethernet II header
contain the same values as the fields Receiver Address and
Transmitter Address present in Monitor Mode

The IPv6 RA packet captured the IEEE 802.11 Data Header in monitor the
"monitor" mode is illustrated below. capture.

The radio tap header provides more flexibility for reporting the
characteristics value of frames. The Radiotap Header the Type field in the Ethernet II header is prepended by 0x86DD
(recognized as "IPv6"); this
particular stack and operating system on value is the Host machine to same value as the RA
packet received from value of
the network (the Radiotap field Type in the Logical-Link Control Header is not present
on in the air). "monitor"
mode capture.

The implementation-dependent Radiotap Header is useful
for piggybacking PHY information from knowledgeable experimenter will no doubt notice the chip's registers as data similarity of
this Ethernet II Header with a capture in normal mode on 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 pure
Ethernet cable interface.

It may be interpreted that an Adaptation layer is formed by inserted in a pure
IEEE 802.11 Data Header,
Logical Link Control Header, IPv6 Base Header and ICMPv6 Header.

IEEE MAC packets in the air, before delivering to the
applications. In detail, this adaptation layer may consist in
elimination of the Radiotap, 802.11 Data Header
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type/Subtype and Frame Ctrl | Duration |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Receiver Address...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
... Receiver Address | Transmitter Address...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
... Transmitter Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BSS Id...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
... BSS Id | Frag Number LLC headers and Seq Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

The value insertion of
the Data Rate field in Ethernet II header. In this way, it can be stated that IPv6 runs
naturally straight over LLC over the Radiotap header is set to 6
Mb/s. This indicates 802.11p MAC layer, as shown by
the rate at which this RA was received.

The value use of the Transmitter address in the IEEE Type 0x86DD, and assuming an adaptation layer
(adapting 802.11 Data Header
is set LLC/MAC to a 48bit value. The value of Ethernet II header).

7. Security Considerations

Any security mechanism at the destination address is
33:33:00:00:00:1 (all-nodes multicast address). The value 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
operates outside the context of a BSS
Id field is ff:ff:ff:ff:ff:ff, which is recognized by (no Association Request/
Response, no Challenge messages). Any attacker can therefore just
sit in the network
protocol analyzer as being "broadcast". The Fragment number and
sequence number fields are together set to 0x90C6.

The value near range of vehicles, sniff the Organization Code field in the Logical-Link Control
Header is network (just set the
interface card's frequency to 0x0, recognized as "Encapsulated Ethernet". The
value of the Type field proper range) and perform attacks
without needing to physically break any wall. Such a link is 0x86DD (hexadecimal 86DD, way
less protected than commonly used links (wired link or otherwise
#86DD), recognized as "IPv6".

A Router Advertisement is periodically sent by protected
802.11).

At the router IP layer, IPsec can be used to protect unicast communications,
and SeND can be used for multicast group address ff02::1. It communications. If no protection
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 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 [RFC4861].

The IPv6 header contains the link local address use of 802.11p interface identifiers.
However, in outdoors vehicular settings, the router
(source) configured via EUI-64 algorithm, and destination address set
to ff02::1. Recent versions privacy risks are more
important than in indoors settings. New risks are induced by the
possibility of network protocol analyzers (e.g.
Wireshark) provide additional informations attacker sniffers deployed along routes which listen
for an IP address, if a
geolocalization database is present. In packets of vehicles passing by. For this example, the
geolocalization database is absent, and reason, in the "GeoIP" information
802.11p deployments, there is
set to unknown for both source and destination addresses (although
the IPv6 source and destination addresses are set a strong necessity to useful values). use protection
tools such as dynamically changing MAC addresses. This "GeoIP" can be a useful information may help
mitigate privacy risks to look up the city,
country, AS number, and other information for a certain level. On another hand, it may
have an IP address.

The Ethernet Type field impact in the logical-link control header is set to
0x86dd which indicates that the frame transports an way typical IPv6 packet. In
the IEEE 802.11 data, the destination address auto-configuration is 33:33:00:00:00:01
which is he corresponding multicast
performed for vehicles (SLAAC would rely on MAC address. The BSS id is a
broadcast address of ff:ff:ff:ff:ff:ff. Due to addresses amd would
hence dynamically change the short link
duration between vehicles 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 roadside infrastructure, there is
no need in IEEE 802.11p to wait for context of a BSS (802.11p links).

Tim Leinmueller contributed the completion idea of association and
authentication procedures before exchanging data. IEEE 802.11p
enabled nodes use the wildcard BSSID (a value use of all 1s) IPv6 over
802.11-OCB for distribution of certificates.

Marios Makassikis, Jose Santa Lozano, Albin Severinson and may
start communicating as soon as they arrive Alexey
Voronov provided significant feedback on the communication
channel.

7.2. Capture experience of using IP
messages over 802.11-OCB in Normal Mode initial trials.

Michelle Wetterwald contributed extensively the MTU discussion
offering the ETSI ITS perspective, as well as other parts of the
document.

10. Acknowledgements

The same IPv6 Router Advertisement packet 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
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 above (monitor
mode) is captured on how.

