Network Working Group F. Templin, Ed.
Internet-Draft Boeing Research & Technology
Intended status: Standards Track A. Whyman
Expires: June 12, 2020 MWA Ltd c/o Inmarsat Global Ltd
December 10, 2019
Transmission of IPv6 Packets over Aeronautical ("aero") Interfaces
draft-templin-atn-aero-interface-08.txt
Abstract
Aeronautical mobile nodes (e.g., aircraft of various configurations)
communicate with networked correspondents over multiple access
network data links and configure mobile routers to connect their on-
board networks. An Air-to-Ground (A/G) interface specification is
therefore needed for coordination with the ground domain network.
This document specifies the transmission of IPv6 packets over
aeronautical ("aero") interfaces.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on June 12, 2020.
Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
Templin & Whyman Expires June 12, 2020 [Page 1]
Internet-Draft IPv6 over AERO Interfaces December 2019
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Aeronautical ("aero") Interface Model . . . . . . . . . . . . 4
5. Maximum Transmission Unit . . . . . . . . . . . . . . . . . . 7
6. Frame Format . . . . . . . . . . . . . . . . . . . . . . . . 7
7. Link-Local Addresses . . . . . . . . . . . . . . . . . . . . 7
8. Address Mapping - Unicast . . . . . . . . . . . . . . . . . . 8
9. Address Mapping - Multicast . . . . . . . . . . . . . . . . . 12
10. Address Mapping for IPv6 Neighbor Discovery Messages . . . . 13
11. Conceptual Sending Algorithm . . . . . . . . . . . . . . . . 13
11.1. Multiple Aero Interfaces . . . . . . . . . . . . . . . . 14
12. Router Discovery and Prefix Registration . . . . . . . . . . 14
13. Detecting and Responding to MSE Failures . . . . . . . . . . 17
14. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
15. Security Considerations . . . . . . . . . . . . . . . . . . . 18
16. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 18
17. References . . . . . . . . . . . . . . . . . . . . . . . . . 18
17.1. Normative References . . . . . . . . . . . . . . . . . . 18
17.2. Informative References . . . . . . . . . . . . . . . . . 19
Appendix A. ARO Extensions for Pseudo-DSCP Mappings . . . . . . 21
Appendix B. Prefix Length Considerations . . . . . . . . . . . . 21
Appendix C. VDL Mode 2 Considerations . . . . . . . . . . . . . 22
Appendix D. Change Log . . . . . . . . . . . . . . . . . . . . . 22
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 25
1. Introduction
Aeronautical Mobile Nodes (MNs) such as aircraft of various
configurations often have multiple data links for communicating with
networked correspondents. These data links may have differing
performance, cost and availability characteristics that can change
dynamically according to mobility patterns, flight phases, proximity
to infrastructure, etc.
Each MN receives an IPv6 Mobile Network Prefix (MNP) that can be used
by on-board networks independently of the access network data links
selected for data transport. The MN performs router discovery (i.e.,
similar to IPv6 customer edge routers [RFC7084]) and acts as a mobile
router on behalf of its on-board networks.
Templin & Whyman Expires June 12, 2020 [Page 2]
Internet-Draft IPv6 over AERO Interfaces December 2019
The MN configures a virtual interface (termed the "aero interface")
as a thin layer over the underlying access network interfaces. The
aero interface is therefore the only interface abstraction exposed to
the IPv6 layer and behaves according to the Non-Broadcast, Multiple
Access (NBMA) interface principle, while underlying access network
interfaces appear as link layer communication channels in the
architecture. The aero interface connects to a virtual overlay cloud
service known as the "aero link". The aero link spans a worldwide
Internetwork that may be either a private-use infrastructure or the
global public Internet itself.
The aero interface provides a traffic engineering nexus for guiding
inbound and outbound traffic to the correct underlying Access Network
(ANET) interface(s). The IPv6 layer sees the aero interface as a
point of connection to the aero link. Each aero link has one or more
associated Mobility Service Prefixes (MSPs) from which aero link MNPs
are derived. If there are multiple aero links, the IPv6 layer will
see multiple aero interfaces.
The aero interface interacts with the ground-domain Mobility Service
(MS) through IPv6 Neighbor Discovery (ND) control message exchanges
[RFC4861]. The MS provides Mobility Service Endpoints (MSEs) that
track MN movements and represent their MNPs in a global routing or
mapping system.
This document specifies the transmission of IPv6 packets [RFC8200]
and MN/MS control messaging over aeronautical ("aero") interfaces.
2. Terminology
The terminology in the normative references applies; especially, the
terms "link" and "interface" are the same as defined in the IPv6
[RFC8200] and IPv6 Neighbor Discovery (ND) [RFC4861] specifications.
The following terms are defined within the scope of this document:
Access Network (ANET)
a data link service network (e.g., an aviation radio access
network, satellite service provider network, cellular operator
network, etc.) protected by physical and/or link layer security.
Each ANET provides an Access Router (AR), and connects to outside
Internetworks via border security devices such as proxys,
firewalls, packet filtering gateways, etc.
ANET interface
a node's attachment to a link in an ANET.
Internetwork (INET)
Templin & Whyman Expires June 12, 2020 [Page 3]
Internet-Draft IPv6 over AERO Interfaces December 2019
a connected network region with a coherent IP addressing plan that
provides transit forwarding services for ANET mobile nodes and
INET correspondents. Examples include private enterprise
networks, aviation networks and the global public Internet itself.
INET interface
a node's attachment to a link in an INET.
aero link
a virtual overlay cloud service configured over one or more INETs
and their connected ANETs. An aero link may comprise multiple
INET segments joined by bridges the same as for any link; the
addressing plans in each segment may be mutually exclusive and
managed by different administrative entities.
aero interface
a node's attachment to an aero link, and configured over one or
more underlying ANET/INET interfaces.
aero address
an IPv6 link-local address constructed as specified in Section 7,
and assigned to an aero interface.
