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diff --git a/doc/rfc/rfc6568.txt b/doc/rfc/rfc6568.txt new file mode 100644 index 0000000..0c269bc --- /dev/null +++ b/doc/rfc/rfc6568.txt @@ -0,0 +1,1571 @@ + + + + + + +Internet Engineering Task Force (IETF) E. Kim +Request for Comments: 6568 ETRI +Category: Informational D. Kaspar +ISSN: 2070-1721 Simula Research Laboratory + JP. Vasseur + Cisco Systems, Inc. + April 2012 + + + Design and Application Spaces + for IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs) + +Abstract + + This document investigates potential application scenarios and use + cases for low-power wireless personal area networks (LoWPANs). This + document provides dimensions of design space for LoWPAN applications. + A list of use cases and market domains that may benefit and motivate + the work currently done in the 6LoWPAN Working Group is provided with + the characteristics of each dimension. A complete list of practical + use cases is not the goal of this document. + +Status of This Memo + + This document is not an Internet Standards Track specification; it is + published for informational purposes. + + This document is a product of the Internet Engineering Task Force + (IETF). It represents the consensus of the IETF community. It has + received public review and has been approved for publication by the + Internet Engineering Steering Group (IESG). Not all documents + approved by the IESG are a candidate for any level of Internet + Standard; see Section 2 of RFC 5741. + + Information about the current status of this document, any errata, + and how to provide feedback on it may be obtained at + http://www.rfc-editor.org/info/rfc6568. + + + + + + + + + + + + + + +Kim, et al. Informational [Page 1] + +RFC 6568 6LoWPAN Design and Applications April 2012 + + +Copyright Notice + + Copyright (c) 2012 IETF Trust and the persons identified as the + document authors. All rights reserved. + + This document is subject to BCP 78 and the IETF Trust's Legal + Provisions Relating to IETF Documents + (http://trustee.ietf.org/license-info) in effect on the date of + publication of this document. Please review these documents + carefully, as they describe your rights and restrictions with respect + to this document. Code Components extracted from this document must + include Simplified BSD License text as described in Section 4.e of + the Trust Legal Provisions and are provided without warranty as + described in the Simplified BSD License. + + This document may contain material from IETF Documents or IETF + Contributions published or made publicly available before November + 10, 2008. The person(s) controlling the copyright in some of this + material may not have granted the IETF Trust the right to allow + modifications of such material outside the IETF Standards Process. + Without obtaining an adequate license from the person(s) controlling + the copyright in such materials, this document may not be modified + outside the IETF Standards Process, and derivative works of it may + not be created outside the IETF Standards Process, except to format + it for publication as an RFC or to translate it into languages other + than English. + + + + + + + + + + + + + + + + + + + + + + + + + +Kim, et al. Informational [Page 2] + +RFC 6568 6LoWPAN Design and Applications April 2012 + + +Table of Contents + + 1. Introduction ....................................................3 + 1.1. Terminology ................................................5 + 1.2. Premise of Network Configuration ...........................5 + 2. Design Space ....................................................6 + 3. Application Scenarios ...........................................8 + 3.1. Industrial Monitoring ......................................8 + 3.1.1. A Use Case and Its Requirements .....................9 + 3.1.2. 6LoWPAN Applicability ..............................10 + 3.2. Structural Monitoring .....................................12 + 3.2.1. A Use Case and Its Requirements ....................12 + 3.2.2. 6LoWPAN Applicability ..............................14 + 3.3. Connected Home ............................................15 + 3.3.1. A Use Case and Its Requirements ....................15 + 3.3.2. 6LoWPAN Applicability ..............................17 + 3.4. Healthcare ................................................18 + 3.4.1. A Use Case and Its Requirements ....................18 + 3.4.2. 6LoWPAN Applicability ..............................19 + 3.5. Vehicle Telematics ........................................20 + 3.5.1. A Use Case and Its Requirements ....................21 + 3.5.2. 6LoWPAN Applicability ..............................21 + 3.6. Agricultural Monitoring ...................................22 + 3.6.1. A Use Case and Its Requirements ....................22 + 3.6.2. 6LoWPAN Applicability ..............................24 + 4. Security Considerations ........................................25 + 5. Acknowledgements ...............................................26 + 6. References .....................................................26 + 6.1. Normative References ......................................26 + 6.2. Informative References ....................................27 + +1. Introduction + + Low-power and lossy networks (LLNs) is the term commonly used to + refer to networks made of highly constrained nodes (limited CPU, + memory, power) interconnected by a variety of "lossy" links + (low-power radio links or Power-Line Communication (PLC)). They are + characterized by low speed, low performance, low cost, and unstable + connectivity. A LoWPAN is a particular instance of an LLN, formed by + devices complying with the IEEE 802.15.4 standard [5]. Their typical + characteristics can be summarized as follows: + + o Limited Processing Capability: The smallest common LoWPAN nodes + have 8-bit processors with clock rates around 10 MHz. Other + models exist with 16-bit and 32-bit cores (typically ARM7), + running at frequencies on the order of tens of MHz. + + + + + +Kim, et al. Informational [Page 3] + +RFC 6568 6LoWPAN Design and Applications April 2012 + + + o Small Memory Capacity: The smallest common LoWPAN nodes have a few + kilobytes of RAM with a few dozen kilobytes of ROM/flash memory. + While memory sizes of nodes continue to grow (e.g., IMote has 64 + KB SRAM, 512 KB Flash memory), the nature of small memory capacity + for LoWPAN nodes remains a challenge. + + o Low Power: Wireless radios for LoWPANs are normally + battery-operated. Their radio frequency (RF) transceivers often + have a current draw of about 10 to 30 mA, depending on the used + transmission power level. In order to reach common indoor ranges + of up to 30 meters and outdoor ranges of 100 meters, the used + transmission power is set around 0 to 3 dBm. Depending on the + processor type, there is an additional battery current consumption + of the CPU itself, commonly on the order of tens of milliamperes. + However, the CPU power consumption can often be reduced by a + thousandfold when switching to sleep mode. + + o Short Range: The Personal Operating Space (POS) defined by + IEEE 802.15.4 implies a range of 10 meters. For real + implementations, the range of LoWPAN radios is typically measured + in tens of meters, but can reach over 100 meters in line-of-sight + situations. + + o Low Bit Rate: The IEEE 802.15.4 standard defines a maximum + over-the-air rate of 250 kbit/s, which is most commonly used in + current deployments. Alternatively, three lower data rates of 