6Lo Working Group Y-G. Hong Internet-Draft ETRI Intended status: Informational C. Gomez Expires: September 13, 2017 UPC/i2cat Y-H. Choi ETRI D-Y. Ko SKtelecom AR. Sangi Huawei Technologies Take. Aanstoot Modio AB March 12, 2017 IPv6 over Constrained Node Networks(6lo) Applicability & Use cases draft-ietf-6lo-use-cases-01 Abstract This document describes the applicability of IPv6 over constrained node networks (6lo) and use cases. It describes the practical deployment scenarios of 6lo technologies with the consideration of 6lo link layer technologies and identifies the requirements. In addition to IEEE 802.15.4, various link layer technologies such as ITU-T G.9959 (Z-Wave), BLE, DECT-ULE, MS/TP, NFC, LTE MTC, PLC (IEEE 1901), and IEEE 802.15.4e(6tisch) are widely used at constrained node networks for typical services. Based on these link layer technologies, IPv6 over networks of resource-constrained nodes has various and practical use cases. To efficiently implement typical services, the applicability and consideration of several design space dimensions are described. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." Hong, et al. Expires September 13, 2017 [Page 1] Internet-Draft 6lo Applicability & Use cases March 2017 This Internet-Draft will expire on September 13, 2017. Copyright Notice Copyright (c) 2017 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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions and Terminology . . . . . . . . . . . . . . . . . 4 3. 6lo Link layer technologies . . . . . . . . . . . . . . . . . 4 3.1. ITU-T G.9959 . . . . . . . . . . . . . . . . . . . . . . 4 3.2. Bluetooth LE . . . . . . . . . . . . . . . . . . . . . . 4 3.3. DECT-ULE . . . . . . . . . . . . . . . . . . . . . . . . 5 3.4. MS/TP . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3.5. NFC . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3.6. LTE MTC . . . . . . . . . . . . . . . . . . . . . . . . . 7 3.7. PLC . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3.8. IEEE 802.15.4e . . . . . . . . . . . . . . . . . . . . . 8 4. 6lo Deployment Scenarios . . . . . . . . . . . . . . . . . . 9 5. Design Space . . . . . . . . . . . . . . . . . . . . . . . . 9 6. 6lo Use Cases . . . . . . . . . . . . . . . . . . . . . . . . 11 6.1. Use case of ITU-T G.9959: Smart Home . . . . . . . . . . 11 6.2. Use case of Bluetooth LE: Smartphone-Based Interaction with Constrained Devices . . . . . . . . . . . . . . . . 13 6.3. Use case of DECT-ULE: Smart Home . . . . . . . . . . . . 14 6.4. Use case of MS/TP: Management of District Heating . . . . 15 6.5. Use case of NFC: Alternative Secure Transfer . . . . . . 17 6.6. Use case of LTE MTC: Gateway for Wireless Backhaul Network . . . . . . . . . . . . . . . . . . . . . . . . . 19 6.7. Use case of PLC: Smart Grid . . . . . . . . . . . . . . . 21 6.8. Use case of IEEE 802.15.4e: Industrial Automation . . . . 24 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 25 8. Security Considerations . . . . . . . . . . . . . . . . . . . 25 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 25 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 25 10.1. Normative References . . . . . . . . . . . . . . . . . . 25 Hong, et al. Expires September 13, 2017 [Page 2] Internet-Draft 6lo Applicability & Use cases March 2017 10.2. Informative References . . . . . . . . . . . . . . . . . 27 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 28 1. Introduction Running IPv6 on constrained node networks has different features from general node networks due to the characteristics of constrained node networks such as small packet size, short link-layer address, low bandwidth, network topology, low power, low cost, and large number of devices [RFC4919]. For example, because some IEEE 802.15.4 link layers have a frame size of 127 octets and IPv6 requires the layer below to support an MTU of 1280 bytes, an appropriate fragmentation and reassembly adaptation layer must be provided at the layer below IPv6. Also, the limited size of IEEE 802.15.4 frame and low energy consumption requirements make the need for header compression. IETF 6lowpan (IPv6 over Low powerWPAN) working group published, an adaptation layer for sending IPv6 packets over IEEE 802.15.4 [RFC4944], compression format for IPv6 datagrams over IEEE 802.15.4-based networks [RFC6282], and Neighbor Discovery Optimization for 6lowpan [RFC6775]. As IoT (Internet of Things) services become more popular, various link layer technologies such as Bluetooth Low Energy (Bluetooth LE), ITU-T G.9959 (Z-Wave), Digital Enhanced Cordless Telecommunications - Ultra Low Energy (DECT-ULE), Master-Slave/Token Passing (MS/TP), Near Field Communication (NFC), Power Line Communication (PLC), and LTE Machine Type Communication are actively used. And the transmission of IPv6 packets over these link layer technologies is required. A number of IPv6-over-foo documents have been developed in the IETF 6lo (IPv6 over Networks of Resource-constrained Nodes) and 6tisch (IPv6 over the TSCH mode of IEEE 802.15.4e) working groups. In the 6lowpan working group, the [RFC6568], "Design and Application Spaces for 6LoWPANs" was published and it describes potential application scenarios and use cases for low-power wireless personal area networks. In this document, various design space dimensions such as deployment, network size, power source, connectivity, multi- hop communication, traffic pattern, security level, mobility, and QoS were analyzed. And it described a fundamental set of 6lowpan application scenarios and use cases: Industrial monitoring-Hospital storage rooms, Structural monitoring-Bridge safety monitoring, Connected home-Home automation and Smart grid assistance, Healthcare- Healthcare at home by tele-assistance, Vehicle telematics-telematics, and Agricultural monitoring-Automated vineyard. Even though the [RFC6568] describes some potential application scenarios and use cases and it lists the design space in the context of 6lowpan, it does not cover the different use cases and design Hong, et al. Expires September 13, 2017 [Page 3] Internet-Draft 6lo Applicability & Use cases March 2017 space in the context of the 6lo working group. The [RFC6568] assumed that the link layer technology is the IEEE802.15.4 and the described application scenarios and use cases were based on the IEEE 802.15.4 technologies. Due to various link layer technologies such as ITU-T G.9959 (Z-Wave), BLE, DECT-ULE, MS/TP, NFC, LTE MTC, Power Line Communication (PLC), and IEEE 802.15.4e(6tisch), potential application scenarios and use cases of 6lo will go beyond the [RFC6568]. This document provides the applicability and use cases of 6lo, considering the following aspects: o 6lo applicability and use cases MAY be uniquely different from those of 6lowpan. o 6lo applicability and use cases SHOULD cover various IoT related wire/wireless link layer technologies providing practical information of such technologies. o 6lo applicability and use cases SHOULD describe characteristics and typical use cases of each link layer technology, and then 6lo use cases's applicability. 