draft-ietf-roll-applicability-home-building-01.txt   draft-ietf-roll-applicability-home-building-02.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: February 18, 2014 INRIA Expires: August 17, 2014 INRIA
R. Cragie R. Cragie
Gridmerge Gridmerge
P. van der Stok P. van der Stok
Consultant Consultant
August 17, 2013 February 13, 2014
Applicability Statement: The use of the RPL protocol set in Home Applicability Statement: The use of the RPL protocol set in Home
Automation and Building Control Automation and Building Control
draft-ietf-roll-applicability-home-building-01 draft-ietf-roll-applicability-home-building-02
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 RPL protocols to implement the features required in and use of RPL protocols to implement the features required for
building and home environments. 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
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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 February 18, 2014. This Internet-Draft will expire on August 17, 2014.
Copyright Notice Copyright Notice
Copyright (c) 2013 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
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
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. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
1.2. Required Reading . . . . . . . . . . . . . . . . . . . . 3 1.2. Required Reading . . . . . . . . . . . . . . . . . . . . 4
1.3. Out of scope requirements . . . . . . . . . . . . . . . . 3 1.3. Out of scope requirements . . . . . . . . . . . . . . . . 4
2. Deployment Scenario . . . . . . . . . . . . . . . . . . . . . 3 2. Deployment Scenario . . . . . . . . . . . . . . . . . . . . . 4
2.1. Network Topologies . . . . . . . . . . . . . . . . . . . 4 2.1. Network Topologies . . . . . . . . . . . . . . . . . . . 5
2.2. Traffic Characteristics . . . . . . . . . . . . . . . . . 5 2.2. Traffic Characteristics . . . . . . . . . . . . . . . . . 6
2.2.1. General . . . . . . . . . . . . . . . . . . . . . . . 6 2.2.1. General . . . . . . . . . . . . . . . . . . . . . . . 7
2.2.2. Source-sink (SS) communication paradigm . . . . . . . 6 2.2.2. Source-sink (SS) communication paradigm . . . . . . . 7
2.2.3. Publish-subscribe (PS, or pub/sub)) communication 2.2.3. Publish-subscribe (PS, or pub/sub)) communication
paradigm . . . . . . . . . . . . . . . . . . . . . . 6 paradigm . . . . . . . . . . . . . . . . . . . . . . 7
2.2.4. Peer-to-peer (P2P) communication paradigm . . . . . . 7 2.2.4. Peer-to-peer (P2P) communication paradigm . . . . . . 8
2.2.5. Peer-to-multipeer (P2MP) communication paradigm . . . 7 2.2.5. Peer-to-multipeer (P2MP) communication paradigm . . . 8
2.2.6. N-cast communication paradigm . . . . . . . . . . . . 7 2.2.6. N-cast communication paradigm . . . . . . . . . . . . 8
2.2.7. RPL applicability per communication paradigm . . . . 7 2.2.7. RPL applicability per communication paradigm . . . . 8
2.3. Layer-2 applicability . . . . . . . . . . . . . . . . . . 8 2.3. Layer-2 applicability . . . . . . . . . . . . . . . . . . 10
3. Using RPL to meet Functional Requirements . . . . . . . . . . 9 3. Using RPL to meet Functional Requirements . . . . . . . . . . 10
4. RPL Profile . . . . . . . . . . . . . . . . . . . . . . . . . 9 4. RPL Profile . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.1. RPL Features . . . . . . . . . . . . . . . . . . . . . . 9 4.1. RPL Features . . . . . . . . . . . . . . . . . . . . . . 11
4.1.1. RPL Instances . . . . . . . . . . . . . . . . . . . . 10 4.1.1. RPL Instances . . . . . . . . . . . . . . . . . . . . 11
4.1.2. Storing vs. Non-Storing Mode . . . . . . . . . . . . 10 4.1.2. Storing vs. Non-Storing Mode . . . . . . . . . . . . 12
4.1.3. DAO Policy . . . . . . . . . . . . . . . . . . . . . 10 4.1.3. DAO Policy . . . . . . . . . . . . . . . . . . . . . 12
4.1.4. Path Metrics . . . . . . . . . . . . . . . . . . . . 10 4.1.4. Path Metrics . . . . . . . . . . . . . . . . . . . . 12
4.1.5. Objective Function . . . . . . . . . . . . . . . . . 10 4.1.5. Objective Function . . . . . . . . . . . . . . . . . 12
4.1.6. DODAG Repair . . . . . . . . . . . . . . . . . . . . 11 4.1.6. DODAG Repair . . . . . . . . . . . . . . . . . . . . 12
4.1.7. Multicast . . . . . . . . . . . . . . . . . . . . . . 11 4.1.7. Multicast . . . . . . . . . . . . . . . . . . . . . . 12
4.1.8. Security . . . . . . . . . . . . . . . . . . . . . . 11 4.1.8. Security . . . . . . . . . . . . . . . . . . . . . . 13
4.1.9. P2P communications . . . . . . . . . . . . . . . . . 12 4.1.9. P2P communications . . . . . . . . . . . . . . . . . 13
4.1.10. IPv6 adddress configuration . . . . . . . . . . . . . 12 4.1.10. IPv6 adddress configuration . . . . . . . . . . . . . 13
4.2. Layer 2 features . . . . . . . . . . . . . . . . . . . . 12 4.2. Layer 2 features . . . . . . . . . . . . . . . . . . . . 14
4.3. Recommended Configuration Defaults and Ranges . . . . . . 12 4.3. Recommended Configuration Defaults and Ranges . . . . . . 14
4.3.1. RPL-P2P parameters . . . . . . . . . . . . . . . . . 12 4.3.1. RPL-P2P parameters . . . . . . . . . . . . . . . . . 14
4.3.2. Trickle parameters . . . . . . . . . . . . . . . . . 13 4.3.2. Trickle parameters . . . . . . . . . . . . . . . . . 14
