Olaf Bergmann

A CoAP-gateway for smart homes

The ”Internet of Things” has led to a number of standardization efforts that can make proprietary protocols for home automation obsolete. One of the latest developments is the Constrained Application Protocol (CoAP) that is intended to be used as the HTTP-replacement for smart objects that are connected to the Internet. Early adaptors in industry and academia already have developed a plethora of applications that build on this new standard and have contributed valuable insights and implementation experience. While most of the new applications interoperate in a reasonable manner, the integration of legacy is one of the biggest challenges. Many existing protocols for home automation have been designed with a narrow focus on very limited devices that communicate with each other in a local network. CoAP, in contrast, mimics the architectural style that represents the fundamental basis of the Web, and therefore follows a very different design approach. In this paper, we present a basic design concept to interconnect CoAP and the proprietary FS20 protocol for home automation. The key aspects of our approach are the mapping of FS20 device addresses to path segments of CoAP URIs and to map FS20 commands to the four basic CoAP operations for creation, retrieval, update and deletion of resources, and the dynamic discovery of new nodes to register their capabilities with the CoAP service. To prove the feasibility of this approach, we have developed a multi-protocol gateway for a popular low-budget integrated access device.

Secure bootstrapping of nodes in a CoAP network

In todays world of home automation, smart objects are interconnected and participate in the Internet of Things. Being part of a very sensible eco-system, these entities must be secured against various kinds of attacks. Smart home appliances such as light bulbs or window shutters have very low processing power and networking capacities and more often than not lack of input/output devices such as keyboards or displays. Therefore, special protocols have been developed to enable lightweight and secure communication. Yet, the secure configuration of new nodes in a network has not been solved satisfactory. In this paper we present a three-phase protocol to bootstrap constrained devices in a wireless sensor network based on IPv6 and the Constrained Application Protocol (CoAP). The protocol phases include service discovery, distribution of security credentials, and application-specific node configuration.

The CHIANTI architecture for robust mobile Internet access

The quality of Internet access for mobile users may suffer from highly variable communication characteristics (packet loss, delay, throughput) and from temporary disconnections. The former occur as a result of changing radio properties, handovers, or variable system load, the latter whenever wireless coverage is insufficient. While quite some research has tackled improving radio coverage to keep users always best connected and numerous approaches pursue improving wireless performance and robustness, these often assume a greenfield deployment or a tight integration with operators. We present the mobility support system architecture developed in the CHIANTI project. While building on related work in various technical respects, the CHIANTI architecture is specifically designed to be instantly and incrementally deployable in todays Internet landscape, considering real-world legal and deployment constraints, and supports roles of different (independent) players. We also report on our proof-of-concept implementation.

Security Requirements for Managing Smart Objects in Home Automation

Enabling technologies for the Internet of Things are well understood, and open standards exist that define how to use the Internet Protocol, Version 6, (IPv6) to interconnect smart objects with each other and to the public Internet. As these devices typically are quite limited in their hardware resources, security is often considered too expensive and is sacrificed for a marginal extension of battery lifetime. Missing security not only exposes the application logic to evildoers but also affects management functions. In this paper, we discuss potential threats to machine-to-machine communication and provide a detailed example how protection requirements can be inferred from a given application scenario.

Keeping users empowered in a cloudy Internet of Things

The Internet of Things includes Smart Objects, small devices with limited abilities, typically made to fulfill a single simple task. They have limited system resources, such as processing power, memory, non-volatile storage, and transmission capacity, are frequently powered from primary batteries, and often lack user interfaces and displays. These devices benefit from being associated with less-constrained devices, in particular for user interactions, as well as for defining their purpose in life in the first place, which includes setting policies relevant to security and privacy. Smart objects will be ubiquitous and attain significant insight into and control over many aspects of everyday life, which makes users expect a very high level of security and privacy of them and of the less-constrained devices controlling them. Cloud-based systems will be hard pressed to fulfill these expectations on their own: The human will need to stay in the loop at least for policy setting.

REST-based access to SMIv2-structured information on constrained devices

Recently, the IETF has generated a number of standards that are intended to be foundational for large networks of constrained devices, also known as the Internet of Things. Among these are a Web transfer protocol realizing the REST (Representational State Transfer) principles, the Constrained Application Protocol (CoAP), and the Concise Binary Object Representation (CBOR). As with the existing Internet, the Internet of Things will need network management. Management of networks has long been governed by the Structure of Management Information V2 (SMIv2), encoded in ASN.1 Basic Encoding Rules (BER) and the Simple Network Management Protocol (SNMP). Supporting multiple protocols and data encoding formats on a very constrained device is wasteful of its capabilities. We examine how CoAP and CBOR could be used for providing REST-based access to SMIv2-structured information on constrained devices in a way that facilitates interoperation with implementations of the existing protocols.