20, + 40, and 100 kbit/s are defined. + + As with any other LLN, a LoWPAN is not necessarily comprised of + sensor nodes only, but may also consist of actuators. For instance, + in an agricultural environment, sensor nodes might be used to detect + low soil humidity and then send commands to activate the sprinkler + system. + + After defining common terminology in Section 1.1 and describing the + characteristics of LoWPANs in Section 2, this document provides a + list of use cases and market domains that may benefit and motivate + the work currently done in the 6LoWPAN Working Group. + + + + + + + + + + + + + +Kim, et al. Informational [Page 4] + +RFC 6568 6LoWPAN Design and Applications April 2012 + + +1.1. Terminology + + Readers are expected to be familiar with all terms and concepts + discussed in "IPv6 over Low-Power Wireless Personal Area Networks + (6LoWPANs): Overview, Assumptions, Problem Statement, and Goals" [2], + and "Transmission of IPv6 Packets over IEEE 802.15.4 Networks" [3]. + + Readers would benefit from reading 6LoWPAN Neighbor Discovery (ND) + [6], 6LoWPAN header compression [7], and 6LoWPAN routing requirements + [8] for details of 6LoWPAN work. + + This document defines the following terms: + + LC (Local Controller) + + A logical functional entity that performs the special role of + coordinating and controlling its child nodes for local data + aggregation, status management of local nodes, etc. There may be + multiple instances of local controller nodes in a LoWPAN. + + LBR (LoWPAN Border Router) + + A border router located at the junction of separate LoWPANs or + between a LoWPAN and another IP network. There may be one or more + LBRs at the LoWPAN boundary. An LBR is the responsible authority + for IPv6 Prefix propagation for the LoWPAN it serves. An isolated + LoWPAN also contains an LBR in the network; the LBR provides the + prefix(es) for the isolated network. + +1.2. Premise of Network Configuration + + The IEEE 802.15.4 standard distinguishes between two types of nodes + -- reduced-function devices (RFDs) and full-function devices (FFDs). + As this distinction is based on some Medium Access Control (MAC) + features that are not always in use, we are not using this + distinction in this document. + + 6LoWPANs can be deployed using either route-over or mesh-under + architectures. As the choice of route-over or mesh-under does not + affect the applicability of 6LoWPAN technologies to the use cases + described in the document, we will use the term "6LoWPAN" to mean + either a route-over or mesh-under network. + + Communication to corresponding nodes outside of the LoWPAN is + becoming increasingly important for convenient data collection and + remote-control purposes. The intermediate LoWPAN nodes act as packet + forwarders on the link layer or as LoWPAN routers, and connect the + entire LoWPAN in a multi-hop fashion. LBRs are used to interconnect + + + +Kim, et al. Informational [Page 5] + +RFC 6568 6LoWPAN Design and Applications April 2012 + + + a LoWPAN to other networks, or to form an extended LoWPAN by + connecting multiple LoWPANs. Before LoWPAN nodes obtain their IPv6 + addresses and the network is configured, each LoWPAN executes a + link-layer configuration either by the mechanisms specified in [6] or + by using a coordinator that is responsible for link-layer short + address allocation. However, the link-layer coordinator + functionality is out of the scope of this document. Details of + address allocation in 6LoWPAN ND are in [6]. + + A LoWPAN can be configured as mesh-under or route-over (see + Terminology in [6]). In a route-over configuration, multi-hop + transmission is carried out by LoWPAN routers using IP routing. In a + mesh-under configuration, the link-local scope reaches to the + boundaries of the LoWPAN, and multi-hop transmission is achieved by + forwarding data at the link layer or in a 6LoWPAN adaptation layer. + More information about mesh-under and route-over is in [6] and [8]. + +2. Design Space + + Inspired by [9], this section lists the dimensions used to describe + the design space of wireless sensor networks in the context of the + 6LoWPAN Working Group. The design space is already limited by the + unique characteristics of a LoWPAN (e.g., low power, short range, low + bit rate), as described in [2]. The possible dimensions for scenario + categorization used in this document are described as follows: + + o Deployment: LoWPAN nodes can be scattered randomly, or they may be + deployed in an organized manner in a LoWPAN. The deployment can + occur at once, or as an iterative process. The selected type of + deployment has an impact on node density and location. This + feature affects how to organize (manually or automatically) the + LoWPAN and how to allocate addresses in the network. + + o Network Size: The network size takes into account nodes that + provide the intended network capability. The number of nodes + involved in a LoWPAN could be small (ten), moderate (several + hundred), or large (over a thousand). + + o Power Source: The power source of nodes, whether the nodes are + battery-powered or mains-powered, influences the network design. + The power may also be harvested from solar cells or other sources + of energy. Hybrid solutions are possible where only part of the + network is mains-powered. + + o Connectivity: Nodes within a LoWPAN are considered "always + connected" when there is a network connection between any two + given nodes. However, due to external factors (e.g., extreme + environment, mobility) or programmed disconnections (e.g., + + + +Kim, et al. Informational [Page 6] + +RFC 6568 6LoWPAN Design and Applications April 2012 + + + sleeping mode), network connectivity can be from "intermittent" + (i.e., regular disconnections) to "sporadic" (i.e., almost always + disconnected). Differences in L2 duty-cycling settings may + additionally impact connectivity due to highly varying bit rates. + + o Multi-Hop Communication: The multi-hop communication factor + highlights the number of hops that have to be traversed to reach + the edge of the network or a destination node within it. A single + hop may be sufficient for simple star topologies, but a multi-hop + communication scheme is required for more elaborate topologies, + such as meshes or trees. In previous work on LoWPANs by academia + and industry, various routing mechanisms were introduced, such as + data-centric, event-driven, address-centric, localization-based, + geographical routing, etc. This document does not make use of + such a fine granularity but rather uses topologies and single/ + multi-hop communication. + + o Traffic Pattern: Several traffic patterns may be used in LoWPANs + -- Point-to-Multipoint (P2MP), Multipoint-to-Point (MP2P), and + Point-to-Point (P2P), to name a few. + + o Security Level: LoWPANs may carry sensitive information and + require high-level security support where the availability, + integrity, and confidentiality of the information are crucial. + + o Mobility: Inherent to the wireless characteristics of LoWPANs, + nodes could move or be moved around. Mobility can be an induced + factor (e.g., sensors in an automobile) -- and hence not + predictable -- or a controlled characteristic (e.g., pre-planned + movement in a supply chain). + + o Quality of Service (QoS): QoS issues in LoWPANs may be very + different from the traditional end-to-end QoS, as in LoWPAN + applications one end is not a single sensor node but often a group + of sensor nodes. Parameters for QoS should