draft-ietf-roll-applicability-home-building-00.txt   draft-ietf-roll-applicability-home-building-01.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: November 14, 2013 INRIA Expires: February 18, 2014 INRIA
R. Cragie R. Cragie
Gridmerge Gridmerge
P. van der Stok P. van der Stok
Consultant Consultant
May 13, 2013 August 17, 2013
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-00 draft-ietf-roll-applicability-home-building-01
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 in
building and home environments. 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 November 14, 2013. This Internet-Draft will expire on February 18, 2014.
Copyright Notice Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the Copyright (c) 2013 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. Requirements Language . . . . . . . . . . . . . . . . . . 3 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
1.2. Overview of requirements . . . . . . . . . . . . . . . . 3 1.2. Required Reading . . . . . . . . . . . . . . . . . . . . 3
1.3. Out of scope requirements . . . . . . . . . . . . . . . . 3 1.3. Out of scope requirements . . . . . . . . . . . . . . . . 3
2. Deployment Scenario . . . . . . . . . . . . . . . . . . . . . 3 2. Deployment Scenario . . . . . . . . . . . . . . . . . . . . . 3
2.1. Network Topologies . . . . . . . . . . . . . . . . . . . 4 2.1. Network Topologies . . . . . . . . . . . . . . . . . . . 4
2.2. Traffic Characteristics . . . . . . . . . . . . . . . . . 5 2.2. Traffic Characteristics . . . . . . . . . . . . . . . . . 5
2.2.1. Human user responsiveness . . . . . . . . . . . . . . 5 2.2.1. General . . . . . . . . . . . . . . . . . . . . . . . 6
2.2.2. Source-sink (SS) communication paradigm . . . . . . . 6 2.2.2. Source-sink (SS) communication paradigm . . . . . . . 6
2.2.3. Peer-to-peer (P2P) communication paradigm . . . . . . 6 2.2.3. Publish-subscribe (PS, or pub/sub)) communication
2.2.4. Peer-to-multipeer (P2MP) communication paradigm . . . 6 paradigm . . . . . . . . . . . . . . . . . . . . . . 6
2.2.5. RPL applicability per communication paradigm . . . . 7 2.2.4. Peer-to-peer (P2P) communication paradigm . . . . . . 7
2.3. Link layer applicability . . . . . . . . . . . . . . . . 7 2.2.5. Peer-to-multipeer (P2MP) communication paradigm . . . 7
3. Using RPL-P2P to meet requirements . . . . . . . . . . . . . 7 2.2.6. N-cast communication paradigm . . . . . . . . . . . . 7
4. RPL Profile for RPL-P2P . . . . . . . . . . . . . . . . . . . 7 2.2.7. RPL applicability per communication paradigm . . . . 7
4.1. RPL Features . . . . . . . . . . . . . . . . . . . . . . 7 2.3. Layer-2 applicability . . . . . . . . . . . . . . . . . . 8
4.1.1. RPL Instances . . . . . . . . . . . . . . . . . . . . 8 3. Using RPL to meet Functional Requirements . . . . . . . . . . 9
4.1.2. Non-Storing Mode . . . . . . . . . . . . . . . . . . 8 4. RPL Profile . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.1.3. DAO Policy . . . . . . . . . . . . . . . . . . . . . 8 4.1. RPL Features . . . . . . . . . . . . . . . . . . . . . . 9
4.1.4. Path Metrics . . . . . . . . . . . . . . . . . . . . 8 4.1.1. RPL Instances . . . . . . . . . . . . . . . . . . . . 10
4.1.5. Objective Function . . . . . . . . . . . . . . . . . 9 4.1.2. Storing vs. Non-Storing Mode . . . . . . . . . . . . 10
4.1.6. DODAG Repair . . . . . . . . . . . . . . . . . . . . 9 4.1.3. DAO Policy . . . . . . . . . . . . . . . . . . . . . 10
4.1.7. Multicast . . . . . . . . . . . . . . . . . . . . . . 9 4.1.4. Path Metrics . . . . . . . . . . . . . . . . . . . . 10
4.1.8. Security . . . . . . . . . . . . . . . . . . . . . . 9 4.1.5. Objective Function . . . . . . . . . . . . . . . . . 10
4.1.9. P2P communications . . . . . . . . . . . . . . . . . 9 4.1.6. DODAG Repair . . . . . . . . . . . . . . . . . . . . 11
4.2. Layer 2 features . . . . . . . . . . . . . . . . . . . . 9 4.1.7. Multicast . . . . . . . . . . . . . . . . . . . . . . 11
4.2.1. Security functions provided by layer-2 . . . . . . . 10 4.1.8. Security . . . . . . . . . . . . . . . . . . . . . . 11
4.2.2. 6LowPAN options assumed . . . . . . . . . . . . . . . 10 4.1.9. P2P communications . . . . . . . . . . . . . . . . . 12
4.2.3. MLE and other things . . . . . . . . . . . . . . . . 10 4.1.10. IPv6 adddress configuration . . . . . . . . . . . . . 12
4.3. Recommended Configuration Defaults and Ranges . . . . . . 10 4.2. Layer 2 features . . . . . . . . . . . . . . . . . . . . 12
5. Manageability Considerations . . . . . . . . . . . . . . . . 10 4.3. Recommended Configuration Defaults and Ranges . . . . . . 12
6. Security Considerations . . . . . . . . . . . . . . . . . . . 10 4.3.1. RPL-P2P parameters . . . . . . . . . . . . . . . . . 12
6.1. Security Considerations during initial deployment . . . . 10 4.3.2. Trickle parameters . . . . . . . . . . . . . . . . . 13
6.2. Security Considerations during incremental deployment . . 10 4.3.3. MPL parameters . . . . . . . . . . . . . . . . . . . 13
7. Other related protocols . . . . . . . . . . . . . . . . . . . 11 5. Manageability Considerations . . . . . . . . . . . . . . . . 13
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 6. Security Considerations . . . . . . . . . . . . . . . . . . . 13
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 11 6.1. Security Considerations for distribution of credentials