2. Conventions and Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. 3. 6lo Link layer technologies 3.1. ITU-T G.9959 The ITU-T G.9959 recommendation [G.9959] targets low-power Personal Area Networks (PANs). G.9959 defines how a unique 32-bit HomeID network identifier is assigned by a network controller and how an 8-bit NodeID host identifier is allocated to each node. NodeIDs are unique within the network identified by the HomeID. The G.9959 HomeID represents an IPv6 subnet that is identified by one or more IPv6 prefixes [RFC7428]. 3.2. Bluetooth LE Bluetooth LE was introduced in Bluetooth 4.0, enhanced in Bluetooth 4.1, and developed even further in successive versions. Bluetooth SIG has also published Internet Protocol Support Profile (IPSP). The IPSP enables discovery of IP-enabled devices and establishment of link-layer connection for transporting IPv6 packets. IPv6 over Hong, et al. Expires September 13, 2017 [Page 4] Internet-Draft 6lo Applicability & Use cases March 2017 Bluetooth LE is dependent on both Bluetooth 4.1 and IPSP 1.0 or newer. Devices such as mobile phones, notebooks, tablets and other handheld computing devices which will include Bluetooth 4.1 chipsets will probably also have the low-energy variant of Bluetooth. Bluetooth LE will also be included in many different types of accessories that collaborate with mobile devices such as phones, tablets and notebook computers. An example of a use case for a Bluetooth LE accessory is a heart rate monitor that sends data via the mobile phone to a server on the Internet [RFC7668]. 3.3. DECT-ULE DECT ULE is a low power air interface technology that is designed to support both circuit switched services, such as voice communication, and packet mode data services at modest data rate. The DECT ULE protocol stack consists of the PHY layer operating at frequencies in the 1880 - 1920 MHz frequency band depending on the region and uses a symbol rate of 1.152 Mbps. Radio bearers are allocated by use of FDMA/TDMA/TDD techniques. In its generic network topology, DECT is defined as a cellular network technology. However, the most common configuration is a star network with a single Fixed Part (FP) defining the network with a number of Portable Parts (PP) attached. The MAC layer supports traditional DECT as this is used for services like discovery, pairing, security features etc. All these features have been reused from DECT. The DECT ULE device can switch to the ULE mode of operation, utilizing the new ULE MAC layer features. The DECT ULE Data Link Control (DLC) provides multiplexing as well as segmentation and re- assembly for larger packets from layers above. The DECT ULE layer also implements per-message authentication and encryption. The DLC layer ensures packet integrity and preserves packet order, but delivery is based on best effort. The current DECT ULE MAC layer standard supports low bandwidth data broadcast. However the usage of this broadcast service has not yet been standardized for higher layers [I-D.ietf-6lo-dect-ule]. 3.4. MS/TP MS/TP is a contention-free access method for the RS-485 physical layer, which is used extensively in building automation networks. Hong, et al. Expires September 13, 2017 [Page 5] Internet-Draft 6lo Applicability & Use cases March 2017 An MS/TP device is typically based on a low-cost microcontroller with limited processing power and memory. Together with low data rates and a small address space, these constraints are similar to those faced in 6lowpan networks and suggest some elements of that solution might be leveraged. MS/TP differs significantly from 6lowpan in at least three aspects: a) MS/TP devices typically have a continuous source of power, b) all MS/TP devices on a segment can communicate directly so there are no hidden node or mesh routing issues, and c) recent changes to MS/TP provide support for large payloads, eliminating the need for link-layer fragmentation and reassembly. MS/TP is designed to enable multidrop networks over shielded twisted pair wiring, although not according to standards, in lower speeds, normally 9600 bit/s, re-purposed telecom wiring is widely in use, keeping deployment cost down. It can support a data rate of 115,200 baud on segments up to 1000 meters in length, or segments up to 1200 meters in length at lower baud rates. An MS/TP link requires only a UART, an RS-485 transceiver with a driver that can be disabled, and a 5ms resolution timer. These features make MS/TP a cost-effective and very reliable field bus for the most numerous and least expensive devices in a building automation network [I-D.ietf-6lo-6lobac]. 3.5. NFC NFC technology enables simple and safe two-way interactions between electronic devices, allowing consumers to perform contactless transactions, access digital content, and connect electronic devices with a single touch. NFC complements many popular consumer level wireless technologies, by utilizing the key elements in existing standards for contactless card technology (ISO/IEC 14443 A&B and JIS-X 6319-4). NFC can be compatible with existing contactless card infrastructure and it enables a consumer to utilize one device across different systems. Extending the capability of contactless card technology, NFC also enables devices to share information at a distance that is less than 10 cm with a maximum communication speed of 424 kbps. Users can share business cards, make transactions, access information from a smart poster or provide credentials for access control systems with a simple touch. NFC's bidirectional communication ability is ideal for establishing connections with other technologies by the simplicity of touch. In addition to the easy connection and quick transactions, simple data sharing is also available [I-D.ietf-6lo-nfc]. Hong, et al. Expires September 13, 2017 [Page 6] Internet-Draft 6lo Applicability & Use cases March 2017 3.6. LTE MTC LTE category defines the overall performance and capabilities of the UE(User Equipment). For example, the maximum down rate of category 1 UE and category 2 UE are 10.3 Mbit/s and 51.0 Mbit/s respectively. There are many categories in LTE standard. 