Path-Aware Semantic Addressing (PASA) for Low power and Lossy Networks
draft-ietf-6lo-path-aware-semantic-addressing-05
| Document | Type | Active Internet-Draft (6lo WG) | |
|---|---|---|---|
| Authors | Luigi Iannone , Guangpeng Li , Zhe Lou , Peng Liu , Rong Long , Kiran Makhijani , Pascal Thubert | ||
| Last updated | 2024-03-21 | ||
| Replaces | draft-li-6lo-path-aware-semantic-addressing | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Intended RFC status | (None) | ||
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| Additional resources | Mailing list discussion | ||
| Stream | WG state | WG Document | |
| Document shepherd | (None) | ||
| IESG | IESG state | I-D Exists | |
| Consensus boilerplate | Unknown | ||
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-ietf-6lo-path-aware-semantic-addressing-05
6lo Working Group L. Iannone, Ed.
Internet-Draft G. Li
Intended status: Standards Track D. Lou
Expires: 23 September 2024 Huawei
P. Liu
R. Long
China Mobile
K. Makhijani
Futurewei
P. Thubert
22 March 2024
Path-Aware Semantic Addressing (PASA) for Low power and Lossy Networks
draft-ietf-6lo-path-aware-semantic-addressing-05
Abstract
This document specifies a topological addressing scheme, Path-Aware
Semantic Addressing (PASA), that enables IP packet stateless
forwarding. The forwarding decision is based solely on the
destination address structure. This document focuses on carrying IP
packets across an LLN (Low power and Lossy Network), in which the
topology is static, the location of the nodes is fixed, and the
connection between the nodes is also rather stable. This
specifications describes the PASA architecture, along with PASA
address allocation, forwarding mechanism, header format design, and
IPv6 interconnection support.
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 23 September 2024.
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Copyright Notice
Copyright (c) 2024 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 include Revised BSD License text as
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provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 4
3. Definition of Terms . . . . . . . . . . . . . . . . . . . . . 4
4. Comprehensive Use Cases . . . . . . . . . . . . . . . . . . . 5
4.1. Smart Grid . . . . . . . . . . . . . . . . . . . . . . . 5
4.2. Smart Home . . . . . . . . . . . . . . . . . . . . . . . 6
4.3. Data Center Monitoring . . . . . . . . . . . . . . . . . 7
4.4. Industrial Operational Technology Networks . . . . . . . 9
5. Architectural Overview . . . . . . . . . . . . . . . . . . . 10
6. PASA Address Assignment . . . . . . . . . . . . . . . . . . . 12
6.1. Tree Address Assignment Function (TAAF) . . . . . . . . . 13
6.2. Limitation on the Number of Child Nodes . . . . . . . . . 15
6.3. PASA TAAF Addresses and IPv6 Addresses . . . . . . . . . 16
7. Forwarding in a PASA Network . . . . . . . . . . . . . . . . 17
7.1. Forwarding toward a local PASA endpoint . . . . . . . . . 17
7.2. Forwarding toward an external IPv6 address . . . . . . . 19
8. PASA-6LoRH Header . . . . . . . . . . . . . . . . . . . . . . 20
8.1. PASA-6LoRH Sequence . . . . . . . . . . . . . . . . . . . 20
8.2. PASA-6LoRH Format . . . . . . . . . . . . . . . . . . . . 20
8.3. PASA-6LoRH and LOWPAN_IPHC co-existence . . . . . . . . . 21
9. Nodes role indication . . . . . . . . . . . . . . . . . . . . 22
10. PASA Address Configuration Procedure . . . . . . . . . . . . 23
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24
11.1. Critical 6LoWPAN Routing Header Type for PASA-6LoRH . . 24
11.2. PASA Address Assignment Function . . . . . . . . . . . . 24
12. Reliability Considerations . . . . . . . . . . . . . . . . . 25
13. Security Considerations . . . . . . . . . . . . . . . . . . . 25
14. Privacy Considerations . . . . . . . . . . . . . . . . . . . 26
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 26
References . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Normative References . . . . . . . . . . . . . . . . . . . . . 26
Informative References . . . . . . . . . . . . . . . . . . . . 27
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Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 29
1. Introduction
There is an ongoing massive expansion of the network edge, driven by
the "Internet of Things" (IoT), especially over low-power links which
often, in the past, did not support IP packet transmission.
Particularly driven by the requirements stemming from Industry 4.0,
Smart Grid and Smart City deployments, more and more devices/things
are connected to the Internet. Sensors in plants/parking bays/mines/
data-centers, temperature/humidity/flash sensors in buildings/
museums, normally are located in a fixed position and are networked
by low power and lossy links even in hardwired networks. Comparing
with traditional scenarios, scalability of the (edge) network along
with lower power consumption are key technical requirements.
Moreover, large-scale Low power Lossy Networks (LLNs) are expected to
be able to carry IPv6 packets over their links, together with an
efficient access to native IPv6 domains.
The work in [SIXLOWPAN], [SIXLO], and [LPWAN] Working Groups
addresses many fundamental issues for those type of deployments,
which can be considered an instantiation of what [RFC8799] defines as
"limited domains". For instance, the 6lowpan compression ([RFC4944],
[RFC6282]) addresses the problem of IPv6 transmission over LLNs,
making it possible to interconnect IPv6-based IoT networks and the
Internet. [RFC8138] introduces a framework for implementing multi-
hop routing on an LLN using a compressed routing header, which works
also with RPL (Routing Protocol for LLNs [RFC6550]). This technique
enables the ability to forward IPv6 packets within the domain without
the need of decompression. In addition, SCHC (Generic Framework for
Static Context Header Compression and Fragmentation [RFC8724])
enables even more compression by using a common stateful static
context.
The aforementioned technologies, which leverage on the presence of a
routing protocol, are suitable in generic IoT scenarios and LLN
networks. The above technologies leverage topology discovery and
routing mechanisms, whereas there are several special-purpose
networks, where routing protocols are not deployed and the networks
are statically manageable [RFC9453] (e.g. PLC [RFC9354] or MS/TP
[RFC8163], and Industrial IoT technologies like [RS485], etc.). In
those kinds of deployments, topologies are planned in advance and
well provisioned, with sensor nodes usually in fixed locations. This
document introduces a topology-based addressing mechanism with that
allows, in the above mentioned scenarios, to avoid the use of routing
protocol in favor of a topological stateless forwarding algorithm
(see Section 4).
