ICN Research Group Y. Zhang Internet-Draft D. Raychadhuri Intended status: Informational WINLAB, Rutgers University Expires: March 26, 2015 L. Grieco Politecnico di Bari (DEI) E. Baccelli INRIA J. Burke UCLA REMAP R. Ravindran (Ed) G. Wang Huawei Technologies September 22, 2014 ICN based Architecture for IoT - Requirements and Challenges draft-zhang-iot-icn-challenges-00 Abstract The Internet of Things (IoT) promises to connect billions of objects to Internet. After deploying many stand-alone IoT systems in different domains, the current trend is to develop a common, "thin waist" of protocols forming a unified, defragmented IoT platform. Such a platform will make objects accessible to applications across organizations and domains. Towards this goal, quite a few proposals have been made to build a unified IoT platform as an overlay on top of today's Internet. Such overlay solutions, however, are inadequate to address the important challenges posed by a heterogeneous, global scale deployment of IoT, especially in terms of mobility, scalability, and communication reliability, due to the inherent inefficiencies of the current Internet. To address this problem, we propose to build a common set of protocols and services, which form an IoT platform, based on the Information Centric Network (ICN) architecture, which we call ICN-IoT. ICN-IoT leverages the salient features of ICN, and thus provides seamless mobility support, scalability, and efficient content and service delivery. This draft sets the IoT requirements and ICN challenges to realize a unified ICN-IoT framework. Towards this, we first identify a list of important requirements which a unified IoT architecture should have to support tens of billions of objects. Then we analyze the current state of art deployment model and discuss important and popular IoT scenarios including the "smart" home, campus, grid, transportation infrastructure, healthcare, Education, and Entertainment. Though we see most of these requirements are met by ICN, we discuss specific challenges ICN has to address to satisfy them considering heterogeneity in IoT environments and scenarios. Zhang, et al. Expires March 26, 2015 [Page 1] Internet-Draft ICN based Architecture for IoT September 2014 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." This Internet-Draft will expire on March 26, 2015. Copyright Notice Copyright (c) 2014 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. IoT Motivation . . . . . . . . . . . . . . . . . . . . . . . 3 2. IoT Architectural Requirements . . . . . . . . . . . . . . . 4 2.1. Naming . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.2. Scalability . . . . . . . . . . . . . . . . . . . . . . . 4 2.3. Resource Constraints . . . . . . . . . . . . . . . . . . 4 2.4. Traffic Characteristics . . . . . . . . . . . . . . . . . 5 2.5. Contextual Communication . . . . . . . . . . . . . . . . 5 2.6. Handling Mobility . . . . . . . . . . . . . . . . . . . . 6 2.7. Storage and Caching . . . . . . . . . . . . . . . . . . . 6 2.8. Security and Privacy . . . . . . . . . . . . . . . . . . 7 2.9. Communication Reliability . . . . . . . . . . . . . . . . 7 2.10. Self-Organization . . . . . . . . . . . . . . . . . . . . 7 2.11. Ad hoc and Infrastructure Mode . . . . . . . . . . . . . 8 2.12. Open API . . . . . . . . . . . . . . . . . . . . . . . . 8 Zhang, et al. Expires March 26, 2015 [Page 2] Internet-Draft ICN based Architecture for IoT September 2014 3. State of the Art . . . . . . . . . . . . . . . . . . . . . . 8 3.1. Silo IoT Architecture . . . . . . . . . . . . . . . . . . 9 3.2. Overlay Based Unified IoT Solutions . . . . . . . . . . . 9 3.2.1. Weaknesses of the Overlay-based Approach . . . . . . 10 4. Popular Scenarios . . . . . . . . . . . . . . . . . . . . . . 11 4.1. Homes . . . . . . . . . . . . . . . . . . . . . . . . . . 12 4.2. Enterprise . . . . . . . . . . . . . . . . . . . . . . . 12 4.3. Smart Grid . . . . . . . . . . . . . . . . . . . . . . . 13 4.4. Transportation . . . . . . . . . . . . . . . . . . . . . 13 4.5. Healthcare . . . . . . . . . . . . . . . . . . . . . . . 14 4.6. Education . . . . . . . . . . . . . . . . . . . . . . . . 15 4.7. Entertainment, arts, and culture . . . . . . . . . . . . 15 5. ICN Challenges for IoT . . . . . . . . . . . . . . . . . . . 16 5.1. Naming . . . . . . . . . . . . . . . . . . . . . . . . . 16 5.2. Caching/Storage . . . . . . . . . . . . . . . . . . . . . 17 5.3. Name Resolution . . . . . . . . . . . . . . . . . . . . . 17 5.4. Contextual Communication . . . . . . . . . . . . . . . . 18 5.5. Routing and Forwarding . . . . . . . . . . . . . . . . . 18 5.6. In-network Computing . . . . . . . . . . . . . . . . . . 19 5.7. Security and Privacy . . . . . . . . . . . . . . . . . . 20 5.8. Energy Efficiency . . . . . . . . . . . . . . . . . . . . 21 6. Informative References . . . . . . . . . . . . . . . . . . . 21 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 25 1. IoT Motivation During the past decade, many standalone Internet of Things (IoT) systems have been developed and deployed in different domains. The recent trend, however, is to evolve towards a globally unified IoT platform, in which billions of objects connect to the Internet, available for interactions among themselves, as well as interactions with many different applications across boundaries of administration and domains. Building a unified IoT platform, however, poses great challenges on the underlying network and systems. To name a few, it needs to support 50-100 Billion networked objects [1], many of which are mobile. The objects will have extremely heterogeneous means of connecting to the Internet, often with severe resource constraints. Interactions between the applications and objects are often real-time and dynamic, requiring strong security and privacy protections. In addition, IoT applications are inherently information centric (e.g., data consumers usually need data sensed from the environment without any reference to the sub-set of motes that will provide the asked information). Taking a general IoT perspective, we begin by presenting IoT architectural requirements, then summarize how state- of-art approaches address these requirements. We then discuss well known IoT scenarios focusing on their unique challenges. The final discussion focuses on IoT challenges from an ICN perspective and requirements posed towards its design. Zhang, et al. Expires March 26, 2015 [Page 3] Internet-Draft ICN based Architecture for IoT September 2014 2. IoT Architectural Requirements A unified IoT platform has to support interactions among a large number of mobile devices across the boundaries of organizations and domains. As a result, it naturally poses stringent requirements in every aspect of the system design. Below, we outline a few important requirements that a unified IoT platform has to address. 