3GPP standards defined the category 0 to be used for low rate IoT service in release 12. Since category 1 and category 0 could be used for low rate IoT service, these categories are called LTE MTC (Machine Type Communication) [LTE_MTC]. LTE MTC offer advantages in comparison to above category 2 and is appropriate to be used for low rate IoT services such as low power and low cost. The below figure shows the primary characteristics of LTE MTC. +------------+---------------------+-------------------+ | Category | Max. Data Rate Down | Max. Data Rate Up | +------------+---------------------+-------------------+ | Category 0 | 1.0 Mbit/s | 1.0 Mbit/s | | | | | | Category 1 | 10.3 Mbit/s | 5.2 Mbit/s | +------------+---------------------+-------------------+ Table 1: Primary characteristics of LTE MTC 3.7. PLC Unlike other dedicated communication infrastructure, the required medium (power conductor) is widely available indoors and outdoors. Moreover, wire d technologies are more susceptible to cause interference but are more rel iable than their wireless counterparts. PLC is a data transmission techniq ue that utilizes power conductors as medium. The below figure shows some available open standards defining PLC. Hong, et al. Expires September 13, 2017 [Page 7] Internet-Draft 6lo Applicability & Use cases March 2017 +-------------+-----------------+------------+-----------+----------+ | PLC Systems | Frequency Range | Type | Data Rate | Distance | +-------------+-----------------+------------+-----------+----------+ | IEEE1901 | <100MHz | Broadband | 200Mbps | 1000m | | | | | | | | IEEE1901.1 | <15MHz | PLC-IoT | 10Mbps | 2000m | | | | | | | | IEEE1901.2 | <500kHz | Narrowband | 200Kbps | 3000m | +-------------+-----------------+------------+-----------+----------+ Table 2: Some Available Open Standards in PLC [IEEE1901] defines broadband variant of PLC but is effective within short range. This standard addresses the requirements of applications with high data rate such as: Internet, HDTV, Audio, Gaming etc. Broadband operates on OFDM (Orthogonal Frequency Division Multiplexing) modulation. [IEEE1901.2] defines narrowband variant of PLC with less data rate but significantly higher transmission range that could be used in an indoor or even an outdoor environment. It supports operating either in Low Voltage (LV) or High Voltage (HV) segment of PLC domain. It is applicable to typical IoT applications such as: Building Automation, Renewable Energy, Advanced Metering, Street Lighting, Electric Vehicle, Smart Grid etc. Narrowband operates either on FSK (Frequency Shift Keying), S (Spread) FSK, BPSK (Binary Phase Shift Keying), SS (Spread Spectrum) or OFDM modulation. Moreover, IEEE 1901.2 standard is based on the 802.15.4 MAC sub-layer and fully endorses the security scheme defined in 802.15.4. [RFC8036]. Specific applications come with requirement of diversity. Although IEEE1901 offers higher data rate but is not applicable for long distance scenario due to losses in higher frequencies. On the other hand, IEEE1901.2 is not applicable for real-time services due to low data rate. The IEEE 1901.1 WG is working on a new standard, namely [IEEE1901.1], that provides extended transmission range as compared to IEEE1901 and higher data rate than IEEE1901.2 [IEEE1901.2]. More intelligent IoT financial services are emerging such as: Self Service Terminal, Bank Transfer, Scratch Card, POS (point of sale) etc. and require extensive data transfers. This standard is also known as PLC-IoT and operates on OFDM modulation e.g. FTT (Fast Fourier Transform) and/or wavelet OFDM. 3.8. IEEE 802.15.4e The Timeslotted Channel Hopping (TSCH) mode was introduced in the IEEE 802.15.4-2015 standard. In a TSCH network, all nodes are synchronized. Time is sliced up into timeslots. The duration of a Hong, et al. Expires September 13, 2017 [Page 8] Internet-Draft 6lo Applicability & Use cases March 2017 timeslot, typically 10ms, is large enough for a node to send a full- sized frame to its neighbor, and for that neighbor to send back an acknowledgment to indicate successful reception. Timeslots are grouped into one of more slotframes, which repeat over time. All the communication in the network is orchestrated by a communication schedule which indicates to each node what to do in each of the timeslots of a slotframe: transmit, listen or sleep. The communication schedule can be built so that the right amount of link- layer resources (the cells in the schedule) are scheduled to satisfy the communication needs of the applications running on the network, while keeping the energy consumption of the nodes very low. Cells can be scheduled in a collision-free way, introducing a high level of determinism to the network. A TSCH network exploits channel hopping: subsequent packets exchanged between neighbor nodes are done on a different frequency. This means that, if a frame isn't received, the transmitter node will re- transmitt the frame on a different frequency. The resulting "channel hopping" efficiently combats external interference and multi-path fading. The main benefits of IEEE 802.15.4 TSCH are: - ultra high reliability. Off-the-shelf commercial products offer over 99.999% end-to-end reliability. - ultra low-power consumption. Off-the-shelf commercial products offer over a decade of battery lifetime. 4. 6lo Deployment Scenarios In this clause, we will describe some 6lo deployment scenarios such as Smart Grid activity in WiSun [TBD] 5. Design Space The [RFC6568] 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). In the RFC 6568, the following design space dimensions are described; Deployment, Network size, Power source, Connectivity, Multi-hop communication, Traffic pattern, Mobility, Quality of Service (QoS). Hong, et al. Expires September 13, 2017 [Page 9] Internet-Draft 6lo Applicability & Use cases March 2017 The design space dimensions of 6lo are a little different from those of the RFC 6568 due to the different characteristics of 6lo link layer technologies. The following design space dimensions can be considered. o Deployment/Bootstrapping: 6lo nodes can be connected randomly, or in an organized manner. The bootstrapping has different characteristics for each link layer technology. o Topology: Topology of 6lo networks may inherently follow the characteristics of each link layer technology. Point-to-point, star, tree or mesh topologies can be configured, depending on the link layer technology considered. o L2-Mesh or L3-Mesh: L2-mesh and L3-mesh may inherently follow the characteristics of each link layer technology. Some link layer technologies may support L2-mesh and some