3. Requirements
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 [RFC2119]. Lower case
uses of these words are not to be interpreted as carrying RFC2119
significance.
4. Aeronautical ("aero") Interface Model
An aero interface is a MN virtual interface configured over one or
more ANET interfaces, which may be physical (e.g., an aeronautical
radio link) or virtual (e.g., an Internet or higher-layer "tunnel").
The MN coordinates with the MS through IPv6 ND message exchanges.
The aero interface architectural layering model is the same as in
[RFC7847], and augmented as shown in Figure 1. The IPv6 layer
therefore sees the aero interface as a single network layer interface
with multiple underlying ANET interfaces that appear as link layer
communication channels in the architecture.
Templin & Whyman Expires June 12, 2020 [Page 4]
Internet-Draft IPv6 over AERO Interfaces December 2019
+----------------------------+
| TCP/UDP |
Session-to-IP +---->| |
Address Binding | +----------------------------+
+---->| IPv6 |
IP Address +---->| |
Binding | +----------------------------+
+---->| aero Interface |
Logical-to- +---->| (aero address) |
Physical | +----------------------------+
Interface +---->| L2 | L2 | | L2 |
Binding |(IF#1)|(IF#2)| ..... |(IF#n)|
+------+------+ +------+
| L1 | L1 | | L1 |
| | | | |
+------+------+ +------+
Figure 1: Aero Interface Architectural Layering Model
The aero virtual interface model gives rise to a number of
opportunities:
o since aero interface link-local addresses are uniquely derived
from an MNP (see: Section 7, no Duplicate Address Detection (DAD)
messaging is necessary over the aero interface.
o ANET interfaces can remain unnumbered in environments where
communications are coordinated entirely over the aero interface.
o as ANET interface properties change (e.g., link quality, cost,
availability, etc.), any active ANET interface can be used to
update the profiles of multiple additional ANET interfaces in a
single message. This allows for timely adaptation and service
continuity under dynamically changing conditions.
o coordinating ANET interfaces in this way allows them to be
represented in a unified MS profile with provisions for mobility
and multilink operations.
o exposing a single virtual interface abstraction to the IPv6 layer
allows for traffic engineering (including QoS based link
selection, packet replication, load balancing, etc.) at the link
layer while still permitting queuing at the IPv6 layer based on,
e.g., traffic class, flow label, etc.
o the IPv6 layer sees the aero interface as a point of connection to
the aero link; if there are multiple aero links (i.e., multiple
MS's), the IPv6 layer will see multiple aero interfaces.
Templin & Whyman Expires June 12, 2020 [Page 5]
Internet-Draft IPv6 over AERO Interfaces December 2019
Other opportunities are discussed in [RFC7847].
Figure 2 depicts the architectural model for a MN connecting to the
MS via multiple independent ANETs. When an ANET interface becomes
active, the MN sends native (i.e., unencapsulated) IPv6 ND messages
via the underlying ANET interface. IPv6 ND messages traverse the
ground domain ANETs until they reach an Access Router (AR#1, AR#2,
.., AR#n). The AR then coordinates with a Mobility Service Endpoint
(MSE#1, MSE#2, ..., MSE#m) in the INET and returns an IPv6 ND message
response to the MN. IPv6 ND messages traverse the ANET at layer 2;
hence, the Hop Limit is not decremented.
+--------------+
| MN |
+--------------+
|aero inteface |
+----+----+----+
+--------|IF#1|IF#2|IF#n|------ +
/ +----+----+----+ \
/ | \
/ Native | IPv6 \
v v v
(:::)-. (:::)-. (:::)-.
.-(::ANET:::) .-(::ANET:::) .-(::ANET:::)
`-(::::)-' `-(::::)-' `-(::::)-'
+----+ +----+ +----+
... |AR#1| .......... |AR#2| ......... |AR#n| ...
. +-|--+ +-|--+ +-|--+ .
. | | |
. v v v .
. <----- Encapsulation -----> .
. .
. +-----+ (:::)-. .
. |MSE#2| .-(::::::::) +-----+ .
. +-----+ .-(::: INET :::)-. |MSE#m| .
. (::::: Routing ::::) +-----+ .
. `-(::: System :::)-' .
. +-----+ `-(:::::::-' .
. |MSE#1| +-----+ +-----+ .
. +-----+ |MSE#3| |MSE#4| .
. +-----+ +-----+ .
. .
. .
. <----- Worldwide Connected Internetwork ----> .
...........................................................
Figure 2: MN/MS Coordination via Multiple ANETs
Templin & Whyman Expires June 12, 2020 [Page 6]
Internet-Draft IPv6 over AERO Interfaces December 2019
After the initial IPv6 ND message exchange, the MN can send and
receive unencapsulated IPv6 data packets over the aero interface.
Traffic engineering will forward the packets via ARs in the correct
underlying ANETs. The AR encapsulates the packets according to the
capabilities provided by the MS and forwards them to the next hop
within the worldwide connected Internetwork via optimal routes.
5. Maximum Transmission Unit
All IPv6 interfaces MUST configure an MTU of at least 1280 bytes
[RFC8200]. The aero interface configures its MTU based on the
largest MTU among all underlying ANET interfaces. The value may be
overridden if an RA message with an MTU option is received.
The aero interface returns internally-generated IPv6 Path MTU
Discovery (PMTUD) Packet Too Big (PTB) messages [RFC8201] for packets
admitted into the aero interface that are too large for the outbound
underlying ANET interface. Similarly, the aero interface performs
PMTUD even if the destination appears to be on the same link since a
proxy on the path could return a PTB message. PMTUD therefore
ensures that the aero interface MTU is adaptive and reflects the
current path used for a given data flow.