4.3.3. MPL parameters . . . . . . . . . . . . . . . . . . . 13 4.3.3. MPL parameters . . . . . . . . . . . . . . . . . . . 14
5. Manageability Considerations . . . . . . . . . . . . . . . . 13 5. Manageability Considerations . . . . . . . . . . . . . . . . 15
6. Security Considerations . . . . . . . . . . . . . . . . . . . 13 6. Security Considerations . . . . . . . . . . . . . . . . . . . 15
6.1. Security Considerations for distribution of credentials 6.1. Security context considerations . . . . . . . . . . . . . 15
required for RPL . . . . . . . . . . . . . . . . . . . . 14 6.2. MPL routing . . . . . . . . . . . . . . . . . . . . . . . 16
6.2. Security Considerations for P2P uses . . . . . . . . . . 14 6.3. Security Considerations for distribution of credentials
7. Other related protocols . . . . . . . . . . . . . . . . . . . 14 required for RPL . . . . . . . . . . . . . . . . . . . . 16
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 6.4. Security Considerations for P2P uses . . . . . . . . . . 16
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14
10. Changelog . . . . . . . . . . . . . . . . . . . . . . . . . . 15 7. Other related protocols . . . . . . . . . . . . . . . . . . . 17
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 15 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
11.1. Normative References . . . . . . . . . . . . . . . . . . 15 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 17
11.2. Informative References . . . . . . . . . . . . . . . . . 17 10. Changelog . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Appendix A. RPL shortcomings in home and building deployments . 17 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 18
A.1. Risk of undesired long P2P routes . . . . . . . . . . . . 17 11.1. Normative References . . . . . . . . . . . . . . . . . . 18
A.1.1. Traffic concentration at the root . . . . . . . . . . 17 11.2. Informative References . . . . . . . . . . . . . . . . . 20
A.1.2. Excessive battery consumption in source nodes . . . . 18 Appendix A. RPL shortcomings in home and building deployments . 21
A.2. Risk of delayed route repair . . . . . . . . . . . . . . 18 A.1. Risk of undesired long P2P routes . . . . . . . . . . . . 21
A.2.1. Broken service . . . . . . . . . . . . . . . . . . . 18 A.1.1. Traffic concentration at the root . . . . . . . . . . 21
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18 A.1.2. Excessive battery consumption in source nodes . . . . 22
A.2. Risk of delayed route repair . . . . . . . . . . . . . . 22
A.2.1. Broken service . . . . . . . . . . . . . . . . . . . 22
Appendix B. Communication failures . . . . . . . . . . . . . . . 22
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 24
1. Introduction 1. Introduction
Home automation and building control application spaces share a Home automation and building control application spaces share a
substantial number of properties. The purpose of this document is to substantial number of properties.
give guidance in the use of the RPL protocol suite to provide the
features required by the requirements documents "Home Automation o Both (home and building) can be disconnected from the ISP and they
Routing Requirements in Low-Power and Lossy Networks" [RFC5826] and will (must) continue to provide control to the occupants of the
"Building Automation Routing Requirements in Low-Power and Lossy home c.q. building. This has an impact on routing because most
Networks" [RFC5867]. control communication does (must) not pass via the border routers.
o Both are confronted with unreliable links and want instant very
reliable reactions. This has impact on routing because of
timeliness and multipath routing.
o The difference between the two mostly appears in the
commissioning, maintenance and user interface which does not
affect the routing.
So the focus of this applicability document is control in buildings
and home, involving: reliability, timeliness, and local routing.
The purpose of this document is to give guidance in the use of the
RPL protocol suite to provide the features required by the
requirements documents "Home Automation Routing Requirements in Low-
Power and Lossy Networks" [RFC5826] and "Building Automation Routing
Requirements in Low-Power and Lossy Networks" [RFC5867].
1.1. Terminology 1.1. Terminology
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].
Additionally, this document uses terminology from [RFC6997], Additionally, this document uses terminology from [RFC6997],
[I-D.ietf-roll-trickle-mcast], and [RFC6550]. [I-D.ietf-roll-trickle-mcast], and [RFC6550].
skipping to change at page 4, line 42 skipping to change at page 5, line 14
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. operation and cost of the network.
In homes the network for audio/video streaming and gaming has
different requirements, where the most important one is the high need
in bandwith for entertainment not needed for control. It is expected
that the entertainment network in the home will mostly be separate
from 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. The wireless sub-network is as DNS, automation servers, etc.
typically a multi-node network with a border router located at a
convenient place in the home (building).