may not support. o Multi-link subnet, single subnet: The selection of multi-link subnet and single subnet depends on connectivity and the number of 6lo nodes. o Data rate: Originally, the link layer technologies of 6lo have low rate of data transmission. But, by adjusting the MTU, it can deliver higher data rate. o Buffering requirements: Some 6lo use case may require more data rate than the link layer technology support. In this case, a buffering mechanism to manage the data is required. o Security Requirements: Some 6lo use case can involve transferring some important and personal data between 6lo nodes. In this case, high-level security support is required. o Mobility across 6lo networks and subnets: The movement of 6lo nodes is dependent on the 6lo use case. If the 6lo nodes can move or moved around, it requires a mobility management mechanism. o Time synchronization requirements: The requirement of time synchronization of the upper layer service is dependent on the 6lo use case. For some 6lo use case related to health service, the measured data must be recorded with exact time and must be transferred with time synchronization. o Reliability and QoS: Some 6lo use case requires high reliability, for example real-time service or health-related services. Hong, et al. Expires September 13, 2017 [Page 10] Internet-Draft 6lo Applicability & Use cases March 2017 o Traffic patterns: 6lo use cases may involve various traffic patterns. For example, some 6lo use case may require short data length and random transmission. Some 6lo use case may require continuous data and periodic data transmission. o Security Bootstrapping: Without the external operations, 6lo nodes must have the security bootstrapping mechanism. o Power use strategy: to enable certain use cases, there may be requirements on the class of energy availability and the strategy followed for using power for communication [RFC7228]. Each link layer technology defines a particular power use strategy which may be tuned [I-D.ietf-lwig-energy-efficient]. Readers are expected to be familiar with RFC 7228 terminology. o Update firmware requirements: Most 6lo use cases will need a mechanism for updating firmware. In these cases support for over the air updates are required, probably in a broadcast mode when bandwith is low and the number of identical devices is high. 6. 6lo Use Cases 6.1. Use case of ITU-T G.9959: Smart Home Z-Wave is one of the main technologies that may be used to enable smart home applications. Born as a proprietary technology, Z-Wave was specifically designed for this particular use case. Recently, the Z-Wave radio interface (physical and MAC layers) has been standardized as the ITU-T G.9959 specification. Example: Use of ITU-T G.9959 for Home Automation Variety of home devices (e.g. light dimmers/switches, plugs, thermostats, blinds/curtains and remote controls) are augmented with ITU-T G.9959 interfaces. A user may turn on/off or may control home appliances by pressing a wall switch or by pressing a button in a remote control. Scenes may be programmed, so that after a given event, the home devices adopt a specific configuration. Sensors may also periodically send measurements of several parameters (e.g. gas presence, light, temperature, humidity, etc.) which are collected at a sink device, or may generate commands for actuators (e.g. a smoke sensor may send an alarm message to a safety system). The devices involved in the described scenario are nodes of a network that follows the mesh topology, which is suitable for path diversity to face indoor multipath propagation issues. The multihop paradigm allows end-to-end connectivity when direct range communication is not possible. Security support is required, specially for safety-related Hong, et al. Expires September 13, 2017 [Page 11] Internet-Draft 6lo Applicability & Use cases March 2017 communication. When a user interaction (e.g. a button press) triggers a message that encapsulates a command, if the message is lost, the user may have to perform further interactions to achieve the desired effect (e.g. a light is turned off). A reaction to a user interaction will be perceived by the user as immediate as long as the reaction takes place within 0.5 seconds [RFC5826]. Dominant parameters in home automation scenarios with ITU-T G.9959: o Deployment/Bootstrapping: Pre-planned. o Topology: Mesh topology. o L2-mesh or L3-mesh: ITU-T G.9959 provides support for L2-mesh, and L3-mesh can also be used (the latter requires an IP-based routing protocol). o Multi-link subnet, single subnet: Multi-link subnet. o Data rate: Small data rate, infrequent transmissions. o Buffering requirements: Low requirement. o Security requirements: Data privacy and security must be provided. Encryption is required. o Mobility: Most devices are static. A few devices (e.g. remote control) are portable. o Time Synchronization: TBD. o Reliability and QoS: Moderate to high level of reliability support. Actions as a result of human-generated traffic should occur after less than 0.5 seconds. o Traffic patterns: Periodic (sensor readings) and aperiodic (user- triggered interaction). o Security Bootstrapping: Required. o Power use strategy: Mix of P1 (Low-power) devices and P9 (Always- on) devices. o Update firmware requirements: TBD. Hong, et al. Expires September 13, 2017 [Page 12] Internet-Draft 6lo Applicability & Use cases March 2017 6.2. Use case of Bluetooth LE: Smartphone-Based Interaction with Constrained Devices The key feature behind the current high Bluetooth LE momentum is its support in a large majority of smartphones in the market. Bluetooth LE can be used to allow the interaction between the smartphone and surrounding sensors or actuators. Furthermore, Bluetooth LE is also the main radio interface currently available in wearables. Since a smartphone typically has several radio interfaces that provide Internet access, such as Wi-Fi or 4G, the smartphone can act as a gateway for nearby devices such as sensors, actuators or wearables. Bluetooth LE may be used in several domains, including healthcare, sports/wellness and home automation. Example: Use of Bluetooth LE-based Body Area Network for fitness A person wears a smartwatch for fitness purposes. The smartwatch has several sensors (e.g. heart rate, accelerometer, gyrometer, GPS, temperature, etc.), a display, and a Bluetooth LE radio interface. The smartwatch can show fitness-related statistics on its display. However, when a paired smartphone is in the range of the smartwatch, the latter can report almost real-time measurements of its sensors to the smartphone, which can forward