2.1. Naming The first step towards realizing a unified IoT platform is the ability to assign names that are unique within the scope and lifetime of each device, data items generated by these devices, or a group of devices towards a common objective. Naming has the following requirements. First, names need to be persistent (within one or more contexts) against dynamic features that are common in IoT systems, such as mobility or migration; Second, names need to be secure based on application requirements. 2.2. Scalability Cisco predicts there will be around 50 Billion IoT devices such as sensors, RFID tags, and actuators, on the Internet by 2020 [1]. As mentioned above, a unified IoT platform needs to name every entity such as data, device, service etc. Scalability has to be addressed at multiple levels of the IoT architecture spanning naming, security, name resolution, routing and forwarding level. In addition, mobility adds further challenge in terms of scalability. Particularly with respect to name resolution the system should be able to insert/update/look up a name within a short latency. To satisfy this requirement, decentralization of the name resolution can be the the key. 2.3. Resource Constraints IoT devices can be broadly classified into two groups: resource- sufficient and resource-constrained. In general, there are the following types of resources: power, computing, storage, and bandwidth. Power constraints of IoT devices limit how much data these devices can communicate, as it has been shown that communications consume more power than other activities for embedded devices. Flexible techniques to collect the relevant information are required, and uploading every single produced data to a central server is undesirable. Computing constraints limit the type and amount of processing these devices can perform. As a result, more complex processing needs to be conducted at opportunistic points, example at Zhang, et al. Expires March 26, 2015 [Page 4] Internet-Draft ICN based Architecture for IoT September 2014 the network edge, hence it is important to balance local computation versus communication cost. Storage constraints of the IoT devices limit the amount of data that can be stored on the devices. This constraint means that unused sensor data may need to be discarded from time to time. Bandwidth constraints of the IoT devices limit the amount of communication. Such devices will have the same implication on the system architecture as with the power constraints; namely, we cannot afford to communicate with every single sensor data generated by the device and/or use complex signaling protocols. User interface constraints refer to whether the device is itself capable of directly interacting with a user should the need arise (e.g., via a display and keypad or LED indicators) or requires the network connectivity, either global or local, to interact with humans. 2.4. Traffic Characteristics IoT traffic can be broadly classified into local area traffic and wide area traffic. Local area traffic is between nearby devices. For example, neighboring cars may work together to detect potential hazards on the highway, sensors deployed in the same room may collaborate to determine how to adjust the heating level in the room. These local area communications often involve data aggregation and filtering, have real time constraints, and require fast device/data/ service discovery and association. At the same time, the IoT platform has to also support wide area communications. For example, commuters can find out real-time traffic and road information and then decide which commuting route to take. Wide area communications require efficient data/service discovery and resolution services. While traffic characteristics for different IoT systems are expected to be different, certain IoT systems have been analyzed and shown to have comparable uplink and downlink traffic volume in some applications such as [2], which means that we have to optimize the bandwidth/energy consumption in both directions. Further, IoT traffic demonstrates certain periodicity and burstiness [2]. As a result, when provisioning the system, the shape of the traffic volume has to be properly accounted for. 2.5. Contextual Communication Many IoT applications shall rely on contextual information such as social, grouping, location, type of ecosystem (home, grid, transport etc.) of devices and data (which are referred to as contexts in this document) to initiate dynamic relationship and communication. For Zhang, et al. Expires March 26, 2015 [Page 5] Internet-Draft ICN based Architecture for IoT September 2014 example, cars traveling on the highway may form a "cluster" based upon their temporal physical proximity as well as the detection of the same event. These temporary groups are referred to as contexts. IoT applications need to support interactions among the members of a context, as well as interactions across contexts. Temporal context can be broadly categorized into two classes, long- term contexts such as those that are based upon social contacts as well as stationary physical locations (e.g., sensors in a car/ building), and short-term contexts such as those that are based upon temporary proximity (e.g., all taxicabs within half a mile of the Time Square at noon on Oct 1, 2013). Between these two classes, short-term contexts are more challenging to support, requiring fast formation, update, lookup and association. 2.6. Handling Mobility There are varying degrees of mobility in a unified IoT platform, ranging from static as in fixed assets to highly dynamic in vehicle- to-vehicle environments. Mobility in the IoT platform can mean 1) the data producer mobility (i.e., location change), 2) the data consumer mobility, 3) IoT Network mobility; and 4) disconnection between the data source and destination pair (e.g., due to unreliable wireless links). The requirement on mobility support is to be able to deliver IoT data below an application acceptable delay constraint in all of the above cases. 