consider collective + data for latency, packet loss, data throughput, etc. In addition, + QoS requirements can be different based on the data delivery + model, such as event-driven, query-driven, continuous real-time, + or continuous non-real-time; these delivery models usually coexist + in LoWPAN applications. QoS issues in LoWPANs are more likely + related to corresponding application-specific data delivery + requirements within resource-constrained LoWPANs. + + + + + + + + + +Kim, et al. Informational [Page 7] + +RFC 6568 6LoWPAN Design and Applications April 2012 + + +3. Application Scenarios + + This section lists a fundamental set of LoWPAN application scenarios + in terms of system design. A complete list of practical use cases is + not the objective of this document. + +3.1. Industrial Monitoring + + LoWPAN applications for industrial monitoring can be associated with + a broad range of methods to increase productivity, energy efficiency, + and safety of industrial operations in engineering facilities and + manufacturing plants. Many companies currently use time-consuming + and expensive manual monitoring to predict failures and to schedule + maintenance or replacements in order to avoid costly manufacturing + downtime. LoWPANs can be inexpensively installed to provide more + frequent and more reliable data. The deployment of LoWPANs can + reduce equipment downtime and eliminate manual equipment monitoring + that is costly to perform. Additionally, data analysis functionality + can be placed into the network, eliminating the need for manual data + transfer and analysis. + + Industrial monitoring can be largely split into the following + application fields: + + o Process Monitoring and Control: This application field combines + advanced energy metering and sub-metering technologies with + wireless sensor networking in order to optimize factory + operations, reduce peak demand, ultimately lower costs for energy, + avoid machine downtimes, and increase operation safety. + + A plant's monitoring boundary often does not cover the entire + facility but only those areas considered critical to the process. + Wireless connectivity that is easy to install extends this line to + include peripheral areas and process measurements that were + previously infeasible or impractical to reach with wired + connections. + + o Machine Surveillance: This application field ensures product + quality and efficient and safe equipment operation. Critical + equipment parameters such as vibration, temperature, and + electrical signature are analyzed for abnormalities that are + suggestive of impending equipment failure. + + + + + + + + + +Kim, et al. Informational [Page 8] + +RFC 6568 6LoWPAN Design and Applications April 2012 + + + o Supply Chain Management and Asset Tracking: With the retail + industry being legally responsible for the quality of sold goods, + early detection of inadequate storage conditions with respect to + temperature will reduce the risk and cost of removing products + from the sales channel. Examples include container shipping, + product identification, cargo monitoring, distribution, and + logistics. + + o Storage Monitoring: This application field includes sensor systems + designed to prevent releases of regulated substances into ground + water, surface water, and soil. This application field may also + include theft/tampering prevention systems for storage facilities + or other infrastructure, such as pipelines. + +3.1.1. A Use Case and Its Requirements + + Example: Hospital Storage Rooms + + In a hospital, maintenance of the right temperature in storage rooms + is very critical. Red blood cells need to be stored at 2 to 6 + degrees Celsius, blood platelets at 20 to 24 degrees C, and blood + plasma below -18 degrees C. For anti-cancer medicine, maintaining a + humidity of 45% to 55% is required. Storage rooms have temperature + sensors and humidity sensors every 25 to 100 m, based on the floor + plan and the location of shelves, as indoor obstacles distort the + radio signals. At each blood pack, a sensor tag can be installed to + track the temperature during delivery. A LoWPAN node is installed in + each container of a set of blood packs. In this case, highly dense + networks must be managed. + + All nodes are statically deployed and manually configured with either + a single- or multi-hop connection. Different types of LoWPAN nodes + are configured based on the service and network requirements. In + particular, LCs play a role in aggregation of the sensed data from + blood packs. In the extended networks, more than one LoWPAN LC can + be installed in a storage room. In the case that the sensed data + from an individual node is urgent event-driven data such as outrange + of temperature or humidity, it will not be accumulated (and further + delayed) by the LCs but immediately relayed. + + All LoWPAN nodes do not move unless the blood packs or a container of + blood packs is moved. Moving nodes get connected by logical + attachment to a new LoWPAN. When containers of blood packs are + transferred to another place in the hospital or by ambulance, the + LoWPAN nodes on the containers associate to a new LoWPAN. + + + + + + +Kim, et al. Informational [Page 9] + +RFC 6568 6LoWPAN Design and Applications April 2012 + + + This type of application works based on both periodic and + event-driven notifications. Periodic data is used for monitoring + temperature and humidity in the storage rooms. The data over or + under a predefined threshold is meaningful to report. Blood cannot + be used if it is exposed to the wrong environment for about 30 + minutes. Thus, event-driven data sensed on abnormal occurrences is + time-critical and requires secure and reliable transmission. + + LoWPANs must be provided with low installation and management costs, + and for the transportation of blood containers, precise location + tracking of containers is important. The hospital network manager or + staff can be provided with an early warning of possible chain + ruptures, for example, by conveniently accessing comprehensive online + reports and data management systems. + + Dominant parameters in industrial monitoring scenarios: + + o Deployment: Pre-planned, manually attached. + + o Network Size: Medium to large size, high node density. + + o Power Source: Battery-operated most of the time. + + o Connectivity: Always on for crucial processes. + + o Multi-Hop Communication: Multi-hop networking. + + o Traffic Pattern: P2P (actuator control), MP2P (data collection). + + o Security Level: Business-critical. Secure transmission must be + guaranteed. + + o Mobility: None (except for asset tracking). + + o QoS: Important for time-critical event-driven data. + + o Other Issues: Sensor network management, location tracking, + real-time early warning. + +3.1.2. 