draft-ietf-roll-applicability-home-building-04.txt   draft-ietf-roll-applicability-home-building-05.txt 
Roll A. Brandt Roll A. Brandt
Internet-Draft Sigma Designs Internet-Draft Sigma Designs
Intended status: Informational E. Baccelli Intended status: Informational E. Baccelli
Expires: January 1, 2015 INRIA Expires: April 9, 2015 INRIA
R. Cragie R. Cragie
Gridmerge ARM
P. van der Stok P. van der Stok
Consultant Consultant
June 30, 2014 October 6, 2014
Applicability Statement: The use of the RPL protocol suite in Home Applicability Statement: The use of the RPL protocol suite in Home
Automation and Building Control Automation and Building Control
draft-ietf-roll-applicability-home-building-04 draft-ietf-roll-applicability-home-building-05
Abstract Abstract
The purpose of this document is to provide guidance in the selection The purpose of this document is to provide guidance in the selection
and use of protocols from the RPL protocol suite to implement the and use of protocols from the RPL protocol suite to implement the
features required for control in building and home environments. features required for control in building and home environments.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
skipping to change at page 1, line 38 skipping to change at page 1, line 38
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 1, 2015. This Internet-Draft will expire on April 9, 2015.
Copyright Notice Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Relationship to other documents . . . . . . . . . . . . . 4 1.1. Relationship to other documents . . . . . . . . . . . . . 4
1.2. Requirements language . . . . . . . . . . . . . . . . . . 4 1.2. Requirements language . . . . . . . . . . . . . . . . . . 4
1.3. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 1.3. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
1.4. Required Reading . . . . . . . . . . . . . . . . . . . . 4 1.4. Required Reading . . . . . . . . . . . . . . . . . . . . 5
1.5. Out of scope requirements . . . . . . . . . . . . . . . . 4 1.5. Out of scope requirements . . . . . . . . . . . . . . . . 5
2. Deployment Scenario . . . . . . . . . . . . . . . . . . . . . 5 2. Deployment Scenario . . . . . . . . . . . . . . . . . . . . . 5
2.1. Network Topologies . . . . . . . . . . . . . . . . . . . 6 2.1. Network Topologies . . . . . . . . . . . . . . . . . . . 6
2.2. Traffic Characteristics . . . . . . . . . . . . . . . . . 7 2.2. Traffic Characteristics . . . . . . . . . . . . . . . . . 7
2.2.1. General . . . . . . . . . . . . . . . . . . . . . . . 8 2.2.1. General . . . . . . . . . . . . . . . . . . . . . . . 8
2.2.2. Source-sink (SS) communication paradigm . . . . . . . 8 2.2.2. Source-sink (SS) communication paradigm . . . . . . . 8
2.2.3. Publish-subscribe (PS, or pub/sub)) communication 2.2.3. Publish-subscribe (PS, or pub/sub)) communication
paradigm . . . . . . . . . . . . . . . . . . . . . . 8 paradigm . . . . . . . . . . . . . . . . . . . . . . 9
2.2.4. Peer-to-peer (P2P) communication paradigm . . . . . . 9 2.2.4. Peer-to-peer (P2P) communication paradigm . . . . . . 9
2.2.5. Peer-to-multipeer (P2MP) communication paradigm . . . 9 2.2.5. Peer-to-multipeer (P2MP) communication paradigm . . . 9
2.2.6. Additional considerations: Duocast and N-cast . . . . 9 2.2.6. Additional considerations: Duocast and N-cast . . . . 10
2.2.7. RPL applicability per communication paradigm . . . . 10 2.2.7. RPL applicability per communication paradigm . . . . 10
2.3. Layer-2 applicability . . . . . . . . . . . . . . . . . . 11 2.3. Layer-2 applicability . . . . . . . . . . . . . . . . . . 11
3. Using RPL to meet Functional Requirements . . . . . . . . . . 11 3. Using RPL to meet Functional Requirements . . . . . . . . . . 11
4. RPL Profile . . . . . . . . . . . . . . . . . . . . . . . . . 12 4. RPL Profile . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.1. RPL Features . . . . . . . . . . . . . . . . . . . . . . 12 4.1. RPL Features . . . . . . . . . . . . . . . . . . . . . . 13
4.1.1. RPL Instances . . . . . . . . . . . . . . . . . . . . 13 4.1.1. RPL Instances . . . . . . . . . . . . . . . . . . . . 13
4.1.2. Storing vs. Non-Storing Mode . . . . . . . . . . . . 13 4.1.2. Storing vs. Non-Storing Mode . . . . . . . . . . . . 13
4.1.3. DAO Policy . . . . . . . . . . . . . . . . . . . . . 13 4.1.3. DAO Policy . . . . . . . . . . . . . . . . . . . . . 13
4.1.4. Path Metrics . . . . . . . . . . . . . . . . . . . . 13 4.1.4. Path Metrics . . . . . . . . . . . . . . . . . . . . 14
4.1.5. Objective Function . . . . . . . . . . . . . . . . . 13 4.1.5. Objective Function . . . . . . . . . . . . . . . . . 14
4.1.6. DODAG Repair . . . . . . . . . . . . . . . . . . . . 13 4.1.6. DODAG Repair . . . . . . . . . . . . . . . . . . . . 14
4.1.7. Multicast . . . . . . . . . . . . . . . . . . . . . . 14 4.1.7. Multicast . . . . . . . . . . . . . . . . . . . . . . 14
4.1.8. Security . . . . . . . . . . . . . . . . . . . . . . 15 4.1.8. Security . . . . . . . . . . . . . . . . . . . . . . 15
4.1.9. P2P communications . . . . . . . . . . . . . . . . . 15 4.1.9. P2P communications . . . . . . . . . . . . . . . . . 15
4.1.10. IPv6 address configuration . . . . . . . . . . . . . 15 4.1.10. IPv6 address configuration . . . . . . . . . . . . . 15
4.2. Layer 2 features . . . . . . . . . . . . . . . . . . . . 15 4.2. Layer 2 features . . . . . . . . . . . . . . . . . . . . 15
4.2.1. Specifics about layer-2 . . . . . . . . . . . . . . . 15 4.2.1. Specifics about layer-2 . . . . . . . . . . . . . . . 16
4.2.2. Services provided at layer-2 . . . . . . . . . . . . 15 4.2.2. Services provided at layer-2 . . . . . . . . . . . . 16
4.2.3. 6LowPAN options assumed . . . . . . . . . . . . . . . 15 4.2.3. 6LowPAN options assumed . . . . . . . . . . . . . . . 16
4.2.4. MLE and other things . . . . . . . . . . . . . . . . 15 4.2.4. MLE and other things . . . . . . . . . . . . . . . . 16
4.3. Recommended Configuration Defaults and Ranges . . . . . . 16 4.3. Recommended Configuration Defaults and Ranges . . . . . . 16
4.3.1. Trickle parameters . . . . . . . . . . . . . . . . . 16 4.3.1. Trickle parameters . . . . . . . . . . . . . . . . . 16
4.3.2. Other Parameters . . . . . . . . . . . . . . . . . . 16 4.3.2. Other Parameters . . . . . . . . . . . . . . . . . . 16
5. MPL Profile . . . . . . . . . . . . . . . . . . . . . . . . . 16 5. MPL Profile . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.1. Recommended configuration Defaults and Ranges . . . . . . 17 5.1. Recommended configuration Defaults and Ranges . . . . . . 17
5.1.1. Trickle parameters . . . . . . . . . . . . . . . . . 17 5.1.1. Real-Time optimizations . . . . . . . . . . . . . . . 17
5.1.2. Other parameters . . . . . . . . . . . . . . . . . . 18 5.1.2. Trickle parameters . . . . . . . . . . . . . . . . . 17
5.1.3. Other parameters . . . . . . . . . . . . . . . . . . 18
6. Manageability Considerations . . . . . . . . . . . . . . . . 18 6. Manageability Considerations . . . . . . . . . . . . . . . . 18
7. Security Considerations . . . . . . . . . . . . . . . . . . . 18 7. Security Considerations . . . . . . . . . . . . . . . . . . . 19
7.1. Security considerations during initial deployment . . . . 18 7.1. Security considerations during initial deployment . . . . 19
7.2. Security Considerations during incremental deployment . . 19 7.2. Security Considerations during incremental deployment . . 20
7.3. Security Considerations for P2P uses . . . . . . . . . . 19 7.3. Security Considerations for P2P uses . . . . . . . . . . 20
7.4. MPL routing . . . . . . . . . . . . . . . . . . . . . . . 20 7.4. MPL routing . . . . . . . . . . . . . . . . . . . . . . . 20
7.5. RPL Security features . . . . . . . . . . . . . . . . . . 20 7.5. RPL Security features . . . . . . . . . . . . . . . . . . 20
8. Other related protocols . . . . . . . . . . . . . . . . . . . 20 8. Other related protocols . . . . . . . . . . . . . . . . . . . 21
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 21 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 21
11. Changelog . . . . . . . . . . . . . . . . . . . . . . . . . . 21 11. Changelog . . . . . . . . . . . . . . . . . . . . . . . . . . 21
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 22 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 23
12.1. Normative References . . . . . . . . . . . . . . . . . . 22 12.1. Normative References . . . . . . . . . . . . . . . . . . 23
12.2. Informative References . . . . . . . . . . . . . . . . . 25 12.2. Informative References . . . . . . . . . . . . . . . . . 25
Appendix A. RPL shortcomings in home and building deployments . 26 Appendix A. RPL shortcomings in home and building deployments . 26
A.1. Risk of undesired long P2P routes . . . . . . . . . . . . 26 A.1. Risk of undesired long P2P routes . . . . . . . . . . . . 26
A.1.1. Traffic concentration at the root . . . . . . . . . . 26 A.1.1. Traffic concentration at the root . . . . . . . . . . 27
A.1.2. Excessive battery consumption in source nodes . . . . 26 A.1.2. Excessive battery consumption in source nodes . . . . 27
A.2. Risk of delayed route repair . . . . . . . . . . . . . . 26 A.2. Risk of delayed route repair . . . . . . . . . . . . . . 27
A.2.1. Broken service . . . . . . . . . . . . . . . . . . . 27 A.2.1. Broken service . . . . . . . . . . . . . . . . . . . 27
Appendix B. Communication failures . . . . . . . . . . . . . . . 27 Appendix B. Communication failures . . . . . . . . . . . . . . . 28
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 28 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 29
1. Introduction 1. Introduction
Home automation and building control applications share a substantial The primary purpose of this document is to give guidance in the use
number of properties. of the RPL protocol suite in two application domains:
o Both (home and building) can be disconnected from the ISP and they o Home automation
will (must) continue to provide control to the occupants of the
home c.q. building. This has an impact on routing because most
control communication does (must) not pass via the border routers.
o Both are confronted with unreliable links and want instant and o Building automation
very reliable reactions. This has impact on routing because of
timeliness and multipath routing.
o The difference between the two mostly appears in the The guidance is based on the features required by the requirements
commissioning, maintenance and user interface which does not documents "Home Automation Routing Requirements in Low-Power and
affect the routing. Lossy Networks" [RFC5826] and "Building Automation Routing
Requirements in Low-Power and Lossy Networks" [RFC5867] respectively.