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This specification document leverages on the 6Lo Routing Header
(6LoRH) as defined in [RFC8138] and LOWPAN_IPHC header compression
[RFC6282]. The use of other compression techniques is out of the
scope of this document, and may be the object of separate
specifications. The proposed addressing is independent of Unique
Local Addresses [RFC4193], which has a dependency on specific link-
layer conventions [RFC6282]. It is also different from stateful
address allocation that requires all nodes to obtain addresses from a
centralized DHCP server, which leads to increased network startup
time and consumption of extra bandwidth. PASA relies on the neighbor
discovery Generic Address Assignment Option (GAAO)
[I-D.iannone-6lo-nd-gaao] in order to recursively assign addresses.
Compared to RPL-based routing [RFC6550], PASA avoids the extra
overhead of address assignment by integrating address assignment and
tree forming together. Furthermore, PASA provides much smaller
forwarding table size than storing mode RPL.
2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. Definition of Terms
PASA Root: The PASA root node is the router responsible for the
management of the whole PASA network and routing/forwarding both
internal and external traffic. It uses the Address Assignment
Function (AAF) and performs the address assignment for its
children. The root node functions as gateway between the PASA
domain and the Internet, acting as what [RFC8505] names 6LBR
(6LowPAN Border Router).
PASA Router: A PASA Router is an internal node, different from the
PASA Root, acting as a router, hence as what [RFC8505] names 6LR
(6LowPAN Router). Similar to the PASA Root, it uses the address
Assignment Function (AAF) and performs the address assignment for
its children.
PASA Host: A PASA Host is a node with no children (i.e., a leaf), it
is what [RFC8505] names 6LN (6LowPAN Node). This node does not
perform the address Assignment Function. It merely requests an
address to its selected parent.
Address Assignment Function (AAF): As defined in
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[I-D.iannone-6lo-nd-gaao]. Used by PASA Root and PASA Routers to
assign addresses to their children.
4. Comprehensive Use Cases
As mentioned in Section 1, the [RFC9453] provides some 6lo use cases
with wired connectivity, tree-based topology, and no mobility
requirement (cf. Table 2 of [RFC9453]). These use cases, where PASA
can be used, include Smart Grid, Smart Building, etc. The PASA
solution utilizes stable and static topology information to allocate
addresses for nodes, which enables stateless forwarding. It saves
overhead of messages triggered by routing protocols and reduces RAM
footprint for routing table storage. Thus, it will reduce the
overall energy consumption. The PASA forwarding logic is simple,
enabling the solution being ported onto very constrained nodes. In
the following, a few use cases are discussed in-depth to demo the
applicability of the PASA solution.
4.1. Smart Grid
A typical smart grid network topology whose purpose is to distribute
electricity to homes in a residential area consists of Smart Circuit
Breaker (SCB), Phase Change Switch (PCS), Cable Branch Box (CBB) and
Power Distribution Cabinet (PDC), as shown in Figure 1. The PDC
containing a few SCBs, phase compensation units, sensors and
actuators is responsible for the power distribution towards CBB. The
CBB containing SCBs and sensors further distributes the power to PCS
and eventually to the home. The smart grid power distribution
network forms a typical tree topology, where the PLC communication
technology is used to collect data (meter numbers, phases, etc.) and
perform control/management of the overall system.
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+---Voltage Transformer
|
+----------+-----------+
| PDC +-+-+ | SCB:Smart Circuit Breaker
| |SCB| | PCS:Phase Change Switch
| +-+-+ | CBB:Cable Branch Box
| +------+-------+ | PDC:Power Distribution
| +-+-+ +-+-+ +-+-+ | Cabinet
| |SCB| |SCB| |SCB| |
| +-+-+ +-+-+ +-+-+ |
+-+---------+-------+--+
/ | +-------------------------+
/ +----------+ |
/ | |
+-----------+----------+ +-----------+----------+ |
| CBB | | | CBB | | Chargers |
| +-------+------+ | | +-------+------+ | ++ |
| +-+-+ +-+-+ +-+-+ | | +-+-+ +-+-+ +-+-+ | ||---+
| |SCB| |SCB| |SCB| | | |SCB| |SCB| |SCB| | ++ |
| +-+-+ +-+-+ +-+-+ | | +-+-+ +-+-+ +-+-+ | ++ |
+---+-------+------+---+ +---+-------+------+---+ ||---+
| | | | | | ++ |
| | | +-++ +-++ +--++
+-+-+ +-+-+ +-+-+ +--+ +--+ +--+|
|PCS| |PCS| |PCS| Monitors for end |
+---+ +---+ +---+ |
+CBB-------+----------+
| +-------+-------+ |
|+-+-+ +-+-+ +-+-+|
||SCB| |SCB| |SCB||
|+---+ +---+ +---+|
+---------------------+
Figure 1: Example of topology of a smart grid.
4.2. Smart Home
Smart home or home domotica is another example, as shown in Figure 2,
where a PLC router (PLC-R) in each room is used to connect home
appliances (boiler, dishwasher, fridge, etc.) and devices (lights,
doorbell, sound boxes, etc.) to home network and sometimes to the
Internet. The network can be further extended if a switch/router is
connected. As it leverages the power line distribution, the network
forms a typical tree topology as well. Some observations and
considerations are:
* Usually a Home Gateway bridges the smart home to the Internet.
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* The Home Gateway, the PLC routers, and most of the home appliance
are fixed in different locations. They rarely move after setup.
* The smart home automation requires any to any communication.
* Lightweight communication stack with limited MCU and RAM
consumption is desired.
/----------\
| Internet |
\-----+----/
|
+------+------+
| Home Gateway|
+------+------+
|
+--------------+----------------------+
+------------------|----++--------|-----------++---------|---------+
| | || | || | Kitchen|
| Living +--+---+|| +---+--+ Bedroom|| +---+--+ |
| Room |PLC-R ||| |PLC-R | || |PLC-R | |
| +---+--+|| +--+---+ || +---+--+ |
| | || | || | |
| +-----+-----+----+ || +----+--+------+ || +------+------+ |
| | | | | || | | | || | | | |
| | | | | || | | | || | | | |
| / \ / \ / \ / \ || / \ / \ / \ || / \ / \ / \ |
|| | | | | || | ||| | | | | |||| | | | | ||
| \_/ \_/ \_/ \_/ || \_/ \_/ \_/ || \_/ \_/ \_/ |
| Switches Door ||Strip Voice Sound||Boiler Fridge Dish|
|Light door bell ||Light Command Boxes|| Washer|
+-----------------------+| Device |+-------------------+
+--------------------+
Figure 2: Example of topology of a smart home.
4.3. Data Center Monitoring
Data centers represent a significant infrastructure, which requires
numerous safeguards in place to protect hardware assets against
cyber-attacks. Besides, environmental issues such as extreme
temperature, high humidity, water leakage and high dust concentration
can cause device failures as well. Therefore, it is critical to
deploy sensors to monitor environmental factors to make sure data
center is running efficiently.