In a building control network, there may be several redundant border The wireless sub-network can be configured according to any of the
routers to each sub-network. Sub-networks often overlap following topologies:
geographically and from a wireless coverage perspective. Due to two
purposes of the network, (i) direct control and (ii) monitoring, o A stand-alone network of 10-100 nodes without border router. This
there may exist two types of routing topologies in a given sub- typically occurs in the home with a stand-alone control network,
network: (i) a tree-shaped collection of routes spanning from a in low cost buildings, and during installation of high end control
central building controller via the border router, on to destination systems in buildings.
nodes in the sub-network; and/or (ii) a flat, un-directed collection
of intra-network routes between functionally related nodes in the o A connected network with one border router. This configuration
sub-network. will happen in homes where home appliances are controlled from
outside the home or via the telephone, and in many building
control scenarios.
o A connected network with multiple border routers. This will
typically happen in installations of large buildings.
Many of the nodes are batery-powered and may be sleeping nodes which
wake-up according to clock signals or external events.
In a building control network, for large installation with multiple
border routers, sub-networks often overlap geographically and from a
wireless coverage perspective. Due to two purposes of the network,
(i) direct control and (ii) monitoring, there may exist two types of
routing topologies in a given sub-network: (i) a tree-shaped
collection of routes spanning from a central building controller via
the border router, on to destination nodes in the sub-network; and/or
(ii) a flat, un-directed collection of intra-network routes between
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 devices with very low memory capacity, such as individual
wall switches. Only a few nodes (such as multi-purpose remote wall switches. Only a few nodes (such as multi-purpose remote
controls) are more expensive devices, which can afford more memory controls) are more expensive 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 or traffic is light-weight point-to-point control style; e.g. Put-Ack or
Get-Response. There are however exceptions. Bulk data transfer is Get-Response. There are however exceptions. Bulk data transfer is
used for firmware update and logging, where firmware updates enter 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 relation between a controlling sensor and Often, there is a direct physical relation between a controlling
the controlled equipment. The bulk of senders and receivers are sensor and the controlled equipment. For example the temperature
separated by a distance that allows one-hop direct path sensor and thermostat are located in the same room sharing the same
climate conditions. Consequently, the bulk of senders and 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. Looking over communication routes exist for quick error recovery. (See Appendix B
time periods of a day, the networks are very lightly loaded. for motivation.)
However, bursts of traffic can be generated by the entry of several
persons simultaneously, the occurrence of a defect, and other Looking over time periods of a day, the networks are very lightly
unforeseen events. Under those conditions, the timeliness must loaded. However, bursts of traffic can be generated by pushing
nevertheless be maintained. Therefore, measures are necessary to permanently the button of a remote control, the occurrence of a
remove any unnecessary traffic. Short routes are preferred. Long defect, and other unforeseen events. Under those conditions, the
multi-hop routes via the border router, should be avoided whenever timeliness must nevertheless be maintained. Therefore, measures are
possible. necessary to remove any unnecessary traffic. Short routes are
preferred. Long multi-hop routes via the border router, should be
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 is focused in that room and no other lights should be dimmed, control applies to that room only and no other lights should be
or switched on/off. In many cases, this means that a multicast dimmed, or switched on/off. In many cases, this means that a
message with a 1-hop and 2-hop radius would suffice to control the multicast message with a 1-hop and 2-hop radius would suffice to
required lights. To reduce network load, it is advisable that control the required lights. The same argument holds for HVAC and
messages to the lights in a room are not distributed any further in other climate control devices. To reduce network load, it is
the mesh than necessary based on intended receivers. advisable that messages to the lights in a room are not distributed
any further in the mesh than necessary based on intended receivers.
2.2.1. General 2.2.1. General
Whilst air conditioning and other environmental-control applications Whilst air conditioning and other environmental-control applications
may accept response delays of tens of seconds or longer, alarm and may accept response delays of tens of seconds or longer, alarm and
light control applications may be regarded as soft real-time systems. light control applications may be regarded as soft real-time systems.
A slight delay is acceptable, but the perceived quality of service A slight delay is acceptable, but the perceived quality of service
degrades significantly if response times exceed 250 msec. If the degrades significantly if response times exceed 250 msec. If the
light does not turn on at short notice, a user may activate the light does not turn on at short notice, a user may activate the
controls again, thus causing a sequence of commands such as controls again, thus causing a sequence of commands such as
Light{on,off,on,off,..} or Volume{up,up,up,up,up,...}. Light{on,off,on,off,..} or Volume{up,up,up,up,up,...}. In addition
the repetitive sending of commands creates an unnecessary loading of
the network, which in turn increases the bad responsiveness of the
network.
2.2.2. Source-sink (SS) communication paradigm 2.2.2. Source-sink (SS) communication paradigm
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 is generated by environmental sensors (often present in a traffic is 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
also generate SS style traffic. The central server in a home also generate SS style traffic. The central server in a home
automation network will be connected mostly to a wired sub-network. automation network will be connected mostly to a wired sub-network,
although it is suspected that cloud services will become available.
The central server in a building automation network may be connected The central server in a building automation network may be connected
to a backbone or be placed outside the building. to a backbone or be placed 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. Alarm sensors,
however, represent an exception. Special provisions with respect to however, represent an exception. Special provisions with respect to
the location of the Alarm server(s) need to be put in place to the location of the Alarm server(s) need to be put in place to
respect the specified delays. respect the specified delays.