For the Host, in multicast discussion, the Normal mode, and depicted
below.

Ethernet II Header
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
...Destination | Source...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
...Source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

One notices that the Radiotap Header is not prepended, and that the
IEEE 802.11 Data Header authors would like to thank Owen
DeLong, Joe Touch, Jen Linkova, Erik Kline, Brian Haberman and the Logical-Link Control Headers are not
present. On another hand, a new header named Ethernet II Header is
present.
participants to discussions in network working groups.

The Destination authours would like to thank participants to the Birds-of-
a-Feather "Intelligent Transportation Systems" meetings held at IETF
in 2016.

11. References

11.1. Normative References

[I-D.ietf-6man-default-iids]
Gont, F., Cooper, A., Thaler, D., and Source addresses S. LIU,
"Recommendation on Stable IPv6 Interface Identifiers",
draft-ietf-6man-default-iids-16 (work in the Ethernet II header
contain the same values as the fields Receiver Address progress),
September 2016.

[I-D.ietf-6man-ug]
Carpenter, B. and
Transmitter Address present S. Jiang, "Significance of IPv6
Interface Identifiers", draft-ietf-6man-ug-06 (work in the
progress), December 2013.

[I-D.ietf-tsvwg-ieee-802-11]
Szigeti, T. and F. Baker, "DiffServ to 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
Mapping", draft-ietf-tsvwg-ieee-802-11-01 (work in the Logical-Link Control Header
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 "monitor"
mode capture.

The knowledgeable experimenter will no doubt notice the similarity transmission
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 IP datagrams over IEEE 802.11 MAC packets 802 networks", STD 43, RFC 1042,
DOI 10.17487/RFC1042, February 1988,
<http://www.rfc-editor.org/info/rfc1042>.

[RFC2119] Bradner, S., "Key words for use in the air, before delivering RFCs to the
applications. In detail, this adaptation layer may consist in
elimination of the Radiotap, 802.11 and LLC headers Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.

[RFC2460] Deering, S. and insertion R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", RFC 2460, DOI 10.17487/RFC2460,
December 1998, <http://www.rfc-editor.org/info/rfc2460>.

[RFC2464] Crawford, M., "Transmission of
the Ethernet II header. In this way, it can be stated that IPv6 runs
naturally straight over LLC Packets over the 802.11p 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).

8. Security Considerations

802.11p 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,
Networks", RFC 2464, DOI 10.17487/RFC2464, December 1998,
<http://www.rfc-editor.org/info/rfc2464>.

[RFC4086] Eastlake 3rd, D., Schiller, J., and SeND can be used S. Crocker,
"Randomness Requirements for multicast communications. If no protection
is used by the IP layer, upper layers should be protected.
Otherwise, the end-user or system should be warned about the risks
they run.

The WAVE protocol stack provides Security", BCP 106, RFC 4086,
DOI 10.17487/RFC4086, June 2005,
<http://www.rfc-editor.org/info/rfc4086>.

[RFC4429] Moore, N., "Optimistic Duplicate Address Detection (DAD)
for strong security when using the
WAVE Short Message Protocol and the WAVE Service Advertisement
[ieeep1609.2-D17].

As with all Ethernet IPv6", RFC 4429, DOI 10.17487/RFC4429, April 2006,
<http://www.rfc-editor.org/info/rfc4429>.

[RFC4861] Narten, T., Nordmark, E., Simpson, W., 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
important than in indoors settings. New risks are induced by the
possibility of attacker sniffers deployed along routes which listen H. Soliman,
"Neighbor Discovery for IP packets of vehicles passing by. For this reason, version 6 (IPv6)", RFC 4861,
DOI 10.17487/RFC4861, September 2007,
<http://www.rfc-editor.org/info/rfc4861>.

[RFC5889] Baccelli, E., Ed. and M. Townsley, Ed., "IP Addressing
Model in the
802.11p 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.

9. IANA Considerations

10. Contributors

Romain Kuntz contributed extensively the concepts described in
Section 6 about IPv6 handovers between links running outside the
context of a BSS (802.11p 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
document.

11. 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 Roy, Ray Hunter,
Tom Kurihara, Michal Sojka, Jan de Jongh, Suresh Krishnan, Dino
Farinacci, Vincent Park, Jaehoon Paul Jeong and Gloria Gwynne. 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.

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.

12. References

12.1. Normative References

[I-D.ietf-6man-default-iids]
Gont, F., Cooper, A., Thaler, D., and S. LIU,
"Recommendation on Stable IPv6 Interface Identifiers",
draft-ietf-6man-default-iids-16 (work in progress),
September 2016.

[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.

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.

[RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", RFC 2460, DOI 10.17487/RFC2460,
December 1998, <http://www.rfc-editor.org/info/rfc2460>.

[RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet
Networks", RFC 2464, DOI 10.17487/RFC2464, December 1998,
<http://www.rfc-editor.org/info/rfc2464>.

[RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker,
"Randomness Requirements for Security", BCP 106, RFC 4086,
DOI 10.17487/RFC4086, June 2005,
<http://www.rfc-editor.org/info/rfc4086>.