the data to a cloud service on the Internet. In addition, the smartwatch can receive notifications (e.g. alarm signals) from the cloud service via the smartphone. On the other hand, the smartphone may locally generate messages for the smartwatch, such as e-mail reception or calendar notifications. The functionality supported by the smartwatch may be complemented by other devices such as other on-body sensors, wireless headsets or head-mounted displays. All such devices may connect to the smartphone creating a star topology network whereby the smartphone is the central component. Dominant parameters in fitness scenarios with Bluetooth LE: o Deployment/Bootstrapping: Pre-planned. o Topology: Star topology. o L2-mesh or L3-mesh: No. o Multi-link subnet, single subnet: Multi-link subnet. o Data rate: TBD. o Buffering requirements: Low requirement. Hong, et al. Expires September 13, 2017 [Page 13] Internet-Draft 6lo Applicability & Use cases March 2017 o Security requirements: For health-critical information, data privacy and security must be provided. Encryption is required. Some types of notifications sent by the smartphone may not need. o Mobility: Low. o Time Synchronization: the link layer, which is based on TDMA, provides a basis for time synchronization. o Reliability and QoS: a relatively low ratio of message losses is acceptable for periodic sensor readings. End-to-end latency of sensor readings should be low for critical notifications or alarms, generated by either the smartphone or an Internet cloud service. o Traffic patterns: periodic (sensor readings) and aperiodic (smartphone-generated notifications). o Security Bootstrapping: Required. o Power use strategy: P1 (Low-power) devices. o Update firmware requirements: TBD. 6.3. Use case of DECT-ULE: Smart Home DECT is a technology widely used for wireless telephone communications in residential scenarios. Since DECT-ULE is a low- power variant of DECT, DECT-ULE can be used to connect constrained devices such as sensors and actuators to a Fixed Part, a device that typically acts as a base station for wireless telephones. Therefore, DECT-ULE is specially suitable for the connected home space in application areas such as home automation, smart metering, safety, healthcare, etc. Example: Use of DECT-ULE for Smart Metering The smart electricity meter of a home is equipped with a DECT-ULE transceiver. This device is in the coverage range of the Fixed Part of the home. The Fixed Part can act as a router connected to the Internet. This way, the smart meter can transmit electricity consumption readings through the DECT-ULE link with the Fixed Part, and the latter can forward such readings to the utility company using Wide Area Network (WAN) links. The meter can also receive queries from the utility company or from an advanced energy control system controlled by the user, which may also be connected to the Fixed Part via DECT-ULE. Hong, et al. Expires September 13, 2017 [Page 14] Internet-Draft 6lo Applicability & Use cases March 2017 Dominant parameters in smart metering scenarios with DECT-ULE: o Deployment/Bootstrapping: Pre-planned. o Topology: Star topology. o L2-mesh or L3-mesh: No. o Multi-link subnet, single subnet: Multi-link subnet. o Data rate: Small data rate, infrequent transmissions. o Buffering requirements: Low requirement. o Security requirements: Data privacy and security must be provided. Encryption is required. o Mobility: No. o Time Synchronization: TBD. o Reliability and QoS: bounded latency, stringent reliability service agreements [RFC8036]. o Traffic patterns: Periodic (meter reading notifications sent by the meter) and aperiodic (user- or company-triggered queries to the meter, and messages triggered by local events such as power outage or leak detection [RFC8036]. o Security Bootstrapping: required. o Power use strategy: P0 (Normally-off) for devices with long sleep intervals (i.e. greater than ~10 seconds) which then may need to resynchronize again, and P1 (Low-power) for short sleep intervals. P9 (Always-on) for the Fixed Part (FP), which is the central node in the star topology. o Update firmware requirements: TBD. 6.4. Use case of MS/TP: Management of District Heating The key feature of MS/TP is it's ability to run on the same cabling as BACnet and some use of ModBus, the defacto standard for low bandwith industry communication. Specially Modbus has been around since the 1980 and is still the standard for talking to fans, heat pumps, water purifying equipment and everything else delivering electricity, clean water and ventilation. Hong, et al. Expires September 13, 2017 [Page 15] Internet-Draft 6lo Applicability & Use cases March 2017 Example: Use of MS/TP for management of district heating The mechanical room in the cellar of an apartment building gets district heating and electricity from the utility providers. The room has a Supervisory Control And Data Acquisition (SCADA) computer talking to a centralized server and command center somewhere else over IP, on the other hand it is controlling the heating, fans and distribution panel over a 2-wire RS-485 based protocol to make sure the logic controller for district heating keeps a constant temperature at the tapwater, the logic controller for heat produktion keeps the right radiator temperature depending on the weather and the fans have a correct speed and are switched off in case district heating fails to prevent cooling out the building and give certain commands in case smoke is detected. Speed is not important, in this usecase, 19,200 bit/s capable equipment is sold as high speed communication capable. Reliability is important, this not working will easily give millions of dollars of damage. Normally the setup is that the SCADA device asks a question to a specific controlling device, gets an answer from the controlling device, asks a new question to some other device. o Deployment/Bootstrapping: Pre-planned. o Topology: Bus, master-slave, token-passing. o Multi-link subnet, single subnet: [TBD], normally single. o Data rate: Small data rate, frequent transmissions. o Buffering requirements: Low. o Security requirements: Security must be provided, authentication is a must. o Mobility: Highly static o Time synchronization: Required. o Reliability and QOS: High, Alerts have to arrive properly, timing is not important. Implication of failing reliability has high probability for life-or-death implications (fire-alarms) or millions of dollars of liability (frozen water heating system in a high rise building) o Traffic patterns: Constant sensor readings and asking devices for error reporting. o Security Bootstrapping: Nice to have, not very important. Hong, et al. Expires September 13, 2017 [Page 16] Internet-Draft 6lo Applicability & Use cases March 2017 o Power use strategy: P9 o Update firmware requirements: Required. 