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 as servers, which paradigm may be closely related to the SS paradigm given that
are connected to the backbone or outside the building, can subscribe servers, which are connected to the backbone or outside the building,
to data collectors that are present at strategic places in the can subscribe to data collectors that are present at strategic places
building automation network. The use of PS will probably differ in the building automation network. The use of PS will probably
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. Some traffic is a common traffic type in home automation networks. Some
building automation networks also rely on P2P traffic while others building automation networks also rely on P2P traffic while others
send all control traffic to a local controller box for advanced scene send all control traffic to a local controller box for advanced scene
and group control. The latter controller boxes can be connected to and group control. The latter controller boxes can be connected to
service control boxes thus generating more SS or PS traffic. service control boxes thus generating more SS or PS traffic.
skipping to change at page 7, line 41 skipping to change at page 8, line 43
sending temperature acquisitions to several fans and valves sending temperature acquisitions to several fans and valves
consecutively. consecutively.
2.2.6. N-cast communication paradigm 2.2.6. N-cast communication paradigm
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 chosen multicast algorithm (e.g. xref target="I-D.ietf-roll- The chosen multicast algorithm (e.g. [I-D.ietf-roll-trickle-mcast])
trickle-mcast"/>) assures that messages are delivered to ALL assures that messages are delivered to ALL destinations.
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 SS over a wireless sub-network to a server reachable
via a border router, the use of RPL [RFC6550] is recommended. Given via a border router, the use of RPL [RFC6550] is recommended. Given
the low resources of the devices, source routing will be used for the low resources of the devices, source routing will be used for
messages from outside the wireless sub-network to the destination in messages from outside the wireless sub-network to the destination in
the wireless sub-network. No specific timing constraints are the wireless sub-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-P2P code into the network stack to it is recommended to load only RPL-P2P code into the network stack to
satisfy memory requirements by reducing code. satisfy memory requirements by reducing code.
All P2P and P2MP traffic, taking place within a wireless sub-network, All P2P and P2MP traffic, taking place within a wireless sub-network,
requires P2P-RPL [RFC6997] to assure responsiveness. Source and requires P2P-RPL [RFC6997] to assure responsiveness. Source and
destination are typically close together to satisfy the living destination are typically close together to satisfy the living
conditions of one room. Consequently, most P2P and P2MP traffic is conditions of one room. Consequently, most P2P and P2MP traffic is
1-hop or 2-hop traffic. Appendix A explains why RPL-P2P is 1-hop or 2-hop traffic. Appendix A explains why RPL-P2P is
preferable to RPL for this type of communication. preferable to RPL for this type of communication. Appendix B
explains why reliability measures such as multi-path routing are
necessary even when 1-hop communication dominates.
Additional advantages of RPL-P2P for home and building automation Additional advantages of RPL-P2P 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 devices with
extremely low memory capacities. Multi-purpose remote controls extremely low memory capacities. Multi-purpose remote controls
for use in a home environment typically have more memory but such for use in a home environment typically have more memory but such
devices are asleep when there is no user activity. RPL-P2P devices are asleep when there is no user activity. RPL-P2P
reactive discovery allows a node to wake up and find new routes reactive discovery allows a node to wake up and find new routes
within a few seconds while memory constrained nodes only have to within a few seconds while memory constrained nodes only have to
keep routes to relevant targets. keep routes to relevant targets.
o The reactive discovery features of RPL-P2P ensure that commands o The reactive discovery features of RPL-P2P ensure that commands
are normally delivered within the 250msec time window and when are normally delivered within the 250 msec time window and when
connectivity needs to be restored, it is typically completed connectivity needs to be restored, it is typically completed
within seconds. In most cases an alternative (earlier discovered) within seconds. In most cases an alternative (earlier discovered)
route will work. Thus, route rediscovery is not even necessary. route will work. Thus, route rediscovery is not even necessary.
o Broadcast storms as happening during road discovery for AODV is
less disruptive for P2P-RPL. P2P-RPL has a "STOP" bit which is
set by the target of a route discovery to notify all other nodes
that no more DIOs should be forwarded for this temporary DAG.
Something looking like a broadcast storm may happen when no target
is responding. And in this case, the Trickle suppression
mechanism kicks in; limiting the number of DIO forwards in dense
networks.
Due to the limited memory of the majority of devices, RPL-P2P MUST be Due to the limited memory of the majority of devices, RPL-P2P MUST be
used with source routing in non-storing mode as explained in used with source routing in non-storing mode as explained in
Section 4.1.2. Section 4.1.2.
N-cast over the wireless network will be done using multicast with N-cast over the wireless network will be done using multicast with
MPL [I-D.ietf-roll-trickle-mcast]. Configuration constraints that MPL [I-D.ietf-roll-trickle-mcast]. Configuration constraints that
are necessary to meet reliability and timeliness with MPL are are necessary to meet reliability and timeliness with MPL are
discussed in Section 4.1.7. 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.brandt-6man-lowpanz]. [I-D.ietf-6lo-lowpanz].
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.
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 MUST be enabled when [IEEE802.15.4] or [G.9959] is acknowledgments MUST be enabled when [IEEE802.15.4] or [G.9959] is
used with RPL and RPL-P2P. used with RPL and RPL-P2P.
3. Using RPL to meet Functional Requirements 3. Using RPL to meet Functional Requirements
RPL-P2P MUST be present in home and building automation networks, as RPL-P2P MUST be present in home automation and building control
point-to-point style traffic is substantial and route repair needs to networks, as point-to-point style traffic is substantial and route
be completed within seconds. RPL-P2P provides a reactive mechanism repair needs to be completed within seconds. RPL-P2P provides a
for quick, efficient and root-independent route discovery/repair. reactive mechanism for quick, efficient and root-independent route
The use of RPL-P2P furthermore allows data traffic to avoid having to discovery/repair. The use of RPL-P2P furthermore allows data traffic
go through a central region around the root of the tree, and to avoid having to go through a central region around the root of the
drastically reduces path length [SOFT11] [INTEROP12]. These tree, and drastically reduces path length [SOFT11] [INTEROP12].