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The network topology of the data center supervision system is
hierarchical, and mainly consists of Network Management System (NMS),
Supervision Center (SC), Field Supervision Unit (FSU), dumb and smart
devices, as shown inFigure 3. The smart devices refer to smart air
conditioner, smart door lock and power equipment with embedded
sensors to report their working status. The dumb devices refer to
the many devices without embedded sensors, which require additional
sensors to collect and update information of environment.
NMS:Network Management System /----\ //------\\
SC :Supervisor Center / \ || ||
FSU:Field Supervisor Unit | SC +---------+| NMS ||
\ / \\------//
\----/
/ \
/ \
/----\ \
/ \ \
| SC | \
\ / \
\--X-/ \
/ \ \
/ \ \
/ \ \
/-/-\ /-\-\ /---\
| FSU | | FSU | | FSU |
\-X-/ \-X-/ \-X-/
/ \ / \ / \
/ \ / \ / \
+---+ /--\ +---+ /--\ +---+ /--\
| | | | | | | | | | | |
| | | | | | | | | | | |
+---+ \--/ +---+ \--/ +---+ \--/
Smart Dumb Smart Dumb Smart Dumb
Device Device Device Device Device Device
Figure 3: Example of topology of a Data Center Power &
Environment Supervisor System.
Both dumb and smart devices are connected to the FSU, which monitors
and connects all devices of the whole floor. The number of ports on
FSU is limited, where one FSU usually contains 8 analog input ports,
16 digital input ports, 4 digital output ports, 8 RS485 ports and 4
IP ports. The terminal devices report working status and
environmental information to FSUs every 3 second. If values that are
abnormal or above a certain threshold are detected, the FSU reports
it to the SC immediately and keeps on reporting it in real-time for
next couple of hours, until the manager issues new commands. The SC
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can be constructed as required. The FSU reports to the local SC
first, then relay the message to the central SC for data analyzing
and management.
In this scenario, deployed devices (usually 600-1000 sensors per
floor), due to the shortage of ports and limitation of voltage
supply, use additional power supply or batteries. Since battery
replacement and maintenance is costly, it is desired to have low
energy consumption for longer service life. We should not only
reduce the power consumption on the device level, but also on the
data transmission level. The data transmission also causes huge
power consumption, which can be reduced by leveraging low power
transmission protocol. The FSU connects to sensors with wired
technology, such as AI/DI/RS232/RS485/single pair Ethernet. Multiple
FSUs will connect to hierarchical supervision centers and then make
data communication with supervision platform by IPv6.
4.4. Industrial Operational Technology Networks
The Operational Technology (OT) networks are not pure IP networks.
Shop floors deploy fieldbus protocols such as Modbus, Profinet/IP,
BacNET, CAN etc. for process control using field devices (sensors and
actuators). To improve automation, Industry 4.0 is looking at means
to integrate process control in OT domain with the applications
residing in IPv6 domains (the enterprise networks). This leads to
three primary requirements:
* Continuity in connectivity between the end devices and
applications, both of which follow different address structures.
* The OT networks are traditionally designed as layer-2 and OT
operators are not expected to deploy or maintain IT style routing
infrastructure, hence auto-configuration mechanisms for device
addresses and reachability are preferred.
* The OT networks are also delay-intolerant; therefore, compact and
lean message structures are favored over encapsulations to
minimize processing and translation overheads.
Using PASA, as described in details later in this document, the
following applies:
* The OT network is represented as PASA domain, interfacing with
native IPv6 applications, e.g., Human-Machine Interface (HMI),
Manufacturing Execution System (MES). In general on shop floors,
devices are at fixed locations or cell-sites and the PASA tree
hierarchy described in Figure 4 applies suitably.
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* In an idealized PASA-based OT domain, a leaf-node could be a field
device (sensor or actuator) that always connects to PLC serving as
last node forwarding traffic to/from the leaves, i.e. sensors and
actuators.
* The border node may be at the root for any IT application
requirement. Then the packet communication inside the PASA domain
will strictly follow PASA structure whereas communications with
IPv6 domain networks will use the Border router for translations.
IPV6 +------+------------+
+---------------| HMI/MES/FW/Gateway|----------+
| PASA +------+------------+ | PASA
| |
+----|------------------+ |
| +--+---+ | |
| |PLC |--------------+-----------+ |
| +---+--+ | | +--------+---------+
| | profinet | +--------+----+ | | |
| | | | +-----+ | | +--+--+ |
| +-----+-----+----+ | | | PLC | | | | PLC | |
| | | | | | | +--+--+ | | +--+--+ |
| | | | | | | | | | | |
| /+\ /+\ /+\ /+\ | | profi|bus | | | modbus |
| \-/ \-/ \-/ \-/ | | +---+---+ | | +-----+------+ |
| sensors/actuators | | | | | | | | | |
| cell-site-A | | | | | | | | | |
+-----------------------+ | /+\ /+\ | | /+\ /+\ /+\ |
| \-/ \-/ | | \-/ \-/ \-/ |
| | | sensors/actuators|
| cell site B | | cell site C |
+-------------+ +------------------+
Figure 4: Example of an Industrial Operational Technology Network
topology.
5. Architectural Overview
Path-Aware Semantic Addressing (PASA) is an efficient topology-based
network layer address assignment and packet forwarding mechanism.
Each PASA node is aware of its own IPv6 address, constructed by an
IPv6 prefix and the PASA itself (see Section 6.3). Inside the PASA
domain, nodes communicate with each other by using PASA addresses.
It is a smaller addressing space compared to the huge /64 IPv6
addressing space, but enabling stateless forwarding using the PASA-
6LoRH header (see Section 8). When IPv6 communication occurs between
nodes inside the PASA domain and external IPv6 nodes, the border
router, which plays as well the role of "root" in the addressing
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tree, performs packet decompression (as per Section 7.2 and
[RFC6282]). Note that packets destined outside the PASA domain do
not need to use the PASA-6LoRh header, since they can be easily
forwarded to the root following the default gateway (see
Section 7.2). However, an IP-in-IP header, as for [RFC8138], is used
to avoid compression/decompression at each hop. The architecture of
PASA network is shown in Figure 5.
/|\ Internet (IPv6)
| --------+--------
IPv6 Domain | |
| |
| +-------+-------+
---------------------------- | Border Router |
| | (PASA Root) |
| +---------------+
|
| O
|
| O O O
| O O
| O O
PASA Domain | O
| O O O O O O
| O
| O O
| O
| O
|
\|/ Low-Power and Lossy Network
Figure 5: The architecture of general PASA networks.