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 required for RPL . . . . . . . . . . . . . . . . . . . . 14
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 6.2. Security Considerations for P2P uses . . . . . . . . . . 14
11.1. Normative References . . . . . . . . . . . . . . . . . . 11 7. Other related protocols . . . . . . . . . . . . . . . . . . . 14
11.2. Informative References . . . . . . . . . . . . . . . . . 12 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14
Appendix A. RPL shortcomings in home and building deployments . 12 10. Changelog . . . . . . . . . . . . . . . . . . . . . . . . . . 15
A.1. Risk of undesired long P2P routes . . . . . . . . . . . . 13 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
A.1.1. Traffic concentration at the root . . . . . . . . . . 13 11.1. Normative References . . . . . . . . . . . . . . . . . . 15
A.1.2. Excessive battery consumption in source nodes . . . . 13 11.2. Informative References . . . . . . . . . . . . . . . . . 17
A.2. Risk of delayed route repair . . . . . . . . . . . . . . 13 Appendix A. RPL shortcomings in home and building deployments . 17
A.2.1. Broken service . . . . . . . . . . . . . . . . . . . 14 A.1. Risk of undesired long P2P routes . . . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14 A.1.1. Traffic concentration at the root . . . . . . . . . . 17
A.1.2. Excessive battery consumption in source nodes . . . . 18
A.2. Risk of delayed route repair . . . . . . . . . . . . . . 18
A.2.1. Broken service . . . . . . . . . . . . . . . . . . . 18
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18
1. Introduction 1. Introduction
TODO: Adapt to new template
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. The purpose of this document is to
give guidance in the use of RPL-P2P to provide the features required give guidance in the use of the RPL protocol suite to provide the
by the requirements documents "Home Automation Routing Requirements features required by the requirements documents "Home Automation
in Low-Power and Lossy Networks" [RFC5826] and "Building Automation Routing Requirements in Low-Power and Lossy Networks" [RFC5826] and
Routing Requirements in Low-Power and Lossy Networks" [RFC5867]. "Building Automation Routing Requirements in Low-Power and Lossy
Networks" [RFC5867].
1.1. Requirements Language 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 RFC 2119. document are to be interpreted as described in [RFC2119].
1.2. Overview of requirements Additionally, this document uses terminology from [RFC6997],
[I-D.ietf-roll-trickle-mcast], and [RFC6550].
1.2. Required Reading
Applicable requirements are described in [RFC5826] and [RFC5867]. Applicable requirements are described in [RFC5826] and [RFC5867].
1.3. Out of scope requirements 1.3. Out of scope requirements
The considered network diameter is limited to a max diameter of 10 The considered network diameter is limited to a max diameter of 10
hops and a typical diameter of 5 hops, which captures the most common hops and a typical diameter of 5 hops, which captures the most common
cases in home automation and building control networks. 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
satisfy the energy saving regulations. Environmental conditions of
buildings can be adapted to suit the comfort of the individuals
present. Consequently when no one is present, energy consumption can
be reduced. Cost is the main driving factor behind utilizing
wireless networking in buildings. Especially for retrofit, wireless
connectivity saves cabling costs.
Networking in buildings is essential to satisfy the energy saving A typical home automation network is comprised of less than 100
regulations. Comfort of buildings is adapted to the presence of nodes. Large building deployments may span 10,000 nodes but to
individuals. When no one is present, energy consumption can be ensure uninterrupted service of light and air conditioning systems in
reduced. Cost is the main driving factor behind wireless networking individual zones of the building, nodes are typically organized in
in buildings. Especially for retrofit, wireless connectivity saves sub-networks. Each sub-network in a building automation deployment
cabling costs. typically contains tens to hundreds of nodes.
A typical home automation network is less than 100 nodes. Large
building deployments may span 10,000 nodes but to ensure
uninterrupted service of light and air conditioning systems in
individual zones of the building, nodes are organized in subnetworks.
Each subnetwork in a building automation deployment typically
contains contains tens to hundreds of nodes.
The main purpose of the network is to provide control over light and The main purpose of the home or building automation network is to
heating/cooling resources. User intervention may be enabled via wall provide control over light and heating/cooling resources. User
controllers combined with movement, light and temperature sensors to intervention may be enabled via wall controllers combined with
enable automatic adjustment of window blinds, reduction of room movement, light and temperature sensors to enable automatic
temperature, etc. adjustment of window blinds, reduction of room temperature, etc. In
general, the sensors and actuators in a home or building typically
have fixed physical locations and will remain in the same home- or
building automation network.