Applications that cannot tolerate loss due to MTU restrictions should
refrain from sending packets larger than 1280 bytes, since dynamic
path changes can reduce the path MTU at any time. Applications that
may benefit from sending larger packets even though the path MTU may
change dynamically can use larger sizes.
6. Frame Format
The aero interface transmits IPv6 packets according to the native
frame format of each underlying ANET interface. For example, for
Ethernet-compatible interfaces the frame format is specified in
[RFC2464], for aeronautical radio interfaces the frame format is
specified in standards such as ICAO Doc 9776 (VDL Mode 2 Technical
Manual), for tunnels over IPv6 the frame format is specified in
[RFC2473], etc.
7. Link-Local Addresses
Aero interfaces assign link-local addresses the same as any IPv6
interface. The link-local address format for aero interfaces is
known as the "aero address".
MN aero addresses begin with the prefix fe80::/64 followed by a
64-bit prefix taken from the MNP (see: Appendix B). The lowest-
numbered aero address serves as the "base" address. The MN uses the
Templin & Whyman Expires June 12, 2020 [Page 7]
Internet-Draft IPv6 over AERO Interfaces December 2019
base aero address in IPv6 ND messages, but accepts packets destined
to all aero addresses equally. For example, for the MNP
2001:db8:1000:2000::/56 the corresponding aero addresses are:
fe80::2001:db8:1000:2000
fe80::2001:db8:1000:2001
fe80::2001:db8:1000:2002
... etc. ...
fe80::2001:db8:1000:20ff
MSE aero addresses are allocated from the range fe80::/96, and MUST
be managed for uniqueness by the collective aero link administrative
authorities. The lower 32 bits of the address includes a unique
integer value, e.g., fe80::1, fe80::2, fe80::3, etc. The address
fe80:: is the IPv6 link-local Subnet Router Anycast address [RFC4291]
and the address fe80::ffff:ffff is reserved; hence, these values are
not available for general assignment.
The IPv6 addressing architecture [RFC4291] reserves the prefix ::/8;
this assures that MNPs will not begin with ::/32 so that MN and MSE
aero addresses cannot overlap.
Since MN aero addresses are based on the distribution of
administratively assured unique MNPs, and since MSE aero addresses
are guaranteed unique through administrative assignment, aero
interfaces set the autoconfiguration variable DupAddrDetectTransmits
to 0 [RFC4862].
IPv4-compatible aero addresses are allocated as fe80::ffff:[v4addr],
i.e., fe80::/10, followed by 70 '0' bits, followed by 16 '1' bits,
followed by a 32bit IPv4 address. IPv4 address usage is outside the
scope of this document.
8. Address Mapping - Unicast
Aero interfaces maintain a neighbor cache for tracking per-neighbor
state and use the link-local address format specified in Section 7.
IPv6 Neighbor Discovery (ND) [RFC4861] messages on aero interfaces
observe the native Source/Target Link-Layer Address Option (S/TLLAO)
formats of the underlying ANET interfaces (e.g., for Ethernet the S/
TLLAO is specified in [RFC2464]).
MNs such as aircraft typically have many wireless data link types
(e.g. satellite-based, cellular, terrestrial, air-to-air directional,
Templin & Whyman Expires June 12, 2020 [Page 8]
Internet-Draft IPv6 over AERO Interfaces December 2019
etc.) with diverse performance, cost and availability properties.
The aero interface would therefore appear to have multiple link layer
connections, and may include information for multiple ANET interfaces
in a single message exchange.
Aero interfaces use a new IPv6 ND option called the "Aero
Registration Option (ARO)". MNs invoke the MS by including an ARO in
Router Solicitation (RS) and (unsolicited) Neighbor Advertisement
(NA) messages, and the MS includes an ARO in unicast Router
Advertisement (RA) responses to an RS.
RS/NA messages sent by the MN include AROs formatted as shown in
Figure 3:
Templin & Whyman Expires June 12, 2020 [Page 9]
Internet-Draft IPv6 over AERO Interfaces December 2019
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Prefix Length |R| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ifIndex[1] | ifType[1] | Flags [1] |Link[1]|QoS[1] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|P00|P01|P02|P03|P04|P05|P06|P07|P08|P09|P10|P11|P12|P13|P14|P15|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|P16|P17|P18|P19|P20|P21|P22|P23|P24|P25|P26|P27|P28|P29|P30|P31|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|P32|P33|P34|P35|P36|P37|P38|P39|P40|P41|P42|P43|P44|P45|P46|P47|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|P48|P49|P50|P51|P52|P53|P54|P55|P56|P57|P58|P59|P60|P61|P62|P63|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ifIndex[2] | ifType[2] | Flags [2] |Link[2]|QoS[2] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|P00|P01|P02|P03|P04|P05|P06|P07|P08|P09|P10|P11|P12|P13|P14|P15|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|P16|P17|P18|P19|P20|P21|P22|P23|P24|P25|P26|P27|P28|P29|P30|P31|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|P32|P33|P34|P35|P36|P37|P38|P39|P40|P41|P42|P43|P44|P45|P46|P47|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|P48|P49|P50|P51|P52|P53|P54|P55|P56|P57|P58|P59|P60|P61|P62|P63|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
... ... ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ifIndex[N] | ifType[N] | Flags [N] |Link[N]|QoS[N] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|P00|P01|P02|P03|P04|P05|P06|P07|P08|P09|P10|P11|P12|P13|P14|P15|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|P16|P17|P18|P19|P20|P21|P22|P23|P24|P25|P26|P27|P28|P29|P30|P31|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|P32|P33|P34|P35|P36|P37|P38|P39|P40|P41|P42|P43|P44|P45|P46|P47|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|P48|P49|P50|P51|P52|P53|P54|P55|P56|P57|P58|P59|P60|P61|P62|P63|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| zero-padding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Aero Registration Option (ARO) Format in RS/NA Messages
In this format:
o Type is set to TBD.