In the PASA network, there are 3 types of nodes, the PASA Root, the
PASA Router and the PASA Host (See Section 3).
PASA Root: Since the root node is responsible for the whole PASA
network and acts as gateway for external traffic, it also operates
the translation between LOWPAN_IPHC and IPv6 formats (cf.
Section 7). It assigns addresses to its children using the AAF.
There is typically one root node in the PASA network.
PASA Router: A PASA Router is basically the root of a subtree and as
such it is a router forwarding traffic between its parent and its
children according to the addressing. When handling a packet, if
the destination is in one of its subtrees, it forwards the packet
to the corresponding child, otherwise it simply sends it to its
parent.
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PASA Host: A PASA Host is a node with no children, hence a leaf. It
operates as an host, since it is either destination or source of
every packet it handles. If it is the source of packets, it
simply sends the packets to its parent.
The address assignment described in this document relies on the
Generic Address Assignment mechanism described in
[I-D.iannone-6lo-nd-gaao] (see Section 10). The use of multicast
messages are limited as for [RFC8505]; no new multicast requirements
are introduced. The PASA Root and PASA Routers have to act as IPv6
ND Registrars. Each node acquiring a PASA address firstly needs to
select a parent node by choosing among the nodes that replied with a
Router Advertisement (RA) after an initial Router Solicitation (RS).
A "first come first served" selection policy is sufficient. Then it
asks for a PASA address. In its reply the parent will propose an
address according to the node's role, which is indicated in the D-bit
of the GAAO message (see Section 10). The proposed address is
algorithmically calculated using the PASA Address Assignment Function
(AAF). The address assigner is the parent of the node and becomes as
well the default gateway from a routing perspective (used for
destinations that are not in the local PASA domain). The node will
then ignore replies from other 6LR neighbors.
The overall design objective is centered on reducing the size of
routing/forwarding tables by using a topological addressing scheme.
PASA reduces the amount of information synchronization messages, so
it actually reduces computation complexity during packets parsing and
forwarding. As such, PASA may save communication energy in an IoT
LLN network.
There are two distinct PASA features that allow PASA to be efficient,
namely:
1. PASA Address Assignment Function (see Section 6),
2. Stateless Forwarding (see Section 7),
these features are separately discussed in the following.
6. PASA Address Assignment
The basic rules for the any assignment function include:
* Routers (Root and routers) run an AAF to generate its children's
addresses.
* All nodes run the same AAF in the same network instance.
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* The maximum length of the PASA address MUST NOT exceed 64 bits.
6.1. Tree Address Assignment Function (TAAF)
In the Tree Address Assignment Function the address of each node is
prefixed by the address of their parent, starting from the root.
Normally, the root role is assigned to the border router when the LLN
bootstraps. An example of a possible result of a PASA deployment is
shown in Figure 6.
root +--------------------------+
1 | append more bits to form |
O ----+ | brother's address |
/ | \ \ +--------------------------+
/ | \ \
/ | \ \
+-------------+ / | \ \
| PASA Router | 10 / 11 110\ \ 111
+-------------+ O - O O O
/ |\ \ | \
/ | \ \ | \
/ | \ \ O O
/ | \ \
100/ 1010| 101 1011 +--------------+
O O O O |Prefix is '10'|
/| /| +--------------+
/ | / |
O O O O +-----------+
1001 10011 10101 101011 | PASA Host |
+-----------+
Figure 6: An example of PASA Tree Addresses Assignment Function.
Every router node stores and maintain two indexes, one for the
children that are also routers and one for the children that are
hosts (starting at 0 for the first child in each role). The first
index is named 'r', as of routers, and the second 'h' as for hosts.
The '+' symbol indicates a concatenation operation. The b()
operation indicates the binary string of '1' with length equal to its
argument, for instance b(3) returns '111'. The allocation function
AAF(role,i) used in this document is defined as:
AAF(role, r, h) = 'address of the node performing the function'
+ (role == host? b(h++):b(r++))
+ (role == host?'1':'0')
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Where 'r' and 'h' are the indexes of respectively the routers and the
hosts at this layer (starting at 0). Taking the example of the
topology in Figure 6, the proposed AAF works as follows.
At the top level, the root has 4 children, two are routers and the
other two are hosts. Starting from the left most node and moving to
the right, the root node applies the AAF as follows:
* For the first child, which is a router:
- A('router', 0, 0) = '1'(root address) + b(0) + '0' = '1' + '' +
'0' = 10
- Index 'r' is increased by one and is now equal 1 (r=1)
* For the second child, which is a host:
- A('host', 1, 0) = '1'(root address) + b(0) + '1' = '1' + '' +
'1' = 11
- Index 'h' is increased by one and is now equal 1 (h=1)
* For the third child, which is a router:
- A('router', 1, 1) = '1'(root address) + b(1) + '0' = '1' + '1'
+ '0' = 110
- Index 'r' is increased by one and is now equal 2 (r=2)
* For the fourth child, which is a host:
- A('host', 2, 1) = '1'(root address) + b(1) + '1' = '1' + '1' +
'1' = 111
- Index 'h' is increased by one and is now equal 2 (h=2)
The first level addresses have now been assigned. Let's now have a
look to how the node 10 (the first router child of the root) applies
the same Allocation Function. Note that node 10 will use its own 'r'
and 'h' indexes initialized to 0. Starting again from the left most
node, node 10 applies the AAF as follows:
* For the first child, which is a router:
- A('router', 0, 0) = '10'(node address) + b(0) + '0' = '10' + ''
+ '0' = 100
- Index 'r' is increased by one and is now equal 1 (r=1)
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* For the second child, which is a host:
- A('host', 1, 0) = '10'(node address) + b(0) + '1' = '10' + '' +
'1' = 101
- Index 'h' is increased by one and is now equal 1 (h=1)
* For the third child, which is a router:
- A('router', 1, 1) = '10'(node address) + b(1) + '0' = '10' +
'1' + '0' = 1010
- Index 'r' is increased by one and is now equal 2 (r=2)
* For the fourth child, which is a host:
- A('host', 2, 1) = '10'(node address) + b(1) + '1' = '10' + '1'
+ '1' = 1011
- Index 'h' is increased by one and is now equal 2 (h=2)
Note how the children of the same parent all have the same prefix (10
in this example) and such parent will be their default gateway. The
proposed AAF algorithmically assigns addresses to the different nodes
without the need to know the topology in advance. However, once the
addresses have been assigned, the proposed AAF encodes the topology
in the addresses themselves, which enables stateless forwarding, but
if used beyond the PASA domain it exposes the internal topology. See
Section 14 for further details. TAAF creates unique addresses for
each node, as such there is no need to perform Duplicate Address
Detection (DAD) procedure.