The Advanced Metering Infrastructure is also considered where
appropriate. The applicability domains distinguish themselves in the
way they are operated, their performance requirements, and the most
likely network structures. An abstract set of distinct communication
paradigms is then used to frame the applicability domains.
So the focus of this applicability document is control in buildings Home automation and building automation application domains share a
and home, involving: reliability, timeliness, and local routing. substantial number of properties:
The purpose of this document is to give guidance in the use of the o In both domains, the network can be disconnected from the ISP and
RPL protocol suite to provide the features required by the must still continue to provide control to the occupants of the
requirements documents "Home Automation Routing Requirements in Low- home/building. Routing needs to be possible independent of the
Power and Lossy Networks" [RFC5826] and "Building Automation Routing existence of a border router
Requirements in Low-Power and Lossy Networks" [RFC5867] [RFC6997].
o Both domains are subject to unreliable links but require instant
and very reliable reactions. This has impact on routing because
of timeliness and multipath routing.
The differences between the two application domains mostly appear in
commissioning, maintenance and the user interface, which do not
typically affect routing. Therefore, the focus of this applicability
document is on reliability, timeliness, and local routing.
1.1. Relationship to other documents 1.1. Relationship to other documents
The ROLL working group has specified a set of routing protocols for The ROLL working group has specified a set of routing protocols for
Lossy and Low- resource Networks (LLN) [RFC6550]. This applicability Lossy and Low- resource Networks (LLN) [RFC6550]. This applicability
text describes a subset of these protocols and the conditions which text describes a subset of those protocols and the conditions under
make the subset the correct choice. The text recommends and which the subset is appropriate and provides recommendations and
motivates the accompanying parameter value ranges. Multiple requirements for the accompanying parameter value ranges.
applicability domains are recognized including: Building and Home,
and Advanced Metering Infrastructure. The applicability domains In addition, an extension document has been produced specifically to
distinguish themselves in the way they are operated, their provide a solution for reactive discovery of point-to-point routes in
performance requirements, and the most probable network structures. LLNs [RFC6997]. The present applicability document provides
Each applicability statement identifies the distinguishing properties recommendations and requirements for the accompanying parameter value
according to a common set of subjects described in as many sections. ranges.
A common set of security threats are described in A common set of security threats are described in
[I-D.ietf-roll-security-threats]. The applicability statements [I-D.ietf-roll-security-threats]. The applicability statements
complement the security threats document by describing preferred complement the security threats document by describing preferred
security settings and solutions within the applicability statement security settings and solutions within the applicability statement
conditions. This applicability statement may recommend more light conditions. This applicability statement recommends more light
weight security solutions and specify the conditions under which weight security solutions and specify the conditions under which
these solutions are appropriate. these solutions are appropriate.
1.2. Requirements language 1.2. Requirements language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
1.3. Terminology 1.3. Terminology
This document uses terminology from [RFC6997], This document uses terminology from [RFC6997],
[I-D.ietf-roll-trickle-mcast], [I-D.ietf-roll-terminology], [I-D.ietf-roll-trickle-mcast], [RFC7102], [IEEE802.15.4], and
[IEEE802.15.4], and [RFC6550]. [RFC6550].
1.4. Required Reading 1.4. Required Reading
Applicable requirements are described in [RFC5826] and [RFC5867]. A Applicable requirements are described in [RFC5826] and [RFC5867]. A
survey of the application field is described in [BCsurvey]. survey of the application field is described in [BCsurvey].
1.5. Out of scope requirements 1.5. Out of scope requirements
The considered network diameter is limited to a max diameter of 10 The considered network diameter is limited to a maximum diameter of
hops and a typical diameter of 5 hops, which captures the most common 10 hops and a typical diameter of 5 hops, which captures the most
cases in home automation and building control networks. common cases in home automation and building control networks.
This document does not consider the applicability of RPL-related This document does not consider the applicability of RPL-related
specifications for urban and industrial applications [RFC5548], specifications for urban and industrial applications [RFC5548],
[RFC5673], which may exhibit significantly larger network diameters. [RFC5673], which may exhibit significantly larger network diameters.
2. Deployment Scenario 2. Deployment Scenario
The use of communications networks in buildings is essential to The use of communications networks in buildings is essential to
satisfy the energy saving regulations. Environmental conditions of satisfy energy saving regulations. Environmental conditions of
buildings can be adapted to suit the comfort of the individuals buildings can be adapted to suit the comfort of the individuals
present. Consequently when no one is present, energy consumption can present inside. Consequently when no one is present, energy
be reduced. Cost is the main driving factor behind utilizing consumption can be reduced. Cost is the main driving factor behind
wireless networking in buildings. Especially for retrofit, wireless deployment of wireless networking in buildings, especially in the
connectivity saves cabling costs. case of retrofitting, where wireless connectivity saves costs
incurred due to cabling and building modifications.
A typical home automation network is comprised of less than 100 A typical home automation network is comprised of less than 100
nodes. Large building deployments may span 10,000 nodes but to nodes. Large building deployments may span 10,000 nodes but to
ensure uninterrupted service of light and air conditioning systems in ensure uninterrupted service of light and air conditioning systems in
individual zones of the building, nodes are typically organized in individual zones of the building, nodes are typically organized in
sub-networks. Each sub-network in a building automation deployment sub-networks. Each sub-network in a building automation deployment
typically contains tens to hundreds of nodes. typically contains tens to hundreds of nodes, and for critical
operations may operate independently from the other sub-networks.
The main purpose of the home or building automation network is to The main purpose of the home or building automation network is to
provide control over light and heating/cooling resources. User provide control over light and heating/cooling resources. User
intervention may be enabled via wall controllers combined with intervention via wall controllers is combined with movement, light
movement, light and temperature sensors to enable automatic and temperature sensors to enable automatic adjustment of window
adjustment of window blinds, reduction of room temperature, etc. In blinds, reduction of room temperature, etc. In general, the sensors
general, the sensors and actuators in a home or building typically and actuators in a home or building typically have fixed physical
have fixed physical locations and will remain in the same home- or locations and will remain in the same home or building automation
building automation network. network.
People expect an immediate and reliable response to their presence or People expect an immediate and reliable response to their presence or
actions. A light not switching on after entry into a room may lead actions. For example, a light not switching on after entry into a
to confusion and a profound dissatisfaction with the lighting room may lead to confusion and a profound dissatisfaction with the
product. lighting product.
Monitoring of functional correctness is at least as important. Monitoring of functional correctness is at least as important.
Devices typically communicate their status regularly and send alarm Devices typically communicate their status regularly and send alarm
messages notifying a malfunction of equipment or network. messages notifying a malfunction of equipment or network.
In building control, the infrastructure of the building management In building control, the infrastructure of the building management
network can be shared with the security/access, the IP telephony, and network can be shared with the security/access, the IP telephony, and
the fire/alarm networks. This approach has a positive impact on the the fire/alarm networks. This approach has a positive impact on the
operation and cost of the network; however, care should be taken to operation and cost of the network; however, care should be taken to
ensure that the availability of the building management network does ensure that the availability of the building management network does
not become compromised beyond the ability for critical functions to not become compromised beyond the ability for critical functions to
perform adequately. perform adequately.
In homes, the network for audio/video streaming and gaming has In homes, the entertainment network for audio/video streaming and
different requirements, where the most important one is the high need gaming has different requirements, where the most important
in bandwidth for entertainment not needed for control. It is requirement is the need for high bandwidth not typically needed for
expected that the entertainment network in the home will mostly be home or building control. It is therefore expected that the
separate from the control network, which also lessens the impact on entertainment network in the home will mostly be separate from the
availability of the control network control network, which also lessens the impact on availability of the
control network
2.1. Network Topologies 2.1. Network Topologies
In general, the home automation network or building control network In general, the home automation network or building control network
consists of wired and wireless sub-networks. In large buildings consists of wired and wireless sub-networks. In large buildings
especially, the wireless sub-networks can be connected to an IP especially, the wireless sub-networks can be connected to an IP
backbone network where all infrastructure services are located, such backbone network where all infrastructure services are located, such
as DNS, automation servers, etc. as DNS, automation servers, etc.
The wireless sub-network can be configured according to any of the The wireless sub-network can be configured according to any of the
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border routers, sub-networks often overlap both geographically and border routers, sub-networks often overlap both geographically and
from a wireless coverage perspective. Due to two purposes of the from a wireless coverage perspective. Due to two purposes of the
network, (i) direct control and (ii) monitoring, there may exist two network, (i) direct control and (ii) monitoring, there may exist two
types of routing topologies in a given sub-network: (i) a tree-shaped types of routing topologies in a given sub-network: (i) a tree-shaped
collection of routes spanning from a central building controller via collection of routes spanning from a central building controller via
the border router, on to destination nodes in the sub-network; and/or the border router, on to destination nodes in the sub-network; and/or
(ii) a flat, un-directed collection of intra-network routes between (ii) a flat, un-directed collection of intra-network routes between
functionally related nodes in the sub-network. functionally related nodes in the sub-network.
The majority of nodes in home and building automation networks are The majority of nodes in home and building automation networks are
typically devices with very low memory capacity, such as individual typically class 0 devices [RFC7228], such as individual wall
wall switches. Only a few nodes (such as multi-purpose remote switches. Only a few nodes (such as multi-purpose remote controls)
controls) are more expensive devices, which can afford more memory are more expensive Class 1 devices, which can afford more memory
capacity. capacity.