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, multiple independent paths are used When reliability is required, multiple independent paths are used
with RPL-P2P. For 1-hop destinations this means that one 1-hop with RPL-P2P. For 1-hop destinations this means that one 1-hop
communication and a second 2-hop communication take place via a communication and a second 2-hop communication take place via a
neigboring node. The same reliability can be achieved by using MPL neigboring node. The same reliability can be achieved by using MPL
where the seed is a repeater and a second repeater is 1 hop removed where the seed is a repeater and a second repeater is 1 hop removed
from the seed and the destination node. from the seed and the destination node.
RPL-P2P is recommended to keep two independent paths per destination
in the source. When one path is temporarily impossible, as described
in Appendix B, the alternative can be used without throwing away the
temporarily failing path. The blocked path can be safely thrown away
after 15 minutes. A new route discovery is done when the number of
paths is exhausted, or when a path needs to abandoned because it
fails over a too long period.
4. RPL Profile 4. RPL Profile
RPL-P2P MUST be used in home and building networks. Non-storing mode RPL-P2P MUST be used in home automation and building control
allows for constrained memory in repeaters when source routing is networks. Non-storing mode allows for constrained memory in
used. Reactive discovery allows for low application response times repeaters when source routing is used. Reactive discovery allows for
even when on-the-fly route repair is needed. low application response times even when on-the-fly route repair is
needed.
4.1. RPL Features 4.1. RPL Features
In one constrained deployment, the link layer master node handing out An important constraint on the application of RPL is the presence of
the logical network identifier and unique node identifiers may be a sleeping nodes.
remote control which returns to sleep once new nodes have been added.
There may be no global routable prefixes at all. Likewise, there may
be no authoritative always-on root node since there is no border
router to host this function.
In another constrained deployment, there may be battery powered For example in the stand-alone network, the link layer node (master
sensors and wall controllers configured to contact other nodes in node, or coordinator)handing out the logical network identifier and
response to events and then return to sleep. Such nodes may never unique node identifiers may be a remote control which returns to
detect the announcement of new prefixes via multicast. sleep once new nodes have been added. Due to the absence of the
border router there may be no global routable prefixes at all.
Likewise, there may be no authoritative always-on root node since
there is no border router to host this function.
In each of the above mentioned constrained deployments, the link In a network with a border router and many sleeping nodes, there may
layer master node SHOULD assume the role as authoritative root node, be battery powered sensors and wall controllers configured to contact
transmitting singlecast RAs with a ULA prefix information option to other nodes in response to events and then return to sleep. Such
nodes during the inclusion process to prepare the nodes for a later nodes may never detect the announcement of new prefixes via
operational phase, where a border router is added. multicast.
In each of the above mentioned constrained deployments, a link layer
node (e.g. coordinator or master) SHOULD assume the role as
authoritative root node, transmitting singlecast RAs with a ULA
prefix information option to nodes during the inclusion process to
prepare the nodes for a later operational phase, where a border
router is added.
A border router SHOULD be designed to be aware of sleeping nodes in A border router SHOULD be designed to be aware of sleeping nodes in
order to support the distribution of updated global prefixes to such order to support the distribution of updated global prefixes to such
sleeping nodes. sleeping nodes.
One COULD implement gateway-centric tree-based routing and global One COULD implement gateway-centric tree-based routing and global
prefix distribution as defined by [RFC6550]. This would however only prefix distribution as defined by [RFC6550]. This would however only
work for always-on nodes. work for always-on nodes.
4.1.1. RPL Instances 4.1.1. RPL Instances
skipping to change at page 11, line 4 skipping to change at page 12, line 26
DAO policies may be needed. DAO policies may be needed.
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 RECOMMENDED. [RFC6551] provides other options. Using other
objective functions than OF0 may affect inter-operability. 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 MUST be supported and is the RECOMMENDED Objective Function to
use. Other Objective Functions MAY be used as well. use. Other Objective Functions MAY be used as well.
4.1.6. DODAG Repair 4.1.6. DODAG Repair
Since RPL-P2P only creates DODAGs on a temporary basis during route Since RPL-P2P only creates DODAGs on a temporary basis during route
repair, there is no need to repair DODAGs. repair, there is no need to repair DODAGs.
TODO: there is a DODAG needed for SS communication.
4.1.7. Multicast 4.1.7. Multicast
Commercial light deployments may have a need for multicast. Several Commercial light deployments may have a need for multicast to
mechanisms exist for achieving such functionality; distribute commands to a group of lights in a timely fashion.
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 RECOMMENDED for home and building
deployments. deployments. This section relies heavily on the conclusions of
[RT-MPL].