6.2. Limitation on the Number of Child Nodes
The maximum number of children of a node is determined by the
specific AAF used. IEEE 802.15.5 has explored the use of a per-
branch setup, which, however, incurs scalability problems [LEE10].
PASA allocation design is more flexible and extensible than the one
proposed in IEEE 802.15.5.
The AAF used as example in this document does not need any specific
setup network by network, though it is still limited by the maximum
length of addresses. The largest address of the network will depend
on the actual topology. Indeed, the maximum length of an address
with the proposed AAF grows linearly at each level of the tree with
the number of siblings from the same parent. Let's take again the
example in Figure 6 and let's assume that the children of node 10 are
all hosts, for the largest address we need 2 bits to encode the
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parent node prefix (10 in this case) to which we need to add a number
of '1' equal to the value of the h index which is the number of hosts
minus one (because the first host has index 0), in this case since
there are 4 hosts, the index value is 3 and we add the '111' string,
hence the address length would be 6 (2 for the prefix, 3 to encode
the 4th host address, and one for the final 1 the ends all hosts'
addresses). In a more formal way the maximum address length at each
level can be calculated as:
Max_Length = length(Parent address) +
length(b(max(r,h)))
+ 1
Where 'r' and 'h' are the indexes counting respectively the routers
and the hosts at this level.
Note that Max_length can never be more than 64 bits, the IID part of
an IPv6 address. This means that, with the proposed AAF, each PASA
Router with an address of length N bits, can have maximum "64 - N -
1" children of the same type. This is because the construction of
the addresses. Each new child's address starts with the address of
the parent, which is N bits, and ends with one bits indicating the
role (either PASA Router or PASA Host), and the whole length can be
at maximum 64 bits, the IID of an IPv6 address.
For the special case of the parent connecting to huge amount of
children, a variant of the proposed AAF (or a new different AAF) can
be designed to fulfill the requirement and optimize the address
allocation (as previously described).
6.3. PASA TAAF Addresses and IPv6 Addresses
Obtaining a full IPv6 address from a PASA address is pretty
straightforward. First the PASA address is concatenated to the
configured IPv6 prefix. Since the length of the PASA address is
smaller than or equal to 64 bits (the interface ID length in IPv6),
the node needs to pad it with zeros ('0') used as most significant
bits. The full IPv6 address will look like: IPv6 prefix +
"000...000" + PASA (or in IPv6 notation <IPv6 Prefix>::<PASA>). This
is equivalent of doing a coalescence operation as described in
[RFC8138] (see as well Section 8.3). The PASA address is assigned by
the root or router as previously described.
PASA does not prevent the normal checksum calculation for the
transport layer (namely TCP or UDP) or IPSec encapsulation. Indeed,
any PASA node is aware of its full IP address, which can be used for
the calculation.
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7. Forwarding in a PASA Network
Internal and external communications in a PASA network work slightly
differently. For internal communications, among PASA endpoints,
packets carry PASA destination addresses in the PASA-6LoRH Header
(defined in Section 8). For external communications, the root is
responsible to perform the translation between PASA addresses and
IPv6 addresses. For instance, for a packet entering into the PASA
domain, the root will extract the PASA of the destination from the
suffix of the IPv6 address, reducing it to the smallest set of quad
that can contain the address, by removing all leading octets that are
just equal to 0x00. Then the root will compress the original IPv6
and transport headers according to [RFC6282] and prepend the PASA-
6LoRH header according to [RFC8138].
The following details the forwarding operations for both internal and
external communication. The intra-network forwarding decision
depends on the specific AAF used. Here we will use the AAF
previously introduced (see Section 6) to illustrate the forwarding
procedure.
7.1. Forwarding toward a local PASA endpoint
Inner-domain packets carry a PASA destination address in the PASA-
6LoRH header. More specifically the destination address field is the
address of another node in the same PASA domain. As such a PASA node
receiving a packet performs the following sequence of actions (also
see Figure 7):
1. Get destination address from the PASA-6LoRH (abbreviated to DA)
and the current node's address (abbreviated to CA). Go to step
2.
2. If length of DA is smaller than length of CA, send the packet to
parent node and exit. Otherwise, go to step 3.
3. If length of DA is equal to length of CA, go to step 4.
Otherwise, go to step 5.
4. If DA and CA are the same, the packet arrived at destination,
exit. Otherwise, send the packet to parent node and exit.
5. Check whether CA is equal to the prefix of DA. If yes, go to
step 6. Otherwise, send the packet to parent node and exit.
6. Calculate which child is the next hop address and forward packet
to it. With the AAF proposed in this document, such operation is
reduced to reading the DA's bits starting from the position
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equals to the length of CA, then skip all '1' until the first '0'
or the last bit of DA. The sub-string obtained in such a way is
the address of direct child of current node.
7. If any exception happens in the above steps, drop the packet and
send an ICMPv6 "No Route to Host" notification back to the source
address.
/-\ DA:Destination Address
|***| CA:Current Node's Address
\_/
|
+--------+--------+
|Parse DA from pkt|
+--------+--------+
|
\|/
+-------+------+
/ \ yes
| Len(DA)<Len(CA)? |-------------------------------+
\ / |
+-------+------+ |
| no |
\|/ |
+-------+------+ +--------------+ |
/ \ yes / \ no |
| Len(DA)=Len(CA)? |------>| CA == DA ? |--->+
\ / \ / |
+-------+------+ +-------+------+ |
| no | yes |
\|/ /-\ |
+-------+------+ |***| |
/ \ no \_/ |
| CA==PrefixOf(DA)?|------------------------------>+
\ / |
+-------+------+ |
| yes |
\|/ \|/
+---------+---------+ +---------+---------+
| Calculate next-hop| | Forward to Parent |
| & | +---------+---------+
| Forward | |
+---------+---------+ |
|<---------------------------------------+
\|/
/-\
|***|
\_/
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Figure 7: Flow Chart of Internal Forwarding Procedure
In the case of packets arriving from the Internet (external IPv6
domain toward the local PASA domain) header adaptation operation is
performed by the root node. It first compresses the IPv6 header
according to [RFC6282] and also described in Section 8.3. The root
builds the PASA address of the destination by removing the prefix and
the leading '0's octets of the suffix of the destination address.
Then the root creates the inner-domain packet with the PASA-6LoRH
header. It uses the PASA address as destination, so to route the
packet as described above to the destination node.