2.2. Traffic Characteristics 2.2. Traffic Characteristics
Traffic may enter the network originating from a central controller Traffic may enter the network originating from a central controller
or it may originate from an intra-network node. The majority of or it may originate from an intra-network node. The majority of
traffic is light-weight point-to-point control style; e.g. Put-Ack traffic is light-weight point-to-point control style; e.g. Put-Ack
or Get-Response. There are however exceptions. Bulk data transfer or Get-Response. There are however exceptions. Bulk data transfer
is used for firmware update and logging, where firmware updates enter is used for firmware update and logging, where firmware updates enter
the network and logs leave the network. Group communication is used the network and logs leave the network. Group communication is used
for service discovery or to control groups of nodes, such as light for service discovery or to control groups of nodes, such as light
fixtures. fixtures.
Often, there is a direct physical relation between a controlling Often, there is a direct physical relation between a controlling
sensor and the controlled equipment. For example the temperature sensor and the controlled equipment. For example the temperature
sensor and thermostat are located in the same room sharing the same sensor and room controller are located in the same room sharing the
climate conditions. Consequently, the bulk of senders and receivers same climate conditions. Consequently, the bulk of senders and
are separated by a distance that allows one-hop direct path receivers are separated by a distance that allows one-hop direct path
communication. A graph of the communication will show several fully communication. A graph of the communication will show several fully
connected subsets of nodes. However, due to interference, multipath connected subsets of nodes. However, due to interference, multipath
fading, reflection and other transmission mechanisms, the one-hop fading, reflection and other transmission mechanisms, the one-hop
direct path may be temporally disconnected. For reliability direct path may be temporally disconnected. For reliability
purposes, it is therefore essential that alternative n-hop purposes, it is therefore essential that alternative n-hop
communication routes exist for quick error recovery. (See Appendix B communication routes exist for quick error recovery. (See Appendix B
for motivation.) for motivation.)
Looking over time periods of a day, the networks are very lightly Looking over time periods of a day, the networks are very lightly
loaded. However, bursts of traffic can be generated by pushing loaded. However, bursts of traffic can be generated by e.g.
permanently the button of a remote control, the occurrence of a incessant pushing of the button of a remote control, the occurrence
defect, and other unforeseen events. Under those conditions, the of a defect, and other unforeseen events. Under those conditions,
timeliness must nevertheless be maintained. Therefore, measures are the timeliness must nevertheless be maintained. Therefore, measures
necessary to remove any unnecessary traffic. Short routes are are necessary to remove any unnecessary traffic. Short routes are
preferred. Long multi-hop routes via the border router, should be preferred. Long multi-hop routes via the border router, should be
avoided whenever possible. avoided whenever possible.
Group communication is essential for lighting control. For example, Group communication is essential for lighting control. For example,
once the presence of a person is detected in a given room, lighting once the presence of a person is detected in a given room, lighting
control applies to that room only and no other lights should be control applies to that room only and no other lights should be
dimmed, or switched on/off. In many cases, this means that a dimmed, or switched on/off. In many cases, this means that a
multicast message with a 1-hop and 2-hop radius would suffice to multicast message with a 1-hop and 2-hop radius would suffice to
control the required lights. The same argument holds for HVAC and control the required lights. The same argument holds for HVAC and
other climate control devices. To reduce network load, it is other climate control devices. To reduce network load, it is
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This paradigm translates to many sources sending messages to the same This paradigm translates to many sources sending messages to the same
sink, sometimes reachable via the border router. As such, source- sink, sometimes reachable via the border router. As such, source-
sink (SS) traffic can be present in home and building networks. The sink (SS) traffic can be present in home and building networks. The
traffic may be generated by environmental sensors (often present in a traffic may be generated by environmental sensors (often present in a
wireless sub-network) which push periodic readings to a central wireless sub-network) which push periodic readings to a central
server. The readings may be used for pure logging, or more often, server. The readings may be used for pure logging, or more often,
processed to adjust light, heating and ventilation. Alarm sensors processed to adjust light, heating and ventilation. Alarm sensors
may also generate SS style traffic. The central server in a home may also generate SS style traffic. The central server in a home
automation network will be connected mostly to a wired network automation network will be connected mostly to a wired network
segment of the home network, although it is suspected that cloud segment of the home network, although it is likely that cloud
services will become available. The central server in a building services will also be used. The central server in a building
automation network may be connected to a backbone or be placed automation network may be connected to a backbone or be placed
outside the building. outside the building.
With regards to message latency, most SS transmissions can tolerate With regards to message latency, most SS transmissions can tolerate
worst-case delays measured in tens of seconds. Alarm sensors, worst-case delays measured in tens of seconds. Fire detectors,
however, represent an exception. Special provisions with respect to however, represent an exception; For example, special provisions with
the location of the Alarm server(s) need to be put in place to respect to the location of the Fire detectors and the smoke dampers
respect the specified delays. need to be put in place to meet the stringent delay requirements.
2.2.3. Publish-subscribe (PS, or pub/sub)) communication paradigm 2.2.3. Publish-subscribe (PS, or pub/sub)) communication paradigm
This paradigm translates to a number of devices expressing their This paradigm translates to a number of devices expressing their
interest for a service provided by a server device. For example, a interest for a service provided by a server device. For example, a
server device can be a sensor delivering temperature readings on the server device can be a sensor delivering temperature readings on the
basis of delivery criteria, like changes in acquisition value or age basis of delivery criteria, like changes in acquisition value or age
of the latest acquisition. In building automation networks, this of the latest acquisition. In building automation networks, this
paradigm may be closely related to the SS paradigm given that paradigm may be closely related to the SS paradigm given that
servers, which are connected to the backbone or outside the building, servers, which are connected to the backbone or outside the building,
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differ significantly from installation to installation. differ significantly from installation to installation.
2.2.4. Peer-to-peer (P2P) communication paradigm 2.2.4. Peer-to-peer (P2P) communication paradigm
This paradigm translates to a device transferring data to another This paradigm translates to a device transferring data to another
device often connected to the same sub-network. Peer-to-peer (P2P) device often connected to the same sub-network. Peer-to-peer (P2P)
traffic is a common traffic type in home automation networks. Most traffic is a common traffic type in home automation networks. Most
building automation networks rely on P2P traffic, described in the building automation networks rely on P2P traffic, described in the
next paragraph. Other building automation networks rely on P2P next paragraph. Other building automation networks rely on P2P
control traffic between controls and a local controller box for control traffic between controls and a local controller box for
advanced scene and group control. The latter controller boxes can be advanced scene and group control. A local controller box can be
connected to service control boxes thus generating more SS or PS further connected to service control boxes, thus generating more SS
traffic. or PS traffic.
P2P traffic is typically generated by remote controls and wall P2P traffic is typically generated by remote controls and wall
controllers which push control messages directly to light or heat controllers which push control messages directly to light or heat
sources. P2P traffic has a strong requirement for low latency since sources. P2P traffic has a stringent requirement for low latency
P2P traffic often carries application messages that are invoked by since P2P traffic often carries application messages that are invoked
humans. As mentioned in Section 2.2.1 application messages should be by humans. As mentioned in Section 2.2.1 application messages should
delivered within a few hundred milliseconds - even when connections be delivered within a few hundred milliseconds - even when
fail momentarily. connections fail momentarily.
2.2.5. Peer-to-multipeer (P2MP) communication paradigm 2.2.5. Peer-to-multipeer (P2MP) communication paradigm
This paradigm translates to a device sending a message as many times This paradigm translates to a device sending a message as many times
as there are destination devices. Peer-to-multipeer (P2MP) traffic as there are destination devices. Peer-to-multipeer (P2MP) traffic
is common in home and building automation networks. Often, a is common in home and building automation networks. Often, a
thermostat in a living room responds to temperature changes by thermostat in a living room responds to temperature changes by
sending temperature acquisitions to several fans and valves sending temperature acquisitions to several fans and valves
consecutively. consecutively. This paradigm is also closely related to the PS
paradigm in the case where a single server device has multiple
subscribers.
2.2.6. Additional considerations: Duocast and N-cast 2.2.6. Additional considerations: Duocast and N-cast
This paradigm translates to a device sending a message to many This paradigm translates to a device sending a message to many
destinations in one network transfer invocation. Multicast is well destinations in one network transfer invocation. Multicast is well
suited for lighting where a presence sensor sends a presence message suited for lighting where a presence sensor sends a presence message
to a set of lighting devices. Multicast increases the probability to a set of lighting devices. Multicast increases the probability
that the message is delivered within the strict time constraints. that the message is delivered within the strict time constraints.
The recommended multicast algorithm (e.g. The recommended multicast algorithm (e.g.
[I-D.ietf-roll-trickle-mcast]) assures that messages are delivered to [I-D.ietf-roll-trickle-mcast]) assures that messages are delivered to
ALL intended destinations. ALL intended destinations.
2.2.7. RPL applicability per communication paradigm 2.2.7. RPL applicability per communication paradigm
In the case of SS over a wireless sub-network to a server reachable In the case of the SS paradigm applied to a wireless sub-network to a
via a border router, the use of RPL [RFC6550] is recommended. Given server reachable via a border router, the use of RPL [RFC6550] in
the low resources of the devices, source routing will be used for non-storing mode is appropriate. Given the low resources of the
messages from outside the wireless sub-network to the destination in devices, source routing will be used from the border router to the
the wireless sub-network. No specific timing constraints are destination in the wireless sub-network for messages generated
outside the mesh network. No specific timing constraints are
associated with the SS type messages so network repair does not associated with the SS type messages so network repair does not
violate the operational constraints. When no SS traffic takes place, violate the operational constraints. When no SS traffic takes place,
it is recommended to load only RPL code enabling P2P mode of it is good practice to load only RPL code enabling P2P mode of
operation [RFC6997] to satisfy memory requirements by reducing the operation [RFC6997] to reduce the code size and satisfy memory
code size. requirements.