2.7. Storage and Caching Storage and caching plays a very significant role depending on the type of IoT ecosystem with the fact that data generated is also subjected to privacy and security guidelines. In a unified IoT platform, depending on application requirements, content caching may or may not be policy driven though the latter would be a more common scenario. If caching is pervasive, intermediate nodes don't need to always forward a content request to its original creator; rather, locating and receiving a cached copy is sufficient for IoT applications. This optimization can greatly reduce the content access latencies. Further, ICN architectures enable a more flexible, heterogeneous and potentially fault-tolerant approach to storage, that provides persistence at a variety of levels in a hierarchical network of devices. Zhang, et al. Expires March 26, 2015 [Page 6] Internet-Draft ICN based Architecture for IoT September 2014 In network storage and caching, however, has the following requirements on the IoT platform. The platform needs to support the efficient resolution of cached copies. Further the platform should strive for the balance between caching, content security/privacy, and regulations. 2.8. Security and Privacy In addition to the fundamental challenge of trust management, a variety of security and privacy concerns also exist in ICNs. The unified IoT platform makes physical objects accessible to applications across organizations and domains. Further, it often integrates with critical infrastructure and industrial systems with life safety implications, bringing with it significant security challenges and regulatory requirements [12]. Security and privacy thus become a serious concern, as does the flexibility and usability of the design approaches. Beyond the overarching trust management challenge, security includes data integrity, authentication, and access control at different layers of the IoT platform. Privacy means that both the content and the context around IoT data need to be protected. These requirements will be driven by various stake holders such as industry, government, consumers etc. 2.9. Communication Reliability IoT applications can be broadly categorized into mission critical and non-mission critical. For mission critical applications, reliable communication is one of the most important features as these applications have strong QoS requirements. Reliable communication requires the following capabilities for the underlying system: (1) seamless mobility support in the face of extreme disruptions (DTN), (2) efficient routing in the presence of intermittent disconnection, (3) QoS aware routing, (4) support for redundancy at all levels of a system (device, service, network, etc.). 2.10. Self-Organization The unified IoT platform should be able to self-organize to meet various application requirements, especially the capability to quickly discover heterogeneous and relevant devices/data/services based on the context. This discovery can be achieved through an efficient platform-wide publish-subscribe service, or through private community grouping/clustering based upon trust and other security requirements. In the former case, the publish-subscribe service must be efficiently implemented, able to support seamless mobility, in- Zhang, et al. Expires March 26, 2015 [Page 7] Internet-Draft ICN based Architecture for IoT September 2014 network caching, name-based routing, etc. In the latter case, the IoT platform needs to discover the private community groups/clusters efficiently. 2.11. Ad hoc and Infrastructure Mode Depending upon whether there is communication infrastructure, an IoT system can operate either in ad-hoc or infrastructure mode. For example, a vehicle may determine to report its location and status information to a server periodically through cellular connection, or, a group of vehicles may form an ad-hoc network that collectively detect road conditions around them. In the cases where infrastructure is unavailable, one of the participating nodes may choose to become the temporary gateway. The unified IoT platform needs to design a common protocol that serves both modes. Such a protocol should be able to provide: (1) energy-efficient topology discovery and data forwarding in the ad-hoc mode, and (2) scalable name resolution in the infrastructure mode. 2.12. Open API General IoT applications involve sensing, processing, and secure content distribution occuring at various timescales depending on the application requirements. This requires open APIs to be generic enough to support Pull, Push, and support Pub/Sub mode of interaction between consumers, content producer, and IoT services, as opposed to proprietary APIs that are common in today's systems. 3. State of the Art Over the years, many stand-alone IoT systems have been deployed in various domains. These systems usually adopt a vertical silo architecture and support a small set of pre-designated applications. A recent trend, however, is to move away from this approach, towards a unified IoT platform in which the existing silo IoT systems, as well as new systems that are rapidly deployed, will make their data and services accessible to general Internet applications (as in ETSI- M2M and oneM2M standards). In such a unified platform, resources can be accessed over Internet and shared across the physical boundaries of the enterprise. However, current approaches to achieve this objective are based upon Internet overlays, whose inherent inefficiencies due to IP protocol [9] hinders the platform from satisfying the IoT requirements outlined earlier (particularly in terms of scalability, security, mobility, and self-organization) Zhang, et al. Expires March 26, 2015 [Page 8] Internet-Draft ICN based Architecture for IoT September 2014 3.1. Silo IoT Architecture [IoT Server] | | ______|_______ _______ { } { } { } {IoT Dev}\ { Internet }---[IoT Application] {_______} [IoTGW]---{ } { } {______________} Figure 1:Silo architecture of standalone IoT systems A typical standalone IoT system is illustrated in Figure 1, which includes devices, a gateway, a server and applications. Many IoT devices have limited power and computing resources, unable to directly run normal IP access network (Ethernet, WIFI, 3G/LTE etc.) protocols. Therefore they use the IoT gateway to the server. Through the IoT server, applications can subscribe to data collected by devices, or interact with devices. There have been quite a few popular protocols for standalone IoT systems, such as DF-1, MelsecNet, Honeywell SDS, BACnet, etc. However, these protocols are operating at the device-level abstraction, instead of information driven, leading to a highly fragmented protocol space with limited interoperability. 