7.2. Forwarding toward an external IPv6 address
When the packet is destined to an external IPv6 address, it is an
outer-domain packet. In this case there is no need to use the PASA-
6LoRH encapsulation. Indeed, since each node has a default gateway
entry in the routing table, namely its parent, all PASA nodes (except
root) just send packets that are destined outside the local domain to
their parent. Eventually all packets will reach the root node, which
acts as border gateway.
When the network forwarding operation are based on [RFC8138], the
source node encapsulates the LOWPAN_IPHC packet with the IP-in-IP
6LoRH Header defined in Section 7 of [RFC8138]. Where the
encapsulator address is always the source address in the LOWPAN_IPHC
header and the destination is always implicitly the root node. The
latter will decapsulate and decompress the packet. Hence, according
to [RFC8138] the IP-in-IP 6LoRH will have the form depicted in
Figure 8.
0 1 2
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|1|0|1| Length | 6LoRH Type 6 | Hop Limit |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 8: IP-in-IP 6LoRH in a PASA domain.
Where the Length field is set to 1 to indicate that only the Hop
Limit field is present. Such a header is positioned before
LOWPAN_IPHC as shown in Figure 9.
+-----------+----....----+--------...------+----...----+
| 11110001 | IP-in-IP | LOWPAN_IPHC | Payload |
| Page 1 | 6LoRH | | |
+-----------+----....----+--------...------+----...----+
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Figure 9: A LowPAN encapsulated IPv6 header compressed packet
with IP-in-IP and LOWPAN_IPHC headers.
8. PASA-6LoRH Header
PASA encodes path information into addresses to enable stateless
forwarding. Such operation can be performed without touching the
stateful forwarding procedure (based on the presence of a routing
protocol like RPL), aka without modifying the 6LowPAN architecture,
rather leveraging on mechanism already defined. In particular, by
using the 6LowPAN Routing Header in Page 1, defined in [RFC8138], it
is possible to define a new Critical 6LowPAN Routing Header Type,
named PASA-6LoRH, that will be used by nodes to perform stateless
PASA forwarding as described in Section 7.
8.1. PASA-6LoRH Sequence
The extension octets typical sequence for a compressed 6LowPAN packet
with PASA Routing Header is shown in Figure 10, following the
specification of [RFC8138].
+-----------+----....----+--------...------+----...----+
| 11110001 | PASA-6LoRH | LOWPAN_IPHC | Payload |
| Page 1 | Type 8 | | |
| |(suggested) | | |
+-----------+----....----+--------...------+----...----+
Figure 10: A lowPAN encapsulated IPv6 header compressed packet
with PASA-6LoRH and LOWPAN_IPHC headers.
Where:
* PASA-6LoRH: is the PASA specific extension. See Section 8.2 for
details.
* LOWPAN_IPHC: IPv6 compressed header according to [RFC6282].
These two fields are followed by the packet payload.
All nodes of a PASA domain MUST recognize the PASA critical 6LoWPAN
Routing Header and be able to handle the packets according to these
specifications. Otherwise, packets can be dropped, hence disrupting
communications.
8.2. PASA-6LoRH Format
The format of the PASA-6LoRH header, is shown in Figure 11.
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0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
| 1 | 0 | 0 | Rsvd | Size | 6LoRH Type |
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
| Octet 1 | Octet 2 |
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
~ ... ~
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
| Octet N-1 | Octet N |
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
Where N = Size + 1, and 6LoRH Type = PASA
Figure 11: The PASA 6Lo Routing Header format.
Where:
* Reserved (Rsvd): Reserved for future use. It MUST be initialized
to zero by the sender and MUST be ignored by the receiver.
* Size: indicates the length of the PASA address in octets. The
length N equals Size plus 1, which indicates that the length of
the PASA address in PASA-6LoRH is at least 1 octet and no more
than 8 octets.
* Octet 1 .. Octet N: the PASA destination address used for
forwarding purposes. See Section 7 for detailed forwarding
operation. PASA addresses are aligned on the least significant
bits. For instance, to encode the address b1011, which is the
address of a host node since it terminates with '1', the
corresponding octet would be b00001011 (or in hexadecimal: 0x0B).
8.3. PASA-6LoRH and LOWPAN_IPHC co-existence
In a PASA domain every node has to use PASA and being able to
compress/uncompress PASA addresses according to this specification.
The reference prefix of the PASA domain represents a context that can
be used to compress addresses in accordance to [RFC6282] and
decompress using the context and the coalescence procedure in
[RFC8138]. As such the simplest mode of co-existence of PASA-6LoRH
with LOWPAN_IPHC is to use stateful address compression in the
LOWPAN_IPHC header using the PASA context, then the PASA engine can
just read the destination address from the LOWPAN_IPHC header,
encoding it in the PASA_6LoRH header according to format previously
described in Section 8.2. However, this mode of operation is sub-
optimal because PASA-6LoRH already includes the destination address,
hence, it can be completely elided from the LOWPAN_IPHC header.
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For nodes sending packets, the first step is to create a compressed
packet using [RFC6282], where the source PASA address is statefully
compressed using the context and the destination PASA address
statefully completely elided. The destination address is then
encoded in the PASA-6LoRH in its shorter form.
In case where the destination address is an address outside the PASA
domain, there is not need to use the the PASA-6LoRH header, since the
packet just need to follow the default route until it reaches the
root node (more details in Section 7.2).
The root node, when relaying a packet coming from outside the PASA
domain, compresses the source address in the LOWPAN_IPHC header
according to [RFC6282] specifications.
The opposite operations need to be performed on the receiving node.
Since the destination address is completely elided in LOWPAN_IPHC the
IID is obtained by its encapsulation, in this case the PASA-6LoRH.
The full destination address, including the IID, can be obtained via
a coalescence operation with the PASA prefix in the context as
described in Section 4.3.1 of [RFC8138]. The source address is
handled as defined in [RFC6282]. As an example, let's assume that
the PASA IPv6 prefix is 2001:db8::/64, as for [RFC8138] the reference
address will be 2001:db8:0:0. Let the PASA address in the PASA-6LoRH
header be b111110, which in hexadecimal is 0x3E, then the complete
IPv6 address is:
2001:db8:0:0:0:0:0:0 Reference address
3E Compressed address
2001:db8:0:0:0:0:0:3E Coalesced address
In compact notation the address is: 2001:db8::3E.
9. Nodes role indication
PASA Routers and Hosts roles can be assigned similarly to IEEE
802.15.4, which distinguishes between Full-Function Devices (FFD) and
Reduced Function Devices (RFD) (cf., [ZigBee]). Such a role is
notified using the 6LowPAN Capability Indication Option (6CIO) as
defined in [RFC7400] and [RFC8505]. In particular, a PASA Root will
set the B-bit to indicate that it is a border router, a PASA Router,
will set the L-bit to indicate it is a router. Nodes not setting
both B and L bits are considered PASA Nodes.