6LoWPAN Applicability + + The network configuration of the above use case can differ + substantially by system design. As illustrated in Figure 1, the + simplest way is to build a star topology inside of each storage room. + Based on the layout and size of the storage room, the LoWPAN can be + configured in a different way -- mesh topology -- as shown in + Figure 2. + + + + +Kim, et al. Informational [Page 10] + +RFC 6568 6LoWPAN Design and Applications April 2012 + + + Each LoWPAN node may reach the LBR by a predefined routing/forwarding + mechanism. Each LoWPAN node configures its link-local address and + obtains a prefix from its LBR by a 6LoWPAN ND procedure [6]. LoWPAN + nodes need to build a multi-hop connection to reach the LCs and LBR. + + Secure data transmission and authentication are crucial in a hospital + scenario, to prevent personal information from being retrieved by an + adversary. Confidential data must be encrypted not only in + transmission, but also when stored on nodes, because nodes can + potentially be stolen. + + The data volume is usually not so large in this case, but is + sensitive to delay. Data aggregators can be installed for each + storage room, or just one data aggregator can collect all data. To + make a light transmission, UDP is likely to be chosen, but a secure + transmission and security mechanism must be added. To increase + security, link-layer mechanisms and/or additional security mechanisms + should be used. + + Because a failure of a LoWPAN node can critically affect the storage + of the blood packs, network management is important in this use case. + A lightweight management mechanism must be provided for this + management. + + The service quality of this case is highly related to effective + handling of event-driven data that is delay intolerant and mission + critical. Wrong humidity and wrong temperature are events that need + to be detected as quickly and reliably as possible. It is important + to provide efficient resource usage for such data with consideration + of minimal usage of energy. Energy-aware QoS support in wireless + sensor networks is a challenging issue [12]. It can be considered to + provide appropriate data aggregation for minimizing delay and + maximizing accuracy of delivery by using power-affluent nodes, or can + be aided by middleware or other types of network elements. + + When a container is moved out of the storage room and connected to + another hospital system (if the hospital buildings are fully or + partly covered with LoWPANs), a mechanism to rebind to a new parent + node and a new LoWPAN must be supported. In the case that it is + moved by an ambulance, it will be connected to an LBR in the vehicle. + This type of mobility is supported by the 6LoWPAN ND and routing + mechanism. + + LoWPANs must be provided with low installation and management costs, + providing benefits such as reduced inventory, and precise location + tracking of containers and mobile equipment (e.g., beds moved in the + hospital, ambulances). + + + + +Kim, et al. Informational [Page 11] + +RFC 6568 6LoWPAN Design and Applications April 2012 + + + LBR + | LBR: LoWPAN Border Router + LC----------LC----------LC LC: Local Controller node + / | \ / | \ / | \ (Data Aggregator) + n n n n n n n n n n: LoWPAN node + + Figure 1: Storage Rooms with a Simple Star Topology + + +------------+-----------+ + | | | LBR: LoWPAN Border Router + LBR LBR LBR (LC) LC: Local Controller node + | | | (Data Aggregator) + LC - n LC - n n n: LoWPAN node + / | | | | / \ + n n - LC n - n - n n - n + | | \ | |\ + n n n - n n n n + + Figure 2: Storage Rooms with a Mesh Topology + +3.2. Structural Monitoring + + Intelligent monitoring in facility management can make safety checks + and periodic monitoring of the architecture status highly efficient. + Mains-powered nodes can be included in the design phase of + construction, or battery-equipped nodes can be added afterwards. All + nodes are static and manually deployed. Some data is not critical + for security protection (such as periodic or query-driven + notification of normal room temperature), but event-driven emergency + data (such as a fire alarm) must be handled in a very critical + manner. + +3.2.1. A Use Case and Its Requirements + + Example: Bridge Safety Monitoring + + A 1000-m-long concrete bridge with 10 pillars is described. Each + pillar and the bridge body contain 5 sensors to measure the water + level, and 5 vibration sensors are used to monitor its structural + health. The LoWPAN nodes are deployed to have 100-m line-of-sight + distance from each other. All nodes are placed statically and + manually configured with a single-hop connection to the local + coordinator. All LoWPAN nodes are immobile while the service is + provided. Except for the pillars, there are no special obstacles + causing attenuation of node signals, but careful configuration is + needed to prevent signal interference between LoWPAN nodes. + + + + + +Kim, et al. Informational [Page 12] + +RFC 6568 6LoWPAN Design and Applications April 2012 + + + The physical network topology is changed in case of node failure. On + the top part of each pillar, a sink node is placed to collect the + sensed data. The sink nodes of each pillar become data-gathering + points of the LoWPAN hosts at the pillar and act as local + coordinators. + + This use case can be extended to medium or large sensor networks to + monitor a building or, for instance, the safety status of highways + and tunnels. Larger networks of the same kind still have similar + characteristics, such as static node placement and manual deployment; + depending on the blueprint of the structure, mesh topologies will be + built with mains-powered relay points. Periodic, query-driven, and + event-driven real-time data gathering is performed, and the emergency + event-driven data must be delivered without delay. + + Dominant parameters in structural monitoring applications: + + o Deployment: Static, organized, pre-planned. + + o Network Size: Small (dozens of nodes) to large. + + o Power Source: Mains-powered nodes are mixed with battery-powered + nodes. (Mains-powered nodes will be used for local coordination + or relays.) + + o Connectivity: Always connected, or intermittent via sleeping mode + scheduling. + + o Multi-Hop Communication: It is recommended that multi-hop mesh + networking be supported. + + o Traffic Pattern: MP2P (data collection), P2P (localized querying). + + o Security Level: Safety-critical. Secure transmission must be + guaranteed. Only authenticated users must be able to access and + handle the data. + + o Mobility: None. + + o QoS: Emergency notification (fire, over-threshold vibrations, + water level, etc.) is required to have priority of delivery and + must be transmitted in a highly reliable manner. + + o Other Issues: Accurate sensing and reliable transmission are + important. In addition, sensor status reports should be + maintained in a reliable monitoring system. + + + + + +Kim, et al. Informational [Page 13] + +RFC 6568 6LoWPAN Design and Applications April 2012 + + +3.2.2. 6LoWPAN Applicability + + The network configuration of this use case can be done via simple + topologies; however, there are many extended use cases for more + complex structures. The example bridge monitoring case may be the + simplest case. (An example topology is illustrated in Figure 3.) + + The LoWPAN nodes are installed in place after manual optimization of + their location. As the communication of the leaf LoWPAN nodes may be + limited to the data-gathering points, both 16-bit and 64-bit + addresses can be used for IPv6 link-local addresses [3]. + + Each pillar might have one LC for data collection. Communication + schedules should be set up between leaf nodes and their LC to + efficiently gather the different types of sensed data. Each data + packet may include meta-information about its data, or the type of + sensors could be encoded in its address during address allocation. + + This type of application works based on periodic, query-driven, and + event-driven notifications. The data over or under a predefined + threshold is meaningful to report. Event-driven data sensed on + abnormal occurrences is time-critical and requires