People expect immediate and reliable responses 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 leads to actions. A light not switching on after entry into a room may lead
confusion and a profound dissatisfaction with the light product. to confusion and a profound dissatisfaction with the lighting
product.
The surveillance of the correct functioning is at least as important. Monitoring of functional correctness is at least as important.
Devices communicate regularly their status and send alarm messages Devices typically communicate their status regularly and send alarm
announcing a dysfunction 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 strong 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.
2.1. Network Topologies 2.1. Network Topologies
The typical home automation network or building control subnetwork In general, The home automation network or building control network
can consist of a wired and one or more wireless subnetworks. consists of wired and wireless sub-networks. In large buildings
Especially in large buildings the wireless network is connected to an especially, the wireless sub-networks can be connected to an IP
IP backbone network where all infrastructure services are located, backbone network where all infrastructure services are located, such
such as DNS, automation servers, etc. The wireless subnetwork is a as DNS, automation servers, etc. The wireless sub-network is
mesh network with a border router located at a convenient place in typically a multi-node network with a border router located at a
the home (building). convenient place in the home (building).
In a building control network there may be several redundant border In a building control network, there may be several redundant border
routers to each subnetwork. Subnetworks often overlap geographically routers to each sub-network. Sub-networks often overlap
(and from a wireless perspective). Due to the two purposes of the geographically and from a wireless coverage perspective. Due to two
network, (i) direct control and (ii) surveillance, there may exist purposes of the network, (i) direct control and (ii) monitoring,
two types of routing topologies in a given subnetwork (i) a tree- there may exist two types of routing topologies in a given sub-
shaped collection of routes spanning from a central building network: (i) a tree-shaped collection of routes spanning from a
controller via the border router, on to destination nodes in the central building controller via the border router, on to destination
subnetwork, and/or (ii) a flat, un-directed collection of intra- nodes in the sub-network; and/or (ii) a flat, un-directed collection
network routes between functionally related nodes in the subnetwork. of intra-network routes between functionally related nodes in the
sub-network.
Nodes in Home and Building automation networks are typically The majority of nodes in home and building automation networks are
inexpensive 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 from a central controller or it may Traffic may enter the network originating from a central controller
originate from an intra-network node. The majority of traffic is or it may originate from an intra-network node. The majority of
light-weight point-to-point control style; e.g. Put-Ack or Get- traffic is light-weight point-to-point control style; e.g. Put-Ack or
Response. There are however exceptions. Bulk data transfer is used Get-Response. There are however exceptions. Bulk data transfer is
for firmware update and logging. Multicast is used for service used for firmware update and logging, where firmware updates enter
discovery or to control groups of nodes, such as light fixtures. the network and logs leave the network. Group communication is used
Firmware updates enter the network while logs leave the network. for service discovery or to control groups of nodes, such as light
fixtures.
Often, there is a direct relation between a controlling sensor and Often, there is a direct relation between a controlling sensor and
the controlled equipment. The bulk of senders and receivers are the controlled equipment. The bulk of senders and receivers are
separated by a distance that allows one-hop direct path 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. Looking over
time periods of a day, the networks are very lightly loaded. time periods of a day, the networks are very lightly loaded.
However, bursts of traffic can be generated by the entry of several However, bursts of traffic can be generated by the entry of several
persons simultaneously, the occurrence of a defect, and other persons simultaneously, the occurrence of a defect, and other
unforeseen events. Under those conditions, the timeliness must unforeseen events. Under those conditions, the timeliness must
nevertheless be maintained. Therefore, measures are necessary to nevertheless be maintained. Therefore, measures are necessary to
remove any unnecessary traffic. Short routes are preferred. Long remove any unnecessary traffic. Short routes are preferred. Long
multi-hop routes via the edge router, should be avoided whenever multi-hop routes via the border router, should be avoided whenever
possible. Group communication is essential for lighting control. possible.
For example, once the presence of a person is detected in a given
room, all involved lights in the room and no other lights should be
dimmed, or switched on/off. Several rooms may be covered by the same
wireless subnetwork. To reduce network load, it is advisable that
messages to the lights in a room are not distributed further in the
mesh than necessary on the basis of intended receivers.
2.2.1. Human user responsiveness Group communication is essential for lighting control. For example,
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,
or switched on/off. In many cases, this means that a multicast
message with a 1-hop and 2-hop radius would suffice to control the
required lights. To reduce network load, it is advisable that
messages to the lights in a room are not distributed any further in
the mesh than necessary based on intended receivers.
While air conditioning and other environmental-control applications 2.2.1. General
may accept certain response delays, alarm and light control
applications may be regarded as soft real-time systems. A slight
delay is acceptable, but the perceived quality of service degrades
significantly if response times exceed 250 msec. If the light does
not turn on at short notice, a user will activate the controls again,
causing a sequence of commands such as Light{on,off,on,off,..} or
Volume{up,up,up,up,up,...}.
The reactive discovery features of RPL-P2P ensures that commands are Whilst air conditioning and other environmental-control applications
normally delivered within the 250msec time window and when may accept response delays of tens of seconds or longer, alarm and
connectivity needs to be restored, it is typically completed within light control applications may be regarded as soft real-time systems.
seconds. In most cases an alternative route will work. Thus, route A slight delay is acceptable, but the perceived quality of service
rediscovery is not even necessary. degrades significantly if response times exceed 250 msec. If the
light does not turn on at short notice, a user may activate the
controls again, thus causing a sequence of commands such as
Light{on,off,on,off,..} or Volume{up,up,up,up,up,...}.