6.5. Use case of NFC: Alternative Secure Transfer According to applications, various secured data can be handled and transferred. Depending on security level of the data, methods for transfer can be alternatively selected. The personal data having serious issues should be transferred securely, but data transfer by using Wi-Fi and Bluetooth connections cannot always be secure because of their a little long radio frequency range. Hackers can overhear the personal data transfer behind hidden areas. Therefore, methods need to be alternatively selected to transfer secured data. Voice and video data, which are not respectively secure and requires long transmission range, can be transferred by 3G/4G technologies, such as WCDMA, GSM, and LTE. Big size data, which are not secure and requires high speed and broad bandwidth, can be transferred by Wi-Fi and wired network technologies. However, the personal data, which pose serious issues if mishandled while transferred in wireless domain, can be securely transferred by NFC technology. It has very short frequency range - nearly single touch communication. Example: Use of NFC for Secure Transfer in Healthcare Services with Tele-Assistance A senior citizen who lives alone wears one to several wearable 6lo devices to measure heartbeat, pulse rate, etc. The 6lo devices are densely installed at home for movement detection. An LoWPAN Border Router (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. Data is gathered in both periodic and event-driven fashion. In this application, event-driven data can be very time-critical. In addition, privacy also becomes a serious issue in this case, as the sensed data is very personal. While the senior citizen is provided audio and video healthcare services by a tele-assistance based on LTE connections, the senior citizen can alternatively use NFC connections to transfer the personal sensed data to the tele-assistance. At this moment, hidden hackers can overhear the data based on the LTE connection, but they cannot gather the personal data over the NFC connection. Hong, et al. Expires September 13, 2017 [Page 17] Internet-Draft 6lo Applicability & Use cases March 2017 +-------------+ +-------------+ |voice & video|....... LTE connection ......>|voice & video| | data |<...... LTE connection .......| data | +-------------+ +-------------+ | sensed data |....... NFC connection ......>| | | |<...... NFC connection .......| personal | | | | result data | +-------------+ +-------------+ (patient) (tele-assistance) Figure 1: Alternative Secure Transfer in Healthcare Services Dominant parameters in secure transfer by using NFC in healthcare services: o Deployment/Bootstrapping: Pre-planned. MP2P/P2MP (data collection), P2P (local diagnostic). o Topology: Small, NFC-enabled device connected to the Internet. o L2-mesh or L3-mesh: NFC does not support L2-mesh, L3-mesh can be configured. o Multi-link subnet, single subnet: a single hop for gateway; patient's body network is mesh topology. o Data rate: Small data rate. o Buffering requirements: Low requirement. o Security requirements: Data privacy and security must be provided. Encryption is required. o Mobility: Moderate (patient's mobility). o Time Synchronization: Highly required. o Reliability and QoS: High level of reliability support (life-or- death implication), role-based. o Traffic patterns: Short data length and periodic (randomly). o Security Bootstrapping: Highly required. 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 Hong, et al. Expires September 13, 2017 [Page 18] Internet-Draft 6lo Applicability & Use cases March 2017 devices that have different duty cycles, and for role-based data control. Reliability and robustness of the network are also essential. o Power use strategy: TBD. o Update firmware requirements: TBD. 6.6. Use case of LTE MTC: Gateway for Wireless Backhaul Network Wireless link layer technologies can be divided into short range connectivity and long range connectivity. BLE, ITU-T G.9959 (Z-Wave), DECT-ULE, MS/TP, NFC are used for short range connectivity. LTE MTC is used for long range connectivity. And there is another long range connectivity technology. It is LPWAN (Low Power Wide Area Network) technology such as LoRa, Sigfox, Wi-Sun etc. Therefore, the use case of LTE MTC could be used in LPWAN. Example: Use of LTE MTC for LoRa gateway LoRa is one of the most promising technology of LPWAN. LoRa network architecture has a star of star topology. LoRa gateway relay the messages from LoRa end device to application server and vice versa. LoRa gateway can have two types of backhaul, wired and wireless backhaul. If a LoRa gateway has wireless backhaul, it should have LTE modem. Since the modem cost of LTE MTC is cheaper than the modem cost of above LTE category 2, it is helpful to design to use LTE MTC. Moreover, the maximum date rate of LoRa end device is 50kbps, it is sufficient to use LTE MTC without using category 2. Dominant parameters in LoRa gateway scenarios in above example: o Deployment/Bootstrapping: Pre-planned. o Topology: Star topology. o L2-mesh or L3-mesh: No. o Multi-link subnet, single subnet: Single subnet. o Data rate: Depends on 3GPP specification. o Buffering requirements: High requirement. o Security requirements: No, because data security is already provided in LoRa specification. Hong, et al. Expires September 13, 2017 [Page 19] Internet-Draft 6lo Applicability & Use cases March 2017 o Mobility: Static. o Time Synchronization: Highly required. o Reliability and QoS: TBD. o Traffic patterns: Random. o Security Bootstrapping: Required. o Power use strategy: P9 (Always-on). o Update firmware requirements: TBD. Example: Use of LTE MTC for controlling car Car sharing services are becoming more popular. Customers wish to control the car with smart phone application. For example, customers wish to lock/unlock the car door with smart phone application, because customers may not have a car key. Customers wish to blow with smart phone application to locate the car easily. Therefore, rental car should have a long range connectivity capable modem such as LoRa end device and LTE UE. However, LoRa may not be used because LoRa has low reliability and may not be supported in an indoor environment such as a basement parking lot. And since message size for car control is very small, it is sufficient to use LTE MTC instead of category 2. Dominant parameters in controlling car scenarios in above example: o Deployment/Bootstrapping: Pre-planned. o Topology: Star topology. o L2-mesh or L3-mesh: No. o Multi-link subnet, single subnet: Single subnet. o Data rate: Depends on 3GPP specification. o Buffering requirements: High requirement. o Security requirements: High requirement. o Mobility: Always dynamic . o Time Synchronization: Highly required. Hong, et al. Expires September 13, 2017 [Page 20] Internet-Draft 6lo Applicability & Use cases March 2017 o Reliability and QoS: TBD. o Traffic patterns: Random. o Security Bootstrapping: Required. o Power use strategy: P1 (Low-power). 