P2P-RPL [RFC6997] is recommended for all P2P and P2MP traffic, taking P2P-RPL [RFC6997] is required for all P2P and P2MP traffic taking
place within a wireless sub-network, to assure responsiveness. place between nodes within a wireless sub-network (excluding the
Source and destination are typically close together to satisfy the border router) to assure responsiveness. Source and destination
living conditions of one room. Consequently, most P2P and P2MP devices are typically physically close based on room layout.
traffic is 1-hop or 2-hop traffic. Appendix A explains why RPL-P2P Consequently, most P2P and P2MP traffic is 1-hop or 2-hop traffic.
is preferable to RPL for this type of communication. Appendix B Appendix A explains why P2P-RPL is preferable to RPL for this type of
explains why reliability measures such as multi-path routing are communication. Appendix B explains why reliability measures such as
necessary even when 1-hop communication dominates. multi-path routing are necessary even when 1-hop communication
dominates.
Additional advantages of RPL-P2P for home and building automation Additional advantages of P2P-RPL for home and building automation
networks are, for example: networks are, for example:
o Individual wall switches are typically inexpensive devices with o Individual wall switches are typically inexpensive class 0 devices
extremely low memory capacities. Multi-purpose remote controls [RFC7228] with extremely low memory capacities. Multi-purpose
for use in a home environment typically have more memory but such remote controls for use in a home environment typically have more
devices are asleep when there is no user activity. RPL-P2P memory but such devices are asleep when there is no user activity.
reactive discovery allows a node to wake up and find new routes P2P-RPL reactive discovery allows a node to wake up and find new
within a few seconds while memory constrained nodes only have to routes within a few seconds while memory constrained nodes only
keep routes to relevant targets. have to keep routes to relevant targets.
o The reactive discovery features of RPL-P2P ensure that commands o The reactive discovery features of P2P-RPL ensure that commands
are normally delivered within the 250 msec time window and when are normally delivered within the 250 msec time window. When
connectivity needs to be restored, it is typically completed connectivity needs to be restored, discovery is typically
within seconds. In most cases an alternative (earlier discovered) completed within seconds. In most cases, an alternative (earlier
route will work. Thus, route rediscovery is not even necessary. discovered) route will work and route rediscovery is not
necessary.
o Broadcast storms as happening during route discovery for AODV is o Broadcast storms typically associated with route discovery for
less disruptive for P2P-RPL. P2P-RPL has a "STOP" bit which is AODV are less disruptive for P2P-RPL. P2P-RPL has a "STOP" bit
set by the target of a route discovery to notify all other nodes which is set by the target of a route discovery to notify all
that no more DIOs should be forwarded for this temporary DAG. other nodes that no more DIOs should be forwarded for this
Something looking like a broadcast storm may happen when no target temporary DAG. Something looking like a broadcast storm may
is responding. And in this case, the Trickle suppression happen when no target is responding however, in this case, the
mechanism kicks in; limiting the number of DIO forwards in dense Trickle suppression mechanism kicks in, limiting the number of DIO
networks. forwards in dense networks.
Due to the limited memory of the majority of devices, RPL-P2P SHOULD Due to the limited memory of the majority of devices, P2P-RPL is
be used with source routing in non-storing mode as explained in preferably deployed with source routing in non-storing mode as
Section 4.1.2. explained in Section 4.1.2.
Multicast with MPL [I-D.ietf-roll-trickle-mcast] is recommended for Multicast with MPL [I-D.ietf-roll-trickle-mcast] is preferably
N-cast over the wireless network. Configuration constraints that are deployed for N-cast over the wireless network. Configuration
necessary to meet reliability and timeliness with MPL are discussed constraints that are necessary to meet reliability and timeliness
in Section 4.1.7. with MPL are discussed in Section 4.1.7.
2.3. Layer-2 applicability 2.3. Layer-2 applicability
This document applies to [IEEE802.15.4] and [G.9959] which are This document applies to [IEEE802.15.4] and [G.9959] which are
adapted to IPv6 by the adaption layers [RFC4944] and adapted to IPv6 by the adaption layers [RFC4944] and
[I-D.ietf-6lo-lowpanz]. [I-D.ietf-6lo-lowpanz]. Other layer-2 technologies, accompanied by
an "IP over Foo" specification, are also relevant provided there is
no frame size issue, and there are link layer acknowledgements.
The above mentioned adaptation layers leverage on the compression The above mentioned adaptation layers leverage on the compression
capabilities of [RFC6554] and [RFC6282]. Header compression allows capabilities of [RFC6554] and [RFC6282]. Header compression allows
small IP packets to fit into a single layer 2 frame even when source small IP packets to fit into a single layer 2 frame even when source
routing is used. A network diameter limited to 5 hops helps to routing is used. A network diameter limited to 5 hops helps to
achieve this. achieve this even while using source routing.
Dropped packets are often experienced in the targeted environments. Dropped packets are often experienced in the targeted environments.
ICMP, UDP and even TCP flows may benefit from link layer unicast ICMP, UDP and even TCP flows may benefit from link layer unicast
acknowledgments and retransmissions. Link layer unicast acknowledgments and retransmissions. Link layer unicast
acknowledgments SHOULD be enabled when [IEEE802.15.4] or [G.9959] is acknowledgments are compulsory when [IEEE802.15.4] or [G.9959] is
used with RPL and RPL-P2P. used with RPL and P2P-RPL.
3. Using RPL to meet Functional Requirements 3. Using RPL to meet Functional Requirements
RPL-P2P SHOULD be present in home automation and building control Several features required by [RFC5826], [RFC5867] challenge the P2P
networks, as point-to-point style traffic is substantial and route paths provided by RPL. Appendix A reviews these challenges. In some
repair needs to be completed within seconds. RPL-P2P provides a cases, a node may need to spontaneously initiate the discovery of a
reactive mechanism for quick, efficient and root-independent route path towards a desired destination that is neither the root of a DAG,
discovery/repair. The use of RPL-P2P furthermore allows data traffic nor a destination originating DAO signalling. Furthermore, P2P paths
provided by RPL are not satisfactory in all cases because they
involve too many intermediate nodes before reaching the destination.
P2P-RPL [RFC6997] is necessary in home automation and building
control networks, as point-to-point style traffic is substantial and
route repair needs to be completed within seconds. P2P-RPL provides
a reactive mechanism for quick, efficient and root-independent route
discovery/repair. The use of P2P-RPL furthermore allows data traffic
to avoid having to go through a central region around the root of the to avoid having to go through a central region around the root of the
tree, and drastically reduces path length [SOFT11] [INTEROP12]. tree, and drastically reduces path length [SOFT11] [INTEROP12].
These characteristics are desirable in home and building automation These characteristics are desirable in home and building automation
networks because they substantially decrease unnecessary network networks because they substantially decrease unnecessary network
congestion around the root of the tree. congestion around the root of the tree.
When reliability is required, RPL-P2P enables the establishment of When more reliability is required, P2P-RPL enables the establishment
multiple independent paths. For 1-hop destinations this means that of multiple independent paths. For 1-hop destinations this means
one 1-hop communication and a second 2-hop communication take place that one 1-hop communication and a second 2-hop communication take
via a neighbouring node. The same two communication paths can be place via a neighbouring node. Such a pair of redundant
achieved by using MPL where the source is a MPL forwarder and a communication paths can be achieved by using MPL where the source is
second MPL forwarder is 1 hop removed from the source and the a MPL forwarder, while a second MPL forwarder is 1 hop away from both
destination node. The source multicasts the message, which may be the source and the destination node. When the source multicasts the
received by both the destination and the 2nd forwarder. The 2nd message, it may be received by both the destination and the 2nd
forwarder forwards the message to the destination, thus providing two forwarder. The 2nd forwarder forwards the message to the
routes from sender to destination. destination, thus providing two routes from sender to destination.
To provide reliability with multiple paths, RPL-P2P is recommended to To provide more reliability with multiple paths, P2P-RPL can maintain
keep two independent P2P paths per destination in the source. When two independent P2P source routes per destination, at the source.
one P2P path is temporarily impossible, as described in Appendix B, Good practice is to use the paths alternately to assess their
the alternative P2P path can be used without throwing away the existence. When one P2P path has failed (possibly only temporarily),
temporarily failing path. The failing P2P path can be safely thrown as described in Appendix B, the alternative P2P path can be used
away after 15 minutes. A new route discovery is done when the number without discarding the failed path. The failed P2P path, unless
of P2P paths is exhausted, or when a P2P path needs to abandoned proven to work again, can be safely discarded after a timeout
because it fails over a too long period. (typically15 minutes). A new route discovery is done when the number
of P2P paths is exhausted due to persistent link failures.
4. RPL Profile 4. RPL Profile
RPL-P2P SHOULD be used in home automation and building control P2P-RPL is necessary in home automation and building control
networks. Its reactive discovery allows for low application response networks. Its reactive discovery allows for low application response
times even when on-the-fly route repair is needed. Non-storing mode times even when on-the-fly route repair is needed. Non-storing mode
SHOULD be used to reduce memory consumption in repeaters with is preferable to reduce memory consumption in repeaters with
constrained memory when source routing is used. constrained memory when source routing is used.
4.1. RPL Features 4.1. RPL Features
An important constraint on the application of RPL is the presence of An important constraint on the application of RPL is the presence of
sleeping nodes. sleeping nodes.
For example in the stand-alone network, the link layer node (master For example, in a stand-alone network, the master node (or
node, or coordinator) handing out the logical network identifier and coordinator) providing the logical layer-2 identifier and unique node
unique node identifiers may be a remote control which returns to identifiers to connected nodes may be a remote control which returns
sleep once new nodes have been added. Due to the absence of the to sleep once new nodes have been added. Due to the absence of the
border router there may be no global routable prefixes at all. border router, there may be no global routable prefixes at all.
Likewise, there may be no authoritative always-on root node since Likewise, there may be no authoritative always-on root node since
there is no border router to host this function. there is no border router to host this function.
In a network with a border router and many sleeping nodes, there may In a network with a border router and many sleeping nodes, there may
be battery powered sensors and wall controllers configured to contact be battery powered sensors and wall controllers configured to contact
other nodes in response to events and then return to sleep. Such other nodes in response to events and then return to sleep. Such
nodes may never detect the announcement of new prefixes via nodes may never detect the announcement of new prefixes via
multicast. multicast.