[RFC4429] Moore, N., "Optimistic Duplicate Address Detection (DAD)
for IPv6", RFC 4429, DOI 10.17487/RFC4429, April 2006,
<http://www.rfc-editor.org/info/rfc4429>.

[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
DOI 10.17487/RFC4861, September 2007,
<http://www.rfc-editor.org/info/rfc4861>.

[RFC5889] Baccelli, E., Ed. and M. Townsley, Ed., "IP Addressing
Model in Ad Hoc Networks", RFC 5889, DOI 10.17487/RFC5889,
September 2010, <http://www.rfc-editor.org/info/rfc5889>.

[RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility
Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July
2011, <http://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)",
RFC 6775, DOI 10.17487/RFC6775, November 2012,
<http://www.rfc-editor.org/info/rfc6775>.

[RFC7721] Cooper, A., Gont, F., and D. Thaler, "Security and Privacy
Considerations for IPv6 Address Generation Mechanisms",
RFC 7721, DOI 10.17487/RFC7721, March 2016,
<http://www.rfc-editor.org/info/rfc7721>.

12.2. Informative References

[etsi-302663-v1.2.1p-2013]
"Intelligent Transport Systems (ITS); Access layer
specification for Intelligent Transport Systems operating
in the 5 GHz frequency band, 2013-07, document
en_302663v010201p.pdf, document freely available at URL
http://www.etsi.org/deliver/etsi_en/302600_302699/302663/
01.02.01_60/en_302663v010201p.pdf downloaded on October
17th, 2013.".

[etsi-draft-102492-2-v1.1.1-2006]
"Electromagnetic compatibility and Radio spectrum Matters
(ERM); Intelligent Transport Systems (ITS); Part 2:
Technical characteristics for pan European harmonized
communications equipment operating in the 5 GHz frequency
range intended for road safety and traffic management, and
for non-safety related ITS applications; System Reference
Document, Draft ETSI TR 102 492-2 V1.1.1, 2006-07,
document tr_10249202v010101p.pdf freely available at URL
http://www.etsi.org/deliver/etsi_tr/102400_102499/
10249202/01.01.01_60/tr_10249202v010101p.pdf downloaded on
October 18th, 2013.".

[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 downloaded on June 5th, 2014.".

[I-D.baccelli-multi-hop-wireless-communication]
Baccelli, E. and C. Perkins, "Multi-hop Ad Hoc Wireless
Communication", draft-baccelli-multi-hop-wireless-
communication-06 (work in progress), July 2011.

[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-
reqs-03 (work in progress), October 2013.

[ieee16094]
"1609.2-2016 - IEEE Standard for Wireless Access in
Vehicular Environments--Security Services for Applications
and Management Messages; document freely available at URL
https://standards.ieee.org/findstds/
standard/1609.2-2016.html retrieved on July 08th, 2016.".

[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 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 retrieved on September 20th,
2013.".

[ieeep1609.0-D2]
"IEEE P1609.0/D2 Draft Guide for Wireless Access in
Vehicular Environments (WAVE) Architecture. pdf, length
879 Kb. Restrictions apply.".

[ieeep1609.2-D17]
"IEEE P1609.2(tm)/D17 Draft Standard for Wireless Access
in Vehicular Environments - Security Services for
Applications and Management Messages. pdf, length 2558
Kb. Restrictions apply.".

[ieeep1609.3-D9-2010]
"IEEE P1609.3(tm)/D9, Draft Standard for Wireless Access
in Vehicular Environments (WAVE) - Networking Services,
August 2010. Authorized licensed use limited to: CEA.
Downloaded on June 19, 2013 at 07:32:34 UTC from IEEE
Xplore. Restrictions apply, document at persistent link
http://ieeexplore.ieee.org/servlet/opac?punumber=5562705".

[ieeep1609.4-D9-2010]
"IEEE P1609.4(tm)/D9 Draft Standard for Wireless Access in
Vehicular Environments (WAVE) - Multi-channel Operation.
Authorized licensed use limited to: CEA. Downloaded on
June 19, 2013 at 07:34:48 UTC from IEEE Xplore.
Restrictions apply. Document at persistent link
http://ieeexplore.ieee.org/servlet/opac?punumber=5551097".

[ipv6-80211p-its]
Shagdar, O., Tsukada, M., Kakiuchi, M., Toukabri, T., and
T. Ernst, "Experimentation Towards IPv6 over IEEE 802.11p
with ITS Station Architecture", International Workshop on
IPv6-based Vehicular Networks, (colocated with IEEE
Intelligent Vehicles Symposium), URL:
http://hal.inria.fr/hal-00702923/en, Downloaded on: 24
October 2013, Availability: free at some sites, paying at
others, May 2012.

[ipv6-wave]
Clausen, T., Baccelli, E., and R. Wakikawa, "IPv6
Operation for WAVE - Wireless Access in Vehicular
Environments", Rapport de Recherche INRIA, number 7383,
URL: http://hal.inria.fr/inria-00517909/, Downloaded on:
24 October 2013, Availability: free at some sites,
September 2010.