2.2.2. Source-sink (SS) communication paradigm 2.2.2. Source-sink (SS) communication paradigm
Source-sink (SS) traffic is a common traffic type in home and This paradigm translates to many sources sending messages to the same
building networks. The traffic is generated by environmental sensors sink, sometimes reachable via the border router. As such, source-
which push periodic readings to a central server. The readings may sink (SS) traffic can be present in home and building networks. The
be used for pure logging, or more often, to adjust light, heating and traffic is generated by environmental sensors (often present in a
ventilation. Alarm sensors also generate SS style traffic. wireless sub-network) which push periodic readings to a central
server. The readings may be used for pure logging, or more often,
processed to adjust light, heating and ventilation. Alarm sensors
also generate SS style traffic. The central server in a home
automation network will be connected mostly to a wired sub-network.
The central server in a building automation network may be connected
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. however, represent an exception. Special provisions with respect to
the location of the Alarm server(s) need to be put in place to
respect the specified delays.
2.2.3. Peer-to-peer (P2P) communication paradigm 2.2.3. Publish-subscribe (PS, or pub/sub)) communication paradigm
Peer-to-peer (P2P) traffic is a common traffic type in home networks. This paradigm translates to a number of devices expressing their
Some building networks also rely on P2P traffic while others send all interest for a service provided by a server device. For example, a
control traffic to a local controller box for advanced scene and server device can be a sensor delivering temperature readings on the
group control; thus generating more SS and P2MP traffic. basis of delivery criteria, like changes in acquisition value or age
of the latest acquisition. In building automation networks, this
paradigm may be closely related to the SS paradigm as servers, which
are connected to the backbone or outside the building, can subscribe
to data collectors that are present at strategic places in the
building automation network. The use of PS will probably differ
significantly from installation to installation.
2.2.4. Peer-to-peer (P2P) communication paradigm
This paradigm translates to a device transferring data to another
device often connected to the same sub-network. Peer-to-peer (P2P)
traffic is a common traffic type in home automation networks. Some
building automation networks also rely on P2P traffic while others
send all control traffic to a local controller box for advanced scene
and group control. The latter controller boxes can be connected to
service control boxes thus generating more SS 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 strong requirement for low latency since
P2P traffic often carries application messages that are invoked by P2P traffic often carries application messages that are invoked by
humans. As mentioned in Section 2.2.1 application messages should be humans. As mentioned in Section 2.2.1 application messages should be
delivered within less than a second - even when a route repair is delivered within a few hundred milliseconds - even when connections
needed before the message can be delivered. . fail momentarily.
2.2.4. Peer-to-multipeer (P2MP) communication paradigm 2.2.5. Peer-to-multipeer (P2MP) communication paradigm
Peer-to-multipeer (P2MP) traffic is common in home and building This paradigm translates to a device sending a message as many times
networks. Often, a wall switch in a living room responds to user as there are destination devices. Peer-to-multipeer (P2MP) traffic
activation by sending commands to a number of light sources is common in home and building automation networks. Often, a
simultaneously. thermostat in a living room responds to temperature changes by
sending temperature acquisitions to several fans and valves
consecutively.
Individual wall switches are typically inexpensive devices with 2.2.6. N-cast communication paradigm
extremely low memory capacities. Multi-purpose remote controls for
use in a home environment typically have more memory but such devices
are asleep when there is no user activity. RPL-P2P reactive
discovery allows a node to wake up and find new routes within a few
seconds while memory constrained nodes only have to keep routes to
relevant targets.
2.2.5. RPL applicability per communication paradigm This paradigm translates to a device sending a message to many
destinations in one network transfer invocation. Multicast is well
suited for lighting where a presence sensor sends a presence message
to a set of lighting devices. Multicast increases the probability
that the message is delivered within the strict time constraints.
The chosen multicast algorithm (e.g. xref target="I-D.ietf-roll-
trickle-mcast"/>) assures that messages are delivered to ALL
destinations.
TODO: align with new template 2.2.7. RPL applicability per communication paradigm
Describe here when we use RPL, RPL-P2P and MPL based on sections on In the case of SS over a wireless sub-network to a server reachable
SS P2P, PMP, and N-cast. via a border router, the use of RPL [RFC6550] is recommended. Given
the low resources of the devices, source routing will be used for
messages from outside the wireless sub-network to the destination in
the wireless sub-network. No specific timing constraints are
associated with the SS type messages so network repair does not
violate the operational constraints. When no SS traffic takes place,
it is recommended to load only RPL-P2P code into the network stack to
satisfy memory requirements by reducing code.
2.3. Link layer applicability All P2P and P2MP traffic, taking place within a wireless sub-network,
requires P2P-RPL [RFC6997] to assure responsiveness. Source and
destination are typically close together to satisfy the living
conditions of one room. Consequently, most P2P and P2MP traffic is
1-hop or 2-hop traffic. Appendix A explains why RPL-P2P is
preferable to RPL for this type of communication.