Templin & Whyman Expires June 12, 2020 [Page 10]
Internet-Draft IPv6 over AERO Interfaces December 2019
o Length is set to the number of 8 octet blocks in the option (with
zero-padding added to the end of the option if necessary to
produce an integral number of 8 octet blocks).
o Prefix Length is set to the length of the MNP embedded in the MN's
aero address.
o R (the "Register" bit) is set to '1' to assert the MNP
registration or set to '0' to request de-registration.
o Reserved is set to the value '0' on transmission.
o A set of N ANET interface "ifIndex-tuples" are included as
follows:
* ifIndex[i] is set to an 8-bit integer value corresponding to a
specific underlying ANET interface. The first ifIndex-tuple
MUST correspond to the ANET interface over which the message is
sent. Once the MN has assigned an ifIndex to an ANET
interface, the assignment MUST remain unchanged while the MN
remains registered in the network. MNs MUST number each
ifIndex with a value between '1' and '255' that represents a
MN-specific 8-bit mapping for the actual ifIndex value assigned
to the ANET interface by network management [RFC2863].
* ifType[i] is set to an 8-bit integer value corresponding to the
underlying ANET interface identified by ifIndex. The value
represents an aero interface-specific 8-bit mapping for the
actual IANA ifType value assigned to the ANET interface by
network management [RFC2863].
* Flags[i] is an 8-bit flags field. All flag bits are currently
undefined and set to the value '0' on transmission. Future
updates may specify new flags.
* Link[i] encodes a 4-bit link metric. The value '0' means the
link is DOWN, and the remaining values mean the link is UP with
metric ranging from '1' ("low") to '15' ("high").
* QoS[i] encodes the number of 4-byte blocks (between '0' and
'15') of two-bit P[i] values that follow. The first 4 blocks
correspond to the 64 Differentiated Service Code Point (DSCP)
values P00 - P63 [RFC2474]. If additional 4-byte P[i] blocks
follow, their values correspond to "pseudo-DSCP" values P64,
P65, P66, etc. numbered consecutively. The pseudo-DSCP values
correspond to ancillary QoS information defined for the
specific aero interface (e.g., see Appendix A).
Templin & Whyman Expires June 12, 2020 [Page 11]
Internet-Draft IPv6 over AERO Interfaces December 2019
* P[i] includes zero or more per-ifIndex 4-byte blocks of two-bit
Preferences. Each P[i] field is set to the value '0'
("disabled"), '1' ("low"), '2' ("medium") or '3' ("high") to
indicate a QoS preference level for ANET interface selection
purposes. The first four blocks always correspond to the 64
DSCP values. If one or more of the blocks are absent (e.g.,
for QoS values 0,1,2,3) the P[i] values for the missing blocks
default to "medium".
Unicast RA messages sent by the MS in response to MN RS messages
include AROs formatted as shown in Figure 4:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length = 1 | Prefix Length |R| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ifIndex | ifType | Flags | Link | QoS |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Aero Registration Option (ARO) Format in RA messages
In this format:
o Type is set to TBD.
o Length is set to the constant value '1' (i.e., 1 unit of 8
octets).
o Prefix Length is set to the length associated with the aero
address of the destination MN.
o R is set to '1' to confirm registration or set to '0' to release/
decline registration.
o ifIndex, ifType, Flags, Link and QoS echo the values of the same
fields that were received in the first ifIndex-tuple of the
soliciting RS. The echoed values provide a nonce that allows the
MN to associate the received RA with the soliciting RS.
9. Address Mapping - Multicast
The multicast address mapping of the native underlying ANET interface
applies. The mobile router on board the aircraft also serves as an
IGMP/MLD Proxy for its EUNs and/or hosted applications per [RFC4605]
while using the link layer address of the router as the link layer
address for all multicast packets.
Templin & Whyman Expires June 12, 2020 [Page 12]
Internet-Draft IPv6 over AERO Interfaces December 2019
10. Address Mapping for IPv6 Neighbor Discovery Messages
Per [RFC4861], IPv6 ND messages may be sent to either a multicast or
unicast link-scoped IPv6 destination address. However, IPv6 ND
messaging must be coordinated between the MN and MS only without
invoking other nodes on the ANET.
For this reason, ANET links maintain unicast link-layer addresses
("MSADDR") for the purpose of supporting MN/MS IPv6 ND messaging.
For Ethernet-compatible ANETs, this specification reserves one
Ethernet unicast address 00-00-5E-00-52-14. For non-Ethernet
statically-addressed ANETs, MSADDR is reserved per the assigned
numbers authority for the ANET addressing space. For still other
ANETs, MSADDR may be dynamically discovered through other means,
e.g., link-layer beacons.
MNs map all IPv6 ND messages they send (i.e., both multicast and
unicast) to an MSADDR instead of to an ordinary unicast or multicast
link-layer address. In this way, all of the MN's IPv6 ND messages
will be received by MS devices that are configured to accept packets
destined to MSADDR. Note that multiple MS devices on the link could
be configured to accept packets destined to MSADDR, e.g., as a basis
for supporting redundancy.
Therefore, ARs MUST accept and process packets destined to MSADDR,
while all other devices MUST NOT process packets destined to MSADDR.
This model has a well-established operational experience in Proxy
Mobile IPv6 (PMIP) [RFC5213][RFC6543].
11. Conceptual Sending Algorithm
The MN's IPv6 layer selects the outbound aero interface according to
standard IPv6 requirements. The aero interface maintains default
routes and neighbor cache entries for MSEs, and may also include
additional neighbor cache entries created through other means (e.g.,
Address Resolution, static configuration, etc.).