3.2. Overlay Based Unified IoT Solutions The current approach to a unified IoT platform is to make IoT gateways and servers adopt standard APIs. IoT devices connect to the Internet through the standard APIs and IoT applications subscribe and receive data through standard control and data APIs. Building on top of today's Internet as an overlay, this is the most practical approach towards a unified IoT platform. There are ongoing standardization efforts including ETSI[3], oneM2M[4],and CORE[5]. Network operators can use standard API to build common IOT gateways and servers for their customers. Figure 2 shows the architecture adopted in this approach. Zhang, et al. Expires March 26, 2015 [Page 9] Internet-Draft ICN based Architecture for IoT September 2014 Publishing----[IoT Server]----Subscribing-- | / | \ | | / | \ | | /______|_______ \ | ___________ | /{ } publishing | { } | | { } | | {Smart Homes}\ | | { Internet }---------[IoT Application] {___________} [IoTGW]---{ }\ | ________________ | { } \ | { } | {______________} [IoTGW]-{Smart Healthcare} | | {________________} Publishing [IoTGW] | ____|_____ | { } ---{Smart Grid} {__________} Figure 2: Implementing an open IoT platform through standarized APIs on the IoT gateways and the server 3.2.1. Weaknesses of the Overlay-based Approach The above overlay-based approach can work with many different protocols, but the system is not designed in a holistic manner to inter-connect heterogeneous devices, services and infrastructure. Another limiting factor is that it is built upon today's IP network, which has inherent weaknesses towards supporting a unified IoT system. As a result, it cannot satisfy some of the requirements we outlined in Section 2: o Naming. In current overlays for IoT systems the naming scheme is host centric, i.e., the name of a given resource/service is linked to the one of device that can provide it. In turn, device names are coupled to IP addresses, which are not persistent in mobile scenarios. On the other side, in IoT systems the same service/ resource could be provided by many different devices thus requiring a different design rationale. o Trust. Trust management schemes are still relatively weak, focusing on securing communication channels rather than managing the data that needs to be secured directly. o Scalability. The overlay-based approach uses IP addresses as names at the network layer, which hinders the support for device/ service mobility or flexible name resolution. Further the Layer 2/3 management, and application-layer addressing and forwarding Zhang, et al. Expires March 26, 2015 [Page 10] Internet-Draft ICN based Architecture for IoT September 2014 required to deploy current IoT solutions limit the scalability and management of these systems. o Resource constraints. The overlay-based approach requires every device to send data to an aggregator or to the IoT server. Resource constraints of the IoT devices, especially in power and bandwidth, will seriously limit the performance of this approach. o Traffic Characteristics. In this approach, applications are written in a host-centric manner suitable for point-to-point communication. IoT requires support for multicasting that is challenging the underlying for overlay systems today. o Contextual Communications. This overlay-based approach cannot react to dynamic contextual changes in a timely fashion. The main reason is that context lists are kept at the IoT server in this approach, and they cannot help efficiently route requests/ information at the network layer. o Mobility. The overlay-based approach cannot seamlessly support device mobility in terms of maintaining the session between data producers and consumers. In this approach, lower-level communications are typically IP driven, which is inefficient for mobility support. o Storage and Caching. The overlay-based approach supports application-centric storage and caching but not what ICN envisions at the network layer, or flexible storage enabled via name-based routing. o Self-Organization. The overlay-based approach is topology-based as it is bound to IP semantics, and thus does not sufficiently satisfy the self-organization requirement. o Ad-hoc and infrastructure mode. As mentioned above, the overlay- based approach lacks self-organization, and thus does not provide efficient support for the ad-hoc mode. 4. Popular Scenarios Several types of IoT applications exists, where the goal is efficient and secure management and communication among objects in the system and with the physical world through sensors, RFIDs and other devices. Below we list a few popular IoT applications. We omit the often used term "smart", though it applies to each IoT scenario below, and posit that IoT-style interconnection of devices to make these environments "smart" in today's terms will simply be the future norm. Zhang, et al. Expires March 26, 2015 [Page 11] Internet-Draft ICN based Architecture for IoT September 2014 4.1. Homes The home [11] is a complex ecosystem of IoT devices and applications including climate control, home security monitoring, smoke detection, electrical metering, health/wellness, and entertainment systems. In a unified IoT platform, we would inter-connect these systems through the Internet, such that they can interact with each other and make decisions at an aggregated level. Also, the systems can be accessed and manipulated remotely. Challenges in the home include topology independent service discovery, common protocol for heterogeneous device/application/service interaction, policy based routing/ forwarding, service mobility as well as privacy protection. Notably, the ease-of-use expectations and training of both users and installers also presents challenges in user interface and user experience design that are impacted by the complexity of network configuration, brittleness to change, configuration of trust management, etc. Finally, it is unlikely that there will be a single "home system", but rather a collection of moderately inter-operable collaborating devices. Homes [13][14] faces the following challenges that are hard to address with IP-based overlay solutions: (1) context-aware control: home systems must make decisions (e.g., on how to control, when to collect data, where to carry out computation, when to interact with end-users, etc.) based upon the contextual information [15]; (2) inter-operatibility: home systems must operate with devices that adopt heterogeneous naming, trust, communication, and control systems; (3) mobility: home systems