[TS103097]
"Intelligent Transport Systems (ITS); Security; Security
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.".

[vip-wave]
Cespedes, S., Lu, N., and X. Shen, "VIP-WAVE: On the
Feasibility of IP Communications in 802.11p Vehicular
Networks", IEEE Transactions on Intelligent Transportation
Systems, Volume 14, Issue 1, URL and Digital Object
Identifier: http://dx.doi.org/10.1109/TITS.2012.2206387,
Downloaded on: 24 October 2013, Availability: free at
some sites, paying at others, March 2013.

Appendix A. ChangeLog

The changes are listed in reverse chronological order, most recent
changes appearing at the top of the list.

From draft-petrescu-ipv6-over-80211p-05.txt to draft-petrescu-ipv6-
over-80211p-06.txt:

o Removed IPv4 text.

o Added text about isues with multicast over 802.11 and OCB mode.

o Shortened the subnet structure section, by referring to an
existing RFC.

o Removed the appendix about distribution of certificates.

o Added text about tradeoff of too frequent RAs, handover
performance and risks of packet loss.

o Removed discussion about other MTU possibilities, kept only the
1500 bytes MTU.

o Keep both header "802.11 Data" and header "802.11 QoS Data".

o Referred to default-iids recommendation of generating stable IIDs.

o Moved the Design Considerations sections to an appendix.

From draft-petrescu-ipv6-over-80211p-02.txt to draft-petrescu-ipv6-
over-80211p-03.txt:

o Added clarification about the "OCBActivated" qualifier in the the
new IEEE 802.11-2012 document; this IEEE document integrates now
all earlier 802.11p features; this also signifies the
dissapearance of an IEEE IEEE 802.11p document altogether.

o Added explanation about FCC not prohibiting IP on channels, and
comments about engineering advice and reliability of IP messages.

o Added possibility to use 6lowpan adaptation layer when in OCB
mode.

o Added appendix about the distribution of certificates to vehicles
by using IPv6-over-802.11p single-hop communications.

o Refined the explanation of 'half-rate' mode.

o Added the privacy concerns and necessity of and potential effects
of dynamically changing MAC addresses.

From draft-petrescu-ipv6-over-80211p-01.txt to draft-petrescu-ipv6-
over-80211p-02.txt:

o updated authorship.

o added explanation about FCC not prohibiting IP on channels, and
comments about engineering advice and reliability of IP messages.

o added possibility to use 6lowpan adaptation layer when in OCB
mode.

o added appendix about the distribution of certificates to vehicles
by using IPv6-over-802.11p single-hop communications.

o refined the explanation of 'half-rate' mode.

o added the privacy concerns and necessity of and potential effects
of dynamically changing MAC addresses.

From draft-petrescu-ipv6-over-80211p-00.txt to draft-petrescu-ipv6-
over-80211p-01.txt:

o updated one author's affiliation detail.

o added 2 more references to published literature about IPv6 over
802.11p.

From draft-petrescu-ipv6-over-80211p-00.txt to draft-petrescu-ipv6-
over-80211p-00.txt:

o first version.

Appendix B. Explicit Prohibition of IPv6 on Channels Related to ITS
Scenarios using 802.11p Networks - an Analysis

B.1. Interpretation of FCC and ETSI documents with respect to running
IP on particular channels

o The FCC created the term "Control Channel" [fcc-cc]. For it, it
defines the channel number to be 178 decimal, and positions it
with a 10MHz width from 5885MHz to 5895MHz. The FCC rules point
to standards document ASTM-E2213 (not freely available at the time
of writing of this draft); in an interpretation of a reviewer of
this document, this means not making any restrictions to the use
of IP on the control channel.

o The FCC created two more terms for particular channels
[fcc-cc-172-184], among others. The channel 172 (5855MHz to
5865MHz)) is designated "exclusively for [V2V] safety
communications for accident avoidance and mitigation, and safety
of life and property applications", and the channel 184 (5915MHz
to 5925MHz) is designated "exclusively for high-power, longer-
distance communications to be used for public-safety applications
involving safety of life and property, including road-intersection
collision mitigation". However, they are not named "control"
channels, and the document does not mention any particular
restriction on the use of IP on either of these channels.

o On another hand, at IEEE, IPv6 is explicitely prohibited on
channel number 178 decimal - the FCC's 'Control Channel'. The
document [ieeep1609.4-D9-2010] prohibits upfront the use of IPv6
traffic on the Control Channel: 'data frames containing IP
datagrams are only allowed on service channels'. Other 'Service
Channels' are allowed to use IP, but the Control Channel is not.