After a packet enters the aero interface, an outbound ANET interface
is selected based on traffic engineering information such as DSCP,
application port number, cost, performance, message size, etc. Aero
interface traffic engineering could also be configured to perform
replication across multiple ANET interfaces for increased reliability
at the expense of packet duplication.
Templin & Whyman Expires June 12, 2020 [Page 13]
Internet-Draft IPv6 over AERO Interfaces December 2019
11.1. Multiple Aero Interfaces
MNs may associate with multiple MS instances concurrently. Each MS
instance represents a distinct aero link distinguished by its
associated MSPs. The MN configures a separate aero interface for
each link so that multiple interfaces (e.g., aero0, aero1, aero2,
etc.) are exposed to the IPv6 layer.
Depending on local policy and configuration, an MN may choose between
alternative active aero interfaces using a packet's DSCP, routing
information or static configuration. Interface selection based on
per-packet source addresses is also enabled when the MSPs for each
aero interface are known (e.g., discovered through Prefix Information
Options (PIOs) and/or Route Information Options (RIOs)).
Each aero interface can be configured over the same or different sets
of ANET interfaces. Each ANET distinguishes between the different
aero links based on the MSPs represented in per-packet IPv6
addresses.
Multiple distinct aero links can therefore be used to support fault
tolerance, load balancing, reliability, etc. The architectural model
parallels Layer 2 Virtual Local Area Networks (VLANs), where the MSPs
serve as (virtual) VLAN tags.
12. Router Discovery and Prefix Registration
ARs process IPv6 ND messages destined to all-routers multicast,
subnet router anycast and unicast link-local IPv6 addresses. ARs
configure the link-layer address MSADDR (see: Section 10) and act as
a proxy for MSE addresses in the range fe80::1 through
fe80::ffff:fffe.
MNs interface with the MS by sending RS messages with AROs. For each
ANET interface, the MN sends RS messages with AROs with link-layer
destination address set to MSADDR and with network-layer destination
address set to either a specific MSE aero address, subnet router
anycast, or all-routers multicast. The MN discovers MSE addresses
either through an RA message response to an initial anycast/multicast
RS or before sending an initial RS message. [RFC5214] provides
example MSE address discovery methods, including information conveyed
during data link login, name service lookups, static configuration,
etc.
The AR receives the RS messages and contacts the corresponding MSE.
When the MSE responds, the AR returns an RA message with source
address set to the MSE address, with an ARO and with any information
Templin & Whyman Expires June 12, 2020 [Page 14]
Internet-Draft IPv6 over AERO Interfaces December 2019
for the link that would normally be delivered in a solicited RA
message.
MNs configure aero interfaces that observe the properties discussed
in the previous section. The aero interface and its underlying
interfaces are said to be in either the "UP" or "DOWN" state
according to administrative actions in conjunction with the interface
connectivity status. An aero interface transitions to UP or DOWN
through administrative action and/or through state transitions of the
underlying interfaces. When a first underlying interface transitions
to UP, the aero interface also transitions to UP. When all
underlying interfaces transition to DOWN, the aero interface also
transitions to DOWN.
When an aero interface transitions to UP, the MN sends initial RS
messages to register its MNP and an initial set of underlying ANET
interfaces that are also UP. The MN sends additional RS messages to
refresh lifetimes and to register/deregister underlying ANET
interfaces as they transition to UP or DOWN.
ARs coordinate with the MSE and return RA messages with configuration
information in response to a MN's RS messages. The RAs include a
Router Lifetime value and any necessary options, such as:
o PIOs with (A; L=0) that include MSPs for the link [RFC8028].
o RIOs [RFC4191] with more-specific routes.
o an MTU option that specifies the maximum acceptable packet size
for the aero link
The AR sends immediate unicast RA responses without delay; therefore,
the 'MAX_RA_DELAY_TIME' and 'MIN_DELAY_BETWEEN_RAS' constants for
multicast RAs do not apply. The AR MAY send periodic and/or event-
driven unsolicited RA messages, but is not required to do so for
unicast advertisements [RFC4861].
The MN sends RS messages from within the aero interface while using
an UP underlying ANET interface as the outbound interface. Each RS
message is formatted as though it originated from the IPv6 layer, but
the process is coordinated wholly from within the aero interface and
is therefore opaque to the IPv6 layer. The MN sends initial RS
messages over an UP underlying interface with its aero address as the
source. The RS messages include AROs with a valid Prefix Length as
well as ifIndex-tuples appropriate for underlying ANET interfaces.
The AR processes RS message and forwards the information in the ARO
to the MSE.
Templin & Whyman Expires June 12, 2020 [Page 15]
Internet-Draft IPv6 over AERO Interfaces December 2019
When the MSE processes the AR information, if the prefix registration
was accepted the MSE injects the MNP into the routing/mapping system
then caches the new Prefix Length, MNP and ifIndex-tuples. The MSE
then coordinates with the AR to return an RA message to the MN with
an ARO with a non-zero Router Lifetime if the prefix assertion was
acceptable; otherwise, with a zero Router Lifetime.
When the MN receives the RA message, it creates a default route with
next hop address set to the MSE found in the RA source address and
with link-layer address set to MSADDR. The AR will then forward
packets acting as a proxy between the MN and the MS.
The MN then manages its underlying ANET interfaces according to their
states as follows:
o When an underlying ANET interface transitions to UP, the MN sends
an RS over the ANET interface with an ARO. The ARO contains a
first ifIndex-tuple with values specific to this ANET interface,
and may contain additional ifIndex-tuples specific to other ANET
interfaces.
o When an underlying ANET interface transitions to DOWN, the MN
sends an RS or unsolicited NA message over any UP ANET interface
with an ARO containing an ifIndex-tuple for the DOWN ANET
interface with Link(i) set to '0'. The MN sends an RS when an
acknowledgement is required, or an unsolicited NA when reliability
is not thought to be a concern (e.g., if redundant transmissions
are sent on multiple ANET interfaces).
o When a MN wishes to release from a current MSE, it sends RS
messages over any UP ANET interfaces with an ARO with R set to 0.
