ACAN- AD HOC CONTEXT AWARE NETWORK Mohamed Khedr, Ahmed Karmouch Multimedia and Mobile Agent Research Lab, School of Information Technology & Engineering (SITE), University of Ottawa 161 Louis Pasteur St. Ottawa, ON, Canada K1N 6N5 mkhedr, karmouch@site.uottawa.ca ABSTRACT: This paper presents the design and system architecture of the Ad hoc Context Aware Network (ACAN), a wireless environment with no pre-configuration and with spontaneous applications running according to the contextual situation. The ACAN is a new vision to the future of the wireless networks where it will consists of sensors that will capture the entities in the environment and the surrounding users, A context manager agent who will interpret the sensor captures information and process it to a higher level context data to be used by the Ad hoc application in a way to minimize the user attention while maximize the relevance of the information provided. ACAN targets the network layer and the application layer and introduces new mechanisms for network configuration, QoS provisioning and more dynamic adaptable and flexible applications. We will explain the architectural model of the ACAN with the required goals and specification, the ACAN new protocol stack will be presented and the Context Aware Service Discovery Protocol (CASDP) with its advantages over the existing service discovery protocols. Keywords: Context aware, Context based service discovery, Ad hoc Context aware network. 1. INTRODUCTION Ad hoc networking has been under development for 20 years and it is characterized as a group of host that communicate without any pre-existing infrastructure, frequently changing network topology and the use of dynamic routing protocols. Most of the research mainly focused on routing techniques [1] and in the modification of the transport protocol to adapt to the limitation of the wireless multihop ad hoc networks [2]. We extend this research to include the application layer where applications are characterized by being ad hoc in nature; applications are not pre-determined and only rise when the current situation requires them. In addition these applications are frequently changing their requirements on services and resources according to the current context that can be extract, interpreted and used by means of physical sensors that provide information about location, time, presence, temperature, noise level, etc. or gathered from network based sensors that provide data about network parameters such as the bandwidth, delay and service level of agreements, or user based sensors that provide information about the user it represents like agenda, favourites etc [9]. These applications need a new network architecture that support auto configuration, mobility and service discovery protocol that could be easily and rapidly updated and continue to operate as the carrying platform moves among different environments which cannot be achieved using current service discovery protocols [8]. In this paper we describe the architecture of an ad hoc context aware active network, the associated proposed protocol stack and the Context Based Service Discovery Protocol. The system consists mainly of wireless nodes that are connected in an ad hoc manner, running and ad hoc applications and adapting to the environment according to context information gathered from sensors that are embedded in the environment. This contextual information is interpreted and passed to the application where the application can either adapt itself to the current situation or adapt the environment to what it needs by deploying active agents to implement the functionalities needed by the application. The rest of the paper is organized as fellows. Next section describes the ACAN architecture and design consideration, section 3 presents the proposed protocol stack, the Context Based Service Discovery Protocol in section 4 and Finally in section 5 we draw our conclusion and future work. 2. ACAN architecture In the last couple of years, a number of research projects that deals with context awareness and service discovery have emerged. Among them are the context aware tool kit in Georgia Tech[5], the Ninja project[10] and the Centaurus project[11]. Unlike our model each of the above projects dealt either with context or service discovery individually. Flexibility, scalability and adaptability are the main characteristics of the ACAN architecture. The layered architecture of the ACAN provides the flexibility required in the system by distributing the tasks and functionalities