o In Europe, basically ETSI considers FCC's "Control Channel" to be
a "Service Channel", and defines a "Control Channel" to be in a
slot considered by FCC as a "Service Channel". In detail, FCC's
"Control Channel" number 178 decimal with 10MHz width (5885MHz to
5895MHz) is defined by ETSI to be a "Service Channel", and is
named 'G5-SCH2' [etsi-302663-v1.2.1p-2013]. This channel is
dedicated to 'ITS Road Safety' by ETSI. Other channels are
dedicated to 'ITS road traffic efficiency' by ETSI. The ETSI's
"Control Channel" - the "G5-CCH" - number 180 decimal (not 178) is
reserved as a 10MHz-width centered on 5900MHz (5895MHz to 5905MHz)
(the 5895MHz-5905MHz channel is a Service Channel for FCC).
Compared to IEEE, ETSI makes no upfront statement with respect to
IP and particular channels; yet it relates the 'In car Internet'
applications ('When nearby a stationary public internet access
point (hotspot), application can use standard IP services for
applications.') to the 'Non-safety-related ITS application'
[etsi-draft-102492-2-v1.1.1-2006]. Under an interpretation of an
author of this Internet Draft, this may mean ETSI may forbid IP on
the 'ITS Road Safety' channels, but may allow IP on 'ITS road
traffic efficiency' channels, or on other 5GHz channels re-used
from BRAN (also dedicated to Broadband Radio Access Networks).

o At EU level in ETSI (but not some countries in EU with varying
adoption levels) the highest power of transmission of 33 dBm is
allowed, but only on two separate 10Mhz-width channels centered on
5900MHz and 5880MHz respectively. It may be that IPv6 is not
allowed on these channels (in the other 'ITS' channels where IP
may be allowed, the levels vary between 20dBm, 23 dBm and 30 dBm;
in some of these channels IP is allowed). A high-power of
transmission means that vehicles may be distanced more
(intuitively, for 33 dBm approximately 2km is possible, Ad Hoc Networks", RFC 5889, DOI 10.17487/RFC5889,
September 2010, <http://www.rfc-editor.org/info/rfc5889>.

[RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility
Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July
2011, <http://www.rfc-editor.org/info/rfc6275>.

[RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C.
Bormann, "Neighbor Discovery Optimization for 20
dBm approximately 50meter).

B.2. Interpretations of Latencies of IP datagrams IPv6 may be "allowed" on any channel. Certain interpretations
consider that communicating IP datagrams may involve longer latencies
than non-IP datagrams; this may make them little adapted for safety
applications which require fast reaction. Certain other views
disagree with this, arguing that IP datagrams are transmitted at the
same speed as any other non-IP datagram over
Low-Power Wireless Personal Area Networks (6LoWPANs)",
RFC 6775, DOI 10.17487/RFC6775, November 2012,
<http://www.rfc-editor.org/info/rfc6775>.

[RFC7721] Cooper, A., Gont, F., and may thus offer same level
of reactivity for safety applications.

Appendix C. 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 D. Thaler, "Security 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:

o The chip must support the frequency bands on which the regulator
recommends the use of ITS communications, Privacy
Considerations for example using IEEE
802.11p 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 IPv6 Address Generation Mechanisms",
RFC 7721, DOI 10.17487/RFC7721, March 2016,
<http://www.rfc-editor.org/info/rfc7721>.

11.2. Informative References

[etsi-302663-v1.2.1p-2013]
"Intelligent Transport Systems (ITS); Access layer
specification for Intelligent Transport Systems operating
in the United States, and up to 33 dBm in
Europe; other regional conditions apply.

Changes needed 5 GHz frequency band, 2013-07, document
en_302663v010201p.pdf, document freely available at URL
http://www.etsi.org/deliver/etsi_en/302600_302699/302663/
01.02.01_60/en_302663v010201p.pdf downloaded on the network stack October
17th, 2013.".

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 5 GHz frequency is divided by two).

* The chip must use dedicated channels
range intended for road safety 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 traffic management, and
for non-safety related ITS applications; System Reference
Document, Draft ETSI TR 102 492-2 V1.1.1, 2006-07,
document tr_10249202v010101p.pdf freely available at URL
http://www.etsi.org/deliver/etsi_tr/102400_102499/
10249202/01.01.01_60/tr_10249202v010101p.pdf downloaded on
October 18th, 2013.".

[fcc-cc] "'Report and Order, Before the location-specific laws.

MAC layer:

* All management frames (beacons, join, leave, 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 others)
emission 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.perkins-intarea-multicast-ieee802]
Perkins, C., Stanley, D., Kumari, W., and reception must be disabled except for frames of
subtype Action 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 Timing Advertisement (defined below).

* No encryption key or method must be used.

* Packet emission W. Klaudel,
"Scenarios and reception must be performed as Requirements for IP 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 Intelligent
Transportation Systems", draft-petrescu-its-scenarios-
reqs-03 (work in progress), October 2013.

[ieee16094]
"1609.2-2016 - IEEE Standard for authentication (Authentication Request/Reply,
Challenge) are not called.

* The beacon interval is always set to 0 (zero).

* Timing Advertisement frames, defined Wireless Access in the amendment, should
be supported. The upper layer should be able to trigger such
frames emission
Vehicular Environments--Security Services for Applications
and Management Messages; document freely available at URL
https://standards.ieee.org/findstds/
standard/1609.2-2016.html retrieved on July 08th, 2016.".

