Towards adaptable ad hoc networks: The routing experience

Network users not only demand new and versatile application support by the networks but they themselves are becoming part of the network (network routers, caches, processors, etc) by contributing their resources to it and being engaged in ad hoc networking structures. As the large and diverse user population becomes more and more part of the networking infrastructure it is clear that networks will be dominated by a new type of network nodes which are much more nomadic, diverse and autonomic than in traditional networks, creating a fairly diverse - in size and characteristics - networking environment. For instance, low cost/high availability/convenience of wireless devices are expected to lead to the deployment of a plethora of wireless networks for diverse applications: from rescue missions to military communications, from collaborative computing and sensor networks to web browsing and e-mail exchange to real time voice and video communications. Each with different constraints and requirements. And, for each type of application there is also a high degree of variability in the networking context: from a low mobile network of a few nodes to a highly mobile network with thousands of nodes. This high degree of variability in the networking environment calls for a new design paradigm where network elements (nodes) should be able to adapt to totally different scenarios, engaging in a different behavior depending on the situation. Thus, next generation networks should be able to learn their environment/context and adapt their behavior accordingly in order to achieve their goals. In this paper we introduce some key mechanisms required to enable broad adaptability. Although these mechanisms are general and common to a large variety of tasks/services (e.g. service discovery, location management, cooperative computing, clustering, etc.) we will discuss them in the context of the routing service, leveraging our past experience on the area. This will allow us to ground the discussion in concrete terms and the reader to better visualize the concepts.