Additional advantages of RPL-P2P for home and building automation
networks are, for example:
o Individual wall switches are typically inexpensive devices with
extremely low memory capacities. Multi-purpose remote controls
for use in a home environment typically have more memory but such
devices are asleep when there is no user activity. RPL-P2P
reactive discovery allows a node to wake up and find new routes
within a few seconds while memory constrained nodes only have to
keep routes to relevant targets.
o The reactive discovery features of RPL-P2P ensure that commands
are normally delivered within the 250msec time window and when
connectivity needs to be restored, it is typically completed
within seconds. In most cases an alternative (earlier discovered)
route will work. Thus, route rediscovery is not even necessary.
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
Section 4.1.2.
N-cast over the wireless network will be done using multicast with
MPL [I-D.ietf-roll-trickle-mcast]. Configuration constraints that
are necessary to meet reliability and timeliness with MPL are
discussed in Section 4.1.7.
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 [I-D.lowpanz]. adapted to IPv6 by the adaption layers [RFC4944] and
[I-D.brandt-6man-lowpanz].
Due to the limited memory of a majority of devices (such as The above mentioned adaptation layers leverage on the compression
individual light dimmers) RPL-P2P MUST be used with source routing in capabilities of [RFC6554] and [RFC6282]. Header compression allows
non-storing mode. The abovementioned adaptation layers leverage on small IP packets to fit into a single layer 2 frame even when source
the compression capabilities of [RFC6554] and [RFC6282]. Header routing is used. A network diameter limited to 5 hops helps to
compression allows small IP packets to fit into a single layer 2 achieve this.
frame even when source routing is used. A network diameter limited
to 5 hops helps achieving this.
Packet drops 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-P2P. used with RPL and RPL-P2P.
3. Using RPL-P2P to meet requirements 3. Using RPL to meet Functional Requirements
RPL-P2P SHOULD be used in home and building networks, as point-to- RPL-P2P MUST be present in home and building automation networks, as
point style traffic is substantial and route repair needs to be point-to-point style traffic is substantial and route repair needs to
completed within seconds. RPL- P2P provides a reactive mechanism for be completed within seconds. RPL-P2P provides a reactive mechanism
quick, efficient and root- independent route discovery/repair. The for quick, efficient and root-independent route discovery/repair.
use of RPL-P2P furthermore allows data traffic to avoid having to go The use of RPL-P2P furthermore allows data traffic to avoid having to
through a central region around the root of the tree, and drastically go through a central region around the root of the tree, and
reduces path length [SOFT11] [INTEROP12]. These characteristics are drastically reduces path length [SOFT11] [INTEROP12]. These
desirable in home and building automation networks because they characteristics are desirable in home and building automation
substantially decrease unnecessary network congestion around the networks because they substantially decrease unnecessary network
tree's root. congestion around the root of the tree.
4. RPL Profile for RPL-P2P When reliability is required, multiple independent paths are used
with RPL-P2P. For 1-hop destinations this means that one 1-hop
communication and a second 2-hop communication take place via a
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
from the seed and the destination node.
4. RPL Profile
RPL-P2P MUST be used in home and building networks. Non-storing mode RPL-P2P MUST be used in home and building networks. Non-storing mode
allows for constrained memory in repeaters when source routing is allows for constrained memory in repeaters when source routing is
used. Reactive discovery allows for low application response times used. Reactive discovery allows for low application response times
even when on-the-fly route repair is needed. even when on-the-fly route repair is needed.
4.1. RPL Features 4.1. RPL Features
TODO: New subsection for prefix and address assignment
In one constrained deployment, the link layer master node handing out In one constrained deployment, the link layer master node handing out
the logical network identifier and unique node identifiers may be a the logical network identifier and unique node identifiers may be a
remote control which returns to sleep once new nodes have been added. remote control which returns to sleep once new nodes have been added.
There may be no global routable prefixes at all. Likewise, there may There may be no global routable prefixes at all. Likewise, there may
be no authoritative always-on root node since there is no border be no authoritative always-on root node since there is no border
router to host this function. router to host this function.
In another constrained deployment, there may be battery powered In another constrained deployment, there may be battery powered
sensors and wall controllers configured to contact other nodes in sensors and wall controllers configured to contact other nodes in
response to events and then return to sleep. Such nodes may never response to events and then return to sleep. Such nodes may never
detect the announcement of new prefixes via multicast. detect the announcement of new prefixes via multicast.
In each of the abovementioned constrained deployments, the link layer In each of the above mentioned constrained deployments, the link
master node SHOULD assume the role as authoritative root node, layer master node SHOULD assume the role as authoritative root node,
transmitting singlecast RAs with a ULA prefix information option to transmitting singlecast RAs with a ULA prefix information option to
nodes during the inclusion process to prepare the nodes for a later nodes during the inclusion process to prepare the nodes for a later
operational phase, where a border router is added. 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
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 MUST be able to join one RPL instance as an instance is created
during each P2P-RPL route discovery operation. A node MAY be during each P2P-RPL route discovery operation. A node MAY be
designed to join multiple RPL instances. designed to join multiple RPL instances.
4.1.2. 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 MUST be used 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
TBD. A node MAY be designed to join multiple RPL instances; in that case
DAO policies may be needed.
DAO policy is out of scope for this applicability statement.
4.1.4. Path Metrics 4.1.4. Path Metrics
TBD.
4.1.5. Objective Function OF0 is RECOMMENDED. [RFC6551] provides other options. Using other
objective functions than OF0 may affect inter-operability.