In each of the above mentioned constrained deployments, a link layer In each of the above mentioned constrained deployments, a link layer
node (e.g. coordinator or master) SHOULD assume the role as node (e.g. coordinator or master) assumes the role as authoritative
authoritative root node, transmitting singlecast RAs with a ULA root node, transmitting singlecast RAs with a ULA prefix information
prefix information option to nodes during the inclusion process to option to nodes during the joining process to prepare the nodes for a
prepare the nodes for a later operational phase, where a border later operational phase, where a border router is added.
router is added.
A border router SHOULD be designed to be aware of sleeping nodes in
order to support the distribution of updated global prefixes to such
sleeping nodes.
One MAY implement gateway-centric tree-based routing and global A border router is designed to be aware of sleeping nodes in order to
prefix distribution as defined by [RFC6550]. This would however only support the distribution of updated global prefixes to such sleeping
work for always-on nodes. nodes.
4.1.1. RPL Instances 4.1.1. RPL Instances
When operating P2P-RPL on a stand-alone basis, there is no When operating P2P-RPL on a stand-alone basis, there is no
authoritative root node maintaining a permanent RPL DODAG. A node authoritative root node maintaining a permanent RPL DODAG. A node
MUST be able to join one RPL instance as an instance is created necessarily joins at least one RPL instance, as a new, temporary
during each P2P-RPL route discovery operation. A node MAY be instance is created during each P2P-RPL route discovery operation. A
designed to join multiple RPL instances. node can be designed to join multiple RPL instances.
4.1.2. Storing vs. Non-Storing Mode 4.1.2. Storing vs. Non-Storing Mode
Non-storing mode MUST be used to cope with the extremely constrained Non-storing mode is necessary to cope with the extremely constrained
memory of a majority of nodes in the network (such as individual memory of a majority of nodes in the network (such as individual
light switches). light switches).
4.1.3. DAO Policy 4.1.3. DAO Policy
A node MAY be designed to join multiple RPL instances; in that case A node can be designed to join multiple RPL instances; in that case
DAO policies may be needed. DAO policies may be needed. However, DAO policy is out of scope for
this applicability statement.
DAO policy is out of scope for this applicability statement.
4.1.4. Path Metrics 4.1.4. Path Metrics
OF0 is RECOMMENDED. [RFC6551] provides other options. Using other OF0 is the recommended metric. [RFC6551] provides other options.
objective functions than OF0 may affect inter-operability. Using other objective functions than OF0 may affect inter-
operability.
4.1.5. Objective Function 4.1.5. Objective Function
OF0 MUST be supported and is the RECOMMENDED Objective Function to OF0 is the recommended Objective Function. Other Objective Functions
use. Other Objective Functions MAY be used as well. should be used only when dictated by circumstances.
4.1.6. DODAG Repair 4.1.6. DODAG Repair
Since RPL-P2P only creates DODAGs on a temporary basis during route Since P2P-RPL only creates DODAGs on a temporary basis during route
repair, there is no need to repair DODAGs. repair or route discovery, there is no need to repair DODAGs.
In general for the SS case, handling of time-varying link For SS traffic, local repair is sufficient. The accompanying process
characteristics and availability, local repair is sufficient. The is known as poisoning and is described in Section 8.2.2.5 of
accompanying process is known as poisoning and is described in [RFC6550]. Given that the majority of nodes in the building do not
Section 8.2.2.5 of [RFC6550]. Given that the plurality of nodes in physically move around, creating new DODAGs should not happen
the building does not move around, creating new DODAGs will not frequently.
happen frequently.
4.1.7. Multicast 4.1.7. Multicast
Commercial light deployments may have a need for multicast to Commercial lighting deployments may have a need for multicast to
distribute commands to a group of lights in a timely fashion. distribute commands to a group of lights in a timely fashion.
Several mechanisms exist for achieving such functionality; Several mechanisms exist for achieving such functionality;
[I-D.ietf-roll-trickle-mcast] is RECOMMENDED for home and building [I-D.ietf-roll-trickle-mcast] is the generally accepted protocol for
deployments. This section relies heavily on the conclusions of home and building deployments. This section relies heavily on the
[RT-MPL]. conclusions of [RT-MPL].
The density of forwarders and the frequency of message generation are The density of forwarders and the frequency of message generation are
important aspects to obtain timeliness during control operations. A important aspects to obtain timeliness during control operations. A
high frequency of message generation can be expected when a remote high frequency of message generation can be expected when a remote
control button is constantly pressed, or when alarm situations arise. control button is incessantly pressed, or when alarm situations
In [RT-MPL] it is shown that short circuiting the buffering and arise.
retries in the IEEE 802.15.4 MAC reduces packet delays. Message loss
is reduced by adding a real-time packet selection procedure before
submitting a packet to the MAC.
Guaranteeing timeliness is intimately related to the density of the Guaranteeing timeliness is intimately related to the density of the
MPL routers. In ideal circumstances the message is propagated as a MPL routers. In ideal circumstances the message is propagated as a
single wave through the network, such that the maximum delay is single wave through the network, such that the maximum delay is
related to the number of hops times the smallest repetition interval related to the number of hops times the smallest repetition interval
of MPL. Each forwarder that receives the message, passes the message of MPL. Each forwarder that receives the message passes the message
on to the next hop by repeating the message. When several copies of on to the next hop by repeating the message. When several copies of
a message reach the forwarder, it is specified that the copy need not a message reach the forwarder, it is specified that the copy need not
be repeated. Repetition of the message can be inhibited by a small be repeated. Repetition of the message can be inhibited by a small
value of k. To assure timeliness, the value of k should be chosen value of k. To assure timeliness, the value of k should be chosen
high enough to make sure that messages are repeated at the first high enough to make sure that messages are repeated at the first
arrival of the message in the forwarder. However, a network that is arrival of the message in the forwarder. However, a network that is
too dense leads to a saturation of the medium that can only be too dense leads to a saturation of the medium that can only be
prevented by selecting a low value of k. Consequently, timeliness is prevented by selecting a low value of k. Consequently, timeliness is
assured by choosing a relatively high value of k but assuring at the assured by choosing a relatively high value of k but assuring at the
same time a low enough density of forwarders to reduce the risk of same time a low enough density of forwarders to reduce the risk of
medium saturation. Depending on the reliability of the network medium saturation. Depending on the reliability of the network
channels, it is advisable to choose the network such that at least 2 channels, it is advisable to choose the network such that at least 2
forwarders per hop repeat messages to the same set of destinations. forwarders per hop repeat messages to the same set of destinations.
There are no rules about selecting forwarders for MPL. In buildings There are no rules about selecting forwarders for MPL. In buildings
with central management tools, the forwarders can be selected, but in with central management tools, the forwarders can be selected, but in
the home is not possible to automatically configure the forwarder the home is not possible to automatically configure the forwarder
topology at this moment. topology at the time of writing this document.
4.1.8. Security 4.1.8. Security
In order to support low-cost devices and devices running on battery, In order to support low-cost devices and devices running on a
RPL MAY use either unsecured messages or secured messages. If RPL is battery, RPL uses either unsecured messages or secured messages. If
used with unsecured messages, link layer security SHOULD be used (see RPL is used with unsecured messages, link layer security is a minimum
Section 7.1). If RPL is used with secured messages, the following security requirement (see Section 7). If RPL is used with secured
RPL security parameter values SHOULD be used: messages, the following RPL security parameter values are
recommended:
o T = '0': Do not use timestamp in the Counter Field. o T = '0': Do not use timestamp in the Counter Field.
o Algorithm = '0': Use CCM with AES-128 o Algorithm = '0': Use CCM with AES-128
o KIM = '10': Use group key, Key Source present, Key Index present o KIM = '10': Use group key, Key Source present, Key Index present
o LVL = 0: Use MAC-32 o LVL = 0: Use MAC-32
4.1.9. P2P communications 4.1.9. P2P communications
[RFC6997] MUST be used to accommodate P2P traffic, which is typically [RFC6997] is recommended to accommodate P2P traffic, which is
substantial in home and building automation networks. typically substantial in home and building automation networks.
4.1.10. IPv6 address configuration 4.1.10. IPv6 address configuration
Assigned IP addresses MUST be routable and unique within the routing Assigned IP addresses follow IETF standards to be routable and unique
domain. within the routing domain.
4.2. Layer 2 features 4.2. Layer 2 features
No particular requirements exist for layer 2 but for the ones cited No particular requirements exist for layer 2 but for the ones cited
in the IP over Foo RFCs. (See Section 2.3) in the IP over Foo RFCs. (See Section 2.3)
4.2.1. Specifics about layer-2 4.2.1. Specifics about layer-2
Not applicable Not applicable
skipping to change at page 16, line 8 skipping to change at page 16, line 24
Not applicable Not applicable
4.2.4. MLE and other things 4.2.4. MLE and other things
Not applicable Not applicable
4.3. Recommended Configuration Defaults and Ranges 4.3. Recommended Configuration Defaults and Ranges
The following sections describe the recommended parameter values for The following sections describe the recommended parameter values for
RPL-P2P and Trickle. P2P-RPL and Trickle.
4.3.1. Trickle parameters 4.3.1. Trickle parameters
Trickle is used to distribute network parameter values to all nodes Trickle is used to distribute network parameter values to all nodes
without stringent time restrictions. Trickle parameter values are: without stringent time restrictions. The recommended Trickle
parameter values are:
o DIOIntervalMin 4 = 16 ms o DIOIntervalMin 4 = 16 ms
o DIOIntervalDoublings 14 o DIOIntervalDoublings 14
o DIORedundancyConstant 1 o DIORedundancyConstant 1
4.3.2. Other Parameters 4.3.2. Other Parameters
This section discusses the RPL-P2P parameters. This section discusses the P2P-RPL parameters.
RPL-P2P [RFC6997] provides the features requested by [RFC5826] and P2P-RPL [RFC6997] provides the features requested by [RFC5826] and
[RFC5867]. RPL-P2P uses a subset of the frame formats and features [RFC5867]. P2P-RPL uses a subset of the frame formats and features
defined for RPL [RFC6550] but may be combined with RPL frame flows in defined for RPL [RFC6550] but may be combined with RPL frame flows in
advanced deployments. advanced deployments.