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 repeater 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. Repetition of the on to the next hop by repeating the message. When several copies of
message can be inhibited by a small value of k. Therefore the value a message reach the forwarder, it is specified that the copy need not
of k should be chosen high enough to make sure that messages are be repeated. Repetition of the message can be inhibited by a small
repeated immediately. However, a network that is too dense leads to value of k. To assure timeliness, the value of k should be chosen
a saturation of the medium that can only be prevented by selecting a high enough to make sure that messages are repeated at the first
low value of k. Consequently, timeliness is assured by choosing a arrival of the message in the forwarder. However, a network that is
relatively high value of k but assuring at the same time a low enough too dense leads to a saturation of the medium that can only be
density of repeaters to reduce the risk of medium saturation. prevented by selecting a low value of k. Consequently, timeliness is
Depending on the reliability of the network channels, it is advisable assured by choosing a relatively high value of k but assuring at the
to choose the network such that at least 2 repeaters (one repeater same time a low enough density of forwarders to reduce the risk of
located on the seed) can repeat messages to the same set of medium saturation. Depending on the reliability of the network
destinations. channels, it is advisable to choose the network such that at least 2
forwarders (one forwarder located on the seed) can repeat messages to
the same set of destinations.
There are no rules about selecting repeaters for MPL. In buildings There are no rules about selecting forwarders for MPL. In buildings
with central managment tools, the repeaters can be selected, but in with central managment tools, the forwarders can be selected, but in
the home is not possible to automatically configure the repeater the home is not possible to automatically configure the forwarder
topology at this moment. topology at this moment.
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 battery,
RPL MAY use either unsecured messages or secured messages. If RPL is RPL MAY use either unsecured messages or secured messages. If RPL is
used with unsecured messages, link layer security SHOULD be used. If used with unsecured messages, link layer security SHOULD be used. If
RPL is used with secured messages, the following RPL security RPL is used with secured messages, the following RPL security
parameter values SHOULD be used: parameter values SHOULD be used:
skipping to change at page 13, line 31 skipping to change at page 15, line 9
possible to choose low MPL repeat intervals (Imin) connected to k possible to choose low MPL repeat intervals (Imin) connected to k
values such that k>2. The minimum value of k is related to: values such that k>2. The minimum value of k is related to:
o Value of Imin. The length of Imin determines the number of o Value of Imin. The length of Imin determines the number of
packets that can be received within the listening period of Imin. packets that can be received within the listening period of Imin.
o Number of repeaters repeating the same 1-hop broadcast message. o Number of repeaters repeating the same 1-hop broadcast message.
These repeaters repeat within the same Imin interval, thus These repeaters repeat within the same Imin interval, thus
increasing the c counter. increasing the c counter.
Suggested MPL parameter values are: Assuming that at most q message copies can reach a given forwarder
within the first repeat interval of length Imin, the following MPL
parameter values are suggested:
o I_min = 10 - 50. o I_min = 10 - 50.
o I_max = 200 - 400. o I_max = 200 - 400.
o k > 2 (see above). o k > q (see condition above).
o max_expiration = 2 - 4. o max_expiration = 2 - 4.
5. Manageability Considerations 5. 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 should be applied building automation scenarios, central control should be applied
based on MIBs. based on MIBs.
6. Security Considerations 6. Security Considerations
Refer to the security considerations of [RFC6997], [RFC6550], and Refer to the security considerations of [RFC6997], [RFC6550],
[I-D.ietf-roll-trickle-mcast]. [I-D.ietf-roll-trickle-mcast].
6.1. Security Considerations for distribution of credentials required 6.1. Security context considerations
Wireless networks are typically secured at the link-layer to prevent
unauthorized parties to access the information exchanged over the
links. In mesh networks, it is good practice to create a network of
nodes which share the same keys for link layer encryptions and
exclude nodes sending non encrypted messages. The consequence is
that unauthorized nodes cannot join 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].
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].
A thorough analysis of security threats and proposed countermeasures
relevant to RPL is done in [I-D.ietf-roll-security-threats].
6.2. MPL routing
The routing of MPL is determined by the enabling of the interfaces
for specified Multicast addresses. The specification of these
addresses can be done via a CoAP application as specified in
[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
specify the Multicast addresses in the MIB. The application of
security measures for the specification of the multicast addresses
assures that the routing of MPL packets is secured.
6.3. Security Considerations for distribution of credentials required
for RPL for RPL
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 or (ii) the credential used for securing RPL security is applied or (ii) the credential used for securing RPL
messages. In both cases, the assumption is that the credential is a messages. In both cases, the assumption is that the credential is a
shared key. Therefore, there MUST be a mechanism in place which shared key. Therefore, there MUST be a mechanism in place which
allows secure distribution of a shared key and configuration of allows secure distribution of a shared key and configuration of
network identity. Both MAY be done using (i) pre-installation using network identity. Both MAY be done using (i) pre-installation using
an out-of-band method, (ii) delivered securely when a device is an out-of-band method, (ii) delivered securely when a device is
introduced into the network or (iii) delivered securely by a trusted introduced into the network or (iii) delivered securely by a trusted
neighboring device. The shared key MUST be stored in a secure neighboring device. The shared key MUST be stored in a secure
fashion which makes it difficult to be read by an unauthorized party. fashion which makes it difficult to be read by an unauthorized party.
An example of a method whereby this can be achieved is detailed in
[SmartObj]
6.2. Security Considerations for P2P uses Securely delivering a key means that the delivery mechanism MUST have
data origin authentication, confidentiality and integrity protection.
Securely storing a key means that the storage mechanism MUST have
confidentiality and integrity protection and MUST only be accessible
by an authorized party.
Refer to the security considerations of [RFC6997]. 6.4. Security Considerations for P2P uses
Refer to the security considerations of [RFC6997]. Many initiatives
are under way to provide light weight security such as:
[I-D.keoh-dice-dtls-profile-iot] and
[I-D.keoh-dice-multicast-security].