secure and + reliable transmission. Alternatively, for energy conservation, all + nodes may have periodic and long sleep modes but wake up on certain + events. To ensure the reliability of such emergency event-driven + data, such data is immediately relayed to a power-affluent or + mains-powered node that usually takes a LoWPAN router role and does + not go into a long sleep status. The data-gathering entity can be + programmed to trigger actuators installed in the infrastructure when + a certain threshold value has been reached. + + Due to the safety-critical data of the structure, authentication and + security are important issues here. Only authenticated users must be + allowed to access the data. Additional security should be provided + at the LBR for restricting access from outside of the LoWPAN. The + LBR may take charge of authentication of LoWPAN nodes. Reliable and + secure data transmission must be guaranteed. + + LBR - LC ----- LC ------ LC LBR: LoWPAN Border Router + /| | | LC: Local Controller node + n n n - n - n n - n n: LoWPAN node + /\ | | | | + n n n - n n - n - n + + Figure 3: A Bridge Monitoring Scenario + + + + + + +Kim, et al. Informational [Page 14] + +RFC 6568 6LoWPAN Design and Applications April 2012 + + +3.3. Connected Home + + The "Connected" Home or "Smart" home is without doubt an area where + LoWPANs can be used to support an increasing number of services: + + o Home safety/security + + o Home automation and control + + o Healthcare (see Section 3.4) + + o Smart appliances and home entertainment systems + + In home environments, LoWPANs typically comprise a few dozen and, + probably in the near future, a few hundred nodes of various types: + sensors, actuators, and connected objects. + +3.3.1. A Use Case and Its Requirements + + Example: Home Automation + + The home automation and control system LoWPAN offers a wide range of + services: local or remote access from the Internet (via a secured + edge router) to monitor the home (temperature, humidity, activation + of remote video surveillance, status of the doors (locked or open), + etc.), as well as home control (activate air conditioning/heating, + door locks, sprinkler systems, etc.). Fairly sophisticated systems + can also optimize the level of energy consumption, thanks to a wide + range of input from various sensors connected to the LoWPAN -- light + sensors, presence detection, temperature, etc. -- in order to control + electric window shades, chillers, air flow control, air conditioning, + and heating. + + With the emergence of "Smart Grid" applications, the LoWPAN may also + have direct interactions with the Grid itself via the Internet to + report the amount of kilowatts that could be load-shed (home to Grid) + and to receive dynamic load-shedding information if/when required + (Grid to home): This application is also referred to as a + Demand-Response application. Another service, known as Demand-Side + Management (DSM), could be provided by utilities to monitor and + report to the user his energy consumption, with a fine granularity + (on a per-device basis). A user can also receive other inputs from + the utility, such as dynamic pricing; according to local policy, the + utility may then turn some appliances on or off in order to reduce + its energy bill. + + + + + + +Kim, et al. Informational [Page 15] + +RFC 6568 6LoWPAN Design and Applications April 2012 + + + In terms of home safety and security, the LoWPAN is made up of motion + sensors and audio sensors, sensors at doors and windows, and video + cameras; additional sensors can be added for safety (gas, water, CO, + Radon, smoke detection). The LoWPAN is typically comprised of a few + dozen nodes forming an ad hoc network with multi-hop routing, since + the nodes may not be in direct range. It is worth mentioning that + the number of devices tends to grow, considering the number of new + applications for the home. In its simplest form, all nodes are + static and communicate with a central control module, but more + sophisticated scenarios may also involve inter-device communication. + For example, a motion/presence sensor may send a multicast message to + a group of lights to be switched on, or a video camera may be + activated to send a video stream to a cell phone via a gateway. + + Ergonomics in connected homes is key, and the LoWPAN must be + self-managed and easy to install. Traffic patterns may vary greatly, + depending on applicability; so does the level of reliability and QoS + expected from the LoWPAN. Humidity sensing is typically not critical + and requires no immediate action, whereas tele-assistance or gas-leak + detection is critical and requires a high degree of reliability. + Furthermore, although some actions may not involve critical data, the + response time and network delays must still be on the order of a few + hundred milliseconds for optimal user experience (e.g., use a remote + control to switch a light on). A minority of nodes are mobile (with + slow motion). With the emergence of energy-related applications, it + becomes crucial to preserve data confidentiality. Connected home + LoWPANs usually do not require multi-topology or QoS routing. Fairly + simple QoS mechanisms are enough for handling emergency data; they + can be programmed to alarm via actuators or to operate sprinklers. + + Dominant parameters for home automation applications: + + o Deployment: Multi-hop topologies. + + o Network Size: Medium number of nodes, potentially high density. + + o Power Source: Mix of battery-powered and mains-powered devices. + + o Connectivity: Intermittent (usage-dependent sleep modes). + + o Multi-Hop Communication: No requirement for multi-topology or QoS + routing. + + o Traffic Pattern: P2P (inter-device), P2MP, and MP2P (polling). + + o Security Level: Authentication and encryption required. + + + + + +Kim, et al. Informational [Page 16] + +RFC 6568 6LoWPAN Design and Applications April 2012 + + + o Mobility: Some degree of mobility. + + o QoS: Support of limited QoS for emergency data (alarm). + +3.3.2. 6LoWPAN Applicability + + In the home automation use case, the network topology is made of a + mix of battery-operated and mains-powered nodes that communicate with + each other. An LBR provides connectivity to the outside world for + control management (Figure 4). + + In the home network, installation and management must be extremely + simple for the user. Link-local IPv6 addresses can be used by nodes + with no external communication, and the LBR allocates routable + addresses to communicate with other LoWPAN nodes not reachable over a + single radio transmission. + + n --- n + | | LBR: LoWPAN Border Router + Internet/ ----- LBR/LC -- n --- n ---- LC LC: Local Controller node + Utility network | | /|\ n: LoWPAN node + n ---- n n n n + + (outside) (home automation system) + + Figure 4: Home Automation Scenario + + In some scenarios, traffic will be sent to a LC for processing; the + LC may in turn decide on local actions (switch a light on, ...). In + other scenarios, all devices will send their data to the LCs, which + in turn may also act as the LBR for data processing and potential + relay of data outside of the LoWPAN. It does not mean that all + devices communicate with each other via the LC and LBR. For the sake + of illustration, some of the data may be processed to trigger local + action (e.g., switch off an appliance), simply store and send data + once enough data has been accumulated (e.g., energy consumption for + the past 6 hours for a set of