6.7. Use case of PLC: Smart Grid Smart grid concept is based on numerous operational and energy measuring sub-systems of an electric grid. It comprises of multiple administrative levels/segments to provide connectivity among these numerous components. Last mile connectivity is established over LV segment, whereas connectivity over electricity distribution takes place in HV segment. Although other wired and wireless technologies are also used in Smart Grid (Advance Metering Infrastructure - AMI, Demand Response - DR, Home Energy Management System - HEMS, Wide Area Situational Awareness - WASA etc), PLC enjoys the advantage of existing (power conductor) medium and better reliable data communication. PLC is a promising wired communication technology in that the electrical power lines are already there and the deployment cost can be comparable to wireless technologies. The 6lo related scenarios lie in the low voltage PLC networks with most applications in the area of Advanced Metering Infrastructure, Vehicle-to-Grid communications, in-home energy management and smart street lighting. Example: Use of PLC for Advanced Metering Infrastructure Household electricity meters transmit time-based data of electric power consumption through PLC. Data concentrators receive all the meter data in their corresponding living districts and send them to the Meter Data Management System (MDMS) through WAN network (e.g. Medium-Voltage PLC, Ethernet or GPRS) for storage and analysis. Two- way communications are enabled which means smart meters can do actions like notification of electricity charges according to the commands from the utility company. With the existing power line infrastructure as communication medium, cost on building up the PLC network is naturally saved, and more importantly, labor operational costs can be minimized from a long- term perspective. Furthermore, this AMI application speeds up electricity charge, reduces losses by restraining power theft and helps to manage the health of the grid based on line loss analysis. Dominant parameters in smart grid scenarios with PLC: Hong, et al. Expires September 13, 2017 [Page 21] Internet-Draft 6lo Applicability & Use cases March 2017 o Deployment/Bootstrapping: Pre-planned. o Topology: Tree topology. o L2-mesh or L3-mesh: No. o Multi-link subnet, single subnet: Single subnet. o Data rate: Small data rate, infrequent transmissions. o Buffering requirements: Low requirement. o Security requirements: Data privacy and security must be provided. Encryption is required. o Mobility: Static. o Time Synchronization: Low requirement. o Reliability and QoS: a relatively low ratio of message losses is acceptable for periodic meter readings. o Traffic patterns: Periodic (upstream meter reading notifications sent by the meter) and aperiodic (utility company-triggered downstream queries and messages to the meter such as notification of electricity charges or leak detection). o Security Bootstrapping: Required. o Power use strategy: Mix of P1 (Low Power) devices and P9 (Always- on) devices. o Update firmware requirements: TBD. Example: Use of PLC (IEEE1901.1) for WASA in Smart Grid Many sub-systems of Smart Grid require low data rate and narrowband variant (IEEE1901.2) of PLC fulfils such requirements. Recently, more complex scenarios are emerging that require higher data rates. (see Table 3). Hong, et al. Expires September 13, 2017 [Page 22] Internet-Draft 6lo Applicability & Use cases March 2017 +--------------+----------+--------------+-------------+---------+ | Sub System | Security | Bandwidth | Reliability | Latency | +--------------+----------+--------------+-------------+---------+ | HEMS | High | 9.6-56kbps | 99% | <2000ms | | | | | | | | AMI-Node | High | 10-100kbps | 99% | <200ms | | | | | | | | AMI-Backhaul | High | 500kbps | 99% | <200ms | | | | | | | | WASA | High | 600-1500kbps | 99% | <200ms | +--------------+----------+--------------+-------------+---------+ Table 3: Some Sub Systems of Smart Grid WASA sub-system is an appropriate example that collects large amount of information about the current state of the grid over wide area from electric substations as well as power transmission lines. The collected feedback is used for monitoring, controlling and protecting all the sub-systems. Dominant parameters in WASA scenario with above example: o Deployment/Bootstrapping: Pre-planned. o Topology: TBD. o L2-mesh or L3-mesh: TBD. o Multi-link subnet, single subnet: TBD. o Data rate: TBD. o Buffering requirements: TBD. o Security requirements: TBD. o Mobility: TBD. o Time Synchronization: TBD. o Reliability and QoS: TBD. o Traffic patterns: TBD. o Security Bootstrapping: TBD. o Power use strategy: P9 (Always-on). Hong, et al. Expires September 13, 2017 [Page 23] Internet-Draft 6lo Applicability & Use cases March 2017 o Update firmware requirements: TBD. 6.8. Use case of IEEE 802.15.4e: Industrial Automation Typical scenario of Industrial Automation where sensor and actuators are connected through the time-slotted radio access (IEEE 802.15.4e). For that, there will be a point-to-point control signal exchange in between sensors and actuators to trigger the critical control information. In such scenarios, point-to-point traffic flows are significant to exchange the controlled information in between sensors and actuators within the constrained networks. Example: Use of IEEE 802.15.4e for P2P communication in closed-loop application AODV-RPL [I-D.ietf-roll-aodv-rpl] is proposed as a standard P2P routing protocol to provide the hop-by-hop data transmission in closed-loop constrained networks. Scheduling Functions i.e. SF0 [I-D.ietf-6tisch-6top-sf0] and SF1 [I-D.satish-6tisch-6top-sf1] is proposed to provide distributed neighbor-to-neighbor and end-to-end resource reservations, respectively for traffic flows in deterministic networks (6TiSCH). The potential scenarios that can make use of the end-to-end resource reservations can be in health-care and industrial applications. AODV-RPL and SF0/SF1 are the significant routing and resource reservation protocols for closed-loop applications in constrained networks. Dominant parameters in P2P scenarios with above example: o Deployment/Bootstrapping: Pre-planned. o Topology: TBD. o L2-mesh or L3-mesh: TBD. o Multi-link subnet, single subnet: TBD. o Data rate: TBD. o Buffering requirements: TBD. o Security requirements: TBD. o Mobility: TBD. o Time Synchronization: TBD. Hong, et al. Expires September 13, 2017 [Page 24] Internet-Draft 6lo Applicability & Use cases March 2017 o Reliability and QoS: TBD. o Traffic patterns: TBD. o Security Bootstrapping: TBD. o Power use strategy: P9 (Always-on). o Update firmware requirements: TBD. 7. IANA Considerations There are no IANA considerations related to this document. 