The corresponding MSE then withdraws the MNP from the routing/
mapping system and returns an RA message with an ARO with Router
Lifetime set to 0.
o When all of a MNs underlying interfaces have transitioned to DOWN,
the MSE withdraws the MNP the same as if it had received a message
with an ARO with R set to 0.
The MN is responsible for retrying each RS exchange up to
MAX_RTR_SOLICITATIONS times separated by RTR_SOLICITATION_INTERVAL
seconds until an RA is received. If no RA is received over multiple
UP ANET interfaces, the MN declares this MSE unreachable and tries a
different MSE.
The IPv6 layer sees the aero interface as an ordinary IPv6 interface.
Therefore, when the IPv6 layer sends an RS message the aero interface
returns an internally-generated RA message as though the message
Templin & Whyman Expires June 12, 2020 [Page 16]
Internet-Draft IPv6 over AERO Interfaces December 2019
originated from an IPv6 router. The internally-generated RA message
contains configuration information (such as Router Lifetime, MTU,
etc.) that is consistent with the information received from the RAs
generated by the MS.
Whether the aero interface IPv6 ND messaging process is initiated
from the receipt of an RS message from the IPv6 layer is an
implementation matter. Some implementations may elect to defer the
IPv6 ND messaging process until an RS is received from the IPv6
layer, while others may elect to initiate the process independently
of any IPv6 layer messaging.
13. Detecting and Responding to MSE Failures
In environments where fast recovery from MSE failure is required, ARs
SHOULD use Bidirectional Forwarding Detection (BFD) [RFC5880] to
track MSE reachability. Nodes that use BFD can quickly detect and
react to failures so that cached information is re-established
through alternate paths. BFD control messaging is carried only over
well-connected ground domain networks (i.e., and not low-end
aeronautical radio links) and can therefore be tuned for rapid
response.
ARs establish BFD sessions with MSEs for which there are currently
active ANET MNs. If an MSE fails, ARs can quickly inform MNs of the
outage by sending RA messages on the ANET interface. The AR sends RA
messages with source address set to the MSEs address, destination
address set to all-nodes multicast, and Router Lifetime set to 0.
The AR SHOULD send MAX_FINAL_RTR_ADVERTISEMENTS RA messages separated
by small delays [RFC4861].
Any MNs on the ANET interface that have been using the (now defunct)
MSE will receive the RA messages and associate with a new MSE. For
this reason, MNs SHOULD maintain multiple MSE associations so that
loss of a single MSE does not necessitate immediate ANET interface
control message signaling.
14. IANA Considerations
The IANA is instructed to allocate an official Type number from the
IPv6 Neighbor Discovery Option Formats registry for the Aero
Registration (AR) option. Implementations set Type to 253 as an
interim value [RFC4727].
The IANA is instructed to allocate one Ethernet unicast address,
00-00-5E-00-52-14 [RFC5214] in the registry "IANA Ethernet Address
Block - Unicast Use".
Templin & Whyman Expires June 12, 2020 [Page 17]
Internet-Draft IPv6 over AERO Interfaces December 2019
15. Security Considerations
Security considerations are the same as defined for the specific
access network interface types, and readers are referred to the
appropriate interface specifications.
IPv6 and IPv6 ND security considerations also apply, and are
specified in the normative references.
16. Acknowledgements
The first version of this document was prepared per the consensus
decision at the 7th Conference of the International Civil Aviation
Organization (ICAO) Working Group-I Mobility Subgroup on March 22,
2019. Consensus to take the document forward to the IETF was reached
at the 9th Conference of the Mobility Subgroup on November 22, 2019.
Attendees and contributors included: Guray Acar, Danny Bharj,
Francois D'Humieres, Pavel Drasil, Nikos Fistas, Giovanni Garofolo,
Bernhard Haindl, Vaughn Maiolla, Tom McParland, Victor Moreno, Madhu
Niraula, Brent Phillips, Liviu Popescu, Jacky Pouzet, Aloke Roy, Greg
Saccone, Robert Segers, Michal Skorepa, Michel Solery, Stephane
Tamalet, Fred Templin, Jean-Marc Vacher, Bela Varkonyi, Tony Whyman,
Fryderyk Wrobel and Dongsong Zeng.
The following individuals are acknowledged for their useful comments:
Pavel Drasil, Zdenek Jaron, Michael Matyas, Madhu Niraula, Greg
Saccone, Stephane Tamalet.
.
17. References
17.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black,
"Definition of the Differentiated Services Field (DS
Field) in the IPv4 and IPv6 Headers", RFC 2474,
DOI 10.17487/RFC2474, December 1998,
<https://www.rfc-editor.org/info/rfc2474>.
[RFC4191] Draves, R. and D. Thaler, "Default Router Preferences and
More-Specific Routes", RFC 4191, DOI 10.17487/RFC4191,
November 2005, <https://www.rfc-editor.org/info/rfc4191>.
Templin & Whyman Expires June 12, 2020 [Page 18]
Internet-Draft IPv6 over AERO Interfaces December 2019
[RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", RFC 4291, DOI 10.17487/RFC4291, February
2006, <https://www.rfc-editor.org/info/rfc4291>.
[RFC4727] Fenner, B., "Experimental Values In IPv4, IPv6, ICMPv4,
ICMPv6, UDP, and TCP Headers", RFC 4727,
DOI 10.17487/RFC4727, November 2006,
<https://www.rfc-editor.org/info/rfc4727>.
[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,
<https://www.rfc-editor.org/info/rfc4861>.
[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862,
DOI 10.17487/RFC4862, September 2007,
<https://www.rfc-editor.org/info/rfc4862>.