Parameter values for RPL-P2P are: The recommended parameter values for P2P-RPL are:
o MinHopRankIncrease 1 o MinHopRankIncrease 1
o MaxRankIncrease 0 o MaxRankIncrease 0
o MaxRank 6 o MaxRank 6
o Objective function: OF0 o Objective function: OF0
5. MPL Profile 5. MPL Profile
MPL is used to distribute values to groups of devices. In MPL, based MPL is used to distribute values to groups of devices. Using MPL,
on Trickle algorithm, also timeliness should be guaranteed. A based on the Trickle algorithm, timeliness should also be guaranteed.
deadline of 200 ms needs to be met when human action is followed by A deadline of 200 ms needs to be met when human action is followed by
an immediately observable action such as switching on lights. The an immediately observable action such as switching on lights. The
deadline needs to be met in a building where the number of hops from deadline needs to be met in a building where the number of hops from
seed to destination varies between 1 and 10. seed to destination varies between 1 and 10.
5.1. Recommended configuration Defaults and Ranges 5.1. Recommended configuration Defaults and Ranges
In [RT-MPL] the large contribution of MAC delays is explained when 5.1.1. Real-Time optimizations
considering MPL intervals between 10 to 100 ms to meet the 200 ms
deadline. It is recommended to set the number of buffers in the MAC
to 1 and not to repeat a failed transmission after a MAC back-off
interval. MPL already repeats the transmission in a controlled
fashion and the MAC should not add to these repetitions.
When the load on the wireless medium is high, [RT-MPL] recommends to When the network is heavily loaded, MAC delays contribute
add a real-time layer between MPL and MAC to throw away too late significantly to the end to end delays when MPL intervals between 10
to 100 ms are used to meet the 200 ms deadline. It is possible to
set the number of buffers in the MAC to 1 and set the number of Back-
off repetitions to 1. The number of MPL repetitions compensates for
the reduced probability of transmission per MAC invocation [RT-MPL].
In addition, end to end delays and message losses are reduced, by
adding a real-time layer between MPL and MAC to throw away too late
messages and favour the most recent ones. messages and favour the most recent ones.
5.1.1. Trickle parameters 5.1.2. Trickle parameters
This section proposes values for the Trickle parameters used by MPL This section proposes values for the Trickle parameters used by MPL
for the distribution of packets that need to meet a 200 ms deadline. for the distribution of packets that need to meet a 200 ms deadline.
The probability of meeting the deadline is increased by (1) choosing The probability of meeting the deadline is increased by (1) choosing
a small Imin value,(2) reducing the number of MPL intervals thus a small Imin value,(2) reducing the number of MPL intervals thus
reducing the load, and (3) reducing the number of MPL forwarders to reducing the load, and (3) reducing the number of MPL forwarders to
also reduce the load. also reduce the load.
The consequence of this approach is that the value of k can be larger The consequence of this approach is that the value of k can be larger
than 1 because network load reduction is already guaranteed by the than 1 because network load reduction is already guaranteed by the
skipping to change at page 17, line 48 skipping to change at page 18, line 15
o Number of repeaters receiving the broadcast message from the same o Number of repeaters receiving the broadcast message from the same
forwarder or seed. These repeaters repeat within the same Imin forwarder or seed. These repeaters repeat within the same Imin
interval, thus increasing the c counter. interval, thus increasing the c counter.
Within the first MPL interval a limited number, q, of messages can be Within the first MPL interval a limited number, q, of messages can be
transmitted. Assuming a 3 ms transmission interval, q is given by q transmitted. Assuming a 3 ms transmission interval, q is given by q
= Imin/3. Assuming that at most q message copies can reach a given = Imin/3. Assuming that at most q message copies can reach a given
forwarder within the first repeat interval of length Imin, the forwarder within the first repeat interval of length Imin, the
related MPL parameter values are suggested in the following sections. related MPL parameter values are suggested in the following sections.
5.1.1.1. Imin 5.1.2.1. Imin
Imin = 10 - 50 ms. The recommended value is Imin = 10 - 50 ms.
When Imin is chosen much smaller, the interference between the copies When Imin is chosen much smaller, the interference between the copies
leads to significant losses given that q is much smaller than the leads to significant losses given that q is much smaller than the
number of repeated packets. With much larger intervals the number of repeated packets. With much larger intervals the
probability that the deadline will be met decreases with increasing probability that the deadline will be met decreases with increasing
hop count. hop count.
5.1.1.2. Imax 5.1.2.2. Imax
Imax = 100 - 400 ms. The recommended value is Imax = 100 - 400 ms.
The value of Imax is less important than the value of max_expiration. The value of Imax is less important than the value of max_expiration.
Given an Imin value of 10 ms, the 3rd MPL interval has a value of Given an Imin value of 10 ms, the 3rd MPL interval has a value of
10*2*2 = 40 ms. When Imin has a value of 40 ms, the 3rd interval has 10*2*2 = 40 ms. When Imin has a value of 40 ms, the 3rd interval has
a value of 160 ms. Given that more than 3 intervals are unnecessary, a value of 160 ms. Given that more than 3 intervals are unnecessary,
the Imax does not contribute much to the performance. the Imax does not contribute much to the performance.
5.1.2. Other parameters 5.1.3. Other parameters
Other parameters are the k parameter and the max_expiration Other parameters are the k parameter and the max_expiration
parameter. parameter.
k > q (see condition above). Under this condition and for small k > q (see condition above). Under this condition and for small
Imin, a value of k=2 or k=3 is usually sufficient to minimize the Imin, a value of k=2 or k=3 is usually sufficient to minimize the
losses of packets in the first repeat interval. losses of packets in the first repeat interval.
max_expiration = 2 - 4. Higher values lead to more network load max_expiration = 2 - 4. Higher values lead to more network load
while generating copies which will probably not meet their deadline. while generating copies which will probably not meet their deadline.
6. Manageability Considerations 6. Manageability Considerations
Manageability is out of scope for home network scenarios. In Manageability is out of scope for home network scenarios. In
building automation scenarios, central control could be applied based building automation scenarios, central control could be applied based
on MIBs. on MIBs.
7. Security Considerations 7. Security Considerations
Refer to the security considerations of [RFC6997], [RFC6550], This section refers to the security considerations of [RFC6997],
[I-D.ietf-roll-trickle-mcast], and the counter measures discussed in [RFC6550], [I-D.ietf-roll-trickle-mcast], and the counter measures
sections 6 and 7 of [I-D.ietf-roll-security-threats]. discussed in sections 6 and 7 of [I-D.ietf-roll-security-threats].
7.1. Security considerations during initial deployment
At initial deployment the network is incrementally increased and
secured at the link layer. Wireless mesh networks are typically
secured at the link-layer in order to prevent unauthorized parties
from accessing the information exchanged over the links. It is good
practice to create a network of nodes which share the same keys for
link layer encryption and exclude nodes sending non encrypted
messages. Together with authentication of the sources, it is
possible to prevent unauthorized nodes joining the mesh. This is
ensured with the Protocol for carrying Authentication for Network
Access (PANA) Relay Element [RFC6345] with the use of PANA [RFC5191]
for network access. A new DTLS based protocol is proposed in
[I-D.kumar-dice-dtls-relay].
This recommendation is in line with the couter measures described in
section 6.1.1 of [I-D.ietf-roll-security-threats]
Unauthorized nodes can access the nodes of the mesh via a router.
End-to-end security between applications is recommended by using DTLS
[RFC6347] or TLS [RFC5246].
7.2. Security Considerations during incremental deployment
Communications network security is based on providing integrity Communications network security is based on providing integrity
protection and encryption to messages. This can be applied at protection and encryption to messages. This can be applied at
various layers in the network protocol stack based on using various various layers in the network protocol stack based on using various
credentials and a network identity. credentials and a network identity.
The credentials which are relevant in the case of RPL are: (i) the The credentials which are relevant in the case of RPL are: (i) the
credential used at the link layer in the case where link layer credential used at the link layer in the case where link layer
security is applied (see Section 7.1) or (ii) the credential used for security is applied (see Section 7.1) or (ii) the credential used for
securing RPL messages. In both cases, the assumption is that the securing RPL messages. In both cases, the assumption is that the
credential is a shared key. Therefore, there MUST be a mechanism in credential is a shared key. Therefore, a mechanism is required which
place which allows secure distribution of a shared key and allows secure distribution of a shared key and configuration of
configuration of network identity. Both MAY be done using (i) pre- network identity. Both can rely on: (i) pre-installation using an
installation using an out-of-band method, (ii) delivered securely out-of-band method, (ii) delivered securely when a device is
when a device is introduced into the network or (iii) delivered introduced into the network or (iii) delivered securely by a trusted
securely by a trusted neighbouring device. The shared key MUST be neighbouring device. The shared key MUST be stored in a secure
stored in a secure fashion which makes it difficult to be read by an fashion which makes it difficult to be read by an unauthorized party.
unauthorized party.
Securely delivering a key means that the delivery mechanism MUST have Securely delivering a key requires a delivery mechanism that has data
data origin authentication, confidentiality and integrity protection. origin authentication, confidentiality and integrity protection. On
On reception of the delivered key, freshness of the delivered key reception of the delivered key, freshness of the delivered key needs
MUST be ensured. Securely storing a key means that the storage to be ensured. Securely storing a key requires a storage mechanism
mechanism MUST have confidentiality and integrity protection and MUST that has confidentiality and integrity protection and is only
only be accessible by an authorized party. accessible by an authorized party.
The network security domain is typically distinct from the
application security domains within the network, of which there may
be more than one. For this reason, end-to-end security between
applications is recommended by using DTLS [RFC6347] or TLS [RFC5246].
7.1. Security considerations during initial deployment
Wireless mesh networks are typically secured at the link layer in
order to prevent unauthorized parties from accessing the information
exchanged over the links. It is good practice to create a network of
nodes which share the same keys for link layer security and exclude
nodes sending unsecured messages. With per-message data origin
authentication, it is possible to prevent unauthorized nodes joining
the mesh.
At initial deployment the network is secured by consecutively
securing nodes at the link layer, thus building a network of secured
nodes. The Protocol for carrying Authentication for Network Access
(PANA) Relay Element [RFC6345] in conjunction with PANA [RFC5191]
provides a framework for network access and delivery of common link
keys. A new DTLS-based protocol is proposed in
[I-D.kumar-dice-dtls-relay].