appliances), or trigger an alarm that + is immediately sent to a datacenter (e.g., gas-leak detection). + + Although in the majority of cases nodes within the LoWPAN will be in + direct range, some nodes will reach the LBR/LC with a path of 2-3 + hops (with the emergence of several low-power media, such as + low-power PLC) in which case LoWPAN routers will be deployed in the + home to interconnect the various IPv6 links. + + + + + + + +Kim, et al. Informational [Page 17] + +RFC 6568 6LoWPAN Design and Applications April 2012 + + + The home LoWPAN must be able to provide extremely reliable + communication in support of some specific applications (e.g., fire, + gas-leak detection, health monitoring), whereas other applications + may not be critical (e.g., humidity monitoring). Such emergency data + has the same QoS issues as does event-driven data in other + applications and can be delivered by pre-defined paths through + mains-powered nodes without being stored in intermediate nodes such + as LCs. Similarly, some information may require the use of security + mechanisms for authentication and confidentiality. + +3.4. Healthcare + + LoWPANs are envisioned to be heavily used in healthcare environments. + They have a high potential for easing the deployment of new services + by getting rid of cumbersome wires and simplifying patient care in + hospitals and at home (home care). In healthcare environments, + delayed or lost information may be a matter of life or death. + + Various systems, ranging from simple wearable remote controls for + tele-assistance or intermediate systems with wearable sensor nodes + monitoring various metrics to more complex systems for studying life + dynamics, can be supported by LoWPANs. In the latter category, a + large amount of data from various LoWPAN nodes can be collected: + movement pattern observation, checks that medicaments have been + taken, object tracking, and more. An example of such a deployment is + described in [10] using the concept of "personal networks". + +3.4.1. A Use Case and Its Requirements + + Example: Healthcare at Home by Tele-Assistance + + A senior citizen who lives alone wears one to several wearable LoWPAN + nodes to measure heartbeat, pulse rate, etc. Dozens of LoWPAN nodes + are densely installed at home for movement detection. An LBR at home + will send the sensed information to a connected healthcare center. + Portable base stations with LCDs may be used to check the data at + home, as well. The different roles of devices have different duty + cycles, which affect node management. + + Multipath interference may often occur due to the mobility of + patients at home, where there are many walls and obstacles. Even + during sleep, the change of body position may affect radio + propagation. + + Data is gathered in both periodic and event-driven fashion. In this + application, event-driven data can be very time-critical. Thus, + real-time and reliable transmission must be guaranteed. + + + + +Kim, et al. Informational [Page 18] + +RFC 6568 6LoWPAN Design and Applications April 2012 + + + Privacy also becomes a serious issue in this case, as the sensed data + is very personal. A small set of secret keys can be shared within + the sensor nodes during bootstrapping procedures in order to build a + secure link without using much memory and energy. In addition, + different data will be provided to the hospital system from that + given to a patient's family members. Role-based access control is + needed to support such services; thus, support of authorization and + authentication is important. + + Dominant parameters in healthcare applications: + + o Deployment: Pre-planned. + + o Network Size: Small, high node density. + + o Power Source: Hybrid. + + o Connectivity: Always on. + + o Multi-Hop Communication: Multi-hop for home-care devices; + patient's body network is star topology. Multipath interference + due to walls and obstacles at home must be considered. + + o Traffic Pattern: MP2P/P2MP (data collection), P2P (local + diagnostic). + + o Security Level: Data privacy and security must be provided. + Encryption is required. It is required that role-based access + control be supported by a lightweight authentication mechanism. + + o Mobility: Moderate (patient's mobility). + + o QoS: High level of reliability support (life-or-death + implication), role-based. + + o Other Issues: Plug-and-play configuration is required for mainly + non-technical end-users. Real-time data acquisition and analysis + are important. Efficient data management is needed for various + devices that have different duty cycles, and for role-based data + control. Reliability and robustness of the network are also + essential. + +3.4.2. 6LoWPAN Applicability + + In this use case, the local network size is rather small (say, 10 + nodes or less). The home care system is statically configured with + multi-hop paths, and the patient's body network can be built as a + star topology. The LBR at home is the sink node in the routing path + + + +Kim, et al. Informational [Page 19] + +RFC 6568 6LoWPAN Design and Applications April 2012 + + + from sources on the patient's body. A plug-and-play configuration is + required. As the communication of the system is limited to a home + environment, both 16-bit and 64-bit addresses can be used for IPv6 + link-local addresses [3]. An example topology is provided in + Figure 5. + + The patient's body network can be simply configured as a star + topology with a LC dealing with data aggregation and dynamic network + attachment when the patient moves around at home. As multipath + interference may often occur due to the patient's mobility at home, + the deployment of LoWPAN nodes and transmission paths should be well + considered. At home, some nodes can be installed with + power-affluence status, and those LoWPAN nodes can be used for + relaying points or data aggregation points. + + The sensed information must be maintained with the identification of + the patient, no matter whether the patient visits the connected + hospital or stays at home. If the patient's LoWPAN uses a globally + unique IPv6 address, the address can be used for patient + identification. However, this incurs a cost in terms of privacy and + security. The hospital LoWPAN to which the patient's information is + transferred needs to operate an additional identification system, + together with a strong authority and authentication mechanism. The + connection between the LBR at home and the LBR at the hospital must + be reliable and secure, as the data is privacy-critical. To achieve + this, an additional policy for security between the two LoWPANs is + recommended. + + n - n I: Internet + | | LBR: Edge Router + LBR --- I -- LBR - n - n - LC LC: Local Controller node + /|\ | | /|\ n: LoWPAN node + .. . .. n -- n n n n + + (hospital) (home system) (patient) + + Figure 5: A Mobile Healthcare Scenario + +3.5. Vehicle Telematics + + LoWPANs play an important role in intelligent transportation systems. + Incorporated into roads, vehicles, and traffic signals, they + contribute to the improvement of safety in transportation systems. + Through traffic or air-quality monitoring, they increase the + possibility of traffic flow optimization, and they help reduce road + congestion. + + + + + +Kim, et al. Informational [Page 20] + +RFC 6568 6LoWPAN Design and Applications April 2012 + + +3.5.1. A Use Case and Its Requirements + + Example: Telematics + + As shown in Figure 6, LoWPAN nodes for motion monitoring are + incorporated