[RFC8028] Baker, F. and B. Carpenter, "First-Hop Router Selection by
Hosts in a Multi-Prefix Network", RFC 8028,
DOI 10.17487/RFC8028, November 2016,
<https://www.rfc-editor.org/info/rfc8028>.
[RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", STD 86, RFC 8200,
DOI 10.17487/RFC8200, July 2017,
<https://www.rfc-editor.org/info/rfc8200>.
[RFC8201] McCann, J., Deering, S., Mogul, J., and R. Hinden, Ed.,
"Path MTU Discovery for IP version 6", STD 87, RFC 8201,
DOI 10.17487/RFC8201, July 2017,
<https://www.rfc-editor.org/info/rfc8201>.
17.2. Informative References
[RFC2225] Laubach, M. and J. Halpern, "Classical IP and ARP over
ATM", RFC 2225, DOI 10.17487/RFC2225, April 1998,
<https://www.rfc-editor.org/info/rfc2225>.
[RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet
Networks", RFC 2464, DOI 10.17487/RFC2464, December 1998,
<https://www.rfc-editor.org/info/rfc2464>.
[RFC2473] Conta, A. and S. Deering, "Generic Packet Tunneling in
IPv6 Specification", RFC 2473, DOI 10.17487/RFC2473,
December 1998, <https://www.rfc-editor.org/info/rfc2473>.
Templin & Whyman Expires June 12, 2020 [Page 19]
Internet-Draft IPv6 over AERO Interfaces December 2019
[RFC2863] McCloghrie, K. and F. Kastenholz, "The Interfaces Group
MIB", RFC 2863, DOI 10.17487/RFC2863, June 2000,
<https://www.rfc-editor.org/info/rfc2863>.
[RFC4605] Fenner, B., He, H., Haberman, B., and H. Sandick,
"Internet Group Management Protocol (IGMP) / Multicast
Listener Discovery (MLD)-Based Multicast Forwarding
("IGMP/MLD Proxying")", RFC 4605, DOI 10.17487/RFC4605,
August 2006, <https://www.rfc-editor.org/info/rfc4605>.
[RFC5213] Gundavelli, S., Ed., Leung, K., Devarapalli, V.,
Chowdhury, K., and B. Patil, "Proxy Mobile IPv6",
RFC 5213, DOI 10.17487/RFC5213, August 2008,
<https://www.rfc-editor.org/info/rfc5213>.
[RFC5214] Templin, F., Gleeson, T., and D. Thaler, "Intra-Site
Automatic Tunnel Addressing Protocol (ISATAP)", RFC 5214,
DOI 10.17487/RFC5214, March 2008,
<https://www.rfc-editor.org/info/rfc5214>.
[RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010,
<https://www.rfc-editor.org/info/rfc5880>.
[RFC6543] Gundavelli, S., "Reserved IPv6 Interface Identifier for
Proxy Mobile IPv6", RFC 6543, DOI 10.17487/RFC6543, May
2012, <https://www.rfc-editor.org/info/rfc6543>.
[RFC7084] Singh, H., Beebee, W., Donley, C., and B. Stark, "Basic
Requirements for IPv6 Customer Edge Routers", RFC 7084,
DOI 10.17487/RFC7084, November 2013,
<https://www.rfc-editor.org/info/rfc7084>.
[RFC7421] Carpenter, B., Ed., Chown, T., Gont, F., Jiang, S.,
Petrescu, A., and A. Yourtchenko, "Analysis of the 64-bit
Boundary in IPv6 Addressing", RFC 7421,
DOI 10.17487/RFC7421, January 2015,
<https://www.rfc-editor.org/info/rfc7421>.
[RFC7847] Melia, T., Ed. and S. Gundavelli, Ed., "Logical-Interface
Support for IP Hosts with Multi-Access Support", RFC 7847,
DOI 10.17487/RFC7847, May 2016,
<https://www.rfc-editor.org/info/rfc7847>.
Templin & Whyman Expires June 12, 2020 [Page 20]
Internet-Draft IPv6 over AERO Interfaces December 2019
Appendix A. ARO Extensions for Pseudo-DSCP Mappings
Adaptation of the aero interface to specific Internetworks such as
the Aeronautical Telecommunications Network with Internet Protocol
Services (ATN/IPS) includes link selection preferences based on
transport port numbers in addition to the existing DSCP-based
preferences. ATN/IPS nodes maintain a map of transport port numbers
to additional "pseudo-DSCP" P[i] preference fields beyond the first
64. For example, TCP port 22 maps to pseudo-DSCP value P67, TCP port
443 maps to P70, UDP port 8060 maps to P76, etc. Figure 5 shows an
example ARO with extended P[i] values beyond the base 64 used for
DSCP mapping (i.e., for QoS values 5 or greater):
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Prefix Length |R| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ifIndex | ifType | Flags | Link |QoS=5+ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|P00|P01|P02|P03|P04|P05|P06|P07|P08|P09|P10|P11|P12|P13|P14|P15|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|P16|P17|P18|P19|P20|P21|P22|P23|P24|P25|P26|P27|P28|P29|P30|P31|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|P32|P33|P34|P35|P36|P37|P38|P39|P40|P41|P42|P43|P44|P45|P46|P47|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|P48|P49|P50|P51|P52|P53|P54|P55|P56|P57|P58|P59|P60|P61|P62|P63|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|P64|P65|P66|P67|P68|P69|P70|P71|P72|P73|P74|P75|P76|P77|P78|P79|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
...
Figure 5: ATN/IPS Extended Aero Option Format
Appendix B. Prefix Length Considerations
The 64-bit boundary in IPv6 addresses [RFC7421] determines the MN
aero address format for encoding the most-significant 64 MNP bits
into the least-significant 64 bits of the prefix fe80::/64 as
discussed in Section 7.