For building control an installer will probably use an installation
tool that establishes a secure communication path with the joining
node. In the home, nodes can be visually inspected by the home owner
and simple measures like pushing buttons simultaneously on joint and
joining devices is probably sufficient.
This recommendation is in line with the countermeasures described in
section 6.1.1 of [I-D.ietf-roll-security-threats]
7.2. Security Considerations during incremental deployment
When nodes are lost, no additional security measures are needed, the
network remains secure as before by not allowing the addition of new
nodes. New nodes can be added by using the same protocols used for
initial deployment. Some protocols may need a state change to a
subset of the secured nodes, other protocols only need the presence
of a "trusted" installation node [RFC6345], [RFC5191], or
[I-D.kumar-dice-dtls-relay].
7.3. Security Considerations for P2P uses 7.3. Security Considerations for P2P uses
Refer to the security considerations of [RFC6997]. Many initiatives Refer to the security considerations of [RFC6997]. Many initiatives
are under way to provide light weight security such as: are under way to provide lighter weight security such as:
[I-D.ietf-dice-profile] and [I-D.keoh-dice-multicast-security]. [I-D.ietf-dice-profile] and [I-D.keoh-dice-multicast-security]
7.4. MPL routing 7.4. MPL routing
The routing of MPL is determined by the enabling of the interfaces The routing of MPL is determined by the enabling of the interfaces
for specified Multicast addresses. The specification of these for specified Multicast addresses. The specification of these
addresses can be done via a CoAP application as specified in addresses can be done via a CoAP application as specified in
[I-D.ietf-core-groupcomm]. An alternative is the creation of a MPL [I-D.ietf-core-groupcomm]. An alternative is the creation of a MPL
MIB and use of SNMPv3 [RFC3411] or CoMI [I-D.vanderstok-core-comi] to MIB and use of SNMPv3 [RFC3411] or equivalent techniques to specify
specify the Multicast addresses in the MIB. The application of the Multicast addresses in the MIB. The application of security
security measures for the specification of the multicast addresses measures for the specification of the multicast addresses assures
assures that the routing of MPL packets is secured. that the routing of MPL packets is secured.
7.5. RPL Security features 7.5. RPL Security features
This section follows the structure of section 7, "RPL security This section follows the structure of section 7, "RPL security
features" of [I-D.ietf-roll-security-threats], where a thorough features" of [I-D.ietf-roll-security-threats], where a thorough
analysis of security threats and proposed counter measures relevant analysis of security threats and proposed counter measures relevant
to RPL and MPL are done. to RPL and MPL are done.
In accordance with section 7.1 of [I-D.ietf-roll-security-threats], In accordance with section 7.1 of [I-D.ietf-roll-security-threats],
"Confidentiality features", a secured RPL protocol must implement "Confidentiality features", a secured RPL protocol implements payload
payload protection, as explained in Section 7.1 of this document. protection, as explained in Section 7 of this document. The
The attributes key-length and life-time of the keys depend on attributes key-length and life-time of the keys depend on operational
operational conditions, maintenance and installation procedures. conditions, maintenance and installation procedures.
Section 7.2 of this document recommends measures to assure integrity Section 7.1 and Section 7.2 of this document recommend link-layer
in accordance with section 7.2 of [I-D.ietf-roll-security-threats], measures to assure integrity in accordance with section 7.2 of
"Integrity features". [I-D.ietf-roll-security-threats], "Integrity features".
The provision of multiple paths recommended in section 7.3 The provision of multiple paths recommended in section 7.3
"Availability features" of [I-D.ietf-roll-security-threats] is also "Availability features" of [I-D.ietf-roll-security-threats] is also
recommended from a reliability point of view. Randomly choosing recommended from a reliability point of view. Randomly choosing
paths MAY be supported. paths is a possibility.
Key management discussed in section 7.4, "Key Management" of Key management discussed in section 7.4, "Key Management" of
[I-D.ietf-roll-security-threats], is not standardized and discussions [I-D.ietf-roll-security-threats], is not standardized and discussions
continue. continue.
Section 7.5, "Considerations on Matching Application Domain Needs" of Section 7.5, "Considerations on Matching Application Domain Needs" of
[I-D.ietf-roll-security-threats] applies as such. [I-D.ietf-roll-security-threats] applies as such.
8. Other related protocols 8. Other related protocols
Application transport protocols may be CoAP over UDP or equivalents. Application and transport protocols used in home and building
Typically, UDP is used for IP transport to keep down the application automation domains are expected to mostly consist in CoAP over UDP,
response time and bandwidth overhead. or equivalents. Typically, UDP is used for IP transport to keep down
the application response time and bandwidth overhead. CoAP is used
Several features required by [RFC5826], [RFC5867] challenge the P2P at the application layer to reduce memory footprint and bandwidth
paths provided by RPL. Appendix A reviews these challenges. In some requirements.
cases, a node may need to spontaneously initiate the discovery of a
path towards a desired destination that is neither the root of a DAG,
nor a destination originating DAO signalling. Furthermore, P2P paths
provided by RPL are not satisfactory in all cases because they
involve too many intermediate nodes before reaching the destination.
9. IANA Considerations 9. IANA Considerations
No considerations for IANA pertain to this document. No considerations for IANA pertain to this document.
10. Acknowledgements 10. Acknowledgements
This document reflects discussions and remarks from several This document reflects discussions and remarks from several
individuals including (in alphabetical order): Mukul Goyal, Sandeep individuals including (in alphabetical order): Mukul Goyal, Sandeep
Kumar, Jerry Martocci, Charles Perkins, Michael Richardson, and Zach Kumar, Jerry Martocci, Charles Perkins, Michael Richardson, and Zach
skipping to change at page 22, line 27 skipping to change at page 23, line 4
threats draft. threats draft.
o Added text to DODAG repair sub-section o Added text to DODAG repair sub-section
Changes from version 3 to version 4. Changes from version 3 to version 4.
o Renumbered sections and moved text to conform to applicability o Renumbered sections and moved text to conform to applicability
template template
o Extended MPL parameter value text o Extended MPL parameter value text
o Added references to building control products o Added references to building control products
Changes from version 4 to version 5.
o Large editing effort to streamline text
o Rearranged Normative and Informative references
o Replaced RFC2119 terminology by non-normative terminology
o Rearranged text of section 7, 7.1, and 7.2 to agree with the
intention of section 7.2
12. References 12. References
12.1. Normative References 12.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3411] Harrington, D., Presuhn, R., and B. Wijnen, "An
Architecture for Describing Simple Network Management
Protocol (SNMP) Management Frameworks", STD 62, RFC 3411,
December 2002.
[RFC4944] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler, [RFC4944] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler,
"Transmission of IPv6 Packets over IEEE 802.15.4 "Transmission of IPv6 Packets over IEEE 802.15.4
Networks", RFC 4944, September 2007. Networks", RFC 4944, September 2007.
[RFC5191] Forsberg, D., Ohba, Y., Patil, B., Tschofenig, H., and A. [RFC5191] Forsberg, D., Ohba, Y., Patil, B., Tschofenig, H., and A.
Yegin, "Protocol for Carrying Authentication for Network Yegin, "Protocol for Carrying Authentication for Network
Access (PANA)", RFC 5191, May 2008. Access (PANA)", RFC 5191, May 2008.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, August 2008. (TLS) Protocol Version 1.2", RFC 5246, August 2008.
skipping to change at page 23, line 25 skipping to change at page 24, line 9
5826, April 2010. 5826, April 2010.
[RFC5867] Martocci, J., De Mil, P., Riou, N., and W. Vermeylen, [RFC5867] Martocci, J., De Mil, P., Riou, N., and W. Vermeylen,
"Building Automation Routing Requirements in Low-Power and "Building Automation Routing Requirements in Low-Power and
Lossy Networks", RFC 5867, June 2010. Lossy Networks", RFC 5867, June 2010.
[RFC6282] Hui, J. and P. Thubert, "Compression Format for IPv6 [RFC6282] Hui, J. and P. Thubert, "Compression Format for IPv6
Datagrams over IEEE 802.15.4-Based Networks", RFC 6282, Datagrams over IEEE 802.15.4-Based Networks", RFC 6282,
September 2011. September 2011.
[RFC6345] Duffy, P., Chakrabarti, S., Cragie, R., Ohba, Y., and A.
Yegin, "Protocol for Carrying Authentication for Network
Access (PANA) Relay Element", RFC 6345, August 2011.
[RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer [RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer
Security Version 1.2", RFC 6347, January 2012. Security Version 1.2", RFC 6347, January 2012.
[RFC6550] Winter, T., Thubert, P., Brandt, A., Hui, J., Kelsey, R., [RFC6550] Winter, T., Thubert, P., Brandt, A., Hui, J., Kelsey, R.,
Levis, P., Pister, K., Struik, R., Vasseur, JP., and R. Levis, P., Pister, K., Struik, R., Vasseur, JP., and R.
Alexander, "RPL: IPv6 Routing Protocol for Low-Power and Alexander, "RPL: IPv6 Routing Protocol for Low-Power and
Lossy Networks", RFC 6550, March 2012. Lossy Networks", RFC 6550, March 2012.
[RFC6551] Vasseur, JP., Kim, M., Pister, K., Dejean, N., and D. [RFC6551] Vasseur, JP., Kim, M., Pister, K., Dejean, N., and D.
Barthel, "Routing Metrics Used for Path Calculation in Barthel, "Routing Metrics Used for Path Calculation in
skipping to change at page 24, line 5 skipping to change at page 24, line 30
[RFC6554] Hui, J., Vasseur, JP., Culler, D., and V. Manral, "An IPv6 [RFC6554] Hui, J., Vasseur, JP., Culler, D., and V. Manral, "An IPv6
Routing Header for Source Routes with the Routing Protocol Routing Header for Source Routes with the Routing Protocol
for Low-Power and Lossy Networks (RPL)", RFC 6554, March for Low-Power and Lossy Networks (RPL)", RFC 6554, March
2012. 2012.
[RFC6997] Goyal, M., Baccelli, E., Philipp, M., Brandt, A., and J. [RFC6997] Goyal, M., Baccelli, E., Philipp, M., Brandt, A., and J.
Martocci, "Reactive Discovery of Point-to-Point Routes in Martocci, "Reactive Discovery of Point-to-Point Routes in
Low-Power and Lossy Networks", RFC 6997, August 2013. Low-Power and Lossy Networks", RFC 6997, August 2013.