Note that since PASA Routers MUST act as IPv6 ND Registrars the E-bit
of the 6CIO MUST be set as well.
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10. PASA Address Configuration Procedure
PASA address configuration leverages on the Generic Address
Assignment Option [I-D.iannone-6lo-nd-gaao]. When a PASA node
bootstraps, it typically does multicast a Routing Solicitation(RS)
and receives one or more unicast Routing Advertisements (RA) messages
from potential parents. The node can choose a parent on a "first
come first served" basis and send a Neighbor Solicitation (NS) with a
GAAO message to request an address to the selected parent (see
{FIG:GAAOReq} for an example of such option).
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 | Status/PfxLen | Opaque |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|C|F| P | I |Rsd| PASA TAAF | Assignment Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
... Registration Ownership Verifier (ROVR) ...
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 12: NS GAAO option example.
The requester MUST indicate its role as indicated in {SEC:role}. If
the node acts as a PASA Router it means that the address will be
further delegated. Otherwise, if the node acts as a PASA Host, the
address will not be further delegated. The parent, acting as IPv6 ND
Registrar will process the received GAAO message and act according to
[I-D.iannone-6lo-nd-gaao], and the corresponding GAAO message for the
NA packet is generated. The NA message will carry the GAAO message
with the AAF filed set to the PASA TAAF value (See Section 11). The
C-bit of the GAAO message MUST be set in order to request
confirmation of address usage through explicit registration. The
returning GAAO message will carry as well the PASA address that the
parent assigns to its child using the procedures described in
Section 6. The PASA address is appended to the GAAO message (see
{FIG:GAAORep}).
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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 | PfxLen | Opaque |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|C|F| P | I |Rsd| PASA TAAF | Assignment Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
... Registration Ownership Verifier (ROVR) ...
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Address/Prefix |
| (128 bits) |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 13: NA GAAO option example.
11. IANA Considerations
This section provides guidance to the Internet Assigned Numbers
Authority (IANA) regarding registration of values related to the PASA
specification, in accordance with BCP 26 [RFC8126].
11.1. Critical 6LoWPAN Routing Header Type for PASA-6LoRH
This document requires IANA to assign one value of the "Critical
6LoWPAN Routing Header Type" registry, to be used according to the
specification in this document, as shown in Table 1.
+===============+=============+=================+
| Value | Description | Reference |
+===============+=============+=================+
| 8 (suggested) | PASA-6LoRH | [This Document] |
+---------------+-------------+-----------------+
Table 1: Critical 6LoWPAN Routing Header Type
for PASA
11.2. PASA Address Assignment Function
This document requires IANA to assign one value of the sub registry
"Address Assignment Function" part of the "Generic Address Assignment
Option Parameters" registry, as shown in Table 2 and to be used
according to the specification in this document.
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+==================+=====================+===========+
| Value | AAF Name | Reference |
+==================+=====================+===========+
| 0x01 (suggested) | PASA Tree Address | [This |
| | Allocation Function | Document] |
+------------------+---------------------+-----------+
Table 2: PASA TAAF.
12. Reliability Considerations
Because PASA uses algorithmically generated addresses based on the
network topology, nodes do not generate and store forwarding table
entries in the normal case. One of the potential issues is the risk
of renumbering of addresses in case of topology changes. Because of
the applicability domain of PASA, the common case of topology change
is known in advance and can be planned, so to reduce disruption due
to renumbering. Another case is temporary link failures, where the
underlying technology is still able to provide connectivity through
alternative links, which is strictly related to the underlying
technology, the network topology, the deployed redundancy, and the
expected reliability.
More complex reliability scenarios and alternative solutions are
beyond the scope of this document, which is focused only on the
address allocation framework and stateless forwarding. Furthermore,
specific reliability solutions can depend as well on the specific
Address Assignment Function used (different from the one presented in
this document). Reliability is discussed in more details in
[I-D.li-6lo-pasa-reliability].
13. Security Considerations
Communication in a PASA domain is based on [RFC4944], [RFC6282], and
[RFC8138], hence, the security considerations of those specifications
apply here as well.
This document re-uses mechanism defined in [RFC8505] and
[I-D.iannone-6lo-nd-gaao], as such the security considerations of
both documents apply to this specification. In particular, the link
layer SHOULD provide sufficient protection to prevent potential
attacks. Recommendations listed in Section 7 of [RFC8505] SHOULD be
applied as well to this specification.
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As discussed in Section 6.2, depending on the AAF in use, the number
of available addresses may encounter some limitation. A rouge node
may leverage on this knowledge to carry out address exhaustion
attacks by impersonating different nodes and performing multiple
registrations to specific PASA-Routers.
14. Privacy Considerations
Depending on the AAF, the algorithmically built addresses may reveal
topology information outside the PASA domain. In particular the Tree
Assignment Function (TAAF) proposed in this specification reveals the
path between the root and a node. For instance, let us take the
example of the address 2001:db8::2B/64. Knowing that this address
belongs to a PASA domain using the AAF of this specification implies
that the PASA address is 0x2B, which in binary form is b101011. The
trailing bit 1 exposes the fact that this is a PASA Host, whose
parent has the address 1010, meaning a PASA Router, whose parent is
10 (just looking at the preceding 0, cf. Section 6), a PASA Router
directly connected to the root. So this leads to the path: 1 -> 10
-> 1010 -> 101011. This example is buildbased on the topology in
Figure 6. In deployments where the domain is directly connected it
is advisable to avoid expose the inner topology to the open Internet.
Acknowledgements
This document received many comments and help from community people.
Erik Kline, Tommaso Pecorella, Esko Dijk, Dominique Barthel, Adnan
Rashid, Michael Richardson, Brian Carpenter, did provide technical
comments for this document. The authors would like to thank all of
them.
References
Normative References
[I-D.iannone-6lo-nd-gaao]
Iannone, L. and Z. Lou, "Generic Address Assignment Option
for 6LowPAN Neighbor Discovery", Work in Progress,
Internet-Draft, draft-iannone-6lo-nd-gaao-02, 1 March
2024, <https://datatracker.ietf.org/doc/html/draft-
iannone-6lo-nd-gaao-02>.
[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/rfc/rfc2119>.
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[RFC4944] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler,
"Transmission of IPv6 Packets over IEEE 802.15.4
Networks", RFC 4944, DOI 10.17487/RFC4944, September 2007,
<https://www.rfc-editor.org/rfc/rfc4944>.