[ieee802.11-2012]
"802.11-2012 - IEEE Standard for Information technology--
Telecommunications and to retrieve information contained in
received Timing Advertisements.

Appendix D. 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 exchange between
systems Local and metropolitan area networks--Specific
requirements Part 11: Wireless LAN Medium Access Control
(MAC) and very short connection makes the 802.11-OCB
link significantly different Physical Layer (PHY) Specifications. Downloaded
on October 17th, 2013, from other 802.11 networks. Also, the
automotive applications have specific requirements IEEE Standards, document
freely available at URL
http://standards.ieee.org/findstds/
standard/802.11-2012.html retrieved on October 17th,
2013.".

[ieee802.11p-2010]
"IEEE Std 802.11p(TM)-2010, IEEE Standard for reliability,
security Information
Technology - Telecommunications and privacy, which further add to the particularity of the
802.11-OCB link.

This section does not address safety-related applications, which are
done information exchange
between systems - Local and metropolitan area networks -
Specific requirements, Part 11: Wireless LAN Medium Access
Control (MAC) and Physical Layer (PHY) Specifications,
Amendment 6: Wireless Access in Vehicular Environments;
document freely available at URL
http://standards.ieee.org/getieee802/
download/802.11p-2010.pdf retrieved on non-IP communications. However, this section will consider
the transmission of such non IP communication September 20th,
2013.".

[ieeep1609.0-D2]
"IEEE P1609.0/D2 Draft Guide for Wireless Access in the design
specification of IPv6 over
Vehicular Environments (WAVE) Architecture. pdf, length
879 Kb. Restrictions apply.".

D.1. Vehicle ID

Automotive networks require the unique representation of each of
their node. Accordingly, a vehicle must be identified by
Xplore. Restrictions apply, document at persistent link
http://ieeexplore.ieee.org/servlet/opac?punumber=5562705".

[ieeep1609.4-D9-2010]
"IEEE P1609.4(tm)/D9 Draft Standard for Wireless Access in
Vehicular Environments (WAVE) - Multi-channel Operation.
Authorized licensed use limited to: CEA. Downloaded on
June 19, 2013 at least
one unique ID. The current specification 07:34:48 UTC from IEEE Xplore.
Restrictions apply. Document at ETSI persistent link
http://ieeexplore.ieee.org/servlet/opac?punumber=5551097".

[TS103097]
"Intelligent Transport Systems (ITS); Security; Security
header and certificate formats; document freely available
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 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 case reverse chronological order, most recent
changes appearing at the top of multiple
802.11-OCB NICs. A mechanims to uniquely identify a vehicle
irrespectively to the different NICs and/or technologies is required.

D.2. Non IP Communications

In IEEE 1609 and ETSI ITS, safety-related communications CANNOT be
used with IP datagrams. For example, Basic Safety Message (BSM, an
IEEE 1609 datagram) list.

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 Cooperative Awareness Message (CAM, an ETSI
ITS-G5 datagram), are each transmitted as a payload that is preceded
by link-layer headers, without 802.11 in OCB mode.

o Introduced an IP header.

Each vehicle taking part of traffic (i.e. having its engine turned on
and being located on a road) MUST use Non IP communication to
periodically broadcast its status appendix listing for information (ID, GPS position,
speed,..) in its immediate neighborhood. Using these mechanisms,
vehicles become 'aware' of the presence set of other vehicles in their
immediate vicinity. Therefore, IP communication being 802.11
messages that may be transmitted by
vehicles taking part of traffic MUST co-exist with Non IP
communication in OCB mode.

o Removed appendix sections "Privacy Requirements", "Authentication
Requirements" and SHOULD NOT break any Non IP mechanism, including
'harmful' interference on the channel.

The ID of the vehicle transmitting Non "Security Certificate Generation".

o Removed appendix section "Non IP communication is
transmitted Communications".

o Introductory phrase in the src MAC address Security Considerations section.

o Improved the definition of the "OCB".

o Introduced theoretical stacked layers about IPv6 and IEEE 1609 / ETSI-ITS-G5
datagrams. Accordingly, non-IP communications expose layers
including EPD.

o Removed the ID appendix describing the details of each
vehicle, which may be considered as prohibiting IPv6 on
certain channels relevant to 802.11-OCB.

o Added a brief reference in the privacy breach. text about a precise clause
in IEEE 802.11-OCB bypasses 1609.3 and .4.

o Clarified the authentication mechanisms definition of IEEE 802.11
networks, in order to transmit non IP communications to without any
delay. This may be considered as a Road Side Unit.

o Removed the discussion about security breach.

IEEE 1609 and ETSI ITS provided strong security and privacy
mechanisms for Non IP Communications. Security (authentication,
encryption) is done by asymetric cryptography, where each vehicle
attaches its public key and its certificate to all of its non IP
messages. Privacy WSA (because is enforced through the use of Pseudonymes. Each
vehicle will be pre-loaded with a large number (>1000s) non-IP).

o Removed mentioning of
pseudonymes generated by a PKI, which will uniquely assign the GeoNetworking discussion.

o Moved references to scientific articles to a
pseudonyme separate 'overview'
draft, and referred to it.