OF0 MUST be supported and is the RECOMMENDED OF to use. Other 4.1.5. Objective Function
Objective Functions MAY be used as well. OF0 MUST be supported and is the RECOMMENDED Objective Function to
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.
4.1.7. Multicast 4.1.7. Multicast
Commercial light deployments may have a need for multicast beyond the Commercial light deployments may have a need for multicast. Several
link-local scope. RPL and P2P-RPL do not provide any means for this mechanisms exist for achieving such functionality;
transmission mode natively. [I-D.ietf-roll-trickle-mcast] is RECOMMENDED for home and building
deployments.
Several mechanisms exist for achieving such functionality; [MPL] is Guaranteeing timeliness is intimately related to the density of the
RECOMMENDED for home and building deployments. MPL routers. In ideal circumstances the message is propagated as a
single wave through the network, such that the maximum delay is
related to the number of hops times the smallest repetition interval
of MPL. Each repeater that receives the message, passes the message
on to the next hop by repeating the message. Repetition of the
message can be inhibited by a small value of k. Therefore the value
of k should be chosen high enough to make sure that messages are
repeated immediately. However, a network that is too dense leads to
a saturation of the medium that can only be prevented by selecting a
low value of k. Consequently, timeliness is assured by choosing a
relatively high value of k but assuring at the same time a low enough
density of repeaters to reduce the risk of medium saturation.
Depending on the reliability of the network channels, it is advisable
to choose the network such that at least 2 repeaters (one repeater
located on the seed) can repeat messages to the same set of
destinations.
[TODO/TBD: text on MPL repeater density] There are no rules about selecting repeaters for MPL. In buildings
with central managment tools, the repeaters can be selected, but in
the home is not possible to automatically configure the repeater
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,
the following RPL security parameter values SHOULD be used: RPL MAY use either unsecured messages or secured messages. If RPL is
used with unsecured messages, link layer security SHOULD be used. If
RPL is used with secured messages, the following RPL security
parameter values SHOULD be used:
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
RPL-P2P [RPL-P2P] MUST be used to accommodate P2P traffic, which is [RFC6997] MUST be used to accommodate P2P traffic, which is typically
typically substantial in home and building automation networks. substantial in home and building automation networks.
4.1.10. IPv6 adddress configuration
Assigned IP addresses MUST be routable and unique within the routing
domain.
4.2. Layer 2 features 4.2. Layer 2 features
For deployments based on No particular requirements exist for layer 2 but for the ones cited
in the IP over Foo RFCs.
[IEEE802.15.4] and [G.9959], security MUST be applied at layer 2 4.3. Recommended Configuration Defaults and Ranges
using the mechanisms provided by the relevant standards. Residential
light control can accept a lower security level than other contexts
(e.g. a nuclear research lab). Safety critical devices like
electronic door locks SHOULD employ additional higher-layer security
while light and heating devices may be sufficiently protected by a
single network key. The border router MAY enforce access policies to
limit access to the trusted LLN domain from the LAN.
4.2.1. Security functions provided by layer-2 The following sections describe the recommended parameter values for
RPL-P2P, Trickle, and MPL.
TBD. 4.3.1. RPL-P2P parameters
4.2.2. 6LowPAN options assumed RPL-P2P [RFC6997] provides the features requested by [RFC5826] and
[RFC5867]. RPL-P2P uses a subset of the frame formats and features
defined for RPL [RFC6550] but may be combined with RPL frame flows in
advanced deployments.
TBD. Parameter values for RPL-P2P are:
4.2.3. MLE and other things o MinHopRankIncrease 1
TBD. o MaxRankIncrease 0
4.3. Recommended Configuration Defaults and Ranges o MaxRank 6
TODO o Objective function: OF0
4.3.2. Trickle parameters
Trickle is used to distribute network parameter values to all nodes
without stringent time restrictions. Trickle parameter values are:
o DIOIntervalMin 4 = 16 ms
o DIOIntervalDoublings 14
o DIORedundancyConstant 1
4.3.3. MPL parameters
MPL is used to distribute values to groups of devices. In MPL, based
on Trickle algorithm, also timeliness should be guaranteed. Under
the condition that the density of MPL repeaters can be limited, it is
possible to choose low MPL repeat intervals (Imin) connected to k
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
packets that can be received within the listening period of Imin.
o Number of repeaters repeating the same 1-hop broadcast message.
These repeaters repeat within the same Imin interval, thus
increasing the c counter.
Suggested MPL parameter values are:
o I_min = 10 - 50.
o I_max = 200 - 400.
o k > 2 (see above).
o max_expiration = 2 - 4.
5. Manageability Considerations 5. Manageability Considerations
TODO Manageability is out of scope for home network scenarios. In
building automation scenarios, central control should be applied
based on MIBs.
6. Security Considerations 6. Security Considerations
TODO Refer to the security considerations of [RFC6997], [RFC6550], and
[I-D.ietf-roll-trickle-mcast].
6.1. Security Considerations during initial deployment
TODO: (This section explains how nodes get their initial trust 6.1. Security Considerations for distribution of credentials required
anchors, initial network keys. It explains if this happens at the for RPL
factory, in a deployment truck, if it is done in the field, perhaps
like http://www.lix.polytechnique.fr/hipercom/SmartObjectSecurity/
papers/CullenJennings.pdf)
6.2. Security Considerations during incremental deployment Communications network security is based on providing integrity
protection and encryption to messages. This can be applied at
various layers in the network protocol stack based on using various
credentials and a network identity.