must deal with mobility caused by the movement of sensors or data receivers; (4) security: a home systems must be able to deal with foreign devices, handle a variety of user permissions (occupants of various types, guests, device manufacturers, installers and integrators, utility and infrastructure providers) and involve users in important security decisions without overwhelming them. 4.2. Enterprise Enterprise building deployments, from university campuses [16] to industrial facilities and retail complexes, drive an additional set of scalability, security, and integration requirements beyond the home, while requiring much of its ease of use and flexibility. Additionally, they bring requirements for integration with business IT systems, though often with the additional support of in-house engineering support. Increasing number of enterprises are equipped with sensing and communication devices inside buildings, laboratories, and plants, at stadiums, in parking lots, on school buses, etc. A unified IoT Zhang, et al. Expires March 26, 2015 [Page 12] Internet-Draft ICN based Architecture for IoT September 2014 platform must integrate many aspects of human interaction, H2M and M2M communication, within the enterprise, and thus enable many IoT applications that can benefit a large body of enterprise affiliates. The challenges in smart enterprise include efficient and secure device/data/resource discovery, inter-operability between different control systems, throughput scaling with number of devices, and unreliable communication due to mobility and telepresence. Enterprises face the following challenges that are hard to address with IP-based overlay solutions: (1) efficient device/data/ resource discovery: enterprise devices must be able to quickly and securely discover requested device, data, or resources; (2) scalability: a enterprise system must be able to scale efficiently with the number and type of sensors and devices across not only a single building but multi-national corporations (for example); (3) mobility: a enterprise system must be able to deal with mobility caused by movement of devices. 4.3. Smart Grid Central to the so-called "smart grid"[17] is data flow and information management, achieved by using sensors and actuators, which enables important capabilities such as substation and distribution automation. In a unified IoT platform, data collected from different smart grids can be integrated to reach more significant optimizations. The challenges for smart grid include reliability, real-time control, secure communications, and data privacy. Deployment of the smart grid [18] [19] faces the following issues that are hard to address with IP-based overlay solutions: (1) scalability: tomorrow's electrical grids must be able to scale gracefully to manage a large number of heterogeneous devices; (2) real time: grids must be able to perform real-time data collection, data processing and control; (3) reliability: grids must be resilient to hardware/software/networking failures; (4) security: grids and associated systems are often considered critical infrastructure -- they must be able to defend against malicious attacks, detect intrusion, and route around disruption. 4.4. Transportation We are currently witnessing the increasing integration of sensors into cars, other vehicles transportation systems [20]. Current production cars already carry many sensors ranging from rain gauges and accelerometers over wheel rotation/traction sensors, to cameras. While intended for internal vehicle functions, these could also be networked and leveraged for applications such as monitoring external Zhang, et al. Expires March 26, 2015 [Page 13] Internet-Draft ICN based Architecture for IoT September 2014 traffic/road conditions. Further, we can build vehicle-to- infrastructure (V2I) and vehicle-to-vehicle (V2V) communications that enable many more applications for safety, convenience, entertainment, etc. The challenges for transportation include fast data/device/ service discovery and association, efficient communications with mobility, trustworthy data collection and exchange. Transportation [20][21] faces the following challenges that are hard to address with IP-based overlay solutions: (1) mobility: a transportation system must deal with a large number of mobile nodes interacting through a combination of infrastructure and ad hoc communication methods; (2) real-time and reliability: transportation systems must be able to operate on real-time and remain resilient in the presence of failures; (3) in-network computing/filtering: transportation systems will benefit from in-network computing/ filtering as such operations can reduce the end-to-end latency; (4) inter-operatibility: transportation systems must operate with heterogeneous device and protocols; (5) security: transportation systems must be resilient to malicious physical and cyber attacks. 4.5. Healthcare As more embedded medical devices, or devices that can monitor human health become increasingly deployed, healthcare is becoming a viable alternative to traditional healthcare solutions [15][22]. Further, consumer applications for managing and interacting with health data are a burgeoning area of research and commercial applications. For future health applications, a unified IoT platform is critical for improved patient care and consumer health support by sharing data across systems, enabling timely actuations, and lowering the time to innovation by simplifying interaction across devices from many manufacturers. Challenges in healthcare include real-time interactions, high reliability, short communication latencies, trustworthy, security and privacy, and well as defining and meeting the regulatory requirements that should impact new devices and their interconnection. Healthcare [22][23] faces the following challenges that are hard to address with IP-based overlay solutions: (1) real-time and reliability: healthcare systems must be able to operate on real-time and remain resilient in the presence of failures; (2) inter- operatibility: healthcare systems must operate with heterogeneous device and protocols; (3) security: healthcare systems must be resilient to malicious physical and cyber attacks and meet the regulatory requirement for data security and interoperability. Zhang, et al. Expires March 26, 2015 [Page 14] Internet-Draft ICN based Architecture for IoT September 2014 4.6. Education IoT technologies enable the instrumentation of a variety of environments (from greenhouses to industrial plants, homes