into roads during road construction. When a car passes + over these nodes, it is then possible to track, for safety purposes, + the trajectory (path) and velocity of the car. + + The lifetime of LoWPAN nodes incorporated into roads is expected to + be as long as the lifetime of the roads (about 10 years). Multi-hop + communication is possible between LoWPAN nodes, and the network + should be able to cope with the deterioration over time of node + density due to power failures. Sink nodes placed at the side of the + road are most likely mains-powered; LoWPAN nodes in the roads run on + batteries. Power-saving schemes might intermittently disconnect the + nodes. A rough estimate of 4 nodes per square meter is needed. + Other applications may involve car-to-car communication for increased + road safety. + + Dominant parameters in vehicle telematics applications: + + o Deployment: Pre-planned (road, vehicle). + + o Network Size: Large (road infrastructure), small (vehicle). + + o Power Source: Hybrid. + + o Connectivity: Intermittent. + + o Multi-Hop Communication: Multi-hop, especially ad hoc. + + o Traffic Pattern: Mostly MP2P, P2MP. + + o Security Level: Handling physical damage and link failure. + + o Mobility: None (road infrastructure), high (vehicle). + +3.5.2. 6LoWPAN Applicability + + For this use case, the network topology includes fixed LBRs that are + mains-powered and have a connection to high-speed networks (e.g., the + Internet) in order to reach the transportation control center + (Figure 6). These LBRs may be logically combined with a LC as a data + sink to gather sensed data from a number of LoWPAN nodes inserted in + the road pavement. In the road infrastructure, a LoWPAN with one LBR + forms a fixed network, and the LoWPAN nodes are installed by manual + optimization of their location. + + + +Kim, et al. Informational [Page 21] + +RFC 6568 6LoWPAN Design and Applications April 2012 + + + +-----+ + | LBR |--------------------------- LBR ... + +-----+ (at the roadside) + -------|------------------------------ + | + n -- n --- n --- n +---|---+ LBR: LoWPAN Border Router + / \ | | n-n-n | n: LoWPAN node + n n n +---|---+ + (cars) + -------------------------------------- + + Figure 6: Telematics Scenario + + Given the fact that nodes are incorporated into the road, tampering + with sensors is difficult for an adversary. However, the application + must be robust against possible attacks and node failures. Sensed + data should thus be used primarily for monitoring purposes, not to + instruct (and potentially mislead) traffic participants. + +3.6. Agricultural Monitoring + + Accurate temporal and spatial monitoring can significantly increase + agricultural productivity. Due to natural limitations, such as a + farmer's inability to check crops at all times of the day, or + inadequate measurement tools, luck often plays too large a role in + the success of harvests. Using a network of strategically placed + sensors, indicators such as temperature, humidity, and soil condition + can be automatically monitored without labor-intensive field + measurements. For example, sensor networks could provide precise + information about crops in real time, enabling businesses to reduce + water, energy, and pesticide usage and enhancing environmental + protection. The sensing data can be used to find optimal + environments for the plants. In addition, the data on planting + conditions can be saved by sensor tags, which can be used in + supply-chain management. + +3.6.1. A Use Case and Its Requirements + + Example: Automated Vineyard + + In a vineyard of medium to large geographical size, between 50 and + 100 LC nodes are manually deployed in order to provide full signal + coverage over the study area. An additional 100 to 1000 leaf nodes + with (possibly heterogeneous) specialized sensors (i.e., humidity, + temperature, soil condition, sunlight) are attached to the LCs in + local wireless star topologies, periodically reporting measurements + to the associated LCs. For example, in a 20-acre vineyard with 8 + parcels of land, 10 LoWPAN nodes are placed within each parcel to + + + +Kim, et al. Informational [Page 22] + +RFC 6568 6LoWPAN Design and Applications April 2012 + + + provide readings on temperature and soil moisture. The LoWPAN nodes + are able to support a multi-hop forwarding/routing scheme to enable + data transmission to a sink node at the edge of the vineyard. Each + of the 8 parcels contains one data aggregator to collect the sensed + data. + + Localization is important for this type of LoWPAN when installed in a + geographically large area, in order to pin down where an event + occurred, and to combine gathered data with the actual positions of + the devices. Using manual deployment, device addresses can be used + for identifying their position and localization. For randomly + deployed nodes, a localization algorithm needs to be applied. + + There might be various types of sensor devices deployed in a single + LoWPAN, each providing raw data with different semantics. Thus, an + additional method is required to correctly interpret sensor readings. + Each data packet may include meta-information about its data, or the + type of sensor could be encoded in its address during address + allocation. + + Dominant parameters in agricultural monitoring: + + o Deployment: Pre-planned. + + The nodes are installed outdoors or in a greenhouse, with high + exposure to water, soil, and dust, in dynamic environments of + moving people and machinery, and with growing crops and foliage. + LoWPAN nodes can be deployed in a predefined manner, with + consideration given to harsh environments. + + o Network Size: Medium to large, low to medium density. + + o Power Source: All nodes are battery-powered except the sink, or + energy harvesting. + + o Connectivity: Intermittent (many sleeping nodes). + + o Multi-Hop Communication: Mesh topology with local star + connections. + + o Traffic Pattern: Mainly MP2P/P2MP. P2P actuator triggering. + + o Security Level: Depends on purpose of the business. Lightweight + security or simple shared-key management can be used, depending on + the purpose of the business. + + + + + + +Kim, et al. Informational [Page 23] + +RFC 6568 6LoWPAN Design and Applications April 2012 + + + o Mobility: All static. + + o Other Issues: Time synchronization among sensors is required, but + the traffic interval may not be frequent (e.g., once every 30 to + 60 minutes). + +3.6.2. 