Replacing a failed node means re-assigning the short address of the The credentials which are relevant in the case of RPL are: (i) the
failed node to the new node added to the network. This again allows credential used at the link layer in the case where link layer
a new node replacing a failed node to obtain the same IPv6 addresses security is applied or (ii) the credential used for securing RPL
as per the lines of [IPHC]. messages. In both cases, the assumption is that the credential is a
shared key. Therefore, there MUST be a mechanism in place which
allows secure distribution of a shared key and configuration of
network identity. Both MAY be done using (i) pre-installation using
an out-of-band method, (ii) delivered securely when a device is
introduced into the network or (iii) delivered securely by a trusted
neighboring device. The shared key MUST be stored in a secure
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]
As it is recommended to base security on a shared group key, it is 6.2. Security Considerations for P2P uses
possible to replace failed nodes. For specific details on how to
replace failed nodes; refer to the actual link layer documentation.
TODO / TBD: Special concerns for adding a new node? Refer to the security considerations of [RFC6997].
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
path towards a desired destination that is neither the root of a DAG, path towards a desired destination that is neither the root of a DAG,
nor a destination originating DAO signaling. Furthermore, P2P paths nor a destination originating DAO signaling. Furthermore, P2P paths
provided by RPL are not satisfactory in all cases because they provided by RPL are not satisfactory in all cases because they
involve too many intermediate nodes before reaching the destination. involve too many intermediate nodes before reaching the destination.
RPL-P2P [RPL-P2P] provides the features requested by [RFC5826] and
[RFC5867]. RPL-P2P uses a subset of the frame formats and features
defined for RPL [RFC6550] but may be combined with RPL frame flows in
advanced deployments.
8. IANA Considerations 8. IANA Considerations
9. Acknowledgements No considerations for IANA pertain to this document.
9. Acknowledgements
This document reflects discussions and remarks from several This document reflects discussions and remarks from several
individuals including (in alphabetical order): Michael Richardson, individuals including (in alphabetical order): Mukul Goyal, Jerry
Mukul Goyal, Jerry Martocci, Charles Perkins, and Zach Shelby Martocci, Charles Perkins, Michael Richardson, and Zach Shelby
10. References 10. Changelog
Changes from version 0 to version 1.
o Adapted section structure to template.
o Standardized the reference syntax.
o Section 2.2, moved everything concerning algorithms to section
2.2.7, and adpted text in 2.2.1-2.2.6.
o Added MPL parameter text to section 4.1.7 and section 4.3.1.
o Replaced all TODO sections with text.
o Consistent use of border router, mintoring, home- and building
network.
o Reformulated security aspects with references to other
publications.
o MPL and RPL parameter values introduced.
11. References 11. References
11.1. Normative References 11.1. Normative References
[RFC5826] , "Home Automation Routing Requirements in Low-Power and [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Lossy Networks", . Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5867] , "Building Automation Routing Requirements in Low-Power [RFC4944] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler,
and Lossy Networks", . "Transmission of IPv6 Packets over IEEE 802.15.4
Networks", RFC 4944, September 2007.
[RFC5673] , "Industrial Routing Requirements in Low-Power and Lossy [RFC5548] Dohler, M., Watteyne, T., Winter, T., and D. Barthel,
Networks", . "Routing Requirements for Urban Low-Power and Lossy
Networks", RFC 5548, May 2009.
[RFC5548] , "Routing Requirements for Urban Low-Power and Lossy [RFC5673] Pister, K., Thubert, P., Dwars, S., and T. Phinney,
Networks", . "Industrial Routing Requirements in Low-Power and Lossy
Networks", RFC 5673, October 2009.
[IEEE802.15.4] [RFC5826] Brandt, A., Buron, J., and G. Porcu, "Home Automation
, "IEEE 802.15.4 - Standard for Local and metropolitan Routing Requirements in Low-Power and Lossy Networks", RFC
area networks -- Part 15.4: Low-Rate Wireless Personal 5826, April 2010.
Area Networks", , <IEEE Standard 802.15.4>.
[RFC4944] , "Transmission of IPv6 Packets over IEEE 802.15.4 [RFC5867] Martocci, J., De Mil, P., Riou, N., and W. Vermeylen,
Networks", . "Building Automation Routing Requirements in Low-Power and
Lossy Networks", RFC 5867, June 2010.
[G.9959] , "ITU-T G.9959 Short range narrow-band digital [RFC6282] Hui, J. and P. Thubert, "Compression Format for IPv6
radiocommunication transceivers - PHY and MAC layer Datagrams over IEEE 802.15.4-Based Networks", RFC 6282,
specifications", , <ITU-T G.9959>. September 2011.
[I-D.lowpanz] [RFC6550] Winter, T., Thubert, P., Brandt, A., Hui, J., Kelsey, R.,
Brandt, A., "Transmission of IPv6 Packets over ITU-T Levis, P., Pister, K., Struik, R., Vasseur, JP., and R.
G.9959 Networks", , <draft-brandt-6man-lowpanz>. Alexander, "RPL: IPv6 Routing Protocol for Low-Power and
Lossy Networks", RFC 6550, March 2012.