Appendix B. Changes Needed on a certificate (and thus software driver 802.11a to become a public/private key pair).

Non IP Communication being developped for safety-critical
applications, complex mechanisms have been provided for their
support. These mechanisms are OPTIONAL for IP Communication, but
SHOULD be used whenever possible.

D.3. 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 driver

The 802.11p amendment modifies both the 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 stack's physical and transmission.

IEEE 802.11-OCB strongly differs from other 802.11 systems
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 operate
outside of be 802.11p compliant:

o The chip must support the context of a Basic Service Set. This means in
practice that IEEE 802.11-OCB does not rely frequency bands on a Base Station for all
Basic Service Set management. In particular, IEEE 802.11-OCB SHALL
NOT which the regulator
recommends the use beacons. Any IPv6 mechanism requiring L2 services from of ITS communications, for example using IEEE
802.11 beacons MUST
802.11p layer, in France: 5875MHz to 5925MHz.

o The chip must support an alternative service.

Channel scanning being disabled, IPv6 over IEEE 802.11-OCB MUST
implement a mechanism for transmitter and receiver the half-rate mode (the internal clock
should be able to converge be divided by two).

o The chip transmit spectrum mask must be compliant to a
common channel.

Authentication not being possible, IPv6 over the "Transmit
spectrum mask" from the IEEE 802.11-OCB MUST
implement an distributed mechanism 802.11p amendment (but experimental
environments tolerate otherwise).

o The chip should be able to authenticate transmitters transmit up to 44.8 dBm when used by
the US government in the United States, and
receivers without up to 33 dBm in
Europe; other regional conditions apply.

Changes needed on 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 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 receivers without should allow the support use
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.

D.4. Privacy requirements

Vehicles will move. As each vehicle moves, it needs higher emission powers. This may require modifications to regularly
announce its network interface and reconfigure its
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 global
view of its network. L2 mechanisms others)
emission and reception must be disabled except for frames of IEEE 802.11-OCB MAY
subtype Action and Timing Advertisement (defined below).

* No encryption key or method must be used.

* Packet emission and reception must be
employed performed as in ad-hoc
mode, using the wildcard BSSID (ff:ff:ff:ff:ff:ff).

* The functions related to assist IPv6 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).

* Timing Advertisement frames, defined in discovering new network interfaces. L3
mechanisms over IEEE 802.11-OCB SHOULD the amendment, should
be used supported. The upper layer should be able to assist IPv6 trigger such
frames emission and to retrieve information contained in
discovering new network interfaces.
received Timing Advertisements.

Appendix C. Design Considerations

The headers of the L2 mechanisms of IEEE networks defined by 802.11-OCB and L3 management
mechanisms of IPv6 are not encrypted, and as such expose at least the
src MAC address in many ways similar to other
networks of the sender. 802.11 family. In theory, the absence encapsulation of mitigations,
adversaries IPv6
over 802.11-OCB could monitor the L2 or L3 management headers, track the
MAC Addresses, and through that track be very similar to the position operation of vehicles IPv6 over
time; in some cases, it is possible to deduce
other networks of the vehicle
manufacturer name from 802.11 family. However, the OUI of high mobility,
strong link asymetry and very short connection makes the MAC address of 802.11-OCB
link significantly different from other 802.11 networks. Also, the interface
(with help of additional databases). It is important that sniffers
along roads not be able
automotive applications have specific requirements for reliability,
security and privacy, which further add to easily identify private information the particularity of
automobiles passing by.

Similary to Non IP safety-critical communications, the obvious
mitigation is to use some form
802.11-OCB link.

C.1. Vehicle ID

Automotive networks require the unique representation of MAC Address Randomization. We can
assume that there will each of
their node. Accordingly, a vehicle must be "renumbering events" causing identified by at least
one unique ID. 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
Addresses to change. Clearly, address uniquely obtained from a change IEEE 802.11-OCB NIC
implicitely generates multiple vehicle IDs in case of MAC Address should induce multiple
802.11-OCB NICs. A mechanims to uniquely identify a simultaneous change of IPv6 Addresses, vehicle
irrespectively to prevent linkage of the
old and new MAC Addresses through continuous use of the same IP
Addresses. different NICs and/or technologies is required.

C.2. Reliability Requirements

The change of an 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 also implies the change of the network
prefix. Prefix delegation mechanisms should be available to vehicles
to obtain new prefixes during "renumbering events".

Changing MAC resolution and IPv6 addresses will disrupt communications, which
goes against the reliability requirements expressed in [TS103097].
We will assume that the renumbering events happen only during "safe"
periods, e.g. when the vehicle has come transmission.

IEEE 802.11-OCB strongly differs from other 802.11 systems to a full stop. The
determination operate
outside of such safe periods is the responsibility context of
implementors. In automobile settings it is common to decide a Basic Service Set. This means in
practice that
certain operations (e.g. software update, or map update) must happen
only during safe periods.