[RFC4291] defines the link-local address format as fe80::/10,followed
by 54 unused bits, followed by the least-significant 64 bits of the
address. If the 64-bit boundary is relaxed through future standards
activity, then the 54 unused bits can be employed for extended coding
of MNPs of length /65 up to /118.
Templin & Whyman Expires June 12, 2020 [Page 21]
Internet-Draft IPv6 over AERO Interfaces December 2019
The extended coding format would continue to encode MNP bits 0-63 in
bits 64-127 of the aero address, while including MNP bits 64-117 in
bits 10-63. For example, the aero address corresponding to the MNP
2001:db8:1111:2222:3333:4444:5555::/112 would be
fe8c:ccd1:1115:5540:2001:db8:1111:2222, and would still be a valid
IPv6 link-local unicast address per [RFC4291].
Appendix C. VDL Mode 2 Considerations
ICAO Doc 9776 is the "Technical Manual for VHF Data Link Mode 2"
(VDLM2) that specifies an essential radio frequency data link service
for aircraft and ground stations in worldwide civil aviation air
traffic management. The VDLM2 link type is "multicast capable"
[RFC4861], but with considerable differences from common multicast
links such as Ethernet and IEEE 802.11.
First, the VDLM2 link data rate is only 31.5Kbps - multiple orders of
magnitude less than most modern wireless networking gear. Second,
due to the low available link bandwidth only VDLM2 ground stations
(i.e., and not aircraft) are permitted to send broadcasts, and even
so only as compact layer 2 "beacons". Third, aircraft employ the
services of ground stations by performing unicast RS/RA exchanges
upon receipt of beacons instead of listening for multicast RA
messages and/or sending multicast RS messages.
This beacon-oriented unicast RS/RA approach is necessary to conserve
the already-scarce available link bandwidth. Moreover, since the
numbers of beaconing ground stations operating within a given spatial
range must be kept as sparse as possible, it would not be feasible to
have different classes of ground stations within the same region
observing different protocols. It is therefore highly desirable that
all ground stations observe a common language of RS/RA as specified
in this document.
Appendix D. Change Log
<< RFC Editor - remove prior to publication >>
Differences from draft-templin-atn-aero-interface-07 to draft-
templin-atn-aero-interface-08:
o Removed "Classic" and "MS-enabled" link model discussion
o Added new figure for MN/AR/MSE model.
o New Section on "Detecting and responding to MSE failure".
Templin & Whyman Expires June 12, 2020 [Page 22]
Internet-Draft IPv6 over AERO Interfaces December 2019
Differences from draft-templin-atn-aero-interface-06 to draft-
templin-atn-aero-interface-07:
o Removed "nonce" field from AR option format. Applications that
require a nonce can include a standard nonce option if they want
to.
o Various editorial cleanups.
Differences from draft-templin-atn-aero-interface-05 to draft-
templin-atn-aero-interface-06:
o New Appendix C on "VDL Mode 2 Considerations"
o New Appendix D on "RS/RA Messaging as a Single Standard API"
o Various significant updates in Section 5, 10 and 12.
Differences from draft-templin-atn-aero-interface-04 to draft-
templin-atn-aero-interface-05:
o Introduced RFC6543 precedent for focusing IPv6 ND messaging to a
reserved unicast link-layer address
o Introduced new IPv6 ND option for Aero Registration
o Specification of MN-to-MSE message exchanges via the ANET access
router as a proxy
o IANA Considerations updated to include registration requests and
set interim RFC4727 option type value.
Differences from draft-templin-atn-aero-interface-03 to draft-
templin-atn-aero-interface-04:
o Removed MNP from aero option format - we already have RIOs and
PIOs, and so do not need another option type to include a Prefix.
o Clarified that the RA message response must include an aero option
to indicate to the MN that the ANET provides a MS.
o MTU interactions with link adaptation clarified.
Differences from draft-templin-atn-aero-interface-02 to draft-
templin-atn-aero-interface-03:
o Sections re-arranged to match RFC4861 structure.
Templin & Whyman Expires June 12, 2020 [Page 23]
Internet-Draft IPv6 over AERO Interfaces December 2019
o Multiple aero interfaces
o Conceptual sending algorithm
Differences from draft-templin-atn-aero-interface-01 to draft-
templin-atn-aero-interface-02:
o Removed discussion of encapsulation (out of scope)
o Simplified MTU section
o Changed to use a new IPv6 ND option (the "aero option") instead of
S/TLLAO
o Explained the nature of the interaction between the mobility
management service and the air interface
Differences from draft-templin-atn-aero-interface-00 to draft-
templin-atn-aero-interface-01:
o Updates based on list review comments on IETF 'atn' list from
4/29/2019 through 5/7/2019 (issue tracker established)
o added list of opportunities afforded by the single virtual link
model
o added discussion of encapsulation considerations to Section 6
o noted that DupAddrDetectTransmits is set to 0
o removed discussion of IPv6 ND options for prefix assertions. The
aero address already includes the MNP, and there are many good
reasons for it to continue to do so. Therefore, also including
the MNP in an IPv6 ND option would be redundant.
o Significant re-work of "Router Discovery" section.
o New Appendix B on Prefix Length considerations
First draft version (draft-templin-atn-aero-interface-00):
o Draft based on consensus decision of ICAO Working Group I Mobility
Subgroup March 22, 2019.
Templin & Whyman Expires June 12, 2020 [Page 24]
Internet-Draft IPv6 over AERO Interfaces December 2019
Authors' Addresses
Fred L. Templin (editor)
Boeing Research & Technology
P.O. Box 3707
Seattle, WA 98124
USA
Email: fltemplin@acm.org
Tony Whyman
MWA Ltd c/o Inmarsat Global Ltd
99 City Road
London EC1Y 1AX
England
Email: tony.whyman@mccallumwhyman.com
Templin & Whyman Expires June 12, 2020 [Page 25]