[RFC6282] Hui, J., Thubert, P., , , , "Compression Format for IPv6 [RFC6551] Vasseur, JP., Kim, M., Pister, K., Dejean, N., and D.
Datagrams over IEEE 802.15.4-Based Networks", RFC6282 , Barthel, "Routing Metrics Used for Path Calculation in
September 2011. Low-Power and Lossy Networks", RFC 6551, March 2012.
[RFC6554] Hui, J., Vasseur, JP., Culler, D., Manral, V., , "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)", RFC6554 , March for Low-Power and Lossy Networks (RPL)", RFC 6554, March
2012. 2012.
[RFC6550] , "RPL: IPv6 Routing Protocol for Low-Power and Lossy [RFC6997] Goyal, M., Baccelli, E., Philipp, M., Brandt, A., and J.
Networks", .
[RPL-P2P] Goyal, M., Baccelli, E., Phillip, 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", draft-ietf-roll-p2p-rpl , Low-Power and Lossy Networks", RFC 6997, August 2013.
May 2012.
[I-D.brandt-6man-lowpanz]
Brandt, A. and J. Buron, "Transmission of IPv6 packets
over ITU-T G.9959 Networks", draft-brandt-6man-lowpanz-02
(work in progress), June 2013.
[I-D.ietf-roll-trickle-mcast]
Hui, J. and R. Kelsey, "Multicast Protocol for Low power
and Lossy Networks (MPL)", draft-ietf-roll-trickle-
mcast-04 (work in progress), February 2013.
[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>.
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., 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, Janurary 2012.
[SmartObj]
Jennings, C., "Transitive Trust Enrollment for Constrained
Devices", Web http://www.lix.polytechnique.fr/hipercom/
SmartObjectSecurity/papers/CullenJennings.pdf, February
2012.
Appendix A. RPL shortcomings in home and building deployments Appendix A. RPL shortcomings in home and building deployments
This document reflects discussions and remarks from several This document reflects discussions and remarks from several
individuals including (in alphabetical order): Charles Perkins, Jerry individuals including (in alphabetical order): Charles Perkins, Jerry
Martocci, Michael Richardson, Mukul Goyal and Zach Shelby. Martocci, Michael Richardson, Mukul Goyal and Zach Shelby.
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
skipping to change at page 13, line 44 skipping to change at page 18, line 18
length. Long routes cause source nodes to stay awake for longer length. Long routes cause source nodes to stay awake for longer
periods before returning to sleep. Thus, a longer route translates periods before returning to sleep. Thus, a longer route translates
proportionally (more or less) into higher battery consumption. proportionally (more or less) into higher battery consumption.
A.2. Risk of delayed route repair A.2. Risk of delayed route repair
The RPL DAG mechanism uses DIO and DAO messages to monitor the health The RPL DAG mechanism uses DIO and DAO messages to monitor the health
of the DAG. In rare occasions, changed radio conditions may render of the DAG. In rare occasions, changed radio conditions may render
routes unusable just after a destination node has returned a DAO routes unusable just after a destination node has returned a DAO
indicating that the destination is reachable. Given enough time, the indicating that the destination is reachable. Given enough time, the
next Trickle timer-controlled DIODAO update will eventually repair next Trickle timer-controlled DIO/DAO update will eventually repair
the broken routes. In a worst-case event this is however too late. the broken routes, however this may not occur in a timely manner
In an apparently stable DAG, Trickle-timer dynamics may reduce the appropriate to the application. In an apparently stable DAG,
update rate to a few times every hour. If a user issues an actuator Trickle-timer dynamics may reduce the update rate to a few times
command, e.g. light on in the time interval between the last DAO every hour. If a user issues an actuator command, e.g. light on in
message was issued the destination module and the time one of the the time interval between the last DAO message was issued the
parents sends the next DIO, the destination cannot be reached. destination module and the time one of the parents sends the next
Nothing in RPL kicks in to restore connectivity in a reactive DIO, the destination cannot be reached. There is no mechanism in RPL
fashion. The consequence is a broken service in home and building to initiate restoration of connectivity in a reactive fashion. The
applications. consequence is a broken service in home and building applications.
A.2.1. Broken service A.2.1. Broken service
Experience from the telecom industry shows that if the voice delay Experience from the telecom industry shows that if the voice delay
exceeds 250ms users start getting confused, frustrated and/or exceeds 250ms, users start getting confused, frustrated and/or
annoyed. In the same way, if the light does not turn on within the annoyed. In the same way, if the light does not turn on within the
same period of time, a home control user will activate the controls same period of time, a home control user will activate the controls
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 the Light{on,off,off,on,off,..} or Volume{up,up,up,up,up,...}. Whether
outcome is nothing or some unintended response this is unacceptable. the outcome is nothing or some unintended response this is
A controlling system must be able to restore connectivity to recover unacceptable. A controlling system must be able to restore
from the error situation. Waiting for an unknown period of time is connectivity to recover from the error situation. Waiting for an
not an option. While this issue was identified during the P2P unknown period of time is not an option. While this issue was
analysis it applies just as well to application scenarios where an IP identified during the P2P analysis, it applies just as well to
application outside the LLN controls actuators, lights, etc. application scenarios where an IP application outside the LLN
controls actuators, lights, etc.
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. 99 change blocks. 
293 lines changed or deleted 491 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/