[RFC6282] Hui, J., Ed. and P. Thubert, "Compression Format for IPv6
Datagrams over IEEE 802.15.4-Based Networks", RFC 6282,
DOI 10.17487/RFC6282, September 2011,
<https://www.rfc-editor.org/rfc/rfc6282>.
[RFC6550] Winter, T., Ed., Thubert, P., Ed., Brandt, A., Hui, J.,
Kelsey, R., Levis, P., Pister, K., Struik, R., Vasseur,
JP., and R. Alexander, "RPL: IPv6 Routing Protocol for
Low-Power and Lossy Networks", RFC 6550,
DOI 10.17487/RFC6550, March 2012,
<https://www.rfc-editor.org/rfc/rfc6550>.
[RFC7400] Bormann, C., "6LoWPAN-GHC: Generic Header Compression for
IPv6 over Low-Power Wireless Personal Area Networks
(6LoWPANs)", RFC 7400, DOI 10.17487/RFC7400, November
2014, <https://www.rfc-editor.org/rfc/rfc7400>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/rfc/rfc8126>.
[RFC8138] Thubert, P., Ed., Bormann, C., Toutain, L., and R. Cragie,
"IPv6 over Low-Power Wireless Personal Area Network
(6LoWPAN) Routing Header", RFC 8138, DOI 10.17487/RFC8138,
April 2017, <https://www.rfc-editor.org/rfc/rfc8138>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.
[RFC8505] Thubert, P., Ed., Nordmark, E., Chakrabarti, S., and C.
Perkins, "Registration Extensions for IPv6 over Low-Power
Wireless Personal Area Network (6LoWPAN) Neighbor
Discovery", RFC 8505, DOI 10.17487/RFC8505, November 2018,
<https://www.rfc-editor.org/rfc/rfc8505>.
Informative References
Iannone, et al. Expires 23 September 2024 [Page 27]
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[I-D.li-6lo-pasa-reliability]
Li, G., Lou, Z., and L. Iannone, "Reliability
Considerations of Path-Aware Semantic Addressing", Work in
Progress, Internet-Draft, draft-li-6lo-pasa-reliability-
03, 4 March 2024, <https://datatracker.ietf.org/doc/html/
draft-li-6lo-pasa-reliability-03>.
[LEE10] Lee, M., Zhang, R., Zheng, J., Ahn, G., Zhu, C., Park, T.,
Cho, S., Shin, C., and J. Ryu, "IEEE 802.15.5 WPAN mesh
standard-low rate part: Meshing the wireless sensor
networks", IEEE Journal on Selected Areas in
Communications vol. 28, no. 7, pp. 973-983,
DOI 10.1109/jsac.2010.100902, September 2010,
<https://doi.org/10.1109/jsac.2010.100902>.
[LPWAN] "IPv6 over Low Power Wide-Area Networks (lpwan) WG", n.d.,
<https://datatracker.ietf.org/wg/lpwan/about/>.
[RFC4193] Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast
Addresses", RFC 4193, DOI 10.17487/RFC4193, October 2005,
<https://www.rfc-editor.org/rfc/rfc4193>.
[RFC8163] Lynn, K., Ed., Martocci, J., Neilson, C., and S.
Donaldson, "Transmission of IPv6 over Master-Slave/Token-
Passing (MS/TP) Networks", RFC 8163, DOI 10.17487/RFC8163,
May 2017, <https://www.rfc-editor.org/rfc/rfc8163>.
[RFC8724] Minaburo, A., Toutain, L., Gomez, C., Barthel, D., and JC.
Zuniga, "SCHC: Generic Framework for Static Context Header
Compression and Fragmentation", RFC 8724,
DOI 10.17487/RFC8724, April 2020,
<https://www.rfc-editor.org/rfc/rfc8724>.
[RFC8799] Carpenter, B. and B. Liu, "Limited Domains and Internet
Protocols", RFC 8799, DOI 10.17487/RFC8799, July 2020,
<https://www.rfc-editor.org/rfc/rfc8799>.
[RFC9354] Hou, J., Liu, B., Hong, Y., Tang, X., and C. Perkins,
"Transmission of IPv6 Packets over Power Line
Communication (PLC) Networks", RFC 9354,
DOI 10.17487/RFC9354, January 2023,
<https://www.rfc-editor.org/rfc/rfc9354>.
[RFC9453] Hong, Y., Gomez, C., Choi, Y., Sangi, A., and S.
Chakrabarti, "Applicability and Use Cases for IPv6 over
Networks of Resource-constrained Nodes (6lo)", RFC 9453,
DOI 10.17487/RFC9453, September 2023,
<https://www.rfc-editor.org/rfc/rfc9453>.
Iannone, et al. Expires 23 September 2024 [Page 28]
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[RS485] "TIA-485-A Revision of EIA-485", n.d..
[SIXLO] "IPv6 over Networks of Resource-constrained Nodes (6lo)
WG", n.d., <https://datatracker.ietf.org/wg/6lo/about/>.
[SIXLOWPAN]
"IPv6 over Low power WPAN (6lowpan) - Concluded WG", n.d.,
<https://datatracker.ietf.org/wg/6lowpan/about/>.
[ZigBee] "ZigBee Wireless Networks and Transceivers",
Elsevier book, DOI 10.1016/b978-0-7506-8393-7.x0001-5,
2008,
<https://doi.org/10.1016/b978-0-7506-8393-7.x0001-5>.
Authors' Addresses
Luigi Iannone (editor)
Huawei Technologies France S.A.S.U.
18, Quai du Point du Jour
92100 Boulogne-Billancourt
France
Email: luigi.iannone@huawei.com
Guangpeng Li
Huawei Technologies
Beiqing Road, Haidian District
Beijing
100095
China
Email: liguangpeng@huawei.com
David Lou
Huawei Technologies Duesseldorf GmbH
Riesstrasse 25
80992 Munich
Germany
Email: zhe.lou@huawei.com
Peng Liu
China Mobile
No. 53, Xibianmen Inner Street, Xicheng District
Beijing
100053
China
Email: liupengyjy@chinamobile.com
Iannone, et al. Expires 23 September 2024 [Page 29]
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Rong Long
China Mobile
No. 53, Xibianmen Inner Street, Xicheng District
Beijing
100053
China
Email: longrong@chinamobile.com
Kiran Makhijani
Futurewei
United States of America
Email: kiranm@futurewei.com
Pascal Thubert
06330 Roquefort-les-Pins
France
Email: pascal.thubert@gmail.com
Iannone, et al. Expires 23 September 2024 [Page 30]