7. Other related protocols 7. Other related protocols
Application transport protocols may be CoAP over UDP or equivalents. Application transport protocols may be CoAP over UDP or equivalents.
Typically, UDP is used for IP transport to keep down the application Typically, UDP is used for IP transport to keep down the application
response time and bandwidth overhead. response time and bandwidth overhead.
Several features required by [RFC5826], [RFC5867] challenge the P2P Several features required by [RFC5826], [RFC5867] challenge the P2P
paths provided by RPL. Appendix A reviews these challenges. In some paths provided by RPL. Appendix A reviews these challenges. In some
cases, a node may need to spontaneously initiate the discovery of a cases, a node may need to spontaneously initiate the discovery of a
skipping to change at page 15, line 31 skipping to change at page 17, line 52
o Replaced all TODO sections with text. o Replaced all TODO sections with text.
o Consistent use of border router, mintoring, home- and building o Consistent use of border router, mintoring, home- and building
network. network.
o Reformulated security aspects with references to other o Reformulated security aspects with references to other
publications. publications.
o MPL and RPL parameter values introduced. o MPL and RPL parameter values introduced.
Changes form version 1 to version 2.
o Clarified common characteristics of control in home and building.
o Clarified failure behavior of point to point communication in
appendix.
o Changed examples, more hvac and less lighting.
o Clarified network topologies.
o replaced reference to smart_object paper by reference to I-D.roll-
security-threats
o Added a concise definition of secure delivery and secure storage
o text about securing network with PANA
11. References 11. References
11.1. Normative References 11.1. 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.
Yegin, "Protocol for Carrying Authentication for Network
Access (PANA)", RFC 5191, May 2008.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, August 2008.
[RFC5548] Dohler, M., Watteyne, T., Winter, T., and D. Barthel, [RFC5548] Dohler, M., Watteyne, T., Winter, T., and D. Barthel,
"Routing Requirements for Urban Low-Power and Lossy "Routing Requirements for Urban Low-Power and Lossy
Networks", RFC 5548, May 2009. Networks", RFC 5548, May 2009.
[RFC5673] Pister, K., Thubert, P., Dwars, S., and T. Phinney, [RFC5673] Pister, K., Thubert, P., Dwars, S., and T. Phinney,
"Industrial Routing Requirements in Low-Power and Lossy "Industrial Routing Requirements in Low-Power and Lossy
Networks", RFC 5673, October 2009. Networks", RFC 5673, October 2009.
[RFC5826] Brandt, A., Buron, J., and G. Porcu, "Home Automation [RFC5826] Brandt, A., Buron, J., and G. Porcu, "Home Automation
Routing Requirements in Low-Power and Lossy Networks", RFC Routing Requirements in Low-Power and Lossy Networks", RFC
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
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
Low-Power and Lossy Networks", RFC 6551, March 2012. Low-Power and Lossy Networks", RFC 6551, March 2012.
[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.brandt-6man-lowpanz] [I-D.ietf-6lo-lowpanz]
Brandt, A. and J. Buron, "Transmission of IPv6 packets Brandt, A. and J. Buron, "Transmission of IPv6 packets
over ITU-T G.9959 Networks", draft-brandt-6man-lowpanz-02 over ITU-T G.9959 Networks", draft-ietf-6lo-lowpanz-02
(work in progress), June 2013. (work in progress), February 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-04 (work in progress), February 2013. mcast-06 (work in progress), January 2014.
[I-D.ietf-roll-security-threats]
Tsao, T., Alexander, R., Dohler, M., Daza, V., Lozano, A.,
and M. Richardson, "A Security Threat Analysis for Routing
Protocol for Low-power and lossy networks (RPL)", draft-
ietf-roll-security-threats-06 (work in progress), December
2013.
[I-D.keoh-dice-dtls-profile-iot]
Keoh, S., Kumar, S., and Z. Shelby, "Profiling of DTLS for
CoAP-based IoT Applications", draft-keoh-dice-dtls-
profile-iot-00 (work in progress), November 2013.
[I-D.keoh-dice-multicast-security]
Keoh, S., Kumar, S., Garcia-Morchon, O., Dijk, E., and A.
Rahman, "DTLS-based Multicast Security for Low-Power and
Lossy Networks (LLNs)", draft-keoh-dice-multicast-
security-04 (work in progress), February 2014.
[I-D.kumar-dice-dtls-relay]
Kumar, S., Keoh, S., and O. Garcia-Morchon, "DTLS Relay
for Constrained Environments", draft-kumar-dice-dtls-
relay-00 (work in progress), October 2013.
[I-D.ietf-core-groupcomm]
Rahman, A. and E. Dijk, "Group Communication for CoAP",
draft-ietf-core-groupcomm-18 (work in progress), December
2013.
[I-D.vanderstok-core-comi]
Stok, P. and B. Greevenbosch, "CoAp Management
Interfaces", draft-vanderstok-core-comi-02 (work in
progress), January 2014.
[IEEE802.15.4] [IEEE802.15.4]
, "IEEE 802.15.4 - Standard for Local and metropolitan "IEEE 802.15.4 - Standard for Local and metropolitan area
area networks -- Part 15.4: Low-Rate Wireless Personal networks -- Part 15.4: Low-Rate Wireless Personal Area
Area Networks", , <IEEE Standard 802.15.4>. Networks", <IEEE Standard 802.15.4>.