6LoWPAN Applicability + + The network configuration in this use case might, in the simplest + case, look like the configuration illustrated in Figure 7. This + static scenario consists of one or more fixed LBRs that are + mains-powered and have a high-bandwidth connection to a backbone + link, which might be placed in a control center or connected to the + Internet. The LBRs are strategically located at the border of + vineyard parcels, acting as data sinks. A number of LCs are placed + along a row of plants with individual LoWPAN nodes spread around + them. + + While the LBRs implement the IPv6 Neighbor Discovery protocol + (RFC 4861 [1]) to connect to the outside of the LoWPAN, the LoWPAN + nodes operate a more energy-conserving ND described in [6], which + includes basic bootstrapping and address assignment. Each LBR can + have predefined forward management information to a central data + aggregation point, if necessary. + + LoWPAN nodes may send event-driven notifications when readings exceed + certain thresholds, such as low soil humidity, which may + automatically trigger a water sprinkler in the local environment. + For increased energy efficiency, all LoWPAN nodes are in periodic + sleep state. However, the LCs need to be aware of sudden events from + the leaf nodes. Their sleep periods should therefore be set to + shorter intervals. Communication schedules must be set up between + master and leaf nodes, and time synchronization is needed to account + for clock drift. + + Also, the result of data collection may activate actuators. Context + awareness, node identification, and data collection at the + application level are necessary. + + + + + + + + + + + + + +Kim, et al. Informational [Page 24] + +RFC 6568 6LoWPAN Design and Applications April 2012 + + + I + | + | n n n n n n n n n I: Internet + | \|/ \|/ \|/ LBR: LoWPAN Border Router + LBR----LC------LC------LC LC: Local Controller node + | /|\ /|\ /|\ n: LoWPAN node + | n n n n n n n n n + | + LBR + ... + + Figure 7: Automated Vineyard Scenario + +4. Security Considerations + + Relevant security considerations are listed by application scenario + in Section 3. The security considerations in RFC 4919 [2] and + RFC 4944 [3] apply as well. + + The physical exposure of LoWPAN nodes (especially in outdoor + networks) allows an adversary to capture, clone, tamper with, or even + destroy these devices. Given the safety issues involved in some use + cases, these threats place high demands for resiliency and + survivability upon the LoWPAN. The generally wireless channels of + LoWPANs are susceptible to several security threats. Without proper + security measures, confidential information might be snooped by a + "man in the middle". An attacker might also modify or introduce data + packets into the network -- for example, to manipulate sensor + readings or to take control of sensors and actuators. This + specification expects that the link layer is sufficiently protected, + either by means of physical or IP security for the backbone link or + with MAC sublayer cryptography. However, link-layer encryption and + authentication may not be sufficient to provide confidentiality, + authentication, integrity, and freshness to both data and signaling + packets. + + Due to their low-power nature, LoWPANs are especially vulnerable to + denial-of-service (DoS) attacks. Example DoS attacks include + attempts to drain a node's battery by excessive querying or to + introduce a high-power jamming signal that makes LoWPAN nodes + dysfunctional. Security solutions must therefore be lightweight and + support node authentication, so that message integrity can be + guaranteed and misbehaving nodes can be denied participation in the + network. A node must authenticate itself to trusted nodes before + taking part in the LoWPAN. + + + + + + +Kim, et al. Informational [Page 25] + +RFC 6568 6LoWPAN Design and Applications April 2012 + + + Considering the power constraints and limited processing capabilities + of IEEE 802.15.4 devices, IPsec is computationally expensive; + Internet key exchange (IKEv2) messaging as described in [4] is not + suited for LoWPANs, as the amount of signaling in these networks + should be minimized. Thus, LoWPANs may need to define their own + key-management method that requires minimum overhead in terms of + packet size and message exchange [11]. IPsec provides authentication + and confidentiality between end nodes and across multiple LoWPAN + links, and may be useful only when two nodes want to apply security + to all exchanged messages. However, in many cases, the security may + be requested at the application layer as needed, while other messages + can flow in the network without security overhead. Recent work [13] + shows some promise for minimal IKEv2 implementations. + + Security requirements may differ by use case. For example, + industrial and structural monitoring applications are safety-critical + and secure transmission must be guaranteed, so that only + authenticated users are able to access and handle the data. In + healthcare systems, data privacy is an important issue. Encryption + is required, and role-based access control is needed for proper + authentication. In home automation scenarios, critical applications + such as door locks require high security and robustness against + intrusion. On the other hand, a remote-controlled light switch has + no critical security threats. + +5. Acknowledgements + + Special thanks to Nicolas Chevrollier for participating in the + initial design of the document. Also, thanks to David Cypher for + giving more insight on the IEEE 802.15.4 standard, and to Irene + Fernandez, Shoichi Sakane, and Paul Chilton for their review and + valuable comments. + +6. References + +6.1. Normative References + + [1] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, + "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, + September 2007. + + [2] Kushalnagar, N., Montenegro, G., and C. Schumacher, "IPv6 over + Low-Power Wireless Personal Area Networks (6LoWPANs): Overview, + Assumptions, Problem Statement, and Goals", RFC 4919, + August 2007. + + + + + + +Kim, et al. Informational [Page 26] + +RFC 6568 6LoWPAN Design and Applications April 2012 + + + [3] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler, + "Transmission of IPv6 Packets over IEEE 802.15.4 Networks", + RFC 4944, September 2007. + + [4] Kaufman, C., Hoffman, P., Nir, Y., and P. Eronen, "Internet Key + Exchange Protocol Version 2 (IKEv2)", RFC 5996, September 2010. + + [5] IEEE Computer Society, "IEEE Standard for Local and + Metropolitan Area Networks -- Part 15.4: Low-Rate Wireless + Personal Area Networks (LR-WPANs)", IEEE Std. 802.15.4-2011, + September 2011. + +6.2. Informative References + + [6] Shelby, Z., Ed., Chakrabarti, S., and E. Nordmark, "Neighbor + Discovery Optimization for Low Power and Lossy Networks + (6LoWPAN)", Work in Progress, October 2011. + + [7] Hui, J., Ed., and P. Thubert, "Compression Format for IPv6 + Datagrams over IEEE 802.15.4-Based Networks", RFC 6282, + September 2011. + + [8] Kim, E., Kaspar, D., Gomez, C., and C. Bormann, "Problem + Statement and Requirements for 6LoWPAN Routing", Work + in Progress, November 2011. + + [9] Roemer, K. and F. Mattern, "The Design Space of Wireless Sensor + Networks", IEEE Wireless Communications, Vol. 11, No. 6, + pp. 54-61, December 2004. + + [10] den Hartog, F., Schmidt, J., and A. de Vries, "On the potential + of personal networks for hospitals", International Journal of + Medical Informatics, 75, pp. 658-663, May 2006. + + [11] Dutertre, B., Cheung, S., and J. Levy, "Lightweight Key + Management in Wireless Sensor Networks by Leveraging Initial + Trust", SDL Technical Report SRI-SDL-04-02, April 2004. + + [12] Chen, D. and P.K. Varshney, "QoS Support in Wireless Sensor + Networks: A Survey", Proc. 2004 Int. Conf. Wireless + Networks (ICWN 2004), June 2004. + + [13] Kivinen, T., "Minimal IKEv2", Work in Progress, February 2011. + + + + + + + + +Kim, et al. Informational [Page 27] + +RFC 6568 6LoWPAN Design and Applications April 2012 + + +Authors' Addresses + + Eunsook Kim + ETRI + 161 Gajeong-dong + Yuseong-gu + Daejeon 305-700 + Korea + + Phone: +82-42-860-6124 + EMail: eunah.ietf@gmail.com + + + Dominik Kaspar + Simula Research Laboratory + Martin Linges v 17 + Snaroya 1367 + Norway + + Phone: +47-6782-8200 + EMail: dokaspar.ietf@gmail.com + + + JP. Vasseur + Cisco Systems, Inc. + 1414 Massachusetts Avenue + Boxborough, MA 01719 + USA + + EMail: jpv@cisco.com + + + + + + + + + + + + + + + + + + + + + +Kim, et al. Informational [Page 28] + |