[I-D.ietf-6lo-lowpanz] [RFC6998] Goyal, M., Baccelli, E., Brandt, A., and J. Martocci, "A
Brandt, A. and J. Buron, "Transmission of IPv6 packets Mechanism to Measure the Routing Metrics along a Point-to-
over ITU-T G.9959 Networks", draft-ietf-6lo-lowpanz-05 Point Route in a Low-Power and Lossy Network", RFC 6998,
(work in progress), May 2014. August 2013.
[RFC7102] Vasseur, JP., "Terms Used in Routing for Low-Power and
Lossy Networks", RFC 7102, January 2014.
[I-D.ietf-roll-trickle-mcast] [I-D.ietf-roll-trickle-mcast]
Hui, J. and R. Kelsey, "Multicast Protocol for Low power Hui, J. and R. Kelsey, "Multicast Protocol for Low power
and Lossy Networks (MPL)", draft-ietf-roll-trickle- and Lossy Networks (MPL)", draft-ietf-roll-trickle-
mcast-09 (work in progress), April 2014. mcast-09 (work in progress), April 2014.
[I-D.ietf-roll-security-threats] [I-D.ietf-roll-security-threats]
Tsao, T., Alexander, R., Dohler, M., Daza, V., Lozano, A., Tsao, T., Alexander, R., Dohler, M., Daza, V., Lozano, A.,
and M. Richardson, "A Security Threat Analysis for Routing and M. Richardson, "A Security Threat Analysis for Routing
Protocol for Low-power and lossy networks (RPL)", draft- Protocol for Low-power and lossy networks (RPL)", draft-
ietf-roll-security-threats-07 (work in progress), June ietf-roll-security-threats-11 (work in progress), October
2014. 2014.
[I-D.ietf-roll-terminology] [IEEE802.15.4]
Vasseur, J., "Terms used in Routing for Low power And "IEEE 802.15.4 - Standard for Local and metropolitan area
Lossy Networks", draft-ietf-roll-terminology-13 (work in networks -- Part 15.4: Low-Rate Wireless Personal Area
progress), October 2013. Networks", <IEEE Standard 802.15.4>.
[G.9959] "ITU-T G.9959 Short range narrow-band digital
radiocommunication transceivers - PHY and MAC layer
specifications", <ITU-T G.9959>.
12.2. Informative References
[RFC3411] Harrington, D., Presuhn, R., and B. Wijnen, "An
Architecture for Describing Simple Network Management
Protocol (SNMP) Management Frameworks", STD 62, RFC 3411,
December 2002.
[RFC6345] Duffy, P., Chakrabarti, S., Cragie, R., Ohba, Y., and A.
Yegin, "Protocol for Carrying Authentication for Network
Access (PANA) Relay Element", RFC 6345, August 2011.
[RFC7228] Bormann, C., Ersue, M., and A. Keranen, "Terminology for
Constrained-Node Networks", RFC 7228, May 2014.
[I-D.ietf-6lo-lowpanz]
Brandt, A. and J. Buron, "Transmission of IPv6 packets
over ITU-T G.9959 Networks", draft-ietf-6lo-lowpanz-07
(work in progress), September 2014.
[I-D.ietf-dice-profile] [I-D.ietf-dice-profile]
Hartke, K. and H. Tschofenig, "A DTLS 1.2 Profile for the Tschofenig, H., "A Datagram Transport Layer Security
Internet of Things", draft-ietf-dice-profile-01 (work in (DTLS) 1.2 Profile for the Internet of Things", draft-
progress), May 2014. ietf-dice-profile-04 (work in progress), August 2014.
[I-D.keoh-dice-multicast-security] [I-D.keoh-dice-multicast-security]
Keoh, S., Kumar, S., Garcia-Morchon, O., Dijk, E., and A. Keoh, S., Kumar, S., Garcia-Morchon, O., Dijk, E., and A.
Rahman, "DTLS-based Multicast Security in Constrained Rahman, "DTLS-based Multicast Security in Constrained
Environments", draft-keoh-dice-multicast-security-07 (work Environments", draft-keoh-dice-multicast-security-08 (work
in progress), May 2014. in progress), July 2014.
[I-D.kumar-dice-dtls-relay] [I-D.kumar-dice-dtls-relay]
Kumar, S., Keoh, S., and O. Garcia-Morchon, "DTLS Relay Kumar, S., Keoh, S., and O. Garcia-Morchon, "DTLS Relay
for Constrained Environments", draft-kumar-dice-dtls- for Constrained Environments", draft-kumar-dice-dtls-
relay-01 (work in progress), April 2014. relay-01 (work in progress), April 2014.
[I-D.ietf-core-groupcomm] [I-D.ietf-core-groupcomm]
Rahman, A. and E. Dijk, "Group Communication for CoAP", Rahman, A. and E. Dijk, "Group Communication for CoAP",
draft-ietf-core-groupcomm-19 (work in progress), June draft-ietf-core-groupcomm-25 (work in progress), September
2014. 2014.
[I-D.vanderstok-core-comi]
Stok, P. and B. Greevenbosch, "CoAp Management
Interfaces", draft-vanderstok-core-comi-04 (work in
progress), May 2014.
[IEEE802.15.4]
"IEEE 802.15.4 - Standard for Local and metropolitan area
networks -- Part 15.4: Low-Rate Wireless Personal Area
Networks", <IEEE Standard 802.15.4>.
[G.9959] "ITU-T G.9959 Short range narrow-band digital
radiocommunication transceivers - PHY and MAC layer
specifications", <ITU-T G.9959>.
[BCsurvey]
Kastner, W., Neugschwandtner, G., Soucek, S., and H.
Newman, "Communication Systems for Building Automation and
Control", Proceedings of the IEEE Vol 93, No 6, June 2005.
12.2. Informative References
[SOFT11] Baccelli, E., Phillip, M., and M. Goyal, "The P2P-RPL [SOFT11] Baccelli, E., Phillip, M., and M. Goyal, "The P2P-RPL
Routing Protocol for IPv6 Sensor Networks: Testbed Routing Protocol for IPv6 Sensor Networks: Testbed
Experiments", Proceedings of the Conference on Software Experiments", Proceedings of the Conference on Software
Telecommunications and Computer Networks, Split, Croatia,, Telecommunications and Computer Networks, Split, Croatia,,
September 2011. September 2011.
[INTEROP12] [INTEROP12]
Baccelli, E., Phillip, M., Brandt, A., Valev , H., and J. Baccelli, E., Phillip, M., Brandt, A., Valev , H., and J.
Buron , "Report on P2P-RPL Interoperability Testing", Buron , "Report on P2P-RPL Interoperability Testing",
RR-7864 INRIA Research Report RR-7864, January 2012. RR-7864 INRIA Research Report RR-7864, January 2012.
skipping to change at page 26, line 8 skipping to change at page 26, line 41
clanton_lighting_control_report_0411.pdf, February 2014. clanton_lighting_control_report_0411.pdf, February 2014.
[RTN2011] Holtman, K. and P. van der Stok, "Real-time routing for [RTN2011] Holtman, K. and P. van der Stok, "Real-time routing for
low-latency 802.15.4 control networks", International low-latency 802.15.4 control networks", International
Workshop on Real-Time Networks; Euromicro Conference on Workshop on Real-Time Networks; Euromicro Conference on
Real-Time Systems, July 2011. Real-Time Systems, July 2011.
[MEAS] Holtman, K., "Connectivity loss in large scale IEEE [MEAS] Holtman, K., "Connectivity loss in large scale IEEE
802.15.4 network", Private Communication, November 2013. 802.15.4 network", Private Communication, November 2013.
[BCsurvey]
Kastner, W., Neugschwandtner, G., Soucek, S., and H.
Newman, "Communication Systems for Building Automation and
Control", Proceedings of the IEEE Vol 93, No 6, June 2005.
Appendix A. RPL shortcomings in home and building deployments Appendix A. RPL shortcomings in home and building deployments
A.1. Risk of undesired long P2P routes A.1. Risk of undesired long P2P routes
The DAG, being a tree structure is formed from a root. If nodes The DAG, being a tree structure is formed from a root. If nodes
residing in different branches have a need for communicating residing in different branches have a need for communicating
internally, DAG mechanisms provided in RPL [RFC6550] will propagate internally, DAG mechanisms provided in RPL [RFC6550] will propagate
traffic towards the root, potentially all the way to the root, and traffic towards the root, potentially all the way to the root, and
down along another branch. In a typical example two nodes could down along another branch [RFC6998]. In a typical example two nodes
reach each other via just two router nodes but in unfortunate cases, could reach each other via just two router nodes but in unfortunate
RPL may send traffic three hops up and three hops down again. This cases, RPL may send traffic three hops up and three hops down again.
leads to several undesired phenomena described in the following This leads to several undesired phenomena described in the following
sections sections
A.1.1. Traffic concentration at the root A.1.1. Traffic concentration at the root
If many P2P data flows have to move up towards the root to get down If many P2P data flows have to move up towards the root to get down
again in another branch there is an increased risk of congestion the again in another branch there is an increased risk of congestion the
nearer to the root of the DAG the data flows. Due to the broadcast nearer to the root of the DAG the data flows. Due to the broadcast
nature of RF systems any child node of the root is not just directing nature of RF systems any child node of the root is not just directing
RF power downwards its sub-tree but just as much upwards towards the RF power downwards its sub-tree but just as much upwards towards the
root; potentially jamming other MP2P traffic leaving the tree or root; potentially jamming other MP2P traffic leaving the tree or
skipping to change at page 29, line 4 skipping to change at page 29, line 42
Anders Brandt Anders Brandt
Sigma Designs Sigma Designs
Email: abr@sdesigns.dk Email: abr@sdesigns.dk
Emmanuel Baccelli Emmanuel Baccelli
INRIA INRIA
Email: Emmanuel.Baccelli@inria.fr Email: Emmanuel.Baccelli@inria.fr
Robert Cragie Robert Cragie
Gridmerge ARM
Email: robert.cragie@gridmerge.com Email: robert.cragie@gridmerge.com
Peter van der Stok Peter van der Stok
Consultant Consultant
Email: consultancy@vanderstok.org Email: consultancy@vanderstok.org
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