MAC Address randomization will IEEE 802.11-OCB does not prevent tracking if the addresses
stay constant rely on a Base Station for long intervals. Suppose all
Basic Service Set management. In particular, IEEE 802.11-OCB SHALL
NOT use beacons. Any IPv6 mechanism requiring L2 services from IEEE
802.11 beacons MUST support an alternative service.

Channel scanning being disabled, IPv6 over IEEE 802.11-OCB MUST
implement a mechanism for example that transmitter and receiver to converge to a vehicle
only renumbers the addresses of its interface when leaving the
vehicle owner's garage in the morning. It would be trivial
common channel.

Authentication not being possible, IPv6 over IEEE 802.11-OCB MUST
implement an distributed mechanism to
observe the "number of the day" at the known garage location, authenticate transmitters and to
associate that with
receivers without the vehicle's identity. There is clearly support of a
tension there. If renumbering events are too infrequent, they will DHCP server.

Time synchronization not protect privacy, but if their are too frequent they will affect
reliability. We expect that implementors will eventually find the
right balance.

D.5. Authentication requirements being available, IPv6 over IEEE 802.11-OCB does not have L2 authentication mechanisms.
Accordingly,
MUST implement a vehicle receiving 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 packet
cannot check
MUST disable management mechanisms requesting acknowledgements or be sure the legitimacy of the src MAC (and associated
ID). This is
replies.

The IEEE 802.11-OCB link having a significant breach of security.

Similarly to Non IP safety-critical communications, short duration time, IPv6 over IEEE
802.11-OCB packets must contain a certificate, including at least the
public key of the sender, that will allow the receiver to
authenticate the packet, and guarantee its legitimacy.

To satisfy the privacy requiremrents of Appendix D.4, the certificate
SHALL be changed at each 'renumbering event'.

D.6. MUST implement fast IPv6 mobility management mechanisms.

C.3. Multiple interfaces

There are considerations for 2 or more IEEE 802.11-OCB interface
cards per vehicle. For each vehicle taking part in road traffic, one
IEEE 802.11-OCB interface card MUST 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.

If Mobile IPv6 with NEMO extensions is used, then the MCoA RFC5648
technology is relevant for Mobile Routers with multiple interfaces,
deployed in vehicles.

The privacy requirements of Appendix D.4 [] imply that if these multiple
interfaces are represented by many network interface, a single
renumbering event SHALL cause renumbering of all these interfaces.
If one MAC changed and another stayed constant, external observers
would be able to correlate old and new values, and the privacy
benefits of randomization would be lost.

The privacy requirements of Non IP safety-critical communications
imply that if a change of pseudonyme occurs, renumbering of all other
interfaces SHALL also occur.

D.7.

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 [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.

D.8. Security Certificate 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". So MUST also the Security Certificates.
Unless unavailable,

Appendix D. IEEE 802.11 Messages Transmitted in OCB mode

For information, at the Security Certificate Generation mechanisms
SHOULD follow time of writing, this is the specification in list of IEEE 1609.2 [ieee16094] or ETSI TS
103 097 [TS103097]. These security mechanisms have the following
characteristics:
802.11 messages that may be transmitted in OCB mode, i.e. when
dot11OCBActivated is true in a STA:

o Authentication - Elliptic Curve Digital Signature Algorithm
(ECDSA) - A Secured Hash Function (SHA-256) will sign the message
with the public key The STA may send management frames of subtype Action and, if the sender.
STA maintains a TSF Timer, subtype Timing Advertisement;

o Encryption - Elliptic Curve Integrated Encryption Scheme (ECIES) -
A Key Derivation Function (KDF) between the sender's public key The STA may send control frames, except those of subtype PS-Poll,
CF-End, and the receiver's private key will generate a symetric key used
to encrypt a packet.

If the mechanisms described in IEEE 1609.2 [ieee16094] or ETSI TS 103
097 [TS103097] are either not supported or not capable CF-End plus CFAck;

o The STA may send data frames of running on
the hardware, an alternative approach based on Pretty-Good-Privacy
(PGP) MAY be used as an alternative. subtype Data, Null, QoS Data, and
QoS Null.

Authors' Addresses

Alexandre Petrescu
CEA, LIST
CEA Saclay
Gif-sur-Yvette , Ile-de-France 91190
France

Phone: +33169089223
Email: Alexandre.Petrescu@cea.fr

Nabil Benamar
Moulay Ismail University
Morocco

Phone: +212670832236
Email: benamar73@gmail.com

Jerome Haerri
Eurecom
Sophia-Antipolis 06904
France

Phone: +33493008134
Email: Jerome.Haerri@eurecom.fr
Christian Huitema
Friday Harbor, WA 98250
U.S.A.

Email: huitema@huitema.net

Jong-Hyouk Lee
Sangmyung University
31, Sangmyeongdae-gil, Dongnam-gu
Cheonan 31066
Republic of Korea

Email: jonghyouk@smu.ac.kr

Thierry Ernst
YoGoKo
France

Email: thierry.ernst@yogoko.fr

Tony Li
Peloton Technology
1060 La Avenida St.
Mountain View, California 94043
United States

Phone: +16503957356
Email: tony.li@tony.li