and vehicles) to support not only their everyday operation but an understanding of how they operate -- a fundamental contribution to education. The diverse uses of hobbyist-oriented microcontroller platforms (e.g., the Arduino) and embedded systems (e.g., the Raspberry PI) point to a burgeoning community that should be supported by the next generation IoT platform because of its fundamental importance to formal and informal education. Educational uses of IoT deployments include both learning about the operation of the system itself as well as the systems being observed and controlled. Such deployments face the following challenges that are hard to address with IP-based overlay solutions: (1) relatively simple communications patterns are obscured by many layers of translation from the host-based addressing of IP (and layer 2 configuration below) to the name-oriented interfaces provided by developers; (2) security considerations with overlay deployments and channel-based limit access to systems where read-only use of data is not a security risk; (3) real-time communication helps make the relationship between physical phenomena and network messages easier to understand in many simple cases; (4) integration of devices from a variety of sources and manufacturers is currently quite difficult because of varying standards for basic communication, and limits experimentation. 4.7. Entertainment, arts, and culture IoT technologies can contribute uniquely to both the worldwide entertainment market and the fundamental human activity of creating and sharing art and culture. By supporting new types of human- computer interaction, IoT can enable new gaming, film/video, and other "content" experiences, integrating them with, for example, the lighting control of the smart home, presentation systems of the smart enterprise, or even the incentive mechanisms of smart healthcare systems (to, say, encourage and measure physical activity). Entertainment, arts, and culture applications generate a variety of challenges for IoT: (1) notably, the ability to securely "repurpose" deployed smart systems (e.g., lighting) to create experiences; (2) low-latency communication to enable end-user responsiveness; (3) integration with infrastructure-based sensing (e.g., computer vision) to create comprehensive interactive environments or to provide user identity information; (4) time synchronization with audio/video playback and rendering in 3D systems (5) simplicity of development and experimentation, to enable the cost- and time-efficient Zhang, et al. Expires March 26, 2015 [Page 15] Internet-Draft ICN based Architecture for IoT September 2014 integration of IoT into experiences being designed without expert engineers of IoT systems; (6) security, because of integration with personal devices and smart environments, as well as billing systems. 5. ICN Challenges for IoT ICN integrates content/service/host abstraction, name-based routing, compute, caching/storage as part of the network infrastructure connecting consumers and services which meets most of the requirements discussed above; however IoT requires special considerations given heterogeneity of devices and interfaces such as for constrained networking [32], data processing, and content distribution models to meet specific application requirements which we identify as challenges in this section. 5.1. Naming According to [27], the main requirement of a name space (and the corresponding Name Resolution System) are: o Scalability: with the IoT the number of data items would inflate the Internet scale up to 2-3 order of magnitudes, thus making scalability a primary requirement of the NRS. Notice that, if hierarchical names are used, scalability can be also faced by leveraging the inherent aggregation capabilities of the hierarchy. o Latency: for real-time or delay sensitive M2M application, the name resolution should not affect the overall QoS. o Locality and network efficiency: in the name resolution process the data items closer to the data consumer should be accesses first (subject to the application requirements) o Agility: some data items could disappear while some other ones are created so that the NRS should be able to effectively take care of these dynamic conditions. o Control/scoping: some information could be accessible only within a given scope so that the NRS shold be able to not disclose all nodel locators to everyone. o Deployability and interoperability: graceful deployability and interoperability with existing platforms is a must to ensure a naming schema to gain success on the market [7]. Further challenges arise for hierarchical naming schema: referring to requirements on "constructable names" and "on-demand publishing" [24] [25]. The former entails that each user is able to construct the Zhang, et al. Expires March 26, 2015 [Page 16] Internet-Draft ICN based Architecture for IoT September 2014 name of a desired data item through specific algorithms and that it is possible to retrieve information also using partially specified names. The latter refers the possibility to request a content that has not yet been published in the past, thus triggering its creation. 5.2. Caching/Storage In-network caching helps bring data closer to consumers, but its usage differs in constrained and infrastructure part of the IoT network. Caching in constrained networks is limited to small amounts in the order of 10KB, while caching in infrastructure part of the network can allow much larger chunks. Caching in ICN-IoT faces several challenges: o The main challenge is to determine which nodes on the routing path should cache the data. According to [28], caching the data on a subset of nodes can achieve a better gain than caching on every en-route routers. In particular, the authors propose a "selective caching" scheme to locate those routers with better hit probabilities to cache data. According to [29], selecting a random router to cache data is as good as caching the content everywhere. o Another challenge in ICN-IoT caching is what to cache for IoT applications. In many IoT applications, customers often access a stream of sensor data, and as a result, caching a particular sensor data item may not be beneficial. In [30], the authors suggest to cache IoT services on intermediate routers, and in [31], the authors suggest to cache control information such as pub/sub lists on intermediate nodes. In addition, it is yet unclear what caching means in the context of actuation in an IoT system. 