8. Security Considerations [TBD] 9. Acknowledgements Carles Gomez has been funded in part by the Spanish Government (Ministerio de Educacion, Cultura y Deporte) through the Jose Castillejo grant CAS15/00336. His contribution to this work has been carried out in part during his stay as a visiting scholar at the Computer Laboratory of the University of Cambridge. Samita Chakrabarti, Thomas Watteyne, Pascal Thubert, Xavier Vilajosana, Daniel Migault, and Jianqiang HOU have provided valuable feedback for this draft. 10. References 10.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC4919] Kushalnagar, N., Montenegro, G., and C. Schumacher, "IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs): Overview, Assumptions, Problem Statement, and Goals", RFC 4919, DOI 10.17487/RFC4919, August 2007, . Hong, et al. Expires September 13, 2017 [Page 25] Internet-Draft 6lo Applicability & Use cases March 2017 [RFC4944] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler, "Transmission of IPv6 Packets over IEEE 802.15.4 Networks", RFC 4944, DOI 10.17487/RFC4944, September 2007, . [RFC5826] Brandt, A., Buron, J., and G. Porcu, "Home Automation Routing Requirements in Low-Power and Lossy Networks", RFC 5826, DOI 10.17487/RFC5826, April 2010, . [RFC6282] Hui, J., Ed. and P. Thubert, "Compression Format for IPv6 Datagrams over IEEE 802.15.4-Based Networks", RFC 6282, DOI 10.17487/RFC6282, September 2011, . [RFC6568] Kim, E., Kaspar, D., and JP. Vasseur, "Design and Application Spaces for IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs)", RFC 6568, DOI 10.17487/RFC6568, April 2012, . [RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C. Bormann, "Neighbor Discovery Optimization for IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs)", RFC 6775, DOI 10.17487/RFC6775, November 2012, . [RFC7228] Bormann, C., Ersue, M., and A. Keranen, "Terminology for Constrained-Node Networks", RFC 7228, DOI 10.17487/RFC7228, May 2014, . [RFC7428] Brandt, A. and J. Buron, "Transmission of IPv6 Packets over ITU-T G.9959 Networks", RFC 7428, DOI 10.17487/RFC7428, February 2015, . [RFC7668] Nieminen, J., Savolainen, T., Isomaki, M., Patil, B., Shelby, Z., and C. Gomez, "IPv6 over BLUETOOTH(R) Low Energy", RFC 7668, DOI 10.17487/RFC7668, October 2015, . [RFC8036] Cam-Winget, N., Ed., Hui, J., and D. Popa, "Applicability Statement for the Routing Protocol for Low-Power and Lossy Networks (RPL) in Advanced Metering Infrastructure (AMI) Networks", RFC 8036, DOI 10.17487/RFC8036, January 2017, . Hong, et al. Expires September 13, 2017 [Page 26] Internet-Draft 6lo Applicability & Use cases March 2017 10.2. Informative References [I-D.ietf-6lo-dect-ule] Mariager, P., Petersen, J., Shelby, Z., Logt, M., and D. Barthel, "Transmission of IPv6 Packets over DECT Ultra Low Energy", draft-ietf-6lo-dect-ule-07 (work in progress), October 2016. [I-D.ietf-6lo-6lobac] Lynn, K., Martocci, J., Neilson, C., and S. Donaldson, "Transmission of IPv6 over MS/TP Networks", draft-ietf- 6lo-6lobac-05 (work in progress), June 2016. [I-D.ietf-6lo-nfc] Choi, Y., Youn, J., and Y. Hong, "Transmission of IPv6 Packets over Near Field Communication", draft-ietf-6lo- nfc-05 (work in progress), October 2016. [I-D.ietf-lwig-energy-efficient] Gomez, C., Kovatsch, M., Tian, H., and Z. Cao, "Energy- Efficient Features of Internet of Things Protocols", draft-ietf-lwig-energy-efficient-05 (work in progress), October 2016. [I-D.ietf-roll-aodv-rpl] Anamalamudi, S., Zhang, M., Sangi, A., Perkins, C., and S. Anand, "Asymmetric AODV-P2P-RPL in Low-Power and Lossy Networks (LLNs)", draft-ietf-roll-aodv-rpl-00 (work in progress), December 2016. [I-D.ietf-6tisch-6top-sf0] Dujovne, D., Grieco, L., Palattella, M., and N. Accettura, "6TiSCH 6top Scheduling Function Zero (SF0)", draft-ietf- 6tisch-6top-sf0-02 (work in progress), October 2016. [I-D.satish-6tisch-6top-sf1] Anamalamudi, S., Zhang, M., Sangi, A., Perkins, C., and S. Anand, "Scheduling Function One (SF1) for hop-by-hop Scheduling in 6tisch Networks", draft-satish-6tisch-6top- sf1-02 (work in progress), August 2016. [G.9959] "International Telecommunication Union, "Short range narrow-band digital radiocommunication transceivers - PHY and MAC layer specifications", ITU-T Recommendation", January 2015. Hong, et al. Expires September 13, 2017 [Page 27] Internet-Draft 6lo Applicability & Use cases March 2017 [LTE_MTC] "3GPP TS 36.306 V13.0.0, 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); User Equipment (UE) radio access capabilities (Release 13)", December 2015. [IEEE1901] "IEEE Standard, IEEE Std. 1901-2010 - IEEE Standard for Broadband over Power Line Networks: Medium Access Control and Physical Layer Specifications", 2010, . [IEEE1901.1] "IEEE Standard (work-in-progress), IEEE-SA Standards Board", . [IEEE1901.2] "IEEE Standard, IEEE Std. 1901.2-2013 - IEEE Standard for Low-Frequency (less than 500 kHz) Narrowband Power Line Communications for Smart Grid Applications", 2013, . Authors' Addresses Yong-Geun Hong ETRI 161 Gajeong-Dong Yuseung-Gu Daejeon 305-700 Korea Phone: +82 42 860 6557 Email: yghong@etri.re.kr Carles Gomez Universitat Politecnica de Catalunya/Fundacio i2cat C/Esteve Terradas, 7 Castelldefels 08860 Spain Email: carlesgo@entel.upc.edu Hong, et al. Expires September 13, 2017 [Page 28] Internet-Draft 6lo Applicability & Use cases March 2017 Younghwan Choi ETRI 218 Gajeongno, Yuseong Daejeon 305-700 Korea Phone: +82 42 860 1429 Email: yhc@etri.re.kr Deoknyong Ko SKtelecom 9-1 Byundang-gu Sunae-dong, Seongnam-si Gyeonggi-do 13595 Korea Phone: +82 10 3356 8052 Email: engineer@sk.com Abdur Rashid Sangi Huawei Technologies No.156 Beiqing Rd. Haidian District Beijing 100095 P.R. China Email: rashid.sangi@huawei.com Take Aanstoot Modio AB S:t Larsgatan 15, 582 24 Linkoping Sweden Email: take@modio.se Hong, et al. Expires September 13, 2017 [Page 29]