[G.9959] , "ITU-T G.9959 Short range narrow-band digital [G.9959] "ITU-T G.9959 Short range narrow-band digital
radiocommunication transceivers - PHY and MAC layer radiocommunication transceivers - PHY and MAC layer
specifications", , <ITU-T G.9959>. specifications", <ITU-T G.9959>.
11.2. Informative References 11.2. 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. 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, Janurary 2012. RR-7864 INRIA Research Report RR-7864, January 2012.
[SmartObj] [RT-MPL] van der Stok, P., "Real-Time IP-based multicast for low-
Jennings, C., "Transitive Trust Enrollment for Constrained resource wireless network", To be published,, April 2014.
Devices", Web http://www.lix.polytechnique.fr/hipercom/
SmartObjectSecurity/papers/CullenJennings.pdf, February
2012.
Appendix A. RPL shortcomings in home and building deployments [RTN2011] Holtman, K. and P. van der Stok, "Real-time routing for
low-latency 802.15.4 control networks", International
Workshop on Real-Time Networks; Euromicro Conference on
Real-Time Systems, July 2011.
This document reflects discussions and remarks from several [MEAS] Holtman, K., "Connectivity loss in large scale IEEE
individuals including (in alphabetical order): Charles Perkins, Jerry 802.15.4 network", Private Communication, November 2013.
Martocci, Michael Richardson, Mukul Goyal and Zach Shelby.
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. In a typical example two nodes could
reach each other via just two router nodes but in unfortunate cases, reach each other via just two router nodes but in unfortunate cases,
RPL may send traffic three hops up and three hops down again. This RPL may send traffic three hops up and three hops down again. This
skipping to change at page 18, line 45 skipping to change at page 22, line 45
again, causing a sequence of commands such as again, causing a sequence of commands such as
Light{on,off,off,on,off,..} or Volume{up,up,up,up,up,...}. Whether Light{on,off,off,on,off,..} or Volume{up,up,up,up,up,...}. Whether
the outcome is nothing or some unintended response this is the outcome is nothing or some unintended response this is
unacceptable. A controlling system must be able to restore unacceptable. A controlling system must be able to restore
connectivity to recover from the error situation. Waiting for an connectivity to recover from the error situation. Waiting for an
unknown period of time is not an option. While this issue was unknown period of time is not an option. While this issue was
identified during the P2P analysis, it applies just as well to identified during the P2P analysis, it applies just as well to
application scenarios where an IP application outside the LLN application scenarios where an IP application outside the LLN
controls actuators, lights, etc. controls actuators, lights, etc.
Appendix B. Communication failures
Measurements on the connectivity between neigbouring nodes are
discussed in [RTN2011] and [MEAS].
The work is motivated by the measurements in literature which affirm
that the range of an antenna is not circle symmetric but that the
signal strength of a given level follows an intricate pattern around
the antenna, and there may be holes within the area delineated by an
iso-strength line. It is reported that communication is not
symmetric: reception of messages from node A by node B does not imply
reception of messages from node B by node A. The quality of the
signal fluctuates over time, and also the the height of the antenna
within a room can have consequences for the range. As function of
the distance from the source, three regions are generally recognized:
(1) a clear region with excellent signal quality, (2) a region with
fluctuating signal quality, (3) a region without reception. In the
text below it is shown that installation of meshes with neigbours in
the clear region is not sufficient.
[RTN2011] extends existing work by:
o Observations over periods of at least a week,
o Testing links that are in the clear region,
o Observation in an office building during working hours,
o Concentrating on one-hop and two-hop routes.
Eight nodes were distributed over a surface of 30m2. All nodes are
at one hop distance from each other and are situated in the clear
region of each other. Each node sends messages to each of its
neigbours, and repeats the message until it arrives. The latency of
the message was measured over periods of at least a week. It is
noticed that latencies longer than a second ocurred without apparent
reasons, but only during working days and never in the weekends. Bad
periods could last for minutes. By sending messages via two paths:
(1) one hop path directly, and (2) two hop path via random neigbour,
the probability of delays larger than 100 ms decreased significantly.
The conclusion is that even for 1-hop communication between not too
distant "Line of Sight" nodes, there are periods of low reception in
which communication deadlines of 200 ms are exceeded. It pays to
send a second message over a 2-hop path to increase the reliability
of timely message transfer.
[MEAS] confirms that temporary bad reception by close neigbours can
occur within other types of areas. Nodes were installed on the
ceiling in a grid with a distance of 30-50 cm between nodes. 200
nodes were distributed over an area of 10m x 5m. It clearly
transpired that with increasing distance the probability of reception
decreases. At the same time a few nodes furthest away from the
sender had a high probability of message reception, while some close
neigbours of the sender did not receive messages. The patterns of
clear reception nodes evolved over time.
The conclusion is that even for direct neighbours reception can
temporarily be bad during periods of several minutes. For a reliable
and timely communication it is imperative to have at least two
communication paths available (e.g. two hop paths next to the 1-hop
path for direct neigbours).
Authors' Addresses Authors' Addresses
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 Gridmerge
Email: robert.cragie@gridmerge.com Email: robert.cragie@gridmerge.com
 End of changes. 59 change blocks. 
182 lines changed or deleted 441 lines changed or added

This html diff was produced by rfcdiff 1.41. The latest version is available from http://tools.ietf.org/tools/rfcdiff/