5.3. Name Resolution Inter-connecting numerous IoT entities, as well as establishing reachability to them, requires a scalable name resolution system considering several dynamic factors like mobility of end points, service replication, in-network caching, failure or migration [1-4][33][34][35][30]. The objective is to achieve scalable name resolution handling static and dynamic ICN entities with low complexity and control overhead. o The first challenge faced by ICN-IoT name resolution is its scalability [35][30]. Firstly, the name resolution service has to support billions of objects and devices that are connected to the Internet, many of which are crossing administrative domain Zhang, et al. Expires March 26, 2015 [Page 17] Internet-Draft ICN based Architecture for IoT September 2014 boundaries. Second of all, in addition to objects/devices, the name resolution service is also responsible for mapping IoT services to their network addresses. Many of these services are based upon contexts, hence dynamically changing, as pointed out in [30]. As a result, the name resolution service should be able to scale gracefully to cover a large number of names/services with wide variations (e.g., hierarchical names, flat names, names with limited scope, etc.) o The second challenge is fast name resolution. This challenge is especially important for applications with stringent latency requirements, such as health monitoring, emergency handling and smart transportation [36]. 5.4. Contextual Communication Contextualization through metadata in ICN control or application payload allows IoT applications to adapt to different environments. This enables intelligent networks which are self-configurable and enable intelligent networking among consumers and producers [30]. For example, let us look at the following smart transportation scenario: "James walks on NYC streets and wants to find an empty cab closest to his location." In this example, the context is the relative locations of James and taxi drivers. A context service, as an IoT middleware, processes the contextual information and bridges the gap between raw sensor information and application requirements. However, extracting contextual information on a real-time basis is very challenging: o We need to have a fast context resolution service through which the involved IoT devices can continuously update its contextual information to the application (e.g., each taxi's location and Jame's information in the above example). o The difficulty of this challenge grows rapidly when the number of devices involved in a context as well as the number of contexts increases. 5.5. Routing and Forwarding Routing in ICN-IoT differs from routing in traditional IP networks in that ICN routing is based upon names instead of locators. Broadly speaking, ICN routing can be categorized into the following two categories: direct name-based routing and indirect routing through name resolution. Zhang, et al. Expires March 26, 2015 [Page 18] Internet-Draft ICN based Architecture for IoT September 2014 o In direct name-based routing, packets are forwarded by the name of the data [37][32][38] or the name of the destination node [39]. Here, the main challenge is to keep the ICN router state required to route/forward data low. This challenge becomes more serious when a flat naming scheme is used. o In indirect routing, packets are forwarded based upon the locator of the destination node, and the locator is obtained through the name resolution service. In particular, the name locator binding can be done either before routing (i.e., static binding) or during routing (i.e., dynamic binding). For static binding, the router state is the same as that in traditional routers, and the main challenge is the need to have fast name resolution, especially when the IoT nodes are mobile. For dynamic binding, ICN routers need to main a name-based routing table, hence the challenge of keeping the state information low. At the same time, the need of fast name resolution is also critical. Finally, another challenge is to quantify the cost associated with mobility management, especially static binding vs. dynamic binding. During a network transaction, either the data producer or the consumer may move away and thus we need to handle the mobility to avoid information loss. ICN may differentiate mobility of a data consumer from that of a producer: o When a consumer moves to a new location after sending out an Interest, the Data may get lost, which requires the consumer to simply resend the Interest. Depending on the network topology and data availability, the new Interest might be forwarded to the same or a different data producer. o If the data producer itself has moved, the challenge is to control the control overhead while flooding it across the network. 5.6. In-network Computing Contextual services for IoT networks require in-network computing, in which each sensor node or ICN router implements context reasoning [30]. Another major purpose of in-network computing is to filer and cleanse sensed data in IoT applications is critical as the data is noisy as is [40]. In-network computing faces different challenges in the constrained and infrastructure parts of the network. o In the constrained part of the network, the challenge rises due to serious resource limitations on IoT devices or sensors. As a Zhang, et al. Expires March 26, 2015 [Page 19] Internet-Draft ICN based Architecture for IoT September 2014 result, the consensus is to include very simple computing functionalities on constrained nodes. o In the infrastructure part of the IoT network, in-network computing faces the challenge of breaking the computing task into smaller pieces and assigning each task to one or more ICN routers [30]. 5.7. Security and Privacy Security and privacy is crucial to all the IoT applications including the use cases discussed in Section 4. In one recent demonstration, it was shown that passive tire pressure sensors in cars could be hacked and used as a gateway into the automotive system [41]. Though ICN includes data-centric security features the mechanisms have to be generic enough to satisfy multiplicity of policy requirements for different applications. In general, we feel that security and privacy protection in IoT systems should mainly focus on the following aspects: confidentiality, integrity, authentication and non-repudiation, and availability. Implementing security and privacy methods faces different challenges in the constrained and infrastructure part of the network. o In the constrained part, energy limitation is the biggest challenge. As an example, let us look at a typical sensor tag. Suppose the tag has a single 16-bit processor, often running at 6 MHz to save energy, with 512Bytes of RAM and 16KB of flash for program storage. Moreover, it has to deliver its data over a wireless link for at least 10,000 hours on a coin cell battery. As a result, traditional security/privacy measures are impossible to be implemented in the constrained part. In this case, one possible solution might be utilizing the physical wireless signals as security measures [42] [30]. o In the infrastructure part, we have several new threats introduced by ICN-IoT [45]: 1. We need to ensure the name of a network element is issued by a trustworthy organization such as in [44]. 2. An intruder may gain access or gather information from a resource it is not entitled to. As a consequence, an adversary may examine, remove or even modify confidential information. Zhang, et al. Expires March 26, 2015 [Page 20] Internet-Draft ICN based Architecture for IoT September 2014 3. An intruder may mimic an authorized user or network process. As a result, the intruder may forge signatures, or impersonate a source address. 4. An adversary may manipulate the message exchange process between network entities. Such manipulation may involve replay, rerouting, mis-routing and deletion of messages. 5. An intruder may insert fake/false sensor data into the network. The consequence might be an increase in delay and performance degradation for network services and applications. 5.8. Energy Efficiency All the optimizations for other components of the ICN-IoT system (described in earlier subsections) can lead to optimized energy efficiency. As a result, we refer the readers to read sections 5.1-5.6 for challenges associated with energy efficiency for ICN-IoT. 6. Informative References [1] Cisco System Inc., CISCO., "Cisco visual networking index: Global mobile data traffic forecast update.", 2009-2014. [2] Shafig, M., Ji, L., Liu, A., Pang, J., and J. Wang, "A first look at cellular machine-to-machine traffic: large scale measurement and characterization.", Proceedings of the ACM Sigmetrics , 2012. [3] The European Telecommunications Standards Institute, ETSI., "http://www.etsi.org/.", 1988. [4] Global Intiative for M2M Standardization, oneM2M., "http://www.onem2m.org/.", 2012. 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Sihvonen, "Towards metrics- driven adaptive security management in E-health IoT applications.", 2012. [24] Jacobson, V., Smetters, D., Plass, M., Stewart, P., Thornton, J., and R. Braynard, "VoCCN: Voice-over Content- Centric Networks", 2009. [25] Piro, G., Cianci, I., Grieco, L., Boggia, G., and P. Camarda, "Information Centric Services in Smart Cities", 2014. [26] Ravindran, R., Biswas, T., Zhang, X., Chakrabort, A., and G. Wang, "Information-centric Networking based Homenet", 2014. [27] Dannewitz, C., D' Ambrosio, M., and V. Vercellone, "Hierarchical DHT-based name resolution for information- centric networks", 2013. [28] Chai, W., He, D., and I. Psaras, "Cache "less for more" in information-centric networks", 2012. [29] Eum, S., Nakauchi, K., Murata, M., Shoji, Yozo., and N. Nishinaga, "Catt: potential based routing with content caching for icn", 2012. [30] Eum, S., Shvartzshnaider, Y., Francisco, J., Martini, R., and D. Raychaudhuri, "Enabling internet-of-things services in the mobilityfirst future internet architecture", 2012. [31] Sun, Y., Qiao, X., Cheng, B., and J. Chen, "A low-delay, lightweight publish/subscribe architecture for delay- sensitive IOT services", 2013. [32] Baccelli, E., Mehlis, C., Hahm, O., Schmidt, T., and M. Wahlisch, "Information Centric Networking in the IoT:Experiments with NDN in the Wild", 2013. Zhang, et al. Expires March 26, 2015 [Page 23] Internet-Draft ICN based Architecture for IoT September 2014 [33] Gronbaek, I., "Architecture for the Internet of Things (IoT): API and interconnect", 2008. [34] Tian, Y., Liu, Y., Yan, Z., Wu, S., and H. Li, "RNS-A Public Resource Name Service Platform for the Internet of Things", 2012. [35] Roussos, G. and P. Chartier, "Scalable id/locator resolution for the iot", 2011. [36] Li, S., Zhang, Y., Raychaudhuri, D., and R. Ravindran, "A Comparative Study of MobilityFirst and NDN based ICN-IoT Architectures", 2011. [37] Amadeo, M., Campolo, C., Iera, A., and A. Molinaro, "Named data networking for IoT: An architectural perspective", 2014. [38] Amadeo, M. and C. Campolo, "Potential of information- centric wireless sensor and actor networking", 2014. [39] Nelson, S., Bhanage, G., and D. Raychaudhuri, "GSTAR: generalized storage-aware routing for mobilityfirst in the future mobile internet", 2014. [40] Trappe, W., Zhang, Y., and B. Nath, "MIAMI: methods and infrastructure for the assurance of measurement information", 2005. [41] Rouf, I., Mustafa, H., Taylor, T., Oh, S., Xu, W., Gruteser, M., Trappe, W., and I. Seskar, "Security and privacy vulnerabilities of in-car wireless networks: A tire pressure monitoring system case study", 2005. [42] Liu, R. and W. Trappe, "Securing Wireless Communications at the Physical Layer", 2010. [43] Xiao, L., Greenstein, L., Mandayam, N., and W. Trappe, "Using the physical layer for wireless authentication in time-variant channels", 2008. [44] Sun, S., Lannom, L., and B. Boesch, "Handle system overview", 2003. [45] Liu, X., Trappe, W., and Y. Zhang, "Secure Name Resolution for Identifier-to-Locator Mappings in the Global Internet", 2003. Zhang, et al. Expires March 26, 2015 [Page 24] Internet-Draft ICN based Architecture for IoT September 2014 Authors' Addresses Prof.Yanyong Zhang WINLAB, Rutgers University 671, U.S 1 North Brunswick, NJ 08902 USA Email: yyzhang@winlab.rutgers.edu Prof. Dipankar Raychadhuri WINLAB, Rutgers University 671, U.S 1 North Brunswick, NJ 08902 USA Email: ray@winlab.rutgers.edu Prof. Luigi Alfredo Grieco Politecnico di Bari (DEI) Via Orabona 4 Bari 70125 Italy Email: alfredo.grieco@poliba.it Prof. Emmanuel Baccelli INRIA Room 148, Takustrasse 9 Berlin 14195 France Email: Emmanuel.Baccelli@inria.fr Jeff Burke UCLA REMAP 102 East Melnitz Hall Los Angeles, CA 90095 USA Email: jburke@ucla.edu Zhang, et al. Expires March 26, 2015 [Page 25] Internet-Draft ICN based Architecture for IoT September 2014 Ravishankar Ravindran Huawei Technologies 2330 Central Expressway Santa Clara, CA 95050 USA Email: ravi.ravindran@huawei.com Guoqiang Wang Huawei Technologies 2330 Central Expressway Santa Clara, CA 95050 USA Email: gq.wang@huawei.